Linus Torvalds [Wed, 9 Nov 2022 20:30:51 +0000 (12:30 -0800)]
mm: delay page_remove_rmap() until after the TLB has been flushed
When we remove a page table entry, we are very careful to only free the
page after we have flushed the TLB, because other CPUs could still be
using the page through stale TLB entries until after the flush.
However, we have removed the rmap entry for that page early, which means
that functions like folio_mkclean() would end up not serializing with the
page table lock because the page had already been made invisible to rmap.
And that is a problem, because while the TLB entry exists, we could end up
with the following situation:
(a) one CPU could come in and clean it, never seeing our mapping of the
page
(b) another CPU could continue to use the stale and dirty TLB entry and
continue to write to said page
resulting in a page that has been dirtied, but then marked clean again,
all while another CPU might have dirtied it some more.
End result: possibly lost dirty data.
This extends our current TLB gather infrastructure to optionally track a
"should I do a delayed page_remove_rmap() for this page after flushing the
TLB". It uses the newly introduced 'encoded page pointer' to do that
without having to keep separate data around.
Note, this is complicated by a couple of issues:
- we want to delay the rmap removal, but not past the page table lock,
because that simplifies the memcg accounting
- only SMP configurations want to delay TLB flushing, since on UP
there are obviously no remote TLBs to worry about, and the page
table lock means there are no preemption issues either
- s390 has its own mmu_gather model that doesn't delay TLB flushing,
and as a result also does not want the delayed rmap. As such, we can
treat S390 like the UP case and use a common fallback for the "no
delays" case.
- we can track an enormous number of pages in our mmu_gather structure,
with MAX_GATHER_BATCH_COUNT batches of MAX_TABLE_BATCH pages each,
all set up to be approximately 10k pending pages.
We do not want to have a huge number of batched pages that we then
need to check for delayed rmap handling inside the page table lock.
Particularly that last point results in a noteworthy detail, where the
normal page batch gathering is limited once we have delayed rmaps pending,
in such a way that only the last batch (the so-called "active batch") in
the mmu_gather structure can have any delayed entries.
NOTE! While the "possibly lost dirty data" sounds catastrophic, for this
all to happen you need to have a user thread doing either madvise() with
MADV_DONTNEED or a full re-mmap() of the area concurrently with another
thread continuing to use said mapping.
So arguably this is about user space doing crazy things, but from a VM
consistency standpoint it's better if we track the dirty bit properly even
when user space goes off the rails.
[akpm@linux-foundation.org: fix UP build, per Linus]
Link: https://lore.kernel.org/all/B88D3073-440A-41C7-95F4-895D3F657EF2@gmail.com/
Link: https://lkml.kernel.org/r/20221109203051.1835763-4-torvalds@linux-foundation.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Hugh Dickins <hughd@google.com>
Reported-by: Nadav Amit <nadav.amit@gmail.com>
Tested-by: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Linus Torvalds [Wed, 9 Nov 2022 20:30:50 +0000 (12:30 -0800)]
mm: mmu_gather: prepare to gather encoded page pointers with flags
This is purely a preparatory patch that makes all the data structures
ready for encoding flags with the mmu_gather page pointers.
The code currently always sets the flag to zero and doesn't use it yet,
but now it's tracking the type state along. The next step will be to
actually start using it.
Link: https://lkml.kernel.org/r/20221109203051.1835763-3-torvalds@linux-foundation.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Linus Torvalds [Wed, 9 Nov 2022 20:30:49 +0000 (12:30 -0800)]
mm: teach release_pages() to take an array of encoded page pointers too
release_pages() already could take either an array of page pointers, or an
array of folio pointers. Expand it to also accept an array of encoded
page pointers, which is what both the existing mlock() use and the
upcoming mmu_gather use of encoded page pointers wants.
Note that release_pages() won't actually use, or react to, any extra
encoded bits. Instead, this is very much a case of "I have walked the
array of encoded pages and done everything the extra bits tell me to do,
now release it all".
Also, while the "either page or folio pointers" dual use was handled with
a cast of the pointer in "release_folios()", this takes a slightly
different approach and uses the "transparent union" attribute to describe
the set of arguments to the function:
https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html
which has been supported by gcc forever, but the kernel hasn't used
before.
That allows us to avoid using various wrappers with casts, and just use
the same function regardless of use.
Link: https://lkml.kernel.org/r/20221109203051.1835763-2-torvalds@linux-foundation.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Linus Torvalds [Wed, 9 Nov 2022 20:30:48 +0000 (12:30 -0800)]
mm: introduce 'encoded' page pointers with embedded extra bits
We already have this notion in parts of the MM code (see the mlock code
with the LRU_PAGE and NEW_PAGE bits), but I'm going to introduce a new
case, and I refuse to do the same thing we've done before where we just
put bits in the raw pointer and say it's still a normal pointer.
So this introduces a 'struct encoded_page' pointer that cannot be used for
anything else than to encode a real page pointer and a couple of extra
bits in the low bits. That way the compiler can trivially track the state
of the pointer and you just explicitly encode and decode the extra bits.
Note that this makes the alignment of 'struct page' explicit even for the
case where CONFIG_HAVE_ALIGNED_STRUCT_PAGE is not set. That is entirely
redundant in almost all cases, since the page structure already contains
several word-sized entries.
However, on m68k, the alignment of even 32-bit data is just 16 bits, and
as such in theory the alignment of 'struct page' could be too. So let's
just make it very very explicit that the alignment needs to be at least 32
bits, giving us a guarantee of two unused low bits in the pointer.
Now, in practice, our page struct array is aligned much more than that
anyway, even on m68k, and our existing code in mm/mlock.c obviously
already depended on that. But since the whole point of this change is to
be careful about the type system when hiding extra bits in the pointer,
let's also be explicit about the assumptions we make.
NOTE! This is being very careful in another way too: it has a build-time
assertion that the 'flags' added to the page pointer actually fit in the
two bits. That means that this helper must be inlined, and can only be
used in contexts where the compiler can statically determine that the
value fits in the available bits.
[akpm@linux-foundation.org: kerneldoc on a forward-declared struct confuses htmldocs]
Link: https://lore.kernel.org/all/Y2tKixpO4RO6DgW5@tuxmaker.boeblingen.de.ibm.com/
Link: https://lkml.kernel.org/r/20221109203051.1835763-1-torvalds@linux-foundation.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Hugh Dickins <hughd@google.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com> [s390]
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Hildenbrand [Tue, 8 Nov 2022 17:46:52 +0000 (18:46 +0100)]
selftests/vm: anon_cow: add mprotect() optimization tests
Let's extend the test to cover the possible mprotect() optimization when
removing write-protection. mprotect() must not allow write-access to a
COW-shared page by accident.
Link: https://lkml.kernel.org/r/20221108174652.198904-8-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Hildenbrand [Tue, 8 Nov 2022 17:46:51 +0000 (18:46 +0100)]
mm: remove unused savedwrite infrastructure
NUMA hinting no longer uses savedwrite, let's rip it out.
... and while at it, drop __pte_write() and __pmd_write() on ppc64.
Link: https://lkml.kernel.org/r/20221108174652.198904-7-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Hildenbrand [Tue, 8 Nov 2022 17:46:50 +0000 (18:46 +0100)]
mm/autonuma: use can_change_(pte|pmd)_writable() to replace savedwrite
commit
b191f9b106ea ("mm: numa: preserve PTE write permissions across a
NUMA hinting fault") added remembering write permissions using ordinary
pte_write() for PROT_NONE mapped pages to avoid write faults when
remapping the page !PROT_NONE on NUMA hinting faults.
That commit noted:
The patch looks hacky but the alternatives looked worse. The tidest was
to rewalk the page tables after a hinting fault but it was more complex
than this approach and the performance was worse. It's not generally
safe to just mark the page writable during the fault if it's a write
fault as it may have been read-only for COW so that approach was
discarded.
Later, commit
288bc54949fc ("mm/autonuma: let architecture override how
the write bit should be stashed in a protnone pte.") introduced a family
of savedwrite PTE functions that didn't necessarily improve the whole
situation.
One confusing thing is that nowadays, if a page is pte_protnone()
and pte_savedwrite() then also pte_write() is true. Another source of
confusion is that there is only a single pte_mk_savedwrite() call in the
kernel. All other write-protection code seems to silently rely on
pte_wrprotect().
Ever since PageAnonExclusive was introduced and we started using it in
mprotect context via commit
64fe24a3e05e ("mm/mprotect: try avoiding write
faults for exclusive anonymous pages when changing protection"), we do
have machinery in place to avoid write faults when changing protection,
which is exactly what we want to do here.
Let's similarly do what ordinary mprotect() does nowadays when upgrading
write permissions and reuse can_change_pte_writable() and
can_change_pmd_writable() to detect if we can upgrade PTE permissions to be
writable.
For anonymous pages there should be absolutely no change: if an
anonymous page is not exclusive, it could not have been mapped writable --
because only exclusive anonymous pages can be mapped writable.
However, there *might* be a change for writable shared mappings that
require writenotify: if they are not dirty, we cannot map them writable.
While it might not matter in practice, we'd need a different way to
identify whether writenotify is actually required -- and ordinary mprotect
would benefit from that as well.
Note that we don't optimize for the actual migration case:
(1) When migration succeeds the new PTE will not be writable because the
source PTE was not writable (protnone); in the future we
might just optimize that case similarly by reusing
can_change_pte_writable()/can_change_pmd_writable() when removing
migration PTEs.
(2) When migration fails, we'd have to recalculate the "writable" flag
because we temporarily dropped the PT lock; for now keep it simple and
set "writable=false".
We'll remove all savedwrite leftovers next.
Link: https://lkml.kernel.org/r/20221108174652.198904-6-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Hildenbrand [Tue, 8 Nov 2022 17:46:49 +0000 (18:46 +0100)]
mm/mprotect: factor out check whether manual PTE write upgrades are required
Let's factor the check out into vma_wants_manual_pte_write_upgrade(), to be
reused in NUMA hinting fault context soon.
Link: https://lkml.kernel.org/r/20221108174652.198904-5-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Hildenbrand [Tue, 8 Nov 2022 17:46:48 +0000 (18:46 +0100)]
mm/huge_memory: try avoiding write faults when changing PMD protection
Let's replicate what we have for PTEs in can_change_pte_writable() also
for PMDs.
While this might look like a pure performance improvement, we'll us this to
get rid of savedwrite handling in do_huge_pmd_numa_page() next. Place
do_huge_pmd_numa_page() strategically good for that purpose.
Note that MM_CP_TRY_CHANGE_WRITABLE is currently only set when we come
via mprotect_fixup().
Link: https://lkml.kernel.org/r/20221108174652.198904-4-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Hildenbrand [Tue, 8 Nov 2022 17:46:47 +0000 (18:46 +0100)]
mm/mprotect: minor can_change_pte_writable() cleanups
We want to replicate this code for handling PMDs soon.
(1) No need to crash the kernel, warning and rejecting is good enough. As
this will no longer get optimized out, drop the pte_write() check: no
harm would be done.
(2) Add a comment why PROT_NONE mapped pages are excluded.
(3) Add a comment regarding MAP_SHARED handling and why we rely on the
dirty bit in the PTE.
Link: https://lkml.kernel.org/r/20221108174652.198904-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Nadav Amit [Tue, 8 Nov 2022 17:46:46 +0000 (18:46 +0100)]
mm/mprotect: allow clean exclusive anon pages to be writable
Patch series "mm/autonuma: replace savedwrite infrastructure", v2.
As discussed in my talk at LPC, we can reuse the same mechanism for
deciding whether to map a pte writable when upgrading permissions via
mprotect() -- e.g., PROT_READ -> PROT_READ|PROT_WRITE -- to replace the
savedwrite infrastructure used for NUMA hinting faults (e.g., PROT_NONE ->
PROT_READ|PROT_WRITE).
Instead of maintaining previous write permissions for a pte/pmd, we
re-determine if the pte/pmd can be writable. The big benefit is that we
have a common logic for deciding whether we can map a pte/pmd writable on
protection changes.
For private mappings, there should be no difference -- from what I
understand, that is what autonuma benchmarks care about.
I ran autonumabench for v1 on a system with 2 NUMA nodes, 96 GiB each via:
perf stat --null --repeat 10
The numa01 benchmark is quite noisy in my environment and I failed to
reduce the noise so far.
numa01:
mm-unstable: 146.88 +- 6.54 seconds time elapsed ( +- 4.45% )
mm-unstable++: 147.45 +- 13.39 seconds time elapsed ( +- 9.08% )
numa02:
mm-unstable: 16.0300 +- 0.0624 seconds time elapsed ( +- 0.39% )
mm-unstable++: 16.1281 +- 0.0945 seconds time elapsed ( +- 0.59% )
It is worth noting that for shared writable mappings that require
writenotify, we will only avoid write faults if the pte/pmd is dirty
(inherited from the older mprotect logic). If we ever care about
optimizing that further, we'd need a different mechanism to identify
whether the FS still needs to get notified on the next write access.
In any case, such an optimization will then not be autonuma-specific, but
mprotect() permission upgrades would similarly benefit from it.
This patch (of 7):
Anonymous pages might have the dirty bit clear, but this should not
prevent mprotect from making them writable if they are exclusive.
Therefore, skip the test whether the page is dirty in this case.
Note that there are already other ways to get a writable PTE mapping an
anonymous page that is clean: for example, via MADV_FREE. In an ideal
world, we'd have a different indication from the FS whether writenotify is
still required.
[david@redhat.com: return directly; update description]
Link: https://lkml.kernel.org/r/20221108174652.198904-1-david@redhat.com
Link: https://lkml.kernel.org/r/20221108174652.198904-2-david@redhat.com
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Rong Tao [Tue, 8 Nov 2022 11:53:48 +0000 (19:53 +0800)]
tools/vm/page_owner: ignore page_owner_sort binary
page_owner_sort was introduced since commit
48c96a368579 ("mm/page_owner:
keep track of page owners"), and we should ignore it.
Link: https://lkml.kernel.org/r/tencent_F6CAC0ABE16839E2B2419BD07316DA65BB06@qq.com
Signed-off-by: Rong Tao <rongtao@cestc.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Hugh Dickins [Tue, 22 Nov 2022 09:51:50 +0000 (01:51 -0800)]
mm,thp,rmap: clean up the end of __split_huge_pmd_locked()
It's hard to add a page_add_anon_rmap() into __split_huge_pmd_locked()'s
HPAGE_PMD_NR set_pte_at() loop, without wincing at the "freeze" case's
HPAGE_PMD_NR page_remove_rmap() loop below it.
It's just a mistake to add rmaps in the "freeze" (insert migration entries
prior to splitting huge page) case: the pmd_migration case already avoids
doing that, so just follow its lead. page_add_ref() versus put_page()
likewise. But why is one more put_page() needed in the "freeze" case?
Because it's removing the pmd rmap, already removed when pmd_migration
(and freeze and pmd_migration are mutually exclusive cases).
Link: https://lkml.kernel.org/r/d43748aa-fece-e0b9-c4ab-f23c9ebc9011@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Carpenter <error27@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Hugh Dickins [Tue, 22 Nov 2022 09:49:36 +0000 (01:49 -0800)]
mm,thp,rmap: subpages_mapcount COMPOUND_MAPPED if PMD-mapped
Can the lock_compound_mapcount() bit_spin_lock apparatus be removed now?
Yes. Not by atomic64_t or cmpxchg games, those get difficult on 32-bit;
but if we slightly abuse subpages_mapcount by additionally demanding that
one bit be set there when the compound page is PMD-mapped, then a cascade
of two atomic ops is able to maintain the stats without bit_spin_lock.
This is harder to reason about than when bit_spin_locked, but I believe
safe; and no drift in stats detected when testing. When there are racing
removes and adds, of course the sequence of operations is less well-
defined; but each operation on subpages_mapcount is atomically good. What
might be disastrous, is if subpages_mapcount could ever fleetingly appear
negative: but the pte lock (or pmd lock) these rmap functions are called
under, ensures that a last remove cannot race ahead of a first add.
Continue to make an exception for hugetlb (PageHuge) pages, though that
exception can be easily removed by a further commit if necessary: leave
subpages_mapcount 0, don't bother with COMPOUND_MAPPED in its case, just
carry on checking compound_mapcount too in folio_mapped(), page_mapped().
Evidence is that this way goes slightly faster than the previous
implementation in all cases (pmds after ptes now taking around 103ms); and
relieves us of worrying about contention on the bit_spin_lock.
Link: https://lkml.kernel.org/r/3978f3ca-5473-55a7-4e14-efea5968d892@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Carpenter <error27@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Hugh Dickins [Tue, 22 Nov 2022 09:42:04 +0000 (01:42 -0800)]
mm,thp,rmap: subpages_mapcount of PTE-mapped subpages
Patch series "mm,thp,rmap: rework the use of subpages_mapcount", v2.
This patch (of 3):
Following suggestion from Linus, instead of counting every PTE map of a
compound page in subpages_mapcount, just count how many of its subpages
are PTE-mapped: this yields the exact number needed for NR_ANON_MAPPED and
NR_FILE_MAPPED stats, without any need for a locked scan of subpages; and
requires updating the count less often.
This does then revert total_mapcount() and folio_mapcount() to needing a
scan of subpages; but they are inherently racy, and need no locking, so
Linus is right that the scans are much better done there. Plus (unlike in
6.1 and previous) subpages_mapcount lets us avoid the scan in the common
case of no PTE maps. And page_mapped() and folio_mapped() remain scanless
and just as efficient with the new meaning of subpages_mapcount: those are
the functions which I most wanted to remove the scan from.
The updated page_dup_compound_rmap() is no longer suitable for use by anon
THP's __split_huge_pmd_locked(); but page_add_anon_rmap() can be used for
that, so long as its VM_BUG_ON_PAGE(!PageLocked) is deleted.
Evidence is that this way goes slightly faster than the previous
implementation for most cases; but significantly faster in the (now
scanless) pmds after ptes case, which started out at 870ms and was brought
down to 495ms by the previous series, now takes around 105ms.
Link: https://lkml.kernel.org/r/a5849eca-22f1-3517-bf29-95d982242742@google.com
Link: https://lkml.kernel.org/r/eec17e16-4e1-7c59-f1bc-5bca90dac919@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Carpenter <error27@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Joao Martins [Mon, 7 Nov 2022 15:39:22 +0000 (15:39 +0000)]
mm/hugetlb_vmemmap: remap head page to newly allocated page
Today with `hugetlb_free_vmemmap=on` the struct page memory that is freed
back to page allocator is as following: for a 2M hugetlb page it will reuse
the first 4K vmemmap page to remap the remaining 7 vmemmap pages, and for a
1G hugetlb it will remap the remaining 4095 vmemmap pages. Essentially,
that means that it breaks the first 4K of a potentially contiguous chunk of
memory of 32K (for 2M hugetlb pages) or 16M (for 1G hugetlb pages). For
this reason the memory that it's free back to page allocator cannot be used
for hugetlb to allocate huge pages of the same size, but rather only of a
smaller huge page size:
Trying to assign a 64G node to hugetlb (on a 128G 2node guest, each node
having 64G):
* Before allocation:
Free pages count per migrate type at order 0 1 2 3
4 5 6 7 8 9 10
...
Node 0, zone Normal, type Movable 340 100 32 15
1 2 0 0 0 1 15558
$ echo 32768 > /sys/devices/system/node/node0/hugepages/hugepages-2048kB/nr_hugepages
$ cat /sys/devices/system/node/node0/hugepages/hugepages-2048kB/nr_hugepages
31987
* After:
Node 0, zone Normal, type Movable 30893 32006 31515 7
0 0 0 0 0 0 0
Notice how the memory freed back are put back into 4K / 8K / 16K page
pools. And it allocates a total of 31987 pages (63974M).
To fix this behaviour rather than remapping second vmemmap page (thus
breaking the contiguous block of memory backing the struct pages)
repopulate the first vmemmap page with a new one. We allocate and copy
from the currently mapped vmemmap page, and then remap it later on.
The same algorithm works if there's a pre initialized walk::reuse_page
and the head page doesn't need to be skipped and instead we remap it
when the @addr being changed is the @reuse_addr.
The new head page is allocated in vmemmap_remap_free() given that on
restore there's no need for functional change. Note that, because right
now one hugepage is remapped at a time, thus only one free 4K page at a
time is needed to remap the head page. Should it fail to allocate said
new page, it reuses the one that's already mapped just like before. As a
result, for every 64G of contiguous hugepages it can give back 1G more
of contiguous memory per 64G, while needing in total 128M new 4K pages
(for 2M hugetlb) or 256k (for 1G hugetlb).
After the changes, try to assign a 64G node to hugetlb (on a 128G 2node
guest, each node with 64G):
* Before allocation
Free pages count per migrate type at order 0 1 2 3
4 5 6 7 8 9 10
...
Node 0, zone Normal, type Movable 1 1 1 0
0 1 0 0 1 1 15564
$ echo 32768 > /sys/devices/system/node/node0/hugepages/hugepages-2048kB/nr_hugepages
$ cat /sys/devices/system/node/node0/hugepages/hugepages-2048kB/nr_hugepages
32394
* After:
Node 0, zone Normal, type Movable 0 50 97 108
96 81 70 46 18 0 0
In the example above, 407 more hugeltb 2M pages are allocated i.e. 814M out
of the 32394 (64788M) allocated. So the memory freed back is indeed being
used back in hugetlb and there's no massive order-0..order-2 pages
accumulated unused.
[joao.m.martins@oracle.com: v3]
Link: https://lkml.kernel.org/r/20221109200623.96867-1-joao.m.martins@oracle.com
[joao.m.martins@oracle.com: add smp_wmb() to ensure page contents are visible prior to PTE write]
Link: https://lkml.kernel.org/r/20221110121214.6297-1-joao.m.martins@oracle.com
Link: https://lkml.kernel.org/r/20221107153922.77094-1-joao.m.martins@oracle.com
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Mon, 7 Nov 2022 16:50:01 +0000 (16:50 +0000)]
selftests/damon: test non-context inputs to rm_contexts file
There was a bug[1] that triggered by writing non-context DAMON debugfs
file names to the 'rm_contexts' DAMON debugfs file. Add a selftest for
the bug to avoid it happen again.
[1] https://lore.kernel.org/damon/
000000000000ede3ac05ec4abf8e@google.com/
Link: https://lkml.kernel.org/r/20221107165001.5717-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Hugh Dickins [Thu, 10 Nov 2022 02:18:49 +0000 (18:18 -0800)]
mm,thp,rmap: handle the normal !PageCompound case first
Commit ("mm,thp,rmap: lock_compound_mapcounts() on THP mapcounts")
propagated the "if (compound) {lock} else if (PageCompound) {lock} else
{atomic}" pattern throughout; but Linus hated the way that gives primacy
to the uncommon case: switch to "if (!PageCompound) {atomic} else if
(compound) {lock} else {lock}" throughout. Linus has a bigger idea for
how to improve it all, but here just make that rearrangement.
Link: https://lkml.kernel.org/r/fca2f694-2098-b0ef-d4e-f1d8b94d318c@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: James Houghton <jthoughton@google.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Hugh Dickins [Thu, 3 Nov 2022 01:53:45 +0000 (18:53 -0700)]
mm,thp,rmap: lock_compound_mapcounts() on THP mapcounts
Fix the races in maintaining compound_mapcount, subpages_mapcount and
subpage _mapcount by using PG_locked in the first tail of any compound
page for a bit_spin_lock() on such modifications; skipping the usual
atomic operations on those fields in this case.
Bring page_remove_file_rmap() and page_remove_anon_compound_rmap() back
into page_remove_rmap() itself. Rearrange page_add_anon_rmap() and
page_add_file_rmap() and page_remove_rmap() to follow the same "if
(compound) {lock} else if (PageCompound) {lock} else {atomic}" pattern
(with a PageTransHuge in the compound test, like before, to avoid BUG_ONs
and optimize away that block when THP is not configured). Move all the
stats updates outside, after the bit_spin_locked section, so that it is
sure to be a leaf lock.
Add page_dup_compound_rmap() to manage compound locking versus atomics in
sync with the rest. In particular, hugetlb pages are still using the
atomics: to avoid unnecessary interference there, and because they never
have subpage mappings; but this exception can easily be changed.
Conveniently, page_dup_compound_rmap() turns out to suit an anon THP's
__split_huge_pmd_locked() too.
bit_spin_lock() is not popular with PREEMPT_RT folks: but PREEMPT_RT
sensibly excludes TRANSPARENT_HUGEPAGE already, so its only exposure is to
the non-hugetlb non-THP pte-mapped compound pages (with large folios being
currently dependent on TRANSPARENT_HUGEPAGE). There is never any scan of
subpages in this case; but we have chosen to use PageCompound tests rather
than PageTransCompound tests to gate the use of lock_compound_mapcounts(),
so that page_mapped() is correct on all compound pages, whether or not
TRANSPARENT_HUGEPAGE is enabled: could that be a problem for PREEMPT_RT,
when there is contention on the lock - under heavy concurrent forking for
example? If so, then it can be turned into a sleeping lock (like
folio_lock()) when PREEMPT_RT.
A simple 100 X munmap(mmap(2GB, MAP_SHARED|MAP_POPULATE, tmpfs), 2GB) took
18 seconds on small pages, and used to take 1 second on huge pages, but
now takes 115 milliseconds on huge pages. Mapping by pmds a second time
used to take 860ms and now takes 86ms; mapping by pmds after mapping by
ptes (when the scan is needed) used to take 870ms and now takes 495ms.
Mapping huge pages by ptes is largely unaffected but variable: between 5%
faster and 5% slower in what I've recorded. Contention on the lock is
likely to behave worse than contention on the atomics behaved.
Link: https://lkml.kernel.org/r/1b42bd1a-8223-e827-602f-d466c2db7d3c@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: James Houghton <jthoughton@google.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Hugh Dickins [Thu, 3 Nov 2022 01:51:38 +0000 (18:51 -0700)]
mm,thp,rmap: simplify compound page mapcount handling
Compound page (folio) mapcount calculations have been different for anon
and file (or shmem) THPs, and involved the obscure PageDoubleMap flag.
And each huge mapping and unmapping of a file (or shmem) THP involved
atomically incrementing and decrementing the mapcount of every subpage of
that huge page, dirtying many struct page cachelines.
Add subpages_mapcount field to the struct folio and first tail page, so
that the total of subpage mapcounts is available in one place near the
head: then page_mapcount() and total_mapcount() and page_mapped(), and
their folio equivalents, are so quick that anon and file and hugetlb don't
need to be optimized differently. Delete the unloved PageDoubleMap.
page_add and page_remove rmap functions must now maintain the
subpages_mapcount as well as the subpage _mapcount, when dealing with pte
mappings of huge pages; and correct maintenance of NR_ANON_MAPPED and
NR_FILE_MAPPED statistics still needs reading through the subpages, using
nr_subpages_unmapped() - but only when first or last pmd mapping finds
subpages_mapcount raised (double-map case, not the common case).
But are those counts (used to decide when to split an anon THP, and in
vmscan's pagecache_reclaimable heuristic) correctly maintained? Not
quite: since page_remove_rmap() (and also split_huge_pmd()) is often
called without page lock, there can be races when a subpage pte mapcount
0<->1 while compound pmd mapcount 0<->1 is scanning - races which the
previous implementation had prevented. The statistics might become
inaccurate, and even drift down until they underflow through 0. That is
not good enough, but is better dealt with in a followup patch.
Update a few comments on first and second tail page overlaid fields.
hugepage_add_new_anon_rmap() has to "increment" compound_mapcount, but
subpages_mapcount and compound_pincount are already correctly at 0, so
delete its reinitialization of compound_pincount.
A simple 100 X munmap(mmap(2GB, MAP_SHARED|MAP_POPULATE, tmpfs), 2GB) took
18 seconds on small pages, and used to take 1 second on huge pages, but
now takes 119 milliseconds on huge pages. Mapping by pmds a second time
used to take 860ms and now takes 92ms; mapping by pmds after mapping by
ptes (when the scan is needed) used to take 870ms and now takes 495ms.
But there might be some benchmarks which would show a slowdown, because
tail struct pages now fall out of cache until final freeing checks them.
Link: https://lkml.kernel.org/r/47ad693-717-79c8-e1ba-46c3a6602e48@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: James Houghton <jthoughton@google.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Hugh Dickins [Thu, 3 Nov 2022 01:48:45 +0000 (18:48 -0700)]
mm,hugetlb: use folio fields in second tail page
Patch series "mm,huge,rmap: unify and speed up compound mapcounts".
This patch (of 3):
We want to declare one more int in the first tail of a compound page: that
first tail page being valuable property, since every compound page has a
first tail, but perhaps no more than that.
No problem on 64-bit: there is already space for it. No problem with
32-bit THPs: 5.18 commit
5232c63f46fd ("mm: Make compound_pincount always
available") kindly cleared the space for it, apparently not realizing that
only 64-bit architectures enable CONFIG_THP_SWAP (whose use of tail
page->private might conflict) - but make sure of that in its Kconfig.
But hugetlb pages use tail page->private of the first tail page for a
subpool pointer, which will conflict; and they also use page->private of
the 2nd, 3rd and 4th tails.
Undo "mm: add private field of first tail to struct page and struct
folio"'s recent addition of private_1 to the folio tail: instead add
hugetlb_subpool, hugetlb_cgroup, hugetlb_cgroup_rsvd, hugetlb_hwpoison to
a second tail page of the folio: THP has long been using several fields of
that tail, so make better use of it for hugetlb too. This is not how a
generic folio should be declared in future, but it is an effective
transitional way to make use of it.
Delete the SUBPAGE_INDEX stuff, but keep __NR_USED_SUBPAGE: now 3.
[hughd@google.com: prefix folio's page_1 and page_2 with double underscore,
give folio's _flags_2 and _head_2 a line documentation each]
Link: https://lkml.kernel.org/r/9e2cb6b-5b58-d3f2-b5ee-5f8a14e8f10@google.com
Link: https://lkml.kernel.org/r/5f52de70-975-e94f-f141-543765736181@google.com
Link: https://lkml.kernel.org/r/3818cc9a-9999-d064-d778-9c94c5911e6@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: James Houghton <jthoughton@google.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mike Kravetz [Fri, 4 Nov 2022 01:16:32 +0000 (18:16 -0700)]
selftests/vm: update hugetlb madvise
Commit
8ebe0a5eaaeb ("mm,madvise,hugetlb: fix unexpected data loss with
MADV_DONTNEED on hugetlbfs") changed how the passed length was interpreted
for hugetlb mappings. It was changed from align up to align down. The
hugetlb-madvise test explicitly tests this behavior. Change test to
expect new behavior.
Link: https://lkml.kernel.org/r/20221104011632.357049-1-mike.kravetz@oracle.com
Link: https://lore.kernel.org/oe-lkp/202211040619.2ec447d7-oliver.sang@intel.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Deming Wang [Fri, 4 Nov 2022 02:38:18 +0000 (22:38 -0400)]
zsmalloc: replace IS_ERR() with IS_ERR_VALUE()
Avoid typecasts that are needed for IS_ERR() and use IS_ERR_VALUE()
instead.
Link: https://lkml.kernel.org/r/20221104023818.1728-1-wangdeming@inspur.com
Signed-off-by: Deming Wang <wangdeming@inspur.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Peter Xu [Sun, 30 Oct 2022 21:41:51 +0000 (17:41 -0400)]
mm: use pte markers for swap errors
PTE markers are ideal mechanism for things like SWP_SWAPIN_ERROR. Using a
whole swap entry type for this purpose can be an overkill, especially if
we already have PTE markers. Define a new bit for swapin error and
replace it with pte markers. Then we can safely drop SWP_SWAPIN_ERROR and
give one device slot back to swap.
We used to have SWP_SWAPIN_ERROR taking the page pfn as part of the swap
entry, but it's never used. Neither do I see how it can be useful because
normally the swapin failure should not be caused by a bad page but bad
swap device. Drop it alongside.
Link: https://lkml.kernel.org/r/20221030214151.402274-3-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Huang Ying <ying.huang@intel.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Peter Xu [Sun, 30 Oct 2022 21:41:50 +0000 (17:41 -0400)]
mm: always compile in pte markers
Patch series "mm: Use pte marker for swapin errors".
This series uses the pte marker to replace the swapin error swap entry,
then we save one more swap entry slot for swap devices. A new pte marker
bit is defined.
This patch (of 2):
The PTE markers code is tiny and now it's enabled for most of the
distributions. It's fine to keep it as-is, but to make a broader use of
it (e.g. replacing read error swap entry) it needs to be there always
otherwise we need special code path to take care of !PTE_MARKER case.
It'll be easier just make pte marker always exist. Use this chance to
extend its usage to anonymous too by simply touching up some of the old
comments, because it'll be used for anonymous pages in the follow up
patches.
Link: https://lkml.kernel.org/r/20221030214151.402274-1-peterx@redhat.com
Link: https://lkml.kernel.org/r/20221030214151.402274-2-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Huang Ying <ying.huang@intel.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Christophe JAILLET [Tue, 1 Nov 2022 21:14:09 +0000 (22:14 +0100)]
mm: use kstrtobool() instead of strtobool()
strtobool() is the same as kstrtobool(). However, the latter is more used
within the kernel.
In order to remove strtobool() and slightly simplify kstrtox.h, switch to
the other function name.
While at it, include the corresponding header file (<linux/kstrtox.h>)
Link: https://lkml.kernel.org/r/03f9401a6c8b87a1c786a2138d16b048f8d0eb53.1667336095.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Christophe JAILLET [Tue, 1 Nov 2022 21:14:08 +0000 (22:14 +0100)]
mm/damon: use kstrtobool() instead of strtobool()
strtobool() is the same as kstrtobool(). However, the latter is more used
within the kernel.
In order to remove strtobool() and slightly simplify kstrtox.h, switch to
the other function name.
While at it, include the corresponding header file (<linux/kstrtox.h>)
Link: https://lkml.kernel.org/r/ed2b46489a513988688decb53850339cc228940c.1667336095.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Tue, 1 Nov 2022 22:03:28 +0000 (22:03 +0000)]
Docs/ABI/damon: document 'schemes/<s>/tried_regions' sysfs directory
Update DAMON ABI document for the 'tried_regions' directory of DAMON
sysfs interface.
Link: https://lkml.kernel.org/r/20221101220328.95765-9-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Tue, 1 Nov 2022 22:03:27 +0000 (22:03 +0000)]
Docs/admin-guide/mm/damon/usage: document schemes/<s>/tried_regions sysfs directory
Document 'tried_regions' directory in DAMON sysfs interface usage in the
administrator guide.
Link: https://lkml.kernel.org/r/20221101220328.95765-8-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Tue, 1 Nov 2022 22:03:26 +0000 (22:03 +0000)]
tools/selftets/damon/sysfs: test tried_regions directory existence
Add a simple test case for ensuring tried_regions directory existence.
Link: https://lkml.kernel.org/r/20221101220328.95765-7-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Tue, 1 Nov 2022 22:03:25 +0000 (22:03 +0000)]
mm/damon/sysfs-schemes: implement DAMOS-tried regions clear command
When there are huge number of DAMON regions that specific scheme actions
are tried to be applied, directories and files under 'tried_regions'
scheme directory could waste some memory. Add another special input
keyword ('clear_schemes_tried_regions') for 'state' file of each kdamond
sysfs directory that can be used for cleanup of the 'tried_regions'
sub-directories.
[sj@kernel.org: skip regions clearing if the scheme directory was removed]
Link: https://lkml.kernel.org/r/20221114182954.4745-3-sj@kernel.org
Link: https://lkml.kernel.org/r/20221101220328.95765-6-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Tue, 1 Nov 2022 22:03:24 +0000 (22:03 +0000)]
mm/damon/sysfs: implement DAMOS tried regions update command
Implement the code for filling the data of 'tried_regions' DAMON sysfs
directory. With this commit, DAMON sysfs interface users can write a
special keyword, 'update_schemes_tried_regions' to the corresponding
'state' file of the kdamond. Then, DAMON sysfs interface will collect the
tried regions information using the 'before_damos_apply()' callback for
one aggregation interval and populate scheme region directories with the
values.
[sj@kernel.org: skip tried regions update if the scheme directory was removed]
Link: https://lkml.kernel.org/r/20221114182954.4745-2-sj@kernel.org
Link: https://lkml.kernel.org/r/20221101220328.95765-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Tue, 1 Nov 2022 22:03:23 +0000 (22:03 +0000)]
mm/damon/sysfs-schemes: implement scheme region directory
Implement region directories under 'tried_regions' directory of each
scheme DAMON sysfs directory. This directory will provide the address
range, the monitored access frequency ('nr_accesses'), and the age of each
DAMON region that corresponding DAMON-based operation scheme has tried to
be applied. Note that this commit doesn't implement the code for filling
the data but only the sysfs directory.
Link: https://lkml.kernel.org/r/20221101220328.95765-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Tue, 1 Nov 2022 22:03:22 +0000 (22:03 +0000)]
mm/damon/sysfs-schemes: implement schemes/tried_regions directory
For efficient and simple query-like DAMON monitoring results readings and
deep level investigations of DAMOS, DAMON kernel API
(include/linux/damon.h) users can use 'before_damos_apply' DAMON callback.
However, DAMON sysfs interface users don't have such option.
Add a directory, namely 'tried_regions', under each scheme directory to
use it as the interface for the purpose. Note that this commit is
implementing only the directory but the data filling.
After the data filling change is made, users will be able to signal DAMON
to fill the directory with the regions that corresponding scheme has tried
to be applied. By setting the access pattern of the scheme, users could
do the efficient query-like monitoring.
Link: https://lkml.kernel.org/r/20221101220328.95765-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Tue, 1 Nov 2022 22:03:21 +0000 (22:03 +0000)]
mm/damon/core: add a callback for scheme target regions check
Patch series "efficiently expose damos action tried regions information".
DAMON users can retrieve the monitoring results via 'after_aggregation'
callbacks if the user is using the kernel API, or 'damon_aggregated'
tracepoint if the user is in the user space. Those are useful if full
monitoring results are necessary. However, if the user has interest in
only a snapshot of the results for some regions having specific access
pattern, the interfaces could be inefficient. For example, some users
only want to know which memory regions are not accessed for more than a
specific time at the moment.
Also, some DAMOS users would want to know exactly to what memory regions
the schemes' actions tried to be applied, for a debugging or a tuning. As
DAMOS has its internal mechanism for quota and regions prioritization, the
users would need to simulate DAMOS' mechanism against the monitoring
results. That's unnecessarily complex.
This patchset implements DAMON kernel API callbacks and sysfs directory
for efficient exposure of the information for the use cases. The new
callback will be called for each region when a DAMOS action is gonna tried
to be applied to it. The sysfs directory will be called 'tried_regions'
and placed under each scheme sysfs directory. Users can write a special
keyworkd, 'update_schemes_regions', to the 'state' file of a kdamond sysfs
directory. Then, DAMON sysfs interface will fill the directory with the
information of regions that corresponding scheme action was tried to be
applied for next one aggregation interval.
Patches Sequence
----------------
The first one (patch 1) implements the callback for the kernel space
users. Following two patches (patches 2 and 3) implements sysfs
directories for the information and its sub directories. Two patches
(patches 4 and 5) for implementing the special keywords for filling the
data to and cleaning up the directories follow. Patch 6 adds a selftest
for the new sysfs directory. Finally, two patches (patches 7 and 8)
document the new feature in the administrator guide and the ABI document.
This patch (of 8):
Getting DAMON monitoring results of only specific access pattern (e.g.,
getting address ranges of memory that not accessed at all for two minutes)
can be useful for efficient monitoring of the system. The information can
also be helpful for deep level investigation of DAMON-based operation
schemes.
For that, users need to record (in case of the user space users) or
iterate (in case of the kernel space users) full monitoring results and
filter it out for the specific access pattern. In case of the DAMOS
investigation, users will even need to simulate DAMOS' quota and
prioritization mechanisms. It's inefficient and complex.
Add a new DAMON callback that will be called before each scheme is applied
to each region. DAMON kernel API users will be able to do the query-like
monitoring results collection, or DAMOS investigation in an efficient and
simple way using it.
Commits for providing the capability to the user space users will follow.
Link: https://lkml.kernel.org/r/20221101220328.95765-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20221101220328.95765-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sidhartha Kumar [Tue, 1 Nov 2022 22:30:59 +0000 (15:30 -0700)]
mm/hugetlb: convert move_hugetlb_state() to folios
Clean up unmap_and_move_huge_page() by converting move_hugetlb_state() to
take in folios.
[akpm@linux-foundation.org: fix CONFIG_HUGETLB_PAGE=n build]
Link: https://lkml.kernel.org/r/20221101223059.460937-10-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Bui Quang Minh <minhquangbui99@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mina Almasry <almasrymina@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sidhartha Kumar [Tue, 1 Nov 2022 22:30:58 +0000 (15:30 -0700)]
mm/hugeltb_cgroup: convert hugetlb_cgroup_commit_charge*() to folios
Convert hugetlb_cgroup_commit_charge*() to internally use folios to clean
up the code after __set_hugetlb_cgroup() was changed to take a folio.
Link: https://lkml.kernel.org/r/20221101223059.460937-9-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Bui Quang Minh <minhquangbui99@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mina Almasry <almasrymina@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sidhartha Kumar [Tue, 1 Nov 2022 22:30:57 +0000 (15:30 -0700)]
mm/hugetlb_cgroup: convert hugetlb_cgroup_uncharge_page() to folios
Continue to use a folio inside free_huge_page() by converting
hugetlb_cgroup_uncharge_page*() to folios.
Link: https://lkml.kernel.org/r/20221101223059.460937-8-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Bui Quang Minh <minhquangbui99@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mina Almasry <almasrymina@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sidhartha Kumar [Tue, 1 Nov 2022 22:30:56 +0000 (15:30 -0700)]
mm/hugetlb: convert free_huge_page to folios
Use folios inside free_huge_page(), this is in preparation for converting
hugetlb_cgroup_uncharge_page() to take in a folio.
Link: https://lkml.kernel.org/r/20221101223059.460937-7-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Bui Quang Minh <minhquangbui99@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mina Almasry <almasrymina@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sidhartha Kumar [Tue, 1 Nov 2022 22:30:55 +0000 (15:30 -0700)]
mm/hugetlb: convert isolate_or_dissolve_huge_page to folios
Removes a call to compound_head() by using a folio when operating on the
head page of a hugetlb compound page.
Link: https://lkml.kernel.org/r/20221101223059.460937-6-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Bui Quang Minh <minhquangbui99@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mina Almasry <almasrymina@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sidhartha Kumar [Tue, 1 Nov 2022 22:30:54 +0000 (15:30 -0700)]
mm/hugetlb_cgroup: convert hugetlb_cgroup_migrate to folios
Cleans up intermediate page to folio conversion code in
hugetlb_cgroup_migrate() by changing its arguments from pages to folios.
Link: https://lkml.kernel.org/r/20221101223059.460937-5-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Bui Quang Minh <minhquangbui99@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mina Almasry <almasrymina@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sidhartha Kumar [Tue, 1 Nov 2022 22:30:53 +0000 (15:30 -0700)]
mm/hugetlb_cgroup: convert set_hugetlb_cgroup*() to folios
Allows __prep_new_huge_page() to operate on a folio by converting
set_hugetlb_cgroup*() to take in a folio.
Link: https://lkml.kernel.org/r/20221101223059.460937-4-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Bui Quang Minh <minhquangbui99@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sidhartha Kumar [Tue, 1 Nov 2022 22:30:52 +0000 (15:30 -0700)]
mm/hugetlb_cgroup: convert hugetlb_cgroup_from_page() to folios
Introduce folios in __remove_hugetlb_page() by converting
hugetlb_cgroup_from_page() to use folios.
Also gets rid of unsed hugetlb_cgroup_from_page_resv() function.
Link: https://lkml.kernel.org/r/20221101223059.460937-3-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Bui Quang Minh <minhquangbui99@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mina Almasry <almasrymina@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sidhartha Kumar [Tue, 1 Nov 2022 22:30:51 +0000 (15:30 -0700)]
mm/hugetlb_cgroup: convert __set_hugetlb_cgroup() to folios
Patch series "convert hugetlb_cgroup helper functions to folios", v2.
This patch series continues the conversion of hugetlb code from being
managed in pages to folios by converting many of the hugetlb_cgroup helper
functions to use folios. This allows the core hugetlb functions to pass
in a folio to these helper functions.
This patch (of 9);
Change __set_hugetlb_cgroup() to use folios so it is explicit that the
function operates on a head page.
Link: https://lkml.kernel.org/r/20221101223059.460937-1-sidhartha.kumar@oracle.com
Link: https://lkml.kernel.org/r/20221101223059.460937-2-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Bui Quang Minh <minhquangbui99@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mina Almasry <almasrymina@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kees Cook [Fri, 28 Oct 2022 15:53:01 +0000 (08:53 -0700)]
mempool: do not use ksize() for poisoning
Nothing appears to be using ksize() within the kmalloc-backed mempools
except the mempool poisoning logic. Use the actual pool size instead of
the ksize() to avoid needing any special handling of the memory as needed
by KASAN, UBSAN_BOUNDS, nor FORTIFY_SOURCE.
[vbabka@suse.cz: for slab mempools pool_data is not object size]
Link: https://lkml.kernel.org/r/13c4bd6e-09d3-efce-43a5-5a99be8bc96b@suse.cz
Link: https://lkml.kernel.org/r/20221028154823.you.615-kees@kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Link: https://lore.kernel.org/lkml/f4fc52c4-7c18-1d76-0c7a-4058ea2486b9@suse.cz/
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reported-by: Anders Roxell <anders.roxell@linaro.org>
Link: https://lore.kernel.org/all/20221031105514.GB69385@mutt/
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam Howlett [Fri, 28 Oct 2022 14:45:34 +0000 (14:45 +0000)]
maple_tree: mte_set_full() and mte_clear_full() clang-analyzer clean up
mte_set_full() and mte_clear_full() were incorrectly setting a pointer to
a value without returning a result. Fix this by returning the modified
pointer to be use as necessary. Also add a third function to return if
the bit is set or not.
Link: https://lore.kernel.org/lkml/20221026120029.12555-1-lukas.bulwahn@gmail.com/
Link: https://lkml.kernel.org/r/20221028144520.2776767-1-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Suggested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Suggested-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Johannes Weiner [Wed, 26 Oct 2022 18:01:33 +0000 (14:01 -0400)]
mm: vmscan: split khugepaged stats from direct reclaim stats
Direct reclaim stats are useful for identifying a potential source for
application latency, as well as spotting issues with kswapd. However,
khugepaged currently distorts the picture: as a kernel thread it doesn't
impose allocation latencies on userspace, and it explicitly opts out of
kswapd reclaim. Its activity showing up in the direct reclaim stats is
misleading. Counting it as kswapd reclaim could also cause confusion when
trying to understand actual kswapd behavior.
Break out khugepaged from the direct reclaim counters into new
pgsteal_khugepaged, pgdemote_khugepaged, pgscan_khugepaged counters.
Test with a huge executable (CONFIG_READ_ONLY_THP_FOR_FS):
pgsteal_kswapd 1342185
pgsteal_direct 0
pgsteal_khugepaged 3623
pgscan_kswapd 1345025
pgscan_direct 0
pgscan_khugepaged 3623
Link: https://lkml.kernel.org/r/20221026180133.377671-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Eric Bergen <ebergen@meta.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Mon, 24 Oct 2022 17:46:19 +0000 (17:46 +0000)]
Docs/admin-guide/mm/damon/usage: fix wrong usage example of init_regions file
DAMON debugfs interface assumes the users will write all inputs at once.
However, redirecting a string of multiple lines sometimes end up writing
line by line. Therefore, the example usage of 'init_regions' file, which
writes input as a string of multiple lines can fail. Fix it to use a
single line string instead. Also update the description of the usage to
not assume users will write inputs in multiple lines.
Link: https://lkml.kernel.org/r/20221024174619.15600-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Vinicius Petrucci <vpetrucci@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Mon, 24 Oct 2022 17:46:18 +0000 (17:46 +0000)]
Docs/admin-guide/mm/damon/usage: describe the rules of sysfs region directories
Patch series "Docs/admin-buide/mm/damon/usage: minor fixes".
DAMON usage document contains an unclear description and a wrong usage
example. This patchset fixes the two minor problems.
This patch (of 2):
Target region directories of DAMON sysfs interface should contain no
overlap and sorted by the address, but not clearly documented. Actually,
a user had an issue[1] due to the poor documentation. Add clear
description of it on the usage document.
[1] https://lore.kernel.org/damon/CAEZ6=UNUcH2BvJj++OrT=XQLdkidU79wmCO=tantSOB36pPNTg@mail.gmail.com/
Link: https://lkml.kernel.org/r/20221024174619.15600-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20221024174619.15600-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: Vinicius Petrucci <vpetrucci@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Muchun Song [Thu, 27 Oct 2022 03:36:41 +0000 (11:36 +0800)]
mm: hugetlb_vmemmap: remove redundant list_del()
The ->lru field will be assigned to a new value in __free_page(). So it
is unnecessary to delete it from the @list. Just remove it to simplify
the code.
Link: https://lkml.kernel.org/r/20221027033641.66709-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tony Luck [Fri, 21 Oct 2022 20:01:20 +0000 (13:01 -0700)]
mm, hwpoison: when copy-on-write hits poison, take page offline
Cannot call memory_failure() directly from the fault handler because
mmap_lock (and others) are held.
It is important, but not urgent, to mark the source page as h/w poisoned
and unmap it from other tasks.
Use memory_failure_queue() to request a call to memory_failure() for the
page with the error.
Also provide a stub version for CONFIG_MEMORY_FAILURE=n
Link: https://lkml.kernel.org/r/20221021200120.175753-3-tony.luck@intel.com
Signed-off-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Shuai Xue <xueshuai@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tony Luck [Fri, 21 Oct 2022 20:01:19 +0000 (13:01 -0700)]
mm, hwpoison: try to recover from copy-on write faults
Patch series "Copy-on-write poison recovery", v3.
Part 1 deals with the process that triggered the copy on write fault with
a store to a shared read-only page. That process is send a SIGBUS with
the usual machine check decoration to specify the virtual address of the
lost page, together with the scope.
Part 2 sets up to asynchronously take the page with the uncorrected error
offline to prevent additional machine check faults. H/t to Miaohe Lin
<linmiaohe@huawei.com> and Shuai Xue <xueshuai@linux.alibaba.com> for
pointing me to the existing function to queue a call to memory_failure().
On x86 there is some duplicate reporting (because the error is also
signalled by the memory controller as well as by the core that triggered
the machine check). Console logs look like this:
This patch (of 2):
If the kernel is copying a page as the result of a copy-on-write
fault and runs into an uncorrectable error, Linux will crash because
it does not have recovery code for this case where poison is consumed
by the kernel.
It is easy to set up a test case. Just inject an error into a private
page, fork(2), and have the child process write to the page.
I wrapped that neatly into a test at:
git://git.kernel.org/pub/scm/linux/kernel/git/aegl/ras-tools.git
just enable ACPI error injection and run:
# ./einj_mem-uc -f copy-on-write
Add a new copy_user_highpage_mc() function that uses copy_mc_to_kernel()
on architectures where that is available (currently x86 and powerpc).
When an error is detected during the page copy, return VM_FAULT_HWPOISON
to caller of wp_page_copy(). This propagates up the call stack. Both x86
and powerpc have code in their fault handler to deal with this code by
sending a SIGBUS to the application.
Note that this patch avoids a system crash and signals the process that
triggered the copy-on-write action. It does not take any action for the
memory error that is still in the shared page. To handle that a call to
memory_failure() is needed. But this cannot be done from wp_page_copy()
because it holds mmap_lock(). Perhaps the architecture fault handlers
can deal with this loose end in a subsequent patch?
On Intel/x86 this loose end will often be handled automatically because
the memory controller provides an additional notification of the h/w
poison in memory, the handler for this will call memory_failure(). This
isn't a 100% solution. If there are multiple errors, not all may be
logged in this way.
[tony.luck@intel.com: add call to kmsan_unpoison_memory(), per Miaohe Lin]
Link: https://lkml.kernel.org/r/20221031201029.102123-2-tony.luck@intel.com
Link: https://lkml.kernel.org/r/20221021200120.175753-1-tony.luck@intel.com
Link: https://lkml.kernel.org/r/20221021200120.175753-2-tony.luck@intel.com
Signed-off-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Shuai Xue <xueshuai@linux.alibaba.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Shakeel Butt [Wed, 9 Nov 2022 01:20:11 +0000 (01:20 +0000)]
percpu_counter: add percpu_counter_sum_all interface
The percpu_counter is used for scenarios where performance is more
important than the accuracy. For percpu_counter users, who want more
accurate information in their slowpath, percpu_counter_sum is provided
which traverses all the online CPUs to accumulate the data. The reason it
only needs to traverse online CPUs is because percpu_counter does
implement CPU offline callback which syncs the local data of the offlined
CPU.
However there is a small race window between the online CPUs traversal of
percpu_counter_sum and the CPU offline callback. The offline callback has
to traverse all the percpu_counters on the system to flush the CPU local
data which can be a lot. During that time, the CPU which is going offline
has already been published as offline to all the readers. So, as the
offline callback is running, percpu_counter_sum can be called for one
counter which has some state on the CPU going offline. Since
percpu_counter_sum only traverses online CPUs, it will skip that specific
CPU and the offline callback might not have flushed the state for that
specific percpu_counter on that offlined CPU.
Normally this is not an issue because percpu_counter users can deal with
some inaccuracy for small time window. However a new user i.e. mm_struct
on the cleanup path wants to check the exact state of the percpu_counter
through check_mm(). For such users, this patch introduces
percpu_counter_sum_all() which traverses all possible CPUs and it is used
in fork.c:check_mm() to avoid the potential race.
This issue is exposed by the later patch "mm: convert mm's rss stats into
percpu_counter".
Link: https://lkml.kernel.org/r/20221109012011.881058-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Shakeel Butt [Mon, 24 Oct 2022 05:28:41 +0000 (05:28 +0000)]
mm: convert mm's rss stats into percpu_counter
Currently mm_struct maintains rss_stats which are updated on page fault
and the unmapping codepaths. For page fault codepath the updates are
cached per thread with the batch of TASK_RSS_EVENTS_THRESH which is 64.
The reason for caching is performance for multithreaded applications
otherwise the rss_stats updates may become hotspot for such applications.
However this optimization comes with the cost of error margin in the rss
stats. The rss_stats for applications with large number of threads can be
very skewed. At worst the error margin is (nr_threads * 64) and we have a
lot of applications with 100s of threads, so the error margin can be very
high. Internally we had to reduce TASK_RSS_EVENTS_THRESH to 32.
Recently we started seeing the unbounded errors for rss_stats for specific
applications which use TCP rx0cp. It seems like vm_insert_pages()
codepath does not sync rss_stats at all.
This patch converts the rss_stats into percpu_counter to convert the error
margin from (nr_threads * 64) to approximately (nr_cpus ^ 2). However
this conversion enable us to get the accurate stats for situations where
accuracy is more important than the cpu cost.
This patch does not make such tradeoffs - we can just use
percpu_counter_add_local() for the updates and percpu_counter_sum() (or
percpu_counter_sync() + percpu_counter_read) for the readers. At the
moment the readers are either procfs interface, oom_killer and memory
reclaim which I think are not performance critical and should be ok with
slow read. However I think we can make that change in a separate patch.
Link: https://lkml.kernel.org/r/20221024052841.3291983-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Tue, 25 Oct 2022 17:36:50 +0000 (17:36 +0000)]
selftests/damon: add tests for DAMON_LRU_SORT's enabled parameter
Add simple test cases for DAMON_LRU_SORT's 'enabled' parameter. Those
tests are focusing on the synchronous behavior of DAMON_RECLAIM enabling
and disabling.
Link: https://lkml.kernel.org/r/20221025173650.90624-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Tue, 25 Oct 2022 17:36:49 +0000 (17:36 +0000)]
mm/damon/lru_sort: enable and disable synchronously
Writing a value to DAMON_RECLAIM's 'enabled' parameter turns on or off
DAMON in an ansychronous way. This means the parameter cannot be used to
read the current status of DAMON_RECLAIM. 'kdamond_pid' parameter should
be used instead for the purpose. The documentation is easy to be read as
it works in a synchronous way, so it is a little bit confusing. It also
makes the user space tooling dirty.
There's no real reason to have the asynchronous behavior, though. Simply
make the parameter works synchronously, rather than updating the document.
Link: https://lkml.kernel.org/r/20221025173650.90624-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Tue, 25 Oct 2022 17:36:48 +0000 (17:36 +0000)]
selftests/damon: add tests for DAMON_RECLAIM's enabled parameter
Add simple test cases for DAMON_RECLAIM's 'enabled' parameter. Those
tests are focusing on the synchronous behavior of DAMON_RECLAIM enabling
and disabling.
Link: https://lkml.kernel.org/r/20221025173650.90624-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Tue, 25 Oct 2022 17:36:47 +0000 (17:36 +0000)]
mm/damon/reclaim: enable and disable synchronously
Patch series "mm/damon/reclaim,lru_sort: enable/disable synchronously".
Writing a value to DAMON_RECLAIM and DAMON_LRU_SORT's 'enabled' parameters
turns on or off DAMON in an ansychronous way. This means the parameter
cannot be used to read the current status of them. 'kdamond_pid'
parameter should be used instead for the purpose. The documentation is
easy to be read as it works in a synchronous way, so it is a little bit
confusing. It also makes the user space tooling dirty.
There's no real reason to have the asynchronous behavior, though. Simply
make the parameter works synchronously, rather than updating the document.
The first and second patches changes the behavior of the 'enabled'
parameter for DAMON_RECLAIM and adds a selftest for the changed behavior,
respectively. Following two patches make the same changes for
DAMON_LRU_SORT.
This patch (of 4):
Writing a value to DAMON_RECLAIM's 'enabled' parameter turns on or off
DAMON in an ansychronous way. This means the parameter cannot be used to
read the current status of DAMON_RECLAIM. 'kdamond_pid' parameter should
be used instead for the purpose. The documentation is easy to be read as
it works in a synchronous way, so it is a little bit confusing. It also
makes the user space tooling dirty.
There's no real reason to have the asynchronous behavior, though. Simply
make the parameter works synchronously, rather than updating the document.
Link: https://lkml.kernel.org/r/20221025173650.90624-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20221025173650.90624-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Wed, 26 Oct 2022 22:59:43 +0000 (22:59 +0000)]
mm/damon/{reclaim,lru_sort}: remove unnecessarily included headers
Some headers that 'reclaim.c' and 'lru_sort.c' are including are
unnecessary now owing to previous cleanups and refactorings. Remove
those.
Link: https://lkml.kernel.org/r/20221026225943.100429-13-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Wed, 26 Oct 2022 22:59:42 +0000 (22:59 +0000)]
mm/damon/modules: deduplicate init steps for DAMON context setup
DAMON_RECLAIM and DAMON_LRU_SORT has duplicated code for DAMON context and
target initializations. Deduplicate the part by implementing a function
for the initialization in 'modules-common.c' and using it.
Link: https://lkml.kernel.org/r/20221026225943.100429-12-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Wed, 26 Oct 2022 22:59:41 +0000 (22:59 +0000)]
mm/damon/sysfs: split out schemes directory implementation to separate file
DAMON sysfs interface for 'schemes' directory is implemented using about
one thousand lines of code. It has no strong dependency with other
parts of its file, so split it out to another file for better code
management.
Link: https://lkml.kernel.org/r/20221026225943.100429-11-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Wed, 26 Oct 2022 22:59:40 +0000 (22:59 +0000)]
mm/damon/sysfs: split out kdamond-independent schemes stats update logic into a new function
'damon_sysfs_schemes_update_stats()' is coupled with both
damon_sysfs_kdamond and damon_sysfs_schemes. It's a wide range of types
dependency. It makes splitting the logics a little bit distracting.
Split the function so that each function is coupled with smaller range of
types.
Link: https://lkml.kernel.org/r/20221026225943.100429-10-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Wed, 26 Oct 2022 22:59:39 +0000 (22:59 +0000)]
mm/damon/sysfs: move unsigned long range directory to common module
The implementation of unsigned long type range directories can be reused
by multiple DAMON sysfs directories including those for DAMON-based
Operation Schemes and the range of number of monitoring regions. Move the
code into the files for DAMON sysfs common logics.
Link: https://lkml.kernel.org/r/20221026225943.100429-9-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Wed, 26 Oct 2022 22:59:38 +0000 (22:59 +0000)]
mm/damon/sysfs: move sysfs_lock to common module
DAMON sysfs interface is implemented in a single file, sysfs.c, which has
about 2,800 lines of code. As the interface is hierarchical and some of
the code can be reused by different hierarchies, it would make more sense
to split out the implementation into common parts and different parts in
multiple files. As the beginning of the work, create files for common
code and move the global mutex for directories modifications protection
into the new file.
Link: https://lkml.kernel.org/r/20221026225943.100429-8-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Wed, 26 Oct 2022 22:59:37 +0000 (22:59 +0000)]
mm/damon/sysfs: remove parameters of damon_sysfs_region_alloc()
'damon_sysfs_region_alloc()' is always called with zero-filled 'struct
damon_addr_range', because the start and end addresses should set by
users. Remove unnecessary parameters of the function and simplify the
body by using 'kzalloc()'.
Link: https://lkml.kernel.org/r/20221026225943.100429-7-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Wed, 26 Oct 2022 22:59:36 +0000 (22:59 +0000)]
mm/damon/sysfs: use damon_addr_range for region's start and end values
DAMON has a struct for each address range but DAMON sysfs interface is
using the low type (unsigned long) for storing the start and end addresses
of regions. Use the dedicated struct for better type safety.
Link: https://lkml.kernel.org/r/20221026225943.100429-6-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Wed, 26 Oct 2022 22:59:35 +0000 (22:59 +0000)]
mm/damon/core: split out scheme quota adjustment logic into a new function
DAMOS quota adjustment logic in 'kdamond_apply_schemes()', has some amount
of code, and the logic is not so straightforward. Split it out to a new
function for better readability.
Link: https://lkml.kernel.org/r/20221026225943.100429-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Wed, 26 Oct 2022 22:59:34 +0000 (22:59 +0000)]
mm/damon/core: split out scheme stat update logic into a new function
The function for applying a given DAMON scheme action to a given DAMON
region, 'damos_apply_scheme()' is not quite short. Make it better to read
by splitting out the stat update logic into a new function.
Link: https://lkml.kernel.org/r/20221026225943.100429-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Wed, 26 Oct 2022 22:59:33 +0000 (22:59 +0000)]
mm/damon/core: split damos application logic into a new function
The DAMOS action applying function, 'damon_do_apply_schemes()', is still
long and not easy to read. Split out the code for applying a single
action to a single region into a new function for better readability.
Link: https://lkml.kernel.org/r/20221026225943.100429-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Wed, 26 Oct 2022 22:59:32 +0000 (22:59 +0000)]
mm/damon/core: split out DAMOS-charged region skip logic into a new function
Patch series "mm/damon: cleanup and refactoring code", v2.
This patchset cleans up and refactors a range of DAMON code including the
core, DAMON sysfs interface, and DAMON modules, for better readability and
convenient future feature implementations.
In detail, this patchset splits unnecessarily long and complex functions
in core into smaller functions (patches 1-4). Then, it cleans up the
DAMON sysfs interface by using more type-safe code (patch 5) and removing
unnecessary function parameters (patch 6). Further, it refactor the code
by distributing the code into multiple files (patches 7-10). Last two
patches (patches 11 and 12) deduplicates and remove unnecessary header
inclusion in DAMON modules (reclaim and lru_sort).
This patch (of 12):
The DAMOS action applying function, 'damon_do_apply_schemes()', is quite
long and not so simple. Split out the already quota-charged region skip
code, which is not a small amount of simple code, into a new function with
some comments for better readability.
Link: https://lkml.kernel.org/r/20221026225943.100429-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20221026225943.100429-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Andrew Morton [Wed, 30 Nov 2022 22:58:42 +0000 (14:58 -0800)]
Merge branch 'mm-hotfixes-stable' into mm-stable
Andrew Morton [Mon, 28 Nov 2022 21:21:40 +0000 (13:21 -0800)]
revert "kbuild: fix -Wimplicit-function-declaration in license_is_gpl_compatible"
It causes build failures with unusual CC/HOSTCC combinations.
Quoting
https://lkml.kernel.org/r/
A222B1E6-69B8-4085-AD1B-
27BDB72CA971@goldelico.com:
HOSTCC scripts/mod/modpost.o - due to target missing
In file included from include/linux/string.h:5,
from scripts/mod/../../include/linux/license.h:5,
from scripts/mod/modpost.c:24:
include/linux/compiler.h:246:10: fatal error: asm/rwonce.h: No such file or directory
246 | #include <asm/rwonce.h>
| ^~~~~~~~~~~~~~
compilation terminated.
...
The problem is that HOSTCC is not necessarily the same compiler or even
architecture as CC and pulling in <linux/compiler.h> or <asm/rwonce.h>
files indirectly isn't a good idea then.
My toolchain is providing HOSTCC = gcc (MacPorts) and CC = arm-linux-gnueabihf
(built from gcc source) and all running on Darwin.
If I change the include to <string.h> I can then "HOSTCC scripts/mod/modpost.c"
but then it fails for "CC kernel/module/main.c" not finding <string.h>:
CC kernel/module/main.o - due to target missing
In file included from kernel/module/main.c:43:0:
./include/linux/license.h:5:20: fatal error: string.h: No such file or directory
#include <string.h>
^
compilation terminated.
Reported-by: "H. Nikolaus Schaller" <hns@goldelico.com>
Cc: Sam James <sam@gentoo.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lee Jones [Fri, 25 Nov 2022 12:07:50 +0000 (12:07 +0000)]
Kconfig.debug: provide a little extra FRAME_WARN leeway when KASAN is enabled
When enabled, KASAN enlarges function's stack-frames. Pushing quite a few
over the current threshold. This can mainly be seen on 32-bit
architectures where the present limit (when !GCC) is a lowly 1024-Bytes.
Link: https://lkml.kernel.org/r/20221125120750.3537134-3-lee@kernel.org
Signed-off-by: Lee Jones <lee@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@gmail.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Leo Li <sunpeng.li@amd.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com>
Cc: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Tom Rix <trix@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lee Jones [Fri, 25 Nov 2022 12:07:49 +0000 (12:07 +0000)]
drm/amdgpu: temporarily disable broken Clang builds due to blown stack-frame
Patch series "Fix a bunch of allmodconfig errors", v2.
Since
b339ec9c229aa ("kbuild: Only default to -Werror if COMPILE_TEST")
WERROR now defaults to COMPILE_TEST meaning that it's enabled for
allmodconfig builds. This leads to some interesting build failures when
using Clang, each resolved in this set.
With this set applied, I am able to obtain a successful allmodconfig Arm
build.
This patch (of 2):
calculate_bandwidth() is presently broken on all !(X86_64 || SPARC64 ||
ARM64) architectures built with Clang (all released versions), whereby the
stack frame gets blown up to well over 5k. This would cause an immediate
kernel panic on most architectures. We'll revert this when the following
bug report has been resolved:
https://github.com/llvm/llvm-project/issues/41896.
Link: https://lkml.kernel.org/r/20221125120750.3537134-1-lee@kernel.org
Link: https://lkml.kernel.org/r/20221125120750.3537134-2-lee@kernel.org
Signed-off-by: Lee Jones <lee@kernel.org>
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@gmail.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Lee Jones <lee@kernel.org>
Cc: Leo Li <sunpeng.li@amd.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com>
Cc: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Tom Rix <trix@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jann Horn [Fri, 25 Nov 2022 21:37:14 +0000 (22:37 +0100)]
mm/khugepaged: invoke MMU notifiers in shmem/file collapse paths
Any codepath that zaps page table entries must invoke MMU notifiers to
ensure that secondary MMUs (like KVM) don't keep accessing pages which
aren't mapped anymore. Secondary MMUs don't hold their own references to
pages that are mirrored over, so failing to notify them can lead to page
use-after-free.
I'm marking this as addressing an issue introduced in commit
f3f0e1d2150b
("khugepaged: add support of collapse for tmpfs/shmem pages"), but most of
the security impact of this only came in commit
27e1f8273113 ("khugepaged:
enable collapse pmd for pte-mapped THP"), which actually omitted flushes
for the removal of present PTEs, not just for the removal of empty page
tables.
Link: https://lkml.kernel.org/r/20221129154730.2274278-3-jannh@google.com
Link: https://lkml.kernel.org/r/20221128180252.1684965-3-jannh@google.com
Link: https://lkml.kernel.org/r/20221125213714.4115729-3-jannh@google.com
Fixes:
f3f0e1d2150b ("khugepaged: add support of collapse for tmpfs/shmem pages")
Signed-off-by: Jann Horn <jannh@google.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jann Horn [Fri, 25 Nov 2022 21:37:13 +0000 (22:37 +0100)]
mm/khugepaged: fix GUP-fast interaction by sending IPI
Since commit
70cbc3cc78a99 ("mm: gup: fix the fast GUP race against THP
collapse"), the lockless_pages_from_mm() fastpath rechecks the pmd_t to
ensure that the page table was not removed by khugepaged in between.
However, lockless_pages_from_mm() still requires that the page table is
not concurrently freed. Fix it by sending IPIs (if the architecture uses
semi-RCU-style page table freeing) before freeing/reusing page tables.
Link: https://lkml.kernel.org/r/20221129154730.2274278-2-jannh@google.com
Link: https://lkml.kernel.org/r/20221128180252.1684965-2-jannh@google.com
Link: https://lkml.kernel.org/r/20221125213714.4115729-2-jannh@google.com
Fixes:
ba76149f47d8 ("thp: khugepaged")
Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jann Horn [Fri, 25 Nov 2022 21:37:12 +0000 (22:37 +0100)]
mm/khugepaged: take the right locks for page table retraction
pagetable walks on address ranges mapped by VMAs can be done under the
mmap lock, the lock of an anon_vma attached to the VMA, or the lock of the
VMA's address_space. Only one of these needs to be held, and it does not
need to be held in exclusive mode.
Under those circumstances, the rules for concurrent access to page table
entries are:
- Terminal page table entries (entries that don't point to another page
table) can be arbitrarily changed under the page table lock, with the
exception that they always need to be consistent for
hardware page table walks and lockless_pages_from_mm().
This includes that they can be changed into non-terminal entries.
- Non-terminal page table entries (which point to another page table)
can not be modified; readers are allowed to READ_ONCE() an entry, verify
that it is non-terminal, and then assume that its value will stay as-is.
Retracting a page table involves modifying a non-terminal entry, so
page-table-level locks are insufficient to protect against concurrent page
table traversal; it requires taking all the higher-level locks under which
it is possible to start a page walk in the relevant range in exclusive
mode.
The collapse_huge_page() path for anonymous THP already follows this rule,
but the shmem/file THP path was getting it wrong, making it possible for
concurrent rmap-based operations to cause corruption.
Link: https://lkml.kernel.org/r/20221129154730.2274278-1-jannh@google.com
Link: https://lkml.kernel.org/r/20221128180252.1684965-1-jannh@google.com
Link: https://lkml.kernel.org/r/20221125213714.4115729-1-jannh@google.com
Fixes:
27e1f8273113 ("khugepaged: enable collapse pmd for pte-mapped THP")
Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Gavin Shan [Thu, 24 Nov 2022 09:55:23 +0000 (17:55 +0800)]
mm: migrate: fix THP's mapcount on isolation
The issue is reported when removing memory through virtio_mem device. The
transparent huge page, experienced copy-on-write fault, is wrongly
regarded as pinned. The transparent huge page is escaped from being
isolated in isolate_migratepages_block(). The transparent huge page can't
be migrated and the corresponding memory block can't be put into offline
state.
Fix it by replacing page_mapcount() with total_mapcount(). With this, the
transparent huge page can be isolated and migrated, and the memory block
can be put into offline state. Besides, The page's refcount is increased
a bit earlier to avoid the page is released when the check is executed.
Link: https://lkml.kernel.org/r/20221124095523.31061-1-gshan@redhat.com
Fixes:
1da2f328fa64 ("mm,thp,compaction,cma: allow THP migration for CMA allocations")
Signed-off-by: Gavin Shan <gshan@redhat.com>
Reported-by: Zhenyu Zhang <zhenyzha@redhat.com>
Tested-by: Zhenyu Zhang <zhenyzha@redhat.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org> [5.7+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Juergen Gross [Wed, 23 Nov 2022 06:45:10 +0000 (07:45 +0100)]
mm: introduce arch_has_hw_nonleaf_pmd_young()
When running as a Xen PV guests commit
eed9a328aa1a ("mm: x86: add
CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG") can cause a protection violation in
pmdp_test_and_clear_young():
BUG: unable to handle page fault for address:
ffff8880083374d0
#PF: supervisor write access in kernel mode
#PF: error_code(0x0003) - permissions violation
PGD 3026067 P4D 3026067 PUD 3027067 PMD
7fee5067 PTE
8010000008337065
Oops: 0003 [#1] PREEMPT SMP NOPTI
CPU: 7 PID: 158 Comm: kswapd0 Not tainted 6.1.0-rc5-
20221118-doflr+ #1
RIP: e030:pmdp_test_and_clear_young+0x25/0x40
This happens because the Xen hypervisor can't emulate direct writes to
page table entries other than PTEs.
This can easily be fixed by introducing arch_has_hw_nonleaf_pmd_young()
similar to arch_has_hw_pte_young() and test that instead of
CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG.
Link: https://lkml.kernel.org/r/20221123064510.16225-1-jgross@suse.com
Fixes:
eed9a328aa1a ("mm: x86: add CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG")
Signed-off-by: Juergen Gross <jgross@suse.com>
Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Acked-by: Yu Zhao <yuzhao@google.com>
Tested-by: Sander Eikelenboom <linux@eikelenboom.it>
Acked-by: David Hildenbrand <david@redhat.com> [core changes]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Juergen Gross [Wed, 30 Nov 2022 22:49:41 +0000 (14:49 -0800)]
mm: add dummy pmd_young() for architectures not having it
In order to avoid #ifdeffery add a dummy pmd_young() implementation as a
fallback. This is required for the later patch "mm: introduce
arch_has_hw_nonleaf_pmd_young()".
Link: https://lkml.kernel.org/r/fd3ac3cd-7349-6bbd-890a-71a9454ca0b3@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Yu Zhao <yuzhao@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Sander Eikelenboom <linux@eikelenboom.it>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Tue, 22 Nov 2022 19:48:31 +0000 (19:48 +0000)]
mm/damon/sysfs: fix wrong empty schemes assumption under online tuning in damon_sysfs_set_schemes()
Commit
da87878010e5 ("mm/damon/sysfs: support online inputs update") made
'damon_sysfs_set_schemes()' to be called for running DAMON context, which
could have schemes. In the case, DAMON sysfs interface is supposed to
update, remove, or add schemes to reflect the sysfs files. However, the
code is assuming the DAMON context wouldn't have schemes at all, and
therefore creates and adds new schemes. As a result, the code doesn't
work as intended for online schemes tuning and could have more than
expected memory footprint. The schemes are all in the DAMON context, so
it doesn't leak the memory, though.
Remove the wrong asssumption (the DAMON context wouldn't have schemes) in
'damon_sysfs_set_schemes()' to fix the bug.
Link: https://lkml.kernel.org/r/20221122194831.3472-1-sj@kernel.org
Fixes:
da87878010e5 ("mm/damon/sysfs: support online inputs update")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> [5.19+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tiezhu Yang [Sat, 19 Nov 2022 02:36:59 +0000 (10:36 +0800)]
tools/vm/slabinfo-gnuplot: use "grep -E" instead of "egrep"
The latest version of grep claims the egrep is now obsolete so the build
now contains warnings that look like:
egrep: warning: egrep is obsolescent; using grep -E
fix this up by moving the related file to use "grep -E" instead.
sed -i "s/egrep/grep -E/g" `grep egrep -rwl tools/vm`
Here are the steps to install the latest grep:
wget http://ftp.gnu.org/gnu/grep/grep-3.8.tar.gz
tar xf grep-3.8.tar.gz
cd grep-3.8 && ./configure && make
sudo make install
export PATH=/usr/local/bin:$PATH
Link: https://lkml.kernel.org/r/1668825419-30584-1-git-send-email-yangtiezhu@loongson.cn
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
ZhangPeng [Sat, 19 Nov 2022 12:05:42 +0000 (21:05 +0900)]
nilfs2: fix NULL pointer dereference in nilfs_palloc_commit_free_entry()
Syzbot reported a null-ptr-deref bug:
NILFS (loop0): segctord starting. Construction interval = 5 seconds, CP
frequency < 30 seconds
general protection fault, probably for non-canonical address
0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
CPU: 1 PID: 3603 Comm: segctord Not tainted
6.1.0-rc2-syzkaller-00105-gb229b6ca5abb #0
Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google
10/11/2022
RIP: 0010:nilfs_palloc_commit_free_entry+0xe5/0x6b0
fs/nilfs2/alloc.c:608
Code: 00 00 00 00 fc ff df 80 3c 02 00 0f 85 cd 05 00 00 48 b8 00 00 00
00 00 fc ff df 4c 8b 73 08 49 8d 7e 10 48 89 fa 48 c1 ea 03 <80> 3c 02
00 0f 85 26 05 00 00 49 8b 46 10 be a6 00 00 00 48 c7 c7
RSP: 0018:
ffffc90003dff830 EFLAGS:
00010212
RAX:
dffffc0000000000 RBX:
ffff88802594e218 RCX:
000000000000000d
RDX:
0000000000000002 RSI:
0000000000002000 RDI:
0000000000000010
RBP:
ffff888071880222 R08:
0000000000000005 R09:
000000000000003f
R10:
000000000000000d R11:
0000000000000000 R12:
ffff888071880158
R13:
ffff88802594e220 R14:
0000000000000000 R15:
0000000000000004
FS:
0000000000000000(0000) GS:
ffff8880b9b00000(0000)
knlGS:
0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0:
0000000080050033
CR2:
00007fb1c08316a8 CR3:
0000000018560000 CR4:
0000000000350ee0
Call Trace:
<TASK>
nilfs_dat_commit_free fs/nilfs2/dat.c:114 [inline]
nilfs_dat_commit_end+0x464/0x5f0 fs/nilfs2/dat.c:193
nilfs_dat_commit_update+0x26/0x40 fs/nilfs2/dat.c:236
nilfs_btree_commit_update_v+0x87/0x4a0 fs/nilfs2/btree.c:1940
nilfs_btree_commit_propagate_v fs/nilfs2/btree.c:2016 [inline]
nilfs_btree_propagate_v fs/nilfs2/btree.c:2046 [inline]
nilfs_btree_propagate+0xa00/0xd60 fs/nilfs2/btree.c:2088
nilfs_bmap_propagate+0x73/0x170 fs/nilfs2/bmap.c:337
nilfs_collect_file_data+0x45/0xd0 fs/nilfs2/segment.c:568
nilfs_segctor_apply_buffers+0x14a/0x470 fs/nilfs2/segment.c:1018
nilfs_segctor_scan_file+0x3f4/0x6f0 fs/nilfs2/segment.c:1067
nilfs_segctor_collect_blocks fs/nilfs2/segment.c:1197 [inline]
nilfs_segctor_collect fs/nilfs2/segment.c:1503 [inline]
nilfs_segctor_do_construct+0x12fc/0x6af0 fs/nilfs2/segment.c:2045
nilfs_segctor_construct+0x8e3/0xb30 fs/nilfs2/segment.c:2379
nilfs_segctor_thread_construct fs/nilfs2/segment.c:2487 [inline]
nilfs_segctor_thread+0x3c3/0xf30 fs/nilfs2/segment.c:2570
kthread+0x2e4/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
</TASK>
...
If DAT metadata file is corrupted on disk, there is a case where
req->pr_desc_bh is NULL and blocknr is 0 at nilfs_dat_commit_end() during
a b-tree operation that cascadingly updates ancestor nodes of the b-tree,
because nilfs_dat_commit_alloc() for a lower level block can initialize
the blocknr on the same DAT entry between nilfs_dat_prepare_end() and
nilfs_dat_commit_end().
If this happens, nilfs_dat_commit_end() calls nilfs_dat_commit_free()
without valid buffer heads in req->pr_desc_bh and req->pr_bitmap_bh, and
causes the NULL pointer dereference above in
nilfs_palloc_commit_free_entry() function, which leads to a crash.
Fix this by adding a NULL check on req->pr_desc_bh and req->pr_bitmap_bh
before nilfs_palloc_commit_free_entry() in nilfs_dat_commit_free().
This also calls nilfs_error() in that case to notify that there is a fatal
flaw in the filesystem metadata and prevent further operations.
Link: https://lkml.kernel.org/r/00000000000097c20205ebaea3d6@google.com
Link: https://lkml.kernel.org/r/20221114040441.1649940-1-zhangpeng362@huawei.com
Link: https://lkml.kernel.org/r/20221119120542.17204-1-konishi.ryusuke@gmail.com
Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+ebe05ee8e98f755f61d0@syzkaller.appspotmail.com
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mike Kravetz [Mon, 14 Nov 2022 23:55:06 +0000 (15:55 -0800)]
hugetlb: don't delete vma_lock in hugetlb MADV_DONTNEED processing
madvise(MADV_DONTNEED) ends up calling zap_page_range() to clear page
tables associated with the address range. For hugetlb vmas,
zap_page_range will call __unmap_hugepage_range_final. However,
__unmap_hugepage_range_final assumes the passed vma is about to be removed
and deletes the vma_lock to prevent pmd sharing as the vma is on the way
out. In the case of madvise(MADV_DONTNEED) the vma remains, but the
missing vma_lock prevents pmd sharing and could potentially lead to issues
with truncation/fault races.
This issue was originally reported here [1] as a BUG triggered in
page_try_dup_anon_rmap. Prior to the introduction of the hugetlb
vma_lock, __unmap_hugepage_range_final cleared the VM_MAYSHARE flag to
prevent pmd sharing. Subsequent faults on this vma were confused as
VM_MAYSHARE indicates a sharable vma, but was not set so page_mapping was
not set in new pages added to the page table. This resulted in pages that
appeared anonymous in a VM_SHARED vma and triggered the BUG.
Address issue by adding a new zap flag ZAP_FLAG_UNMAP to indicate an unmap
call from unmap_vmas(). This is used to indicate the 'final' unmapping of
a hugetlb vma. When called via MADV_DONTNEED, this flag is not set and
the vm_lock is not deleted.
[1] https://lore.kernel.org/lkml/CAO4mrfdLMXsao9RF4fUE8-Wfde8xmjsKrTNMNC9wjUb6JudD0g@mail.gmail.com/
Link: https://lkml.kernel.org/r/20221114235507.294320-3-mike.kravetz@oracle.com
Fixes:
90e7e7f5ef3f ("mm: enable MADV_DONTNEED for hugetlb mappings")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reported-by: Wei Chen <harperchen1110@gmail.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mike Kravetz [Mon, 14 Nov 2022 23:55:05 +0000 (15:55 -0800)]
madvise: use zap_page_range_single for madvise dontneed
This series addresses the issue first reported in [1], and fully described
in patch 2. Patches 1 and 2 address the user visible issue and are tagged
for stable backports.
While exploring solutions to this issue, related problems with mmu
notification calls were discovered. This is addressed in the patch
"hugetlb: remove duplicate mmu notifications:". Since there are no user
visible effects, this third is not tagged for stable backports.
Previous discussions suggested further cleanup by removing the
routine zap_page_range. This is possible because zap_page_range_single
is now exported, and all callers of zap_page_range pass ranges entirely
within a single vma. This work will be done in a later patch so as not
to distract from this bug fix.
[1] https://lore.kernel.org/lkml/CAO4mrfdLMXsao9RF4fUE8-Wfde8xmjsKrTNMNC9wjUb6JudD0g@mail.gmail.com/
This patch (of 2):
Expose the routine zap_page_range_single to zap a range within a single
vma. The madvise routine madvise_dontneed_single_vma can use this routine
as it explicitly operates on a single vma. Also, update the mmu
notification range in zap_page_range_single to take hugetlb pmd sharing
into account. This is required as MADV_DONTNEED supports hugetlb vmas.
Link: https://lkml.kernel.org/r/20221114235507.294320-1-mike.kravetz@oracle.com
Link: https://lkml.kernel.org/r/20221114235507.294320-2-mike.kravetz@oracle.com
Fixes:
90e7e7f5ef3f ("mm: enable MADV_DONTNEED for hugetlb mappings")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reported-by: Wei Chen <harperchen1110@gmail.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Yang Shi [Tue, 8 Nov 2022 18:43:57 +0000 (10:43 -0800)]
mm: replace VM_WARN_ON to pr_warn if the node is offline with __GFP_THISNODE
Syzbot reported the below splat:
WARNING: CPU: 1 PID: 3646 at include/linux/gfp.h:221 __alloc_pages_node
include/linux/gfp.h:221 [inline]
WARNING: CPU: 1 PID: 3646 at include/linux/gfp.h:221
hpage_collapse_alloc_page mm/khugepaged.c:807 [inline]
WARNING: CPU: 1 PID: 3646 at include/linux/gfp.h:221
alloc_charge_hpage+0x802/0xaa0 mm/khugepaged.c:963
Modules linked in:
CPU: 1 PID: 3646 Comm: syz-executor210 Not tainted
6.1.0-rc1-syzkaller-00454-ga70385240892 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 10/11/2022
RIP: 0010:__alloc_pages_node include/linux/gfp.h:221 [inline]
RIP: 0010:hpage_collapse_alloc_page mm/khugepaged.c:807 [inline]
RIP: 0010:alloc_charge_hpage+0x802/0xaa0 mm/khugepaged.c:963
Code: e5 01 4c 89 ee e8 6e f9 ae ff 4d 85 ed 0f 84 28 fc ff ff e8 70 fc
ae ff 48 8d 6b ff 4c 8d 63 07 e9 16 fc ff ff e8 5e fc ae ff <0f> 0b e9
96 fa ff ff 41 bc 1a 00 00 00 e9 86 fd ff ff e8 47 fc ae
RSP: 0018:
ffffc90003fdf7d8 EFLAGS:
00010293
RAX:
0000000000000000 RBX:
0000000000000000 RCX:
0000000000000000
RDX:
ffff888077f457c0 RSI:
ffffffff81cd8f42 RDI:
0000000000000001
RBP:
ffff888079388c0c R08:
0000000000000001 R09:
0000000000000000
R10:
0000000000000000 R11:
0000000000000000 R12:
0000000000000000
R13:
dffffc0000000000 R14:
0000000000000000 R15:
0000000000000000
FS:
00007f6b48ccf700(0000) GS:
ffff8880b9b00000(0000)
knlGS:
0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0:
0000000080050033
CR2:
00007f6b48a819f0 CR3:
00000000171e7000 CR4:
00000000003506e0
DR0:
0000000000000000 DR1:
0000000000000000 DR2:
0000000000000000
DR3:
0000000000000000 DR6:
00000000fffe0ff0 DR7:
0000000000000400
Call Trace:
<TASK>
collapse_file+0x1ca/0x5780 mm/khugepaged.c:1715
hpage_collapse_scan_file+0xd6c/0x17a0 mm/khugepaged.c:2156
madvise_collapse+0x53a/0xb40 mm/khugepaged.c:2611
madvise_vma_behavior+0xd0a/0x1cc0 mm/madvise.c:1066
madvise_walk_vmas+0x1c7/0x2b0 mm/madvise.c:1240
do_madvise.part.0+0x24a/0x340 mm/madvise.c:1419
do_madvise mm/madvise.c:1432 [inline]
__do_sys_madvise mm/madvise.c:1432 [inline]
__se_sys_madvise mm/madvise.c:1430 [inline]
__x64_sys_madvise+0x113/0x150 mm/madvise.c:1430
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f6b48a4eef9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 15 00 00 90 48 89 f8 48 89
f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01
f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:
00007f6b48ccf318 EFLAGS:
00000246 ORIG_RAX:
000000000000001c
RAX:
ffffffffffffffda RBX:
00007f6b48af0048 RCX:
00007f6b48a4eef9
RDX:
0000000000000019 RSI:
0000000000600003 RDI:
0000000020000000
RBP:
00007f6b48af0040 R08:
0000000000000000 R09:
0000000000000000
R10:
0000000000000000 R11:
0000000000000246 R12:
00007f6b48aa53a4
R13:
00007f6b48bffcbf R14:
00007f6b48ccf400 R15:
0000000000022000
</TASK>
It is because khugepaged allocates pages with __GFP_THISNODE, but the
preferred node is bogus. The previous patch fixed the khugepaged code to
avoid allocating page from non-existing node. But it is still racy
against memory hotremove. There is no synchronization with the memory
hotplug so it is possible that memory gets offline during a longer taking
scanning.
So this warning still seems not quite helpful because:
* There is no guarantee the node is online for __GFP_THISNODE context
for all the callsites.
* Kernel just fails the allocation regardless the warning, and it looks
all callsites handle the allocation failure gracefully.
Although while the warning has helped to identify a buggy code, it is not
safe in general and this warning could panic the system with panic-on-warn
configuration which tends to be used surprisingly often. So replace
VM_WARN_ON to pr_warn(). And the warning will be triggered if
__GFP_NOWARN is set since the allocator would print out warning for such
case if __GFP_NOWARN is not set.
[shy828301@gmail.com: rename nid to this_node and gfp to warn_gfp]
Link: https://lkml.kernel.org/r/20221123193014.153983-1-shy828301@gmail.com
[akpm@linux-foundation.org: fix whitespace]
[akpm@linux-foundation.org: print gfp_mask instead of warn_gfp, per Michel]
Link: https://lkml.kernel.org/r/20221108184357.55614-3-shy828301@gmail.com
Fixes:
7d8faaf15545 ("mm/madvise: introduce MADV_COLLAPSE sync hugepage collapse")
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reported-by: <syzbot+0044b22d177870ee974f@syzkaller.appspotmail.com>
Suggested-by: Michal Hocko <mhocko@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Li Hua [Mon, 21 Nov 2022 03:06:20 +0000 (11:06 +0800)]
test_kprobes: fix implicit declaration error of test_kprobes
If KPROBES_SANITY_TEST and ARCH_CORRECT_STACKTRACE_ON_KRETPROBE is enabled, but
STACKTRACE is not set. Build failed as below:
lib/test_kprobes.c: In function `stacktrace_return_handler':
lib/test_kprobes.c:228:8: error: implicit declaration of function `stack_trace_save'; did you mean `stacktrace_driver'? [-Werror=implicit-function-declaration]
ret = stack_trace_save(stack_buf, STACK_BUF_SIZE, 0);
^~~~~~~~~~~~~~~~
stacktrace_driver
cc1: all warnings being treated as errors
scripts/Makefile.build:250: recipe for target 'lib/test_kprobes.o' failed
make[2]: *** [lib/test_kprobes.o] Error 1
To fix this error, Select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE is enabled.
Link: https://lkml.kernel.org/r/20221121030620.63181-1-hucool.lihua@huawei.com
Fixes:
1f6d3a8f5e39 ("kprobes: Add a test case for stacktrace from kretprobe handler")
Signed-off-by: Li Hua <hucool.lihua@huawei.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Chen Zhongjin [Fri, 18 Nov 2022 06:33:04 +0000 (14:33 +0800)]
nilfs2: fix nilfs_sufile_mark_dirty() not set segment usage as dirty
When extending segments, nilfs_sufile_alloc() is called to get an
unassigned segment, then mark it as dirty to avoid accidentally allocating
the same segment in the future.
But for some special cases such as a corrupted image it can be unreliable.
If such corruption of the dirty state of the segment occurs, nilfs2 may
reallocate a segment that is in use and pick the same segment for writing
twice at the same time.
This will cause the problem reported by syzkaller:
https://syzkaller.appspot.com/bug?id=
c7c4748e11ffcc367cef04f76e02e931833cbd24
This case started with segbuf1.segnum = 3, nextnum = 4 when constructed.
It supposed segment 4 has already been allocated and marked as dirty.
However the dirty state was corrupted and segment 4 usage was not dirty.
For the first time nilfs_segctor_extend_segments() segment 4 was allocated
again, which made segbuf2 and next segbuf3 had same segment 4.
sb_getblk() will get same bh for segbuf2 and segbuf3, and this bh is added
to both buffer lists of two segbuf. It makes the lists broken which
causes NULL pointer dereference.
Fix the problem by setting usage as dirty every time in
nilfs_sufile_mark_dirty(), which is called during constructing current
segment to be written out and before allocating next segment.
[chenzhongjin@huawei.com: add lock protection per Ryusuke]
Link: https://lkml.kernel.org/r/20221121091141.214703-1-chenzhongjin@huawei.com
Link: https://lkml.kernel.org/r/20221118063304.140187-1-chenzhongjin@huawei.com
Fixes:
9ff05123e3bf ("nilfs2: segment constructor")
Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
Reported-by: <syzbot+77e4f0...@syzkaller.appspotmail.com>
Reported-by: Liu Shixin <liushixin2@huawei.com>
Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Aneesh Kumar K.V [Fri, 18 Nov 2022 07:06:03 +0000 (12:36 +0530)]
mm/cgroup/reclaim: fix dirty pages throttling on cgroup v1
balance_dirty_pages doesn't do the required dirty throttling on cgroupv1.
See commit
9badce000e2c ("cgroup, writeback: don't enable cgroup writeback
on traditional hierarchies"). Instead, the kernel depends on writeback
throttling in shrink_folio_list to achieve the same goal. With large
memory systems, the flusher may not be able to writeback quickly enough
such that we will start finding pages in the shrink_folio_list already in
writeback. Hence for cgroupv1 let's do a reclaim throttle after waking up
the flusher.
The below test which used to fail on a 256GB system completes till the the
file system is full with this change.
root@lp2:/sys/fs/cgroup/memory# mkdir test
root@lp2:/sys/fs/cgroup/memory# cd test/
root@lp2:/sys/fs/cgroup/memory/test# echo 120M > memory.limit_in_bytes
root@lp2:/sys/fs/cgroup/memory/test# echo $$ > tasks
root@lp2:/sys/fs/cgroup/memory/test# dd if=/dev/zero of=/home/kvaneesh/test bs=1M
Killed
Link: https://lkml.kernel.org/r/20221118070603.84081-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: zefan li <lizefan.x@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Qi Zheng [Fri, 18 Nov 2022 10:00:11 +0000 (18:00 +0800)]
mm: fix unexpected changes to {failslab|fail_page_alloc}.attr
When we specify __GFP_NOWARN, we only expect that no warnings will be
issued for current caller. But in the __should_failslab() and
__should_fail_alloc_page(), the local GFP flags alter the global
{failslab|fail_page_alloc}.attr, which is persistent and shared by all
tasks. This is not what we expected, let's fix it.
[akpm@linux-foundation.org: unexport should_fail_ex()]
Link: https://lkml.kernel.org/r/20221118100011.2634-1-zhengqi.arch@bytedance.com
Fixes:
3f913fc5f974 ("mm: fix missing handler for __GFP_NOWARN")
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Akinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Chen Wandun [Fri, 18 Nov 2022 13:38:50 +0000 (21:38 +0800)]
swapfile: fix soft lockup in scan_swap_map_slots
A softlockup occurs in scan free swap slot under huge memory pressure.
The test scenario is: 64 CPU cores, 64GB memory, and 28 zram devices, the
disksize of each zram device is 50MB.
LATENCY_LIMIT is used to prevent softlockups in scan_swap_map_slots(), but
the real loop number would more than LATENCY_LIMIT because of "goto checks
and goto scan" repeatly without decreasing latency limit.
In order to fix it, decrease latency_ration in advance.
There is also a suspicious place that will cause softlockups in
get_swap_pages(). In this function, the "goto start_over" may result in
continuous scanning of the swap partition. If there is no cond_sched in
scan_swap_map_slots(), it would cause a softlockup (I am not sure about
this).
WARN: soft lockup - CPU#11 stuck for 11s! [kswapd0:466]
CPU: 11 PID: 466 Comm: kswapd@ Kdump: loaded Tainted: G
dump backtrace+0x0/0x1le4
show stack+0x20/@x2c
dump_stack+0xd8/0x140
watchdog print_info+0x48/0x54
watchdog_process_before_softlockup+0x98/0xa0
watchdog_timer_fn+0xlac/0x2d0
hrtimer_rum_queues+0xb0/0x130
hrtimer_interrupt+0x13c/0x3c0
arch_timer_handler_virt+0x3c/0x50
handLe_percpu_devid_irq+0x90/0x1f4
handle domain irq+0x84/0x100
gic_handle_irq+0x88/0x2b0
e11 ira+0xhB/Bx140
scan_swap_map_slots+0x678/0x890
get_swap_pages+0x29c/0x440
get_swap_page+0x120/0x2e0
add_to_swap+UX2U/0XyC
shrink_page_list+0x5d0/0x152c
shrink_inactive_list+0xl6c/Bx500
shrink_lruvec+0x270/0x304
WARN: soft lockup - CPU#32 stuck for 11s! [stress-ng:309915]
watchdog_timer_fn+0x1ac/0x2d0
__run_hrtimer+0x98/0x2a0
__hrtimer_run_queues+0xb0/0x130
hrtimer_interrupt+0x13c/0x3c0
arch_timer_handler_virt+0x3c/0x50
handle_percpu_devid_irq+0x90/0x1f4
__handle_domain_irq+0x84/0x100
gic_handle_irq+0x88/0x2b0
el1_irq+0xb8/0x140
get_swap_pages+0x1e8/0x440
get_swap_page+0x1c8/0x2e0
add_to_swap+0x20/0x9c
shrink_page_list+0x5d0/0x152c
reclaim_pages+0x160/0x310
madvise_cold_or_pageout_pte_range+0x7bc/0xe3c
walk_pmd_range.isra.0+0xac/0x22c
walk_pud_range+0xfc/0x1c0
walk_pgd_range+0x158/0x1b0
__walk_page_range+0x64/0x100
walk_page_range+0x104/0x150
Link: https://lkml.kernel.org/r/20221118133850.3360369-1-chenwandun@huawei.com
Fixes:
048c27fd7281 ("[PATCH] swap: scan_swap_map latency breaks")
Signed-off-by: Chen Wandun <chenwandun@huawei.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: <xialonglong1@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mike Kravetz [Fri, 18 Nov 2022 19:52:49 +0000 (11:52 -0800)]
hugetlb: fix __prep_compound_gigantic_page page flag setting
Commit
2b21624fc232 ("hugetlb: freeze allocated pages before creating
hugetlb pages") changed the order page flags were cleared and set in the
head page. It moved the __ClearPageReserved after __SetPageHead.
However, there is a check to make sure __ClearPageReserved is never done
on a head page. If CONFIG_DEBUG_VM_PGFLAGS is enabled, the following BUG
will be hit when creating a hugetlb gigantic page:
page dumped because: VM_BUG_ON_PAGE(1 && PageCompound(page))
------------[ cut here ]------------
kernel BUG at include/linux/page-flags.h:500!
Call Trace will differ depending on whether hugetlb page is created
at boot time or run time.
Make sure to __ClearPageReserved BEFORE __SetPageHead.
Link: https://lkml.kernel.org/r/20221118195249.178319-1-mike.kravetz@oracle.com
Fixes:
2b21624fc232 ("hugetlb: freeze allocated pages before creating hugetlb pages")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Tested-by: Tarun Sahu <tsahu@linux.ibm.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Marco Elver [Fri, 18 Nov 2022 15:22:16 +0000 (16:22 +0100)]
kfence: fix stack trace pruning
Commit
b14051352465 ("mm/sl[au]b: generalize kmalloc subsystem")
refactored large parts of the kmalloc subsystem, resulting in the stack
trace pruning logic done by KFENCE to no longer work.
While
b14051352465 attempted to fix the situation by including
'__kmem_cache_free' in the list of functions KFENCE should skip through,
this only works when the compiler actually optimized the tail call from
kfree() to __kmem_cache_free() into a jump (and thus kfree() _not_
appearing in the full stack trace to begin with).
In some configurations, the compiler no longer optimizes the tail call
into a jump, and __kmem_cache_free() appears in the stack trace. This
means that the pruned stack trace shown by KFENCE would include kfree()
which is not intended - for example:
| BUG: KFENCE: invalid free in kfree+0x7c/0x120
|
| Invalid free of 0xffff8883ed8fefe0 (in kfence-#126):
| kfree+0x7c/0x120
| test_double_free+0x116/0x1a9
| kunit_try_run_case+0x90/0xd0
| [...]
Fix it by moving __kmem_cache_free() to the list of functions that may be
tail called by an allocator entry function, making the pruning logic work
in both the optimized and unoptimized tail call cases.
Link: https://lkml.kernel.org/r/20221118152216.3914899-1-elver@google.com
Fixes:
b14051352465 ("mm/sl[au]b: generalize kmalloc subsystem")
Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Feng Tang <feng.tang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Yosry Ahmed [Thu, 17 Nov 2022 04:32:47 +0000 (04:32 +0000)]
proc/meminfo: fix spacing in SecPageTables
SecPageTables has a tab after it instead of a space, this can break
fragile parsers that depend on spaces after the stat names.
Link: https://lkml.kernel.org/r/20221117043247.133294-1-yosryahmed@google.com
Fixes:
ebc97a52b5d6cd5f ("mm: add NR_SECONDARY_PAGETABLE to count secondary page table uses.")
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Sean Christopherson <seanjc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Yu Zhao [Wed, 16 Nov 2022 01:38:07 +0000 (18:38 -0700)]
mm: multi-gen LRU: retry folios written back while isolated
The page reclaim isolates a batch of folios from the tail of one of the
LRU lists and works on those folios one by one. For a suitable
swap-backed folio, if the swap device is async, it queues that folio for
writeback. After the page reclaim finishes an entire batch, it puts back
the folios it queued for writeback to the head of the original LRU list.
In the meantime, the page writeback flushes the queued folios also by
batches. Its batching logic is independent from that of the page reclaim.
For each of the folios it writes back, the page writeback calls
folio_rotate_reclaimable() which tries to rotate a folio to the tail.
folio_rotate_reclaimable() only works for a folio after the page reclaim
has put it back. If an async swap device is fast enough, the page
writeback can finish with that folio while the page reclaim is still
working on the rest of the batch containing it. In this case, that folio
will remain at the head and the page reclaim will not retry it before
reaching there.
This patch adds a retry to evict_folios(). After evict_folios() has
finished an entire batch and before it puts back folios it cannot free
immediately, it retries those that may have missed the rotation.
Before this patch, ~60% of folios swapped to an Intel Optane missed
folio_rotate_reclaimable(). After this patch, ~99% of missed folios were
reclaimed upon retry.
This problem affects relatively slow async swap devices like Samsung 980
Pro much less and does not affect sync swap devices like zram or zswap at
all.
Link: https://lkml.kernel.org/r/20221116013808.3995280-1-yuzhao@google.com
Fixes:
ac35a4902374 ("mm: multi-gen LRU: minimal implementation")
Signed-off-by: Yu Zhao <yuzhao@google.com>
Cc: "Yin, Fengwei" <fengwei.yin@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Satya Priya [Wed, 16 Nov 2022 10:50:17 +0000 (16:20 +0530)]
mailmap: update email address for Satya Priya
Add and also update email address, skakit@codeaurora.org is no longer
active.
Link: https://lkml.kernel.org/r/20221116105017.3018971-1-quic_c_skakit@quicinc.com
Signed-off-by: Satya Priya <quic_c_skakit@quicinc.com>
Cc: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Alistair Popple [Fri, 11 Nov 2022 00:51:35 +0000 (11:51 +1100)]
mm/migrate_device: return number of migrating pages in args->cpages
migrate_vma->cpages originally contained a count of the number of pages
migrating including non-present pages which can be populated directly on
the target.
Commit
241f68859656 ("mm/migrate_device.c: refactor migrate_vma and
migrate_device_coherent_page()") inadvertantly changed this to contain
just the number of pages that were unmapped. Usage of migrate_vma->cpages
isn't documented, but most drivers use it to see if all the requested
addresses can be migrated so restore the original behaviour.
Link: https://lkml.kernel.org/r/20221111005135.1344004-1-apopple@nvidia.com
Fixes:
241f68859656 ("mm/migrate_device.c: refactor migrate_vma and migrate_deivce_coherent_page()")
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reported-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Alex Sierra <alex.sierra@amd.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sam James [Wed, 16 Nov 2022 18:26:34 +0000 (18:26 +0000)]
kbuild: fix -Wimplicit-function-declaration in license_is_gpl_compatible
Add missing <linux/string.h> include for strcmp.
Clang 16 makes -Wimplicit-function-declaration an error by default.
Unfortunately, out of tree modules may use this in configure scripts,
which means failure might cause silent miscompilation or misconfiguration.
For more information, see LWN.net [0] or LLVM's Discourse [1], gentoo-dev@ [2],
or the (new) c-std-porting mailing list [3].
[0] https://lwn.net/Articles/913505/
[1] https://discourse.llvm.org/t/configure-script-breakage-with-the-new-werror-implicit-function-declaration/65213
[2] https://archives.gentoo.org/gentoo-dev/message/
dd9f2d3082b8b6f8dfbccb0639e6e240
[3] hosted at lists.linux.dev.
[akpm@linux-foundation.org: remember "linux/"]
Link: https://lkml.kernel.org/r/20221116182634.2823136-1-sam@gentoo.org
Signed-off-by: Sam James <sam@gentoo.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Alex Hung [Mon, 14 Nov 2022 00:13:02 +0000 (17:13 -0700)]
MAINTAINERS: update Alex Hung's email address
Use my personal email address.
Link: https://lkml.kernel.org/r/20221114001302.671897-2-alex.hung@amd.com
Signed-off-by: Alex Hung <alexhung@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Alex Hung [Mon, 14 Nov 2022 00:13:01 +0000 (17:13 -0700)]
mailmap: update Alex Hung's email address
I am no longer at Canonical and add entry of my personal email address.
Link: https://lkml.kernel.org/r/20221114001302.671897-1-alex.hung@amd.com
Signed-off-by: Alex Hung <alexhung@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>