Lorenzo Stoakes [Wed, 22 Mar 2023 18:57:03 +0000 (18:57 +0000)]
iov_iter: add copy_page_to_iter_nofault()
Provide a means to copy a page to user space from an iterator, aborting if
a page fault would occur. This supports compound pages, but may be passed
a tail page with an offset extending further into the compound page, so we
cannot pass a folio.
This allows for this function to be called from atomic context and _try_
to user pages if they are faulted in, aborting if not.
The function does not use _copy_to_iter() in order to not specify
might_fault(), this is similar to copy_page_from_iter_atomic().
This is being added in order that an iteratable form of vread() can be
implemented while holding spinlocks.
Link: https://lkml.kernel.org/r/19734729defb0f498a76bdec1bef3ac48a3af3e8.1679511146.git.lstoakes@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Liu Shixin <liushixin2@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Wed, 22 Mar 2023 18:57:02 +0000 (18:57 +0000)]
fs/proc/kcore: convert read_kcore() to read_kcore_iter()
For the time being we still use a bounce buffer for vread(), however in
the next patch we will convert this to interact directly with the iterator
and eliminate the bounce buffer altogether.
Link: https://lkml.kernel.org/r/ebe12c8d70eebd71f487d80095605f3ad0d1489c.1679511146.git.lstoakes@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Liu Shixin <liushixin2@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Wed, 22 Mar 2023 18:57:01 +0000 (18:57 +0000)]
fs/proc/kcore: avoid bounce buffer for ktext data
Patch series "convert read_kcore(), vread() to use iterators", v8.
While reviewing Baoquan's recent changes to permit vread() access to
vm_map_ram regions of vmalloc allocations, Willy pointed out [1] that it
would be nice to refactor vread() as a whole, since its only user is
read_kcore() and the existing form of vread() necessitates the use of a
bounce buffer.
This patch series does exactly that, as well as adjusting how we read the
kernel text section to avoid the use of a bounce buffer in this case as
well.
This has been tested against the test case which motivated Baoquan's
changes in the first place [2] which continues to function correctly, as
do the vmalloc self tests.
This patch (of 4):
Commit
df04abfd181a ("fs/proc/kcore.c: Add bounce buffer for ktext data")
introduced the use of a bounce buffer to retrieve kernel text data for
/proc/kcore in order to avoid failures arising from hardened user copies
enabled by CONFIG_HARDENED_USERCOPY in check_kernel_text_object().
We can avoid doing this if instead of copy_to_user() we use
_copy_to_user() which bypasses the hardening check. This is more
efficient than using a bounce buffer and simplifies the code.
We do so as part an overall effort to eliminate bounce buffer usage in the
function with an eye to converting it an iterator read.
Link: https://lkml.kernel.org/r/cover.1679566220.git.lstoakes@gmail.com
Link: https://lore.kernel.org/all/Y8WfDSRkc%2FOHP3oD@casper.infradead.org/
Link: https://lore.kernel.org/all/87ilk6gos2.fsf@oracle.com/T/#u
Link: https://lkml.kernel.org/r/fd39b0bfa7edc76d360def7d034baaee71d90158.1679511146.git.lstoakes@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Liu Shixin <liushixin2@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kirill A. Shutemov [Tue, 21 Mar 2023 00:24:15 +0000 (03:24 +0300)]
mm/page_alloc: make deferred page init free pages in MAX_ORDER blocks
Normal page init path frees pages during the boot in MAX_ORDER chunks, but
deferred page init path does it in pageblock blocks.
Change deferred page init path to work in MAX_ORDER blocks.
For cases when MAX_ORDER is larger than pageblock, set migrate type to
MIGRATE_MOVABLE for all pageblocks covered by the page.
Link: https://lkml.kernel.org/r/20230321002415.20843-1-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Sun, 12 Mar 2023 23:40:15 +0000 (23:40 +0000)]
drm/ttm: remove comment referencing now-removed vmf_insert_mixed_prot()
This function no longer exists, however the prot != vma->vm_page_prot case
discussion has been retained and moved to vmf_insert_pfn_prot() so refer
to this instead.
Link: https://lkml.kernel.org/r/db403b3622b94a87bd93528cc1d6b44ae88adcdd.1678661628.git.lstoakes@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Aaron Tomlin <atomlin@atomlin.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: "Russell King (Oracle)" <linux@armlinux.org.uk>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Sun, 12 Mar 2023 23:40:14 +0000 (23:40 +0000)]
mm: remove vmf_insert_pfn_xxx_prot() for huge page-table entries
This functionality's sole user, the drm ttm module, removed support for it
in commit
0d979509539e ("drm/ttm: remove ttm_bo_vm_insert_huge()") as the
whole approach is currently unworkable without a PMD/PUD special bit and
updates to GUP.
Link: https://lkml.kernel.org/r/604c2ad79659d4b8a6e3e1611c6219d5d3233988.1678661628.git.lstoakes@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Aaron Tomlin <atomlin@atomlin.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: "Russell King (Oracle)" <linux@armlinux.org.uk>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Sun, 12 Mar 2023 23:40:13 +0000 (23:40 +0000)]
mm: remove unused vmf_insert_mixed_prot()
Patch series "Remove drm/ttm-specific mm changes".
Functionality was added specifically for the DRM TTM driver to support
mapping memory for VM_MIXEDMAP VMAs with customised protection flags,
however this has now been rolled back as issues were found with this
approach.
This series removes the mm changes too, retaining some of the useful
comments.
This patch (of 3):
The sole user of vmf_insert_mixed_prot(), the drm ttm module, stopped
using this in commit
f91142c62161 ("drm/ttm: nuke VM_MIXEDMAP on BO
mappings v3") citing use of VM_MIXEDMAP in this case being terribly
broken.
Remove this now-dead code and references to it, but retain the useful
description of the prot != vma->vm_page_prot case, moving it to
vmf_insert_pfn_prot() instead.
Link: https://lkml.kernel.org/r/cover.1678661628.git.lstoakes@gmail.com
Link: https://lkml.kernel.org/r/a069644388e6f1593a7020d15840e6fc9f39bcaf.1678661628.git.lstoakes@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Aaron Tomlin <atomlin@atomlin.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: "Russell King (Oracle)" <linux@armlinux.org.uk>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tomas Mudrunka [Tue, 21 Mar 2023 10:34:30 +0000 (11:34 +0100)]
mm/memtest: add results of early memtest to /proc/meminfo
Currently the memtest results were only presented in dmesg.
When running a large fleet of devices without ECC RAM it's currently not
easy to do bulk monitoring for memory corruption. You have to parse
dmesg, but that's a ring buffer so the error might disappear after some
time. In general I do not consider dmesg to be a great API to query RAM
status.
In several companies I've seen such errors remain undetected and cause
issues for way too long. So I think it makes sense to provide a
monitoring API, so that we can safely detect and act upon them.
This adds /proc/meminfo entry which can be easily used by scripts.
Link: https://lkml.kernel.org/r/20230321103430.7130-1-tomas.mudrunka@gmail.com
Signed-off-by: Tomas Mudrunka <tomas.mudrunka@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mike Rapoport (IBM) [Tue, 21 Mar 2023 17:05:13 +0000 (19:05 +0200)]
MAINTAINERS: extend memblock entry to include MM initialization
and add mm/mm_init.c to memblock entry in MAINTAINERS
Link: https://lkml.kernel.org/r/20230321170513.2401534-15-rppt@kernel.org
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Doug Berger <opendmb@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mike Rapoport (IBM) [Tue, 21 Mar 2023 17:05:12 +0000 (19:05 +0200)]
mm: move vmalloc_init() declaration to mm/internal.h
vmalloc_init() is called only from mm_core_init(), there is no need to
declare it in include/linux/vmalloc.h
Move vmalloc_init() declaration to mm/internal.h
Link: https://lkml.kernel.org/r/20230321170513.2401534-14-rppt@kernel.org
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Doug Berger <opendmb@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mike Rapoport (IBM) [Tue, 21 Mar 2023 17:05:11 +0000 (19:05 +0200)]
mm: move kmem_cache_init() declaration to mm/slab.h
kmem_cache_init() is called only from mm_core_init(), there is no need to
declare it in include/linux/slab.h
Move kmem_cache_init() declaration to mm/slab.h
Link: https://lkml.kernel.org/r/20230321170513.2401534-13-rppt@kernel.org
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Doug Berger <opendmb@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mike Rapoport (IBM) [Tue, 21 Mar 2023 17:05:10 +0000 (19:05 +0200)]
mm: move mem_init_print_info() to mm_init.c
mem_init_print_info() is only called from mm_core_init().
Move it close to the caller and make it static.
Link: https://lkml.kernel.org/r/20230321170513.2401534-12-rppt@kernel.org
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Doug Berger <opendmb@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mike Rapoport (IBM) [Tue, 21 Mar 2023 17:05:09 +0000 (19:05 +0200)]
init,mm: fold late call to page_ext_init() to page_alloc_init_late()
When deferred initialization of struct pages is enabled, page_ext_init()
must be called after all the deferred initialization is done, but there is
no point to keep it a separate call from kernel_init_freeable() right
after page_alloc_init_late().
Fold the call to page_ext_init() into page_alloc_init_late() and localize
deferred_struct_pages variable.
Link: https://lkml.kernel.org/r/20230321170513.2401534-11-rppt@kernel.org
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Doug Berger <opendmb@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mike Rapoport (IBM) [Tue, 21 Mar 2023 17:05:08 +0000 (19:05 +0200)]
mm: move init_mem_debugging_and_hardening() to mm/mm_init.c
init_mem_debugging_and_hardening() is only called from mm_core_init().
Move it close to the caller, make it static and rename it to
mem_debugging_and_hardening_init() for consistency with surrounding
convention.
Link: https://lkml.kernel.org/r/20230321170513.2401534-10-rppt@kernel.org
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Doug Berger <opendmb@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mike Rapoport (IBM) [Tue, 21 Mar 2023 17:05:07 +0000 (19:05 +0200)]
mm: call {ptlock,pgtable}_cache_init() directly from mm_core_init()
and drop pgtable_init() as it has no real value and its name is
misleading.
Link: https://lkml.kernel.org/r/20230321170513.2401534-9-rppt@kernel.org
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Doug Berger <opendmb@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Sergei Shtylyov <sergei.shtylyov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mike Rapoport (IBM) [Tue, 21 Mar 2023 17:05:06 +0000 (19:05 +0200)]
init,mm: move mm_init() to mm/mm_init.c and rename it to mm_core_init()
Make mm_init() a part of mm/ codebase. mm_core_init() better describes
what the function does and does not clash with mm_init() in kernel/fork.c
Link: https://lkml.kernel.org/r/20230321170513.2401534-8-rppt@kernel.org
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Doug Berger <opendmb@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mike Rapoport (IBM) [Tue, 21 Mar 2023 17:05:05 +0000 (19:05 +0200)]
init: fold build_all_zonelists() and page_alloc_init_cpuhp() to mm_init()
Both build_all_zonelists() and page_alloc_init_cpuhp() must be called
after SMP setup is complete but before the page allocator is set up.
Still, they both are a part of memory management initialization, so move
them to mm_init().
Link: https://lkml.kernel.org/r/20230321170513.2401534-7-rppt@kernel.org
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Doug Berger <opendmb@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mike Rapoport (IBM) [Tue, 21 Mar 2023 17:05:04 +0000 (19:05 +0200)]
mm/page_alloc: rename page_alloc_init() to page_alloc_init_cpuhp()
The page_alloc_init() name is really misleading because all this function
does is sets up CPU hotplug callbacks for the page allocator.
Rename it to page_alloc_init_cpuhp() so that name will reflect what the
function does.
Link: https://lkml.kernel.org/r/20230321170513.2401534-6-rppt@kernel.org
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Doug Berger <opendmb@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mike Rapoport (IBM) [Tue, 21 Mar 2023 17:05:03 +0000 (19:05 +0200)]
mm: handle hashdist initialization in mm/mm_init.c
The hashdist variable must be initialized before the first call to
alloc_large_system_hash() and free_area_init() looks like a better place
for it than page_alloc_init().
Move hashdist handling to mm/mm_init.c
Link: https://lkml.kernel.org/r/20230321170513.2401534-5-rppt@kernel.org
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Doug Berger <opendmb@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mike Rapoport (IBM) [Tue, 21 Mar 2023 17:05:02 +0000 (19:05 +0200)]
mm: move most of core MM initialization to mm/mm_init.c
The bulk of memory management initialization code is spread all over
mm/page_alloc.c and makes navigating through page allocator functionality
difficult.
Move most of the functions marked __init and __meminit to mm/mm_init.c to
make it better localized and allow some more spare room before
mm/page_alloc.c reaches 10k lines.
No functional changes.
Link: https://lkml.kernel.org/r/20230321170513.2401534-4-rppt@kernel.org
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Doug Berger <opendmb@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mike Rapoport (IBM) [Tue, 21 Mar 2023 17:05:01 +0000 (19:05 +0200)]
mm/page_alloc: add helper for checking if check_pages_enabled
Instead of duplicating long static_branch_enabled(&check_pages_enabled)
wrap it in a helper function is_check_pages_enabled()
Link: https://lkml.kernel.org/r/20230321170513.2401534-3-rppt@kernel.org
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Doug Berger <opendmb@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mike Rapoport (IBM) [Tue, 21 Mar 2023 17:05:00 +0000 (19:05 +0200)]
mips: fix comment about pgtable_init()
Patch series "mm: move core MM initialization to mm/mm_init.c", v2.
This set moves most of the core MM initialization to mm/mm_init.c.
This largely includes free_area_init() and its helpers, functions used at
boot time, mm_init() from init/main.c and some of the functions it calls.
Aside from gaining some more space before mm/page_alloc.c hits 10k lines,
this makes mm/page_alloc.c to be mostly about buddy allocator and moves
the init code out of the way, which IMO improves maintainability.
Besides, this allows to move a couple of declarations out of include/linux
and make them private to mm/.
And as an added bonus there a slight decrease in vmlinux size. For
tinyconfig and defconfig on x86 I've got
tinyconfig:
text data bss dec hex filename
853206 289376 1200128 2342710 23bf36 a/vmlinux
853198 289344 1200128 2342670 23bf0e b/vmlinux
defconfig:
text data bss dec hex filename
26152959 9730634 2170884
38054477 244aa4d a/vmlinux
26152945 9730602 2170884
38054431 244aa1f b/vmlinux
This patch (of 14):
Comment about fixrange_init() says that its called from pgtable_init()
while the actual caller is pagetabe_init().
Update comment to match the code.
Link: https://lkml.kernel.org/r/20230321170513.2401534-1-rppt@kernel.org
Link: https://lkml.kernel.org/r/20230321170513.2401534-2-rppt@kernel.org
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Philippe Mathieu-Daud <philmd@linaro.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Doug Berger <opendmb@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Tue, 21 Mar 2023 18:09:55 +0000 (18:09 +0000)]
MAINTAINERS: add Lorenzo as vmalloc reviewer
I have recently been involved in both reviewing and submitting patches to
the vmalloc code in mm and would be willing and happy to help out with
review going forward if it would be helpful!
Link: https://lkml.kernel.org/r/55f663af6100c84a71a0065ac0ed22463aa340de.1679421959.git.lstoakes@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Acked-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mike Rapoport (IBM) [Sun, 19 Mar 2023 11:42:14 +0000 (13:42 +0200)]
mm: move get_page_from_free_area() to mm/page_alloc.c
The get_page_from_free_area() helper is only used in mm/page_alloc.c so
move it there to reduce noise in include/linux/mmzone.h
Link: https://lkml.kernel.org/r/20230319114214.2133332-1-rppt@kernel.org
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Fri, 17 Mar 2023 21:58:26 +0000 (21:58 +0000)]
mm: prefer fault_around_pages to fault_around_bytes
All use of this value is now at page granularity, so specify the variable
as such too. This simplifies the logic.
We maintain the debugfs entry to ensure that there are no user-visible
changes.
Link: https://lkml.kernel.org/r/4995bad07fe9baa51c786fa0d81819dddfb57654.1679089214.git.lstoakes@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Fri, 17 Mar 2023 21:58:25 +0000 (21:58 +0000)]
mm: refactor do_fault_around()
Patch series "Refactor do_fault_around()"
Refactor do_fault_around() to avoid bitwise tricks and rather difficult to
follow logic. Additionally, prefer fault_around_pages to
fault_around_bytes as the operations are performed at a base page
granularity.
This patch (of 2):
The existing logic is confusing and fails to abstract a number of bitwise
tricks.
Use ALIGN_DOWN() to perform alignment, pte_index() to obtain a PTE index
and represent the address range using PTE offsets, which naturally make it
clear that the operation is intended to occur within only a single PTE and
prevent spanning of more than one page table.
We rely on the fact that fault_around_bytes will always be page-aligned,
at least one page in size, a power of two and that it will not exceed
PAGE_SIZE * PTRS_PER_PTE in size (i.e. the address space mapped by a
PTE). These are all guaranteed by fault_around_bytes_set().
Link: https://lkml.kernel.org/r/cover.1679089214.git.lstoakes@gmail.com
Link: https://lkml.kernel.org/r/d125db1c3665a63b80cea29d56407825482e2262.1679089214.git.lstoakes@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Baolin Wang [Thu, 16 Mar 2023 11:06:47 +0000 (19:06 +0800)]
mm: compaction: fix the possible deadlock when isolating hugetlb pages
When trying to isolate a migratable pageblock, it can contain several
normal pages or several hugetlb pages (e.g. CONT-PTE 64K hugetlb on arm64)
in a pageblock. That means we may hold the lru lock of a normal page to
continue to isolate the next hugetlb page by isolate_or_dissolve_huge_page()
in the same migratable pageblock.
However in the isolate_or_dissolve_huge_page(), it may allocate a new hugetlb
page and dissolve the old one by alloc_and_dissolve_hugetlb_folio() if the
hugetlb's refcount is zero. That means we can still enter the direct compaction
path to allocate a new hugetlb page under the current lru lock, which
may cause possible deadlock.
To avoid this possible deadlock, we should release the lru lock when
trying to isolate a hugetbl page. Moreover it does not make sense to take
the lru lock to isolate a hugetlb, which is not in the lru list.
Link: https://lkml.kernel.org/r/7ab3bffebe59fb419234a68dec1e4572a2518563.1678962352.git.baolin.wang@linux.alibaba.com
Fixes:
369fa227c219 ("mm: make alloc_contig_range handle free hugetlb pages")
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: William Lam <william.lam@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Baolin Wang [Thu, 16 Mar 2023 11:06:46 +0000 (19:06 +0800)]
mm: compaction: consider the number of scanning compound pages in isolate fail path
commit
b717d6b93b54 ("mm: compaction: include compound page count for
scanning in pageblock isolation") added compound page statistics for
scanning in pageblock isolation, to make sure the number of scanned pages
is always larger than the number of isolated pages when isolating
mirgratable or free pageblock.
However, when failing to isolate the pages when scanning the migratable or
free pageblocks, the isolation failure path did not consider the scanning
statistics of the compound pages, which result in showing the incorrect
number of scanned pages in tracepoints or in vmstats which will confuse
people about the page scanning pressure in memory compaction.
Thus we should take into account the number of scanning pages when failing
to isolate the compound pages to make the statistics accurate.
Link: https://lkml.kernel.org/r/73d6250a90707649cc010731aedc27f946d722ed.1678962352.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: William Lam <william.lam@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Vlastimil Babka [Thu, 9 Mar 2023 11:12:58 +0000 (12:12 +0100)]
mm/mremap: simplify vma expansion again
This effectively reverts
d014cd7c1c35 ("mm, mremap: fix mremap() expanding
for vma's with vm_ops->close()"). After the recent changes, vma_merge()
is able to handle the expansion properly even when the vma being expanded
has a vm_ops->close operation, so we don't need to special case it
anymore.
Link: https://lkml.kernel.org/r/20230309111258.24079-11-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Vlastimil Babka [Thu, 9 Mar 2023 11:12:57 +0000 (12:12 +0100)]
mm/mmap: start distinguishing if vma can be removed in mergeability test
Since pre-git times, is_mergeable_vma() returns false for a vma with
vm_ops->close, so that no owner assumptions are violated in case the vma
is removed as part of the merge.
This check is currently very conservative and can prevent merging even
situations where vma can't be removed, such as simple expansion of
previous vma, as evidenced by commit
d014cd7c1c35 ("mm, mremap: fix
mremap() expanding for vma's with vm_ops->close()")
In order to allow more merging when appropriate and simplify the code that
was made more complex by commit
d014cd7c1c35, start distinguishing cases
where the vma can be really removed, and allow merging with vm_ops->close
otherwise.
As a first step, add a may_remove_vma parameter to is_mergeable_vma().
can_vma_merge_before() sets it to true, because when called from
vma_merge(), a removal of the vma is possible.
In can_vma_merge_after(), pass the parameter as false, because no
removal can occur in each of its callers:
- vma_merge() calls it on the 'prev' vma, which is never removed
- mmap_region() and do_brk_flags() call it to determine if it can expand
a vma, which is not removed
As a result, vma's with vm_ops->close may now merge with compatible ranges
in more situations than previously. We can also revert commit
d014cd7c1c35 as the next step to simplify mremap code again.
[vbabka@suse.cz: adjust comment as suggested by Lorenzo]
Link: https://lkml.kernel.org/r/74f2ea6c-f1a9-6dd7-260c-25e660f42379@suse.cz
Link: https://lkml.kernel.org/r/20230309111258.24079-10-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Vlastimil Babka [Thu, 9 Mar 2023 11:12:56 +0000 (12:12 +0100)]
mm/mmap/vma_merge: convert mergeability checks to return bool
The comments already mention returning 'true' so make the code match them.
Link: https://lkml.kernel.org/r/20230309111258.24079-9-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Vlastimil Babka [Thu, 9 Mar 2023 11:12:55 +0000 (12:12 +0100)]
mm/mmap/vma_merge: rename adj_next to adj_start
The variable 'adj_next' holds the value by which we adjust vm_start of a
vma in variable 'adjust', that's either 'next' or 'mid', so the current
name is inaccurate. Rename it to 'adj_start'.
Link: https://lkml.kernel.org/r/20230309111258.24079-8-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Vlastimil Babka [Thu, 9 Mar 2023 11:12:54 +0000 (12:12 +0100)]
mm/mmap/vma_merge: set mid to NULL if not applicable
There are several places where we test if 'mid' is really the area NNNN in
the diagram and the tests have two variants and are non-obvious to follow.
Instead, set 'mid' to NULL up-front if it's not the NNNN area, and
simplify the tests.
Also update the description in comment accordingly.
[vbabka@suse.cz: adjust/add comments as suggested by Lorenzo]
Link: https://lkml.kernel.org/r/def43190-53f7-a607-d1b0-b657565f4288@suse.cz
Link: https://lkml.kernel.org/r/20230309111258.24079-7-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Vlastimil Babka [Thu, 9 Mar 2023 11:12:53 +0000 (12:12 +0100)]
mm/mmap/vma_merge: initialize mid and next in natural order
It is more intuitive to go from prev to mid and then next. No functional
change.
Link: https://lkml.kernel.org/r/20230309111258.24079-6-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Vlastimil Babka [Thu, 9 Mar 2023 11:12:52 +0000 (12:12 +0100)]
mm/mmap/vma_merge: use the proper vma pointer in case 4
Almost all cases now use the 'next' pointer for the vma following the
merged area, and the cases diagram shows it as XXXX. Case 4 is different
as it uses 'mid' and NNNN, so change it for consistency. No functional
change.
Link: https://lkml.kernel.org/r/20230309111258.24079-5-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Vlastimil Babka [Thu, 9 Mar 2023 11:12:51 +0000 (12:12 +0100)]
mm/mmap/vma_merge: use the proper vma pointers in cases 1 and 6
Case 1 is now shown in the comment as next vma being merged with prev, so
use 'next' instead of 'mid'. In case 1 they both point to the same vma.
As a consequence, in case 6, the dup_anon_vma() is now tried first on
'next' and then on 'mid', before it was the opposite order. This is not a
functional change, as those two vma's cannnot have a different anon_vma,
as that would have prevented the merging in the first place.
Link: https://lkml.kernel.org/r/20230309111258.24079-4-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Vlastimil Babka [Thu, 9 Mar 2023 11:12:50 +0000 (12:12 +0100)]
mm/mmap/vma_merge: use the proper vma pointer in case 3
In case 3 we we use 'next' for everything but vma_pgoff. So use 'next'
for that as well, instead of 'mid', for consistency. Then in case 8 we
have to use 'mid' explicitly, which should also make the intent more
obvious.
Adjust the diagram for cases 1-3 in the comment to match the code - we are
using 'next' for case 3 so mark the range with XXXX instead of NNNN. For
case 2 that's a no-op as the code doesn't touch 'next' or 'mid'. For case
1 it's now wrong but that will be fixed next.
No functional change.
Link: https://lkml.kernel.org/r/20230309111258.24079-3-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Vlastimil Babka [Thu, 9 Mar 2023 11:12:49 +0000 (12:12 +0100)]
mm/mmap/vma_merge: use only primary pointers for preparing merge
Patch series "cleanup vma_merge() and improve mergeability tests".
My initial goal here was to try making the check for vm_ops->close in
is_mergeable_vma() only be applied for vma's that would be truly removed
as part of the merge (see Patch 9). This would then allow reverting the
quick fix
d014cd7c1c35 ("mm, mremap: fix mremap() expanding for vma's with
vm_ops->close()"). This was successful enough to allow the revert (Patch
10). Checks using can_vma_merge_before() are still pessimistic about
possible vma removal, and making them precise would probably complicate
the vma_merge() code too much.
Liam's 6.3-rc1 simplification of vma_merge() and removal of __vma_adjust()
was very much helpful in understanding the vma_merge() implementation and
especially when vma removals can happen, which is now very obvious. While
studing the code, I've found ways to make it hopefully even more easy to
follow, so that's the patches 1-8. That made me also notice a bug that's
now already fixed in 6.3-rc1.
This patch (of 10):
In the merging preparation part of vma_merge(), some vma pointer variables
are assigned for later execution of the merge, but also read from in the
block itself. The code is easier follow and check against the cases
diagram in the comment if the code reads only from the "primary" vma
variables prev, mid, next instead. No functional change.
Link: https://lkml.kernel.org/r/20230309111258.24079-1-vbabka@suse.cz
Link: https://lkml.kernel.org/r/20230309111258.24079-2-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>]
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Axel Rasmussen [Tue, 14 Mar 2023 22:12:50 +0000 (15:12 -0700)]
mm: userfaultfd: add UFFDIO_CONTINUE_MODE_WP to install WP PTEs
UFFDIO_COPY already has UFFDIO_COPY_MODE_WP, so when installing a new PTE
to resolve a missing fault, one can install a write-protected one. This
is useful when using UFFDIO_REGISTER_MODE_{MISSING,WP} in combination.
This was motivated by testing HugeTLB HGM [1], and in particular its
interaction with userfaultfd features. Existing userfaultfd code supports
using WP and MINOR modes together (i.e. you can register an area with
both enabled), but without this CONTINUE flag the combination is in
practice unusable.
So, add an analogous UFFDIO_CONTINUE_MODE_WP, which does the same thing as
UFFDIO_COPY_MODE_WP, but for *minor* faults.
Update the selftest to do some very basic exercising of the new flag.
Update Documentation/ to describe how these flags are used (neither the
COPY nor the new CONTINUE versions of this mode flag were described there
before).
[1]: https://patchwork.kernel.org/project/linux-mm/cover/
20230218002819.1486479-1-jthoughton@google.com/
Link: https://lkml.kernel.org/r/20230314221250.682452-5-axelrasmussen@google.com
Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
Acked-by: Peter Xu <peterx@redhat.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nadav Amit <namit@vmware.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Axel Rasmussen [Tue, 14 Mar 2023 22:12:49 +0000 (15:12 -0700)]
mm: userfaultfd: combine 'mode' and 'wp_copy' arguments
Many userfaultfd ioctl functions take both a 'mode' and a 'wp_copy'
argument. In future commits we plan to plumb the flags through to more
places, so we'd be proliferating the very long argument list even further.
Let's take the time to simplify the argument list. Combine the two
arguments into one - and generalize, so when we add more flags in the
future, it doesn't imply more function arguments.
Since the modes (copy, zeropage, continue) are mutually exclusive, store
them as an integer value (0, 1, 2) in the low bits. Place combine-able
flag bits in the high bits.
This is quite similar to an earlier patch proposed by Nadav Amit
("userfaultfd: introduce uffd_flags" [1]). The main difference is that
patch only handled flags, whereas this patch *also* combines the "mode"
argument into the same type to shorten the argument list.
[1]: https://lore.kernel.org/all/
20220619233449.181323-2-namit@vmware.com/
Link: https://lkml.kernel.org/r/20230314221250.682452-4-axelrasmussen@google.com
Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
Acked-by: James Houghton <jthoughton@google.com>
Acked-by: Peter Xu <peterx@redhat.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Axel Rasmussen [Tue, 14 Mar 2023 22:12:48 +0000 (15:12 -0700)]
mm: userfaultfd: don't pass around both mm and vma
Quite a few userfaultfd functions took both mm and vma pointers as
arguments. Since the mm is trivially accessible via vma->vm_mm, there's
no reason to pass both; it just needlessly extends the already long
argument list.
Get rid of the mm pointer, where possible, to shorten the argument list.
Link: https://lkml.kernel.org/r/20230314221250.682452-3-axelrasmussen@google.com
Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
Acked-by: Peter Xu <peterx@redhat.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nadav Amit <namit@vmware.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Axel Rasmussen [Tue, 14 Mar 2023 22:12:47 +0000 (15:12 -0700)]
mm: userfaultfd: rename functions for clarity + consistency
Patch series "mm: userfaultfd: refactor and add UFFDIO_CONTINUE_MODE_WP",
v5.
- Commits 1-3 refactor userfaultfd ioctl code without behavior changes, with the
main goal of improving consistency and reducing the number of function args.
- Commit 4 adds UFFDIO_CONTINUE_MODE_WP.
This patch (of 4):
The basic problem is, over time we've added new userfaultfd ioctls, and
we've refactored the code so functions which used to handle only one case
are now re-used to deal with several cases. While this happened, we
didn't bother to rename the functions.
Similarly, as we added new functions, we cargo-culted pieces of the
now-inconsistent naming scheme, so those functions too ended up with names
that don't make a lot of sense.
A key point here is, "copy" in most userfaultfd code refers specifically
to UFFDIO_COPY, where we allocate a new page and copy its contents from
userspace. There are many functions with "copy" in the name that don't
actually do this (at least in some cases).
So, rename things into a consistent scheme. The high level idea is that
the call stack for userfaultfd ioctls becomes:
userfaultfd_ioctl
-> userfaultfd_(particular ioctl)
-> mfill_atomic_(particular kind of fill operation)
-> mfill_atomic /* loops over pages in range */
-> mfill_atomic_pte /* deals with single pages */
-> mfill_atomic_pte_(particular kind of fill operation)
-> mfill_atomic_install_pte
There are of course some special cases (shmem, hugetlb), but this is the
general structure which all function names now adhere to.
Link: https://lkml.kernel.org/r/20230314221250.682452-1-axelrasmussen@google.com
Link: https://lkml.kernel.org/r/20230314221250.682452-2-axelrasmussen@google.com
Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
Acked-by: Peter Xu <peterx@redhat.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nadav Amit <namit@vmware.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mike Rapoport (IBM) [Wed, 22 Mar 2023 08:15:20 +0000 (10:15 +0200)]
mips: drop ranges for definition of ARCH_FORCE_MAX_ORDER
MIPS defines insane ranges for ARCH_FORCE_MAX_ORDER allowing MAX_ORDER up
to 63, which implies maximal contiguous allocation size of 2^63 pages.
Drop bogus definitions of ranges for ARCH_FORCE_MAX_ORDER and leave it a
simple integer with sensible defaults.
Users that *really* need to change the value of ARCH_FORCE_MAX_ORDER will
be able to do so but they won't be mislead by the bogus ranges.
Link: https://lkml.kernel.org/r/20230322081520.2516226-1-rppt@kernel.org
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mike Rapoport (IBM) [Wed, 22 Mar 2023 08:17:27 +0000 (10:17 +0200)]
loongarch: drop ranges for definition of ARCH_FORCE_MAX_ORDER
LoongArch defines insane ranges for ARCH_FORCE_MAX_ORDER allowing
MAX_ORDER up to 63, which implies maximal contiguous allocation size of
2^63 pages.
Drop bogus definitions of ranges for ARCH_FORCE_MAX_ORDER and leave it a
simple integer with sensible defaults.
Users that *really* need to change the value of ARCH_FORCE_MAX_ORDER will
be able to do so but they won't be mislead by the bogus ranges.
Link: https://lkml.kernel.org/r/20230322081727.2516291-1-rppt@kernel.org
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kirill A. Shutemov [Wed, 15 Mar 2023 11:31:33 +0000 (14:31 +0300)]
mm, treewide: redefine MAX_ORDER sanely
MAX_ORDER currently defined as number of orders page allocator supports:
user can ask buddy allocator for page order between 0 and MAX_ORDER-1.
This definition is counter-intuitive and lead to number of bugs all over
the kernel.
Change the definition of MAX_ORDER to be inclusive: the range of orders
user can ask from buddy allocator is 0..MAX_ORDER now.
[kirill@shutemov.name: fix min() warning]
Link: https://lkml.kernel.org/r/20230315153800.32wib3n5rickolvh@box
[akpm@linux-foundation.org: fix another min_t warning]
[kirill@shutemov.name: fixups per Zi Yan]
Link: https://lkml.kernel.org/r/20230316232144.b7ic4cif4kjiabws@box.shutemov.name
[akpm@linux-foundation.org: fix underlining in docs]
Link: https://lore.kernel.org/oe-kbuild-all/202303191025.VRCTk6mP-lkp@intel.com/
Link: https://lkml.kernel.org/r/20230315113133.11326-11-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc]
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kirill A. Shutemov [Wed, 15 Mar 2023 11:31:32 +0000 (14:31 +0300)]
iommu: fix MAX_ORDER usage in __iommu_dma_alloc_pages()
MAX_ORDER is not inclusive: the maximum allocation order buddy allocator
can deliver is MAX_ORDER-1.
Fix MAX_ORDER usage in __iommu_dma_alloc_pages().
Also use GENMASK() instead of hard to read "(2U << order) - 1" magic.
Link: https://lkml.kernel.org/r/20230315113133.11326-10-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Acked-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kirill A. Shutemov [Wed, 15 Mar 2023 11:31:31 +0000 (14:31 +0300)]
mm/slub: fix MAX_ORDER usage in calculate_order()
MAX_ORDER is not inclusive: the maximum allocation order buddy allocator
can deliver is MAX_ORDER-1.
Fix MAX_ORDER usage in calculate_order().
Link: https://lkml.kernel.org/r/20230315113133.11326-9-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kirill A. Shutemov [Wed, 15 Mar 2023 11:31:30 +0000 (14:31 +0300)]
mm/page_reporting: fix MAX_ORDER usage in page_reporting_register()
MAX_ORDER is not inclusive: the maximum allocation order buddy allocator
can deliver is MAX_ORDER-1.
Fix MAX_ORDER usage in page_reporting_register().
Link: https://lkml.kernel.org/r/20230315113133.11326-8-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kirill A. Shutemov [Wed, 15 Mar 2023 11:31:29 +0000 (14:31 +0300)]
perf/core: fix MAX_ORDER usage in rb_alloc_aux_page()
MAX_ORDER is not inclusive: the maximum allocation order buddy allocator
can deliver is MAX_ORDER-1.
Fix MAX_ORDER usage in rb_alloc_aux_page().
Link: https://lkml.kernel.org/r/20230315113133.11326-7-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kirill A. Shutemov [Wed, 15 Mar 2023 11:31:28 +0000 (14:31 +0300)]
genwqe: fix MAX_ORDER usage
MAX_ORDER is not inclusive: the maximum allocation order buddy allocator
can deliver is MAX_ORDER-1.
Fix MAX_ORDER usage in genwqe driver.
Link: https://lkml.kernel.org/r/20230315113133.11326-6-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Frank Haverkamp <haver@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kirill A. Shutemov [Wed, 15 Mar 2023 11:31:27 +0000 (14:31 +0300)]
drm/i915: fix MAX_ORDER usage in i915_gem_object_get_pages_internal()
MAX_ORDER is not inclusive: the maximum allocation order buddy allocator
can deliver is MAX_ORDER-1.
Fix MAX_ORDER usage in i915_gem_object_get_pages_internal().
Link: https://lkml.kernel.org/r/20230315113133.11326-5-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kirill A. Shutemov [Wed, 15 Mar 2023 11:31:26 +0000 (14:31 +0300)]
floppy: fix MAX_ORDER usage
MAX_ORDER is not inclusive: the maximum allocation order buddy allocator
can deliver is MAX_ORDER-1.
Fix MAX_ORDER usage in floppy code.
Also allocation buffer exactly PAGE_SIZE << MAX_ORDER bytes is okay. Fix
MAX_LEN check.
Link: https://lkml.kernel.org/r/20230315113133.11326-4-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Denis Efremov <efremov@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kirill A. Shutemov [Wed, 15 Mar 2023 11:31:25 +0000 (14:31 +0300)]
um: fix MAX_ORDER usage in linux_main()
MAX_ORDER is not inclusive: the maximum allocation order buddy allocator
can deliver is MAX_ORDER-1.
Fix MAX_ORDER usage in linux_main().
Link: https://lkml.kernel.org/r/20230315113133.11326-3-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kirill A. Shutemov [Wed, 15 Mar 2023 11:31:24 +0000 (14:31 +0300)]
sparc/mm: fix MAX_ORDER usage in tsb_grow()
Patch series "Fix confusion around MAX_ORDER".
MAX_ORDER currently defined as number of orders page allocator supports:
user can ask buddy allocator for page order between 0 and MAX_ORDER-1.
This definition is counter-intuitive and lead to number of bugs all over
the kernel.
Fix the bugs and then change the definition of MAX_ORDER to be
inclusive: the range of orders user can ask from buddy allocator is
0..MAX_ORDER now.
This patch (of 10):
MAX_ORDER is not inclusive: the maximum allocation order buddy allocator
can deliver is MAX_ORDER-1.
Fix MAX_ORDER usage in tsb_grow().
Link: https://lkml.kernel.org/r/20230315113133.11326-1-kirill.shutemov@linux.intel.com
Link: https://lkml.kernel.org/r/20230315113133.11326-2-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: David Miller <davem@davemloft.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Peter Xu [Thu, 9 Mar 2023 22:37:11 +0000 (17:37 -0500)]
selftests/mm: smoke test UFFD_FEATURE_WP_UNPOPULATED
Enable it by default on the stress test, and add some smoke tests for the
pte markers on anonymous.
Link: https://lkml.kernel.org/r/20230309223711.823547-3-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Paul Gofman <pgofman@codeweavers.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Peter Xu [Thu, 9 Mar 2023 22:37:10 +0000 (17:37 -0500)]
mm/uffd: UFFD_FEATURE_WP_UNPOPULATED
Patch series "mm/uffd: Add feature bit UFFD_FEATURE_WP_UNPOPULATED", v4.
The new feature bit makes anonymous memory acts the same as file memory on
userfaultfd-wp in that it'll also wr-protect none ptes.
It can be useful in two cases:
(1) Uffd-wp app that needs to wr-protect none ptes like QEMU snapshot,
so pre-fault can be replaced by enabling this flag and speed up
protections
(2) It helps to implement async uffd-wp mode that Muhammad is working on [1]
It's debatable whether this is the most ideal solution because with the
new feature bit set, wr-protect none pte needs to pre-populate the
pgtables to the last level (PAGE_SIZE). But it seems fine so far to
service either purpose above, so we can leave optimizations for later.
The series brings pte markers to anonymous memory too. There's some
change in the common mm code path in the 1st patch, great to have some eye
looking at it, but hopefully they're still relatively straightforward.
This patch (of 2):
This is a new feature that controls how uffd-wp handles none ptes. When
it's set, the kernel will handle anonymous memory the same way as file
memory, by allowing the user to wr-protect unpopulated ptes.
File memories handles none ptes consistently by allowing wr-protecting of
none ptes because of the unawareness of page cache being exist or not.
For anonymous it was not as persistent because we used to assume that we
don't need protections on none ptes or known zero pages.
One use case of such a feature bit was VM live snapshot, where if without
wr-protecting empty ptes the snapshot can contain random rubbish in the
holes of the anonymous memory, which can cause misbehave of the guest when
the guest OS assumes the pages should be all zeros.
QEMU worked it around by pre-populate the section with reads to fill in
zero page entries before starting the whole snapshot process [1].
Recently there's another need raised on using userfaultfd wr-protect for
detecting dirty pages (to replace soft-dirty in some cases) [2]. In that
case if without being able to wr-protect none ptes by default, the dirty
info can get lost, since we cannot treat every none pte to be dirty (the
current design is identify a page dirty based on uffd-wp bit being
cleared).
In general, we want to be able to wr-protect empty ptes too even for
anonymous.
This patch implements UFFD_FEATURE_WP_UNPOPULATED so that it'll make
uffd-wp handling on none ptes being consistent no matter what the memory
type is underneath. It doesn't have any impact on file memories so far
because we already have pte markers taking care of that. So it only
affects anonymous.
The feature bit is by default off, so the old behavior will be maintained.
Sometimes it may be wanted because the wr-protect of none ptes will
contain overheads not only during UFFDIO_WRITEPROTECT (by applying pte
markers to anonymous), but also on creating the pgtables to store the pte
markers. So there's potentially less chance of using thp on the first
fault for a none pmd or larger than a pmd.
The major implementation part is teaching the whole kernel to understand
pte markers even for anonymously mapped ranges, meanwhile allowing the
UFFDIO_WRITEPROTECT ioctl to apply pte markers for anonymous too when the
new feature bit is set.
Note that even if the patch subject starts with mm/uffd, there're a few
small refactors to major mm path of handling anonymous page faults. But
they should be straightforward.
With WP_UNPOPUATED, application like QEMU can avoid pre-read faults all
the memory before wr-protect during taking a live snapshot. Quotting from
Muhammad's test result here [3] based on a simple program [4]:
(1) With huge page disabled
echo madvise > /sys/kernel/mm/transparent_hugepage/enabled
./uffd_wp_perf
Test DEFAULT: 4
Test PRE-READ: 1111453 (pre-fault 1101011)
Test MADVISE: 278276 (pre-fault 266378)
Test WP-UNPOPULATE: 11712
(2) With Huge page enabled
echo always > /sys/kernel/mm/transparent_hugepage/enabled
./uffd_wp_perf
Test DEFAULT: 4
Test PRE-READ: 22521 (pre-fault 22348)
Test MADVISE: 4909 (pre-fault 4743)
Test WP-UNPOPULATE: 14448
There'll be a great perf boost for no-thp case, while for thp enabled with
extreme case of all-thp-zero WP_UNPOPULATED can be slower than MADVISE,
but that's low possibility in reality, also the overhead was not reduced
but postponed until a follow up write on any huge zero thp, so potentially
it is faster by making the follow up writes slower.
[1] https://lore.kernel.org/all/
20210401092226.102804-4-andrey.gruzdev@virtuozzo.com/
[2] https://lore.kernel.org/all/Y+v2HJ8+3i%2FKzDBu@x1n/
[3] https://lore.kernel.org/all/
d0eb0a13-16dc-1ac1-653a-
78b7273781e3@collabora.com/
[4] https://github.com/xzpeter/clibs/blob/master/uffd-test/uffd-wp-perf.c
[peterx@redhat.com: comment changes, oneliner fix to khugepaged]
Link: https://lkml.kernel.org/r/ZB2/8jPhD3fpx5U8@x1n
Link: https://lkml.kernel.org/r/20230309223711.823547-1-peterx@redhat.com
Link: https://lkml.kernel.org/r/20230309223711.823547-2-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Paul Gofman <pgofman@codeweavers.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Andrey Konovalov [Fri, 10 Mar 2023 23:43:33 +0000 (00:43 +0100)]
kasan: suppress recursive reports for HW_TAGS
KASAN suppresses reports for bad accesses done by the KASAN reporting
code. The reporting code might access poisoned memory for reporting
purposes.
Software KASAN modes do this by suppressing reports during reporting via
current->kasan_depth, the same way they suppress reports during accesses
to poisoned slab metadata.
Hardware Tag-Based KASAN does not use current->kasan_depth, and instead
resets pointer tags for accesses to poisoned memory done by the reporting
code.
Despite that, a recursive report can still happen:
1. On hardware with faulty MTE support. This was observed by Weizhao
Ouyang on a faulty hardware that caused memory tags to randomly change
from time to time.
2. Theoretically, due to a previous MTE-undetected memory corruption.
A recursive report can happen via:
1. Accessing a pointer with a non-reset tag in the reporting code, e.g.
slab->slab_cache, which is what Weizhao Ouyang observed.
2. Theoretically, via external non-annotated routines, e.g. stackdepot.
To resolve this issue, resetting tags for all of the pointers in the
reporting code and all the used external routines would be impractical.
Instead, disable tag checking done by the CPU for the duration of KASAN
reporting for Hardware Tag-Based KASAN.
Without this fix, Hardware Tag-Based KASAN reporting code might deadlock.
[andreyknvl@google.com: disable preemption instead of migration, fix comment typo]
Link: https://lkml.kernel.org/r/d14417c8bc5eea7589e99381203432f15c0f9138.1680114854.git.andreyknvl@google.com
Link: https://lkml.kernel.org/r/59f433e00f7fa985e8bf9f7caf78574db16b67ab.1678491668.git.andreyknvl@google.com
Fixes:
2e903b914797 ("kasan, arm64: implement HW_TAGS runtime")
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reported-by: Weizhao Ouyang <ouyangweizhao@zeku.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Andrey Konovalov [Fri, 10 Mar 2023 23:43:32 +0000 (00:43 +0100)]
kasan, arm64: add arch_suppress_tag_checks_start/stop
Add two new tagging-related routines arch_suppress_tag_checks_start/stop
that suppress MTE tag checking via the TCO register.
These rouines are used in the next patch.
[andreyknvl@google.com: drop __ from mte_disable/enable_tco names]
Link: https://lkml.kernel.org/r/7ad5e5a9db79e3aba08d8f43aca24350b04080f6.1680114854.git.andreyknvl@google.com
Link: https://lkml.kernel.org/r/75a362551c3c54b70ae59a3492cabb51c105fa6b.1678491668.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Weizhao Ouyang <ouyangweizhao@zeku.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Vincenzo Frascino [Fri, 10 Mar 2023 23:43:31 +0000 (00:43 +0100)]
arm64: mte: rename TCO routines
The TCO related routines are used in uaccess methods and
load_unaligned_zeropad() but are unrelated to both even if the naming
suggest otherwise.
Improve the readability of the code moving the away from uaccess.h and
pre-pending them with "mte".
[andreyknvl@google.com: drop __ from mte_disable/enable_tco names]
Link: https://lkml.kernel.org/r/74d26337b2360733956114069e96ff11c296a944.1680114854.git.andreyknvl@google.com
Link: https://lkml.kernel.org/r/a48e7adce1248c0f9603a457776d59daa0ef734b.1678491668.git.andreyknvl@google.com
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Weizhao Ouyang <ouyangweizhao@zeku.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Andrey Konovalov [Fri, 10 Mar 2023 23:43:30 +0000 (00:43 +0100)]
kasan, arm64: rename tagging-related routines
Rename arch_enable_tagging_sync/async/asymm to
arch_enable_tag_checks_sync/async/asymm, as the new name better reflects
their function.
Also rename kasan_enable_tagging to kasan_enable_hw_tags for the same
reason.
Link: https://lkml.kernel.org/r/069ef5b77715c1ac8d69b186725576c32b149491.1678491668.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Weizhao Ouyang <ouyangweizhao@zeku.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Andrey Konovalov [Fri, 10 Mar 2023 23:43:29 +0000 (00:43 +0100)]
kasan: drop empty tagging-related defines
mm/kasan/kasan.h provides a number of empty defines for a few
arch-specific tagging-related routines, in case the architecture code
didn't define them.
The original idea was to simplify integration in case another architecture
starts supporting memory tagging. However, right now, if any of those
routines are not provided by an architecture, Hardware Tag-Based KASAN
won't work.
Drop the empty defines, as it would be better to get compiler errors
rather than runtime crashes when adding support for a new architecture.
Also drop empty hw_enable_tagging_sync/async/asymm defines for
!CONFIG_KASAN_HW_TAGS case, as those are only used in mm/kasan/hw_tags.c.
Link: https://lkml.kernel.org/r/bc919c144f8684a7fd9ba70c356ac2a75e775e29.1678491668.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com> [arm64]
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Weizhao Ouyang <ouyangweizhao@zeku.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Christoph Hellwig [Tue, 7 Mar 2023 14:34:10 +0000 (15:34 +0100)]
mm: return an ERR_PTR from __filemap_get_folio
Instead of returning NULL for all errors, distinguish between:
- no entry found and not asked to allocated (-ENOENT)
- failed to allocate memory (-ENOMEM)
- would block (-EAGAIN)
so that callers don't have to guess the error based on the passed in
flags.
Also pass through the error through the direct callers: filemap_get_folio,
filemap_lock_folio filemap_grab_folio and filemap_get_incore_folio.
[hch@lst.de: fix null-pointer deref]
Link: https://lkml.kernel.org/r/20230310070023.GA13563@lst.de
Link: https://lkml.kernel.org/r/20230310043137.GA1624890@u2004
Link: https://lkml.kernel.org/r/20230307143410.28031-8-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com> [nilfs2]
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Christoph Hellwig [Tue, 7 Mar 2023 14:34:09 +0000 (15:34 +0100)]
mm: remove FGP_ENTRY
FGP_ENTRY is unused now, so remove it.
Link: https://lkml.kernel.org/r/20230307143410.28031-7-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Christoph Hellwig [Tue, 7 Mar 2023 14:34:08 +0000 (15:34 +0100)]
shmem: open code the page cache lookup in shmem_get_folio_gfp
Use the very low level filemap_get_entry helper to look up the entry in
the xarray, and then:
- don't bother locking the folio if only doing a userfault notification
- open code locking the page and checking for truncation in a related
code block
This will allow to eventually remove the FGP_ENTRY flag.
[hughd@google.com: adjust the new comment line]
Link: https://lkml.kernel.org/r/af178ebb-1076-a38c-1dc1-2a37ccce4a3@google.com
Link: https://lkml.kernel.org/r/20230307143410.28031-6-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Hugh Dickins [Mon, 20 Mar 2023 05:19:21 +0000 (22:19 -0700)]
shmem: shmem_get_partial_folio use filemap_get_entry
To avoid use of the FGP_ENTRY flag, adapt shmem_get_partial_folio() to use
filemap_get_entry() and folio_lock() instead of __filemap_get_folio().
Update "page" in the comments there to "folio".
Link: https://lkml.kernel.org/r/9d1aaa4-1337-fb81-6f37-74ebc96f9ef@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Christoph Hellwig [Tue, 7 Mar 2023 14:34:06 +0000 (15:34 +0100)]
mm: use filemap_get_entry in filemap_get_incore_folio
filemap_get_incore_folio wants to look at the details of xa_is_value
entries, but doesn't need any of the other logic in filemap_get_folio.
Switch it to use the lower-level filemap_get_entry interface.
Link: https://lkml.kernel.org/r/20230307143410.28031-4-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Christoph Hellwig [Tue, 7 Mar 2023 14:34:05 +0000 (15:34 +0100)]
mm: make mapping_get_entry available outside of filemap.c
mapping_get_entry is useful for page cache API users that need to know
about xa_value internals. Rename it and make it available in pagemap.h.
Link: https://lkml.kernel.org/r/20230307143410.28031-3-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Christoph Hellwig [Tue, 7 Mar 2023 14:34:04 +0000 (15:34 +0100)]
mm: don't look at xarray value entries in split_huge_pages_in_file
Patch series "return an ERR_PTR from __filemap_get_folio", v3.
__filemap_get_folio and its wrappers can return NULL for three different
conditions, which in some cases requires the caller to reverse engineer
the decision making. This is fixed by returning an ERR_PTR instead of
NULL and thus transporting the reason for the failure. But to make
that work we first need to ensure that no xa_value special case is
returned and thus return the FGP_ENTRY flag. It turns out that flag
is barely used and can usually be deal with in a better way.
This patch (of 7):
split_huge_pages_in_file never wants to do anything with the special value
enties. Switch to using filemap_get_folio to not even see them.
Link: https://lkml.kernel.org/r/20230307143410.28031-1-hch@lst.de
Link: https://lkml.kernel.org/r/20230307143410.28031-2-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Keith Busch [Thu, 26 Jan 2023 21:51:25 +0000 (13:51 -0800)]
dmapool: create/destroy cleanup
Set the 'empty' bool directly from the result of the function that
determines its value instead of adding additional logic.
Link: https://lkml.kernel.org/r/20230126215125.4069751-13-kbusch@meta.com
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Keith Busch [Thu, 26 Jan 2023 21:51:24 +0000 (13:51 -0800)]
dmapool: link blocks across pages
The allocated dmapool pages are never freed for the lifetime of the pool.
There is no need for the two level list+stack lookup for finding a free
block since nothing is ever removed from the list. Just use a simple
stack, reducing time complexity to constant.
The implementation inserts the stack linking elements and the dma handle
of the block within itself when freed. This means the smallest possible
dmapool block is increased to at most 16 bytes to accommodate these
fields, but there are no exisiting users requesting a dma pool smaller
than that anyway.
Removing the list has a significant change in performance. Using the
kernel's micro-benchmarking self test:
Before:
# modprobe dmapool_test
dmapool test: size:16 blocks:8192 time:57282
dmapool test: size:64 blocks:8192 time:172562
dmapool test: size:256 blocks:8192 time:789247
dmapool test: size:1024 blocks:2048 time:371823
dmapool test: size:4096 blocks:1024 time:362237
After:
# modprobe dmapool_test
dmapool test: size:16 blocks:8192 time:24997
dmapool test: size:64 blocks:8192 time:26584
dmapool test: size:256 blocks:8192 time:33542
dmapool test: size:1024 blocks:2048 time:9022
dmapool test: size:4096 blocks:1024 time:6045
The module test allocates quite a few blocks that may not accurately
represent how these pools are used in real life. For a more marco level
benchmark, running fio high-depth + high-batched on nvme, this patch shows
submission and completion latency reduced by ~100usec each, 1% IOPs
improvement, and perf record's time spent in dma_pool_alloc/free were
reduced by half.
[kbusch@kernel.org: push new blocks in ascending order]
Link: https://lkml.kernel.org/r/20230221165400.1595247-1-kbusch@meta.com
Link: https://lkml.kernel.org/r/20230126215125.4069751-12-kbusch@meta.com
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Keith Busch [Thu, 26 Jan 2023 21:51:23 +0000 (13:51 -0800)]
dmapool: don't memset on free twice
If debug is enabled, dmapool will poison the range, so no need to clear it
to 0 immediately before writing over it.
Link: https://lkml.kernel.org/r/20230126215125.4069751-11-kbusch@meta.com
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Keith Busch [Thu, 26 Jan 2023 21:51:22 +0000 (13:51 -0800)]
dmapool: simplify freeing
The actions for busy and not busy are mostly the same, so combine these
and remove the unnecessary function. Also, the pool is about to be freed
so there's no need to poison the page data since we only check for poison
on alloc, which can't be done on a freed pool.
Link: https://lkml.kernel.org/r/20230126215125.4069751-10-kbusch@meta.com
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Keith Busch [Thu, 26 Jan 2023 21:51:21 +0000 (13:51 -0800)]
dmapool: consolidate page initialization
Various fields of the dma pool are set in different places. Move it all
to one function.
Link: https://lkml.kernel.org/r/20230126215125.4069751-9-kbusch@meta.com
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Keith Busch [Thu, 26 Jan 2023 21:51:20 +0000 (13:51 -0800)]
dmapool: rearrange page alloc failure handling
Handle the error in a condition so the good path can be in the normal
flow.
Link: https://lkml.kernel.org/r/20230126215125.4069751-8-kbusch@meta.com
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Keith Busch [Thu, 26 Jan 2023 21:51:19 +0000 (13:51 -0800)]
dmapool: move debug code to own functions
Clean up the normal path by moving the debug code outside it.
Link: https://lkml.kernel.org/r/20230126215125.4069751-7-kbusch@meta.com
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tony Battersby [Thu, 26 Jan 2023 21:51:18 +0000 (13:51 -0800)]
dmapool: speedup DMAPOOL_DEBUG with init_on_alloc
Avoid double-memset of the same allocated memory in dma_pool_alloc() when
both DMAPOOL_DEBUG is enabled and init_on_alloc=1.
Link: https://lkml.kernel.org/r/20230126215125.4069751-6-kbusch@meta.com
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tony Battersby [Thu, 26 Jan 2023 21:51:17 +0000 (13:51 -0800)]
dmapool: cleanup integer types
To represent the size of a single allocation, dmapool currently uses
'unsigned int' in some places and 'size_t' in other places. Standardize
on 'unsigned int' to reduce overhead, but use 'size_t' when counting all
the blocks in the entire pool.
Link: https://lkml.kernel.org/r/20230126215125.4069751-5-kbusch@meta.com
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tony Battersby [Thu, 26 Jan 2023 21:51:16 +0000 (13:51 -0800)]
dmapool: use sysfs_emit() instead of scnprintf()
Use sysfs_emit instead of scnprintf, snprintf or sprintf.
Link: https://lkml.kernel.org/r/20230126215125.4069751-4-kbusch@meta.com
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tony Battersby [Thu, 26 Jan 2023 21:51:15 +0000 (13:51 -0800)]
dmapool: remove checks for dev == NULL
dmapool originally tried to support pools without a device because
dma_alloc_coherent() supports allocations without a device. But nobody
ended up using dma pools without a device, and trying to do so will result
in an oops. So remove the checks for pool->dev == NULL since they are
unneeded bloat.
[kbusch@kernel.org: add check for null dev on create]
Link: https://lkml.kernel.org/r/20230126215125.4069751-3-kbusch@meta.com
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Keith Busch [Thu, 26 Jan 2023 21:51:14 +0000 (13:51 -0800)]
dmapool: add alloc/free performance test
Patch series "dmapool enhancements", v4.
Time spent in dma_pool alloc/free increases linearly with the number of
pages backing the pool. We can reduce this to constant time with minor
changes to how free pages are tracked.
This patch (of 12):
Provide a module that allocates and frees many blocks of various sizes and
report how long it takes. This is intended to provide a consistent way to
measure how changes to the dma_pool_alloc/free routines affect timing.
Link: https://lkml.kernel.org/r/20230126215125.4069751-1-kbusch@meta.com
Link: https://lkml.kernel.org/r/20230126215125.4069751-2-kbusch@meta.com
Signed-off-by: Keith Busch <kbusch@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Peter Xu [Wed, 15 Mar 2023 17:16:42 +0000 (13:16 -0400)]
mm/thp: rename TRANSPARENT_HUGEPAGE_NEVER_DAX to _UNSUPPORTED
TRANSPARENT_HUGEPAGE_NEVER_DAX has nothing to do with DAX. It's set when
has_transparent_hugepage() returns false, checked in hugepage_vma_check()
and will disable THP completely if false. Rename it to
TRANSPARENT_HUGEPAGE_UNSUPPORTED to reflect its real purpose.
[peterx@redhat.com: fix comment, per David]
Link: https://lkml.kernel.org/r/ZBMzQW674oHQJV7F@x1n
Link: https://lkml.kernel.org/r/20230315171642.1244625-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kefeng Wang [Mon, 13 Mar 2023 05:39:29 +0000 (13:39 +0800)]
mm: memory-failure: directly use IS_ENABLED(CONFIG_HWPOISON_INJECT)
It's more clear and simple to just use IS_ENABLED(CONFIG_HWPOISON_INJECT)
to check whether or not to enable HWPoison injector module instead of
CONFIG_HWPOISON_INJECT/CONFIG_HWPOISON_INJECT_MODULE.
Link: https://lkml.kernel.org/r/20230313053929.84607-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Qi Zheng [Mon, 13 Mar 2023 11:28:19 +0000 (19:28 +0800)]
mm: shrinkers: convert shrinker_rwsem to mutex
Now there are no readers of shrinker_rwsem, so we can simply replace it
with mutex lock.
Link: https://lkml.kernel.org/r/20230313112819.38938-9-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Kirill Tkhai <tkhai@ya.ru>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Christian König <christian.koenig@amd.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Sultan Alsawaf <sultan@kerneltoast.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Qi Zheng [Mon, 13 Mar 2023 11:28:18 +0000 (19:28 +0800)]
mm: vmscan: remove shrinker_rwsem from synchronize_shrinkers()
Currently, the synchronize_shrinkers() is only used by TTM pool. It only
requires that no shrinkers run in parallel, and doesn't care about
registering and unregistering of shrinkers.
Since slab shrink is protected by SRCU, synchronize_srcu() is sufficient
to ensure that no shrinker is running in parallel. So the shrinker_rwsem
in synchronize_shrinkers() is no longer needed, just remove it.
Link: https://lkml.kernel.org/r/20230313112819.38938-8-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Kirill Tkhai <tkhai@ya.ru>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Christian König <christian.koenig@amd.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Sultan Alsawaf <sultan@kerneltoast.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Qi Zheng [Mon, 13 Mar 2023 11:28:17 +0000 (19:28 +0800)]
mm: vmscan: hold write lock to reparent shrinker nr_deferred
For now, reparent_shrinker_deferred() is the only holder of read lock of
shrinker_rwsem. And it already holds the global cgroup_mutex, so it will
not be called in parallel.
Therefore, in order to convert shrinker_rwsem to shrinker_mutex later,
here we change to hold the write lock of shrinker_rwsem to reparent.
Link: https://lkml.kernel.org/r/20230313112819.38938-7-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Kirill Tkhai <tkhai@ya.ru>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Christian König <christian.koenig@amd.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Sultan Alsawaf <sultan@kerneltoast.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Qi Zheng [Mon, 13 Mar 2023 11:28:16 +0000 (19:28 +0800)]
mm: shrinkers: make count and scan in shrinker debugfs lockless
Like global and memcg slab shrink, also use SRCU to make count and scan
operations in memory shrinker debugfs lockless.
Link: https://lkml.kernel.org/r/20230313112819.38938-6-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Kirill Tkhai <tkhai@ya.ru>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Christian König <christian.koenig@amd.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Sultan Alsawaf <sultan@kerneltoast.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kirill Tkhai [Mon, 13 Mar 2023 11:28:15 +0000 (19:28 +0800)]
mm: vmscan: add shrinker_srcu_generation
After we make slab shrink lockless with SRCU, the longest sleep
unregister_shrinker() will be a sleep waiting for all do_shrink_slab()
calls.
To avoid long unbreakable action in the unregister_shrinker(), add
shrinker_srcu_generation to restore a check similar to the
rwsem_is_contendent() check that we had before.
And for memcg slab shrink, we unlock SRCU and continue iterations from the
next shrinker id.
Link: https://lkml.kernel.org/r/20230313112819.38938-5-zhengqi.arch@bytedance.com
Signed-off-by: Kirill Tkhai <tkhai@ya.ru>
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Christian König <christian.koenig@amd.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Sultan Alsawaf <sultan@kerneltoast.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Qi Zheng [Mon, 13 Mar 2023 11:28:14 +0000 (19:28 +0800)]
mm: vmscan: make memcg slab shrink lockless
Like global slab shrink, this commit also uses SRCU to make memcg slab
shrink lockless.
We can reproduce the down_read_trylock() hotspot through the
following script:
```
DIR="/root/shrinker/memcg/mnt"
do_create()
{
mkdir -p /sys/fs/cgroup/memory/test
mkdir -p /sys/fs/cgroup/perf_event/test
echo 4G > /sys/fs/cgroup/memory/test/memory.limit_in_bytes
for i in `seq 0 $1`;
do
mkdir -p /sys/fs/cgroup/memory/test/$i;
echo $$ > /sys/fs/cgroup/memory/test/$i/cgroup.procs;
echo $$ > /sys/fs/cgroup/perf_event/test/cgroup.procs;
mkdir -p $DIR/$i;
done
}
do_mount()
{
for i in `seq $1 $2`;
do
mount -t tmpfs $i $DIR/$i;
done
}
do_touch()
{
for i in `seq $1 $2`;
do
echo $$ > /sys/fs/cgroup/memory/test/$i/cgroup.procs;
echo $$ > /sys/fs/cgroup/perf_event/test/cgroup.procs;
dd if=/dev/zero of=$DIR/$i/file$i bs=1M count=1 &
done
}
case "$1" in
touch)
do_touch $2 $3
;;
test)
do_create 4000
do_mount 0 4000
do_touch 0 3000
;;
*)
exit 1
;;
esac
```
Save the above script, then run test and touch commands.
Then we can use the following perf command to view hotspots:
perf top -U -F 999
1) Before applying this patchset:
32.31% [kernel] [k] down_read_trylock
19.40% [kernel] [k] pv_native_safe_halt
16.24% [kernel] [k] up_read
15.70% [kernel] [k] shrink_slab
4.69% [kernel] [k] _find_next_bit
2.62% [kernel] [k] shrink_node
1.78% [kernel] [k] shrink_lruvec
0.76% [kernel] [k] do_shrink_slab
2) After applying this patchset:
27.83% [kernel] [k] _find_next_bit
16.97% [kernel] [k] shrink_slab
15.82% [kernel] [k] pv_native_safe_halt
9.58% [kernel] [k] shrink_node
8.31% [kernel] [k] shrink_lruvec
5.64% [kernel] [k] do_shrink_slab
3.88% [kernel] [k] mem_cgroup_iter
At the same time, we use the following perf command to capture
IPC information:
perf stat -e cycles,instructions -G test -a --repeat 5 -- sleep 10
1) Before applying this patchset:
Performance counter stats for 'system wide' (5 runs):
454187219766 cycles test ( +- 1.84% )
78896433101 instructions test # 0.17 insn per cycle ( +- 0.44% )
10.0020430 +- 0.0000366 seconds time elapsed ( +- 0.00% )
2) After applying this patchset:
Performance counter stats for 'system wide' (5 runs):
841954709443 cycles test ( +- 15.80% ) (98.69%)
527258677936 instructions test # 0.63 insn per cycle ( +- 15.11% ) (98.68%)
10.01064 +- 0.00831 seconds time elapsed ( +- 0.08% )
We can see that IPC drops very seriously when calling
down_read_trylock() at high frequency. After using SRCU,
the IPC is at a normal level.
Link: https://lkml.kernel.org/r/20230313112819.38938-4-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: Kirill Tkhai <tkhai@ya.ru>
Acked-by: Vlastimil Babka <Vbabka@suse.cz>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Christian König <christian.koenig@amd.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Sultan Alsawaf <sultan@kerneltoast.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Qi Zheng [Mon, 13 Mar 2023 11:28:13 +0000 (19:28 +0800)]
mm: vmscan: make global slab shrink lockless
The shrinker_rwsem is a global read-write lock in shrinkers subsystem,
which protects most operations such as slab shrink, registration and
unregistration of shrinkers, etc. This can easily cause problems in the
following cases.
1) When the memory pressure is high and there are many
filesystems mounted or unmounted at the same time,
slab shrink will be affected (down_read_trylock()
failed).
Such as the real workload mentioned by Kirill Tkhai:
```
One of the real workloads from my experience is start
of an overcommitted node containing many starting
containers after node crash (or many resuming containers
after reboot for kernel update). In these cases memory
pressure is huge, and the node goes round in long reclaim.
```
2) If a shrinker is blocked (such as the case mentioned
in [1]) and a writer comes in (such as mount a fs),
then this writer will be blocked and cause all
subsequent shrinker-related operations to be blocked.
Even if there is no competitor when shrinking slab, there may still be a
problem. If we have a long shrinker list and we do not reclaim enough
memory with each shrinker, then the down_read_trylock() may be called with
high frequency. Because of the poor multicore scalability of atomic
operations, this can lead to a significant drop in IPC (instructions per
cycle).
So many times in history ([2],[3],[4],[5]), some people wanted to replace
shrinker_rwsem trylock with SRCU in the slab shrink, but all these patches
were abandoned because SRCU was not unconditionally enabled.
But now, since commit
1cd0bd06093c ("rcu: Remove CONFIG_SRCU"), the SRCU
is unconditionally enabled. So it's time to use SRCU to protect readers
who previously held shrinker_rwsem.
This commit uses SRCU to make global slab shrink lockless,
the memcg slab shrink is handled in the subsequent patch.
[1]. https://lore.kernel.org/lkml/
20191129214541.3110-1-ptikhomirov@virtuozzo.com/
[2]. https://lore.kernel.org/all/
1437080113.3596.2.camel@stgolabs.net/
[3]. https://lore.kernel.org/lkml/
1510609063-3327-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp/
[4]. https://lore.kernel.org/lkml/
153365347929.19074.
12509495712735843805.stgit@localhost.localdomain/
[5]. https://lore.kernel.org/lkml/
20210927074823.5825-1-sultan@kerneltoast.com/
Link: https://lkml.kernel.org/r/20230313112819.38938-3-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Kirill Tkhai <tkhai@ya.ru>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Christian König <christian.koenig@amd.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Qi Zheng [Mon, 13 Mar 2023 11:28:12 +0000 (19:28 +0800)]
mm: vmscan: add a map_nr_max field to shrinker_info
Patch series "make slab shrink lockless", v5.
This patch series aims to make slab shrink lockless.
1. Background
=============
On our servers, we often find the following system cpu hotspots:
52.22% [kernel] [k] down_read_trylock
19.60% [kernel] [k] up_read
8.86% [kernel] [k] shrink_slab
2.44% [kernel] [k] idr_find
1.25% [kernel] [k] count_shadow_nodes
1.18% [kernel] [k] shrink lruvec
0.71% [kernel] [k] mem_cgroup_iter
0.71% [kernel] [k] shrink_node
0.55% [kernel] [k] find_next_bit
And we used bpftrace to capture its calltrace as follows:
@[
down_read_trylock+1
shrink_slab+128
shrink_node+371
do_try_to_free_pages+232
try_to_free_pages+243
_alloc_pages_slowpath+771
_alloc_pages_nodemask+702
pagecache_get_page+255
filemap_fault+1361
ext4_filemap_fault+44
__do_fault+76
handle_mm_fault+3543
do_user_addr_fault+442
do_page_fault+48
page_fault+62
]: 1161690
@[
down_read_trylock+1
shrink_slab+128
shrink_node+371
balance_pgdat+690
kswapd+389
kthread+246
ret_from_fork+31
]: 8424884
@[
down_read_trylock+1
shrink_slab+128
shrink_node+371
do_try_to_free_pages+232
try_to_free_pages+243
__alloc_pages_slowpath+771
__alloc_pages_nodemask+702
__do_page_cache_readahead+244
filemap_fault+1674
ext4_filemap_fault+44
__do_fault+76
handle_mm_fault+3543
do_user_addr_fault+442
do_page_fault+48
page_fault+62
]:
20917631
We can see that down_read_trylock() of shrinker_rwsem is being called with
high frequency at that time. Because of the poor multicore scalability of
atomic operations, this can lead to a significant drop in IPC
(instructions per cycle).
And more, the shrinker_rwsem is a global read-write lock in shrinkers
subsystem, which protects most operations such as slab shrink,
registration and unregistration of shrinkers, etc. This can easily cause
problems in the following cases.
1) When the memory pressure is high and there are many filesystems
mounted or unmounted at the same time, slab shrink will be affected
(down_read_trylock() failed).
Such as the real workload mentioned by Kirill Tkhai:
```
One of the real workloads from my experience is start of an
overcommitted node containing many starting containers after node crash
(or many resuming containers after reboot for kernel update). In these
cases memory pressure is huge, and the node goes round in long reclaim.
```
2) If a shrinker is blocked (such as the case mentioned in [1]) and a
writer comes in (such as mount a fs), then this writer will be blocked
and cause all subsequent shrinker-related operations to be blocked.
[1]. https://lore.kernel.org/lkml/
20191129214541.3110-1-ptikhomirov@virtuozzo.com/
All the above cases can be solved by replacing the shrinker_rwsem trylocks
with SRCU.
2. Survey
=========
Before doing the code implementation, I found that there were many similar
submissions in the community:
a. Davidlohr Bueso submitted a patch in 2015.
Subject: [PATCH -next v2] mm: srcu-ify shrinkers
Link: https://lore.kernel.org/all/1437080113.3596.2.camel@stgolabs.net/
Result: It was finally merged into the linux-next branch,
but failed on arm allnoconfig (without CONFIG_SRCU)
b. Tetsuo Handa submitted a patchset in 2017.
Subject: [PATCH 1/2] mm,vmscan: Kill global shrinker lock.
Link: https://lore.kernel.org/lkml/1510609063-3327-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp/
Result: Finally chose to use the current simple way (break
when rwsem_is_contended()). And Christoph Hellwig suggested to
using SRCU, but SRCU was not unconditionally enabled at the
time.
c. Kirill Tkhai submitted a patchset in 2018.
Subject: [PATCH RFC 00/10] Introduce lockless shrink_slab()
Link: https://lore.kernel.org/lkml/153365347929.19074.12509495712735843805.stgit@localhost.localdomain/
Result: At that time, SRCU was not unconditionally enabled,
and there were some objections to enabling SRCU. Later,
because Kirill's focus was moved to other things, this patchset
was not continued to be updated.
d. Sultan Alsawaf submitted a patch in 2021.
Subject: [PATCH] mm: vmscan: Replace shrinker_rwsem trylocks with SRCU protection
Link: https://lore.kernel.org/lkml/20210927074823.5825-1-sultan@kerneltoast.com/
Result: Rejected because SRCU was not unconditionally enabled.
We can find that almost all these historical commits were abandoned
because SRCU was not unconditionally enabled. But now SRCU has been
unconditionally enable by Paul E. McKenney in 2023 [2], so it's time to
replace shrinker_rwsem trylocks with SRCU.
[2] https://lore.kernel.org/lkml/
20230105003759.GA1769545@paulmck-ThinkPad-P17-Gen-1/
3. Reproduction and testing
===========================
We can reproduce the down_read_trylock() hotspot through the following script:
```
#!/bin/bash
DIR="/root/shrinker/memcg/mnt"
do_create()
{
mkdir -p /sys/fs/cgroup/memory/test
mkdir -p /sys/fs/cgroup/perf_event/test
echo 4G > /sys/fs/cgroup/memory/test/memory.limit_in_bytes
for i in `seq 0 $1`;
do
mkdir -p /sys/fs/cgroup/memory/test/$i;
echo $$ > /sys/fs/cgroup/memory/test/$i/cgroup.procs;
echo $$ > /sys/fs/cgroup/perf_event/test/cgroup.procs;
mkdir -p $DIR/$i;
done
}
do_mount()
{
for i in `seq $1 $2`;
do
mount -t tmpfs $i $DIR/$i;
done
}
do_touch()
{
for i in `seq $1 $2`;
do
echo $$ > /sys/fs/cgroup/memory/test/$i/cgroup.procs;
echo $$ > /sys/fs/cgroup/perf_event/test/cgroup.procs;
dd if=/dev/zero of=$DIR/$i/file$i bs=1M count=1 &
done
}
case "$1" in
touch)
do_touch $2 $3
;;
test)
do_create 4000
do_mount 0 4000
do_touch 0 3000
;;
*)
exit 1
;;
esac
```
Save the above script, then run test and touch commands. Then we can use
the following perf command to view hotspots:
perf top -U -F 999
1) Before applying this patchset:
32.31% [kernel] [k] down_read_trylock
19.40% [kernel] [k] pv_native_safe_halt
16.24% [kernel] [k] up_read
15.70% [kernel] [k] shrink_slab
4.69% [kernel] [k] _find_next_bit
2.62% [kernel] [k] shrink_node
1.78% [kernel] [k] shrink_lruvec
0.76% [kernel] [k] do_shrink_slab
2) After applying this patchset:
27.83% [kernel] [k] _find_next_bit
16.97% [kernel] [k] shrink_slab
15.82% [kernel] [k] pv_native_safe_halt
9.58% [kernel] [k] shrink_node
8.31% [kernel] [k] shrink_lruvec
5.64% [kernel] [k] do_shrink_slab
3.88% [kernel] [k] mem_cgroup_iter
At the same time, we use the following perf command to capture IPC
information:
perf stat -e cycles,instructions -G test -a --repeat 5 -- sleep 10
1) Before applying this patchset:
Performance counter stats for 'system wide' (5 runs):
454187219766 cycles test ( +- 1.84% )
78896433101 instructions test # 0.17 insn per cycle ( +- 0.44% )
10.0020430 +- 0.0000366 seconds time elapsed ( +- 0.00% )
2) After applying this patchset:
Performance counter stats for 'system wide' (5 runs):
841954709443 cycles test ( +- 15.80% ) (98.69%)
527258677936 instructions test # 0.63 insn per cycle ( +- 15.11% ) (98.68%)
10.01064 +- 0.00831 seconds time elapsed ( +- 0.08% )
We can see that IPC drops very seriously when calling down_read_trylock()
at high frequency. After using SRCU, the IPC is at a normal level.
This patch (of 8):
To prepare for the subsequent lockless memcg slab shrink, add a map_nr_max
field to struct shrinker_info to records its own real shrinker_nr_max.
Link: https://lkml.kernel.org/r/20230313112819.38938-1-zhengqi.arch@bytedance.com
Link: https://lkml.kernel.org/r/20230313112819.38938-2-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Suggested-by: Kirill Tkhai <tkhai@ya.ru>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Kirill Tkhai <tkhai@ya.ru>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Christian König <christian.koenig@amd.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Sultan Alsawaf <sultan@kerneltoast.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Mon, 13 Mar 2023 12:27:14 +0000 (12:27 +0000)]
mm: prefer xxx_page() alloc/free functions for order-0 pages
Update instances of alloc_pages(..., 0), __get_free_pages(..., 0) and
__free_pages(..., 0) to use alloc_page(), __get_free_page() and
__free_page() respectively in core code.
Link: https://lkml.kernel.org/r/50c48ca4789f1da2a65795f2346f5ae3eff7d665.1678710232.git.lstoakes@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Peter Collingbourne [Fri, 10 Mar 2023 04:29:14 +0000 (20:29 -0800)]
kasan: remove PG_skip_kasan_poison flag
Code inspection reveals that PG_skip_kasan_poison is redundant with
kasantag, because the former is intended to be set iff the latter is the
match-all tag. It can also be observed that it's basically pointless to
poison pages which have kasantag=0, because any pages with this tag would
have been pointed to by pointers with match-all tags, so poisoning the
pages would have little to no effect in terms of bug detection.
Therefore, change the condition in should_skip_kasan_poison() to check
kasantag instead, and remove PG_skip_kasan_poison and associated flags.
Link: https://lkml.kernel.org/r/20230310042914.3805818-3-pcc@google.com
Link: https://linux-review.googlesource.com/id/I57f825f2eaeaf7e8389d6cf4597c8a5821359838
Signed-off-by: Peter Collingbourne <pcc@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sebastian Andrzej Siewior [Fri, 10 Mar 2023 16:29:05 +0000 (17:29 +0100)]
io-mapping: don't disable preempt on RT in io_mapping_map_atomic_wc().
io_mapping_map_atomic_wc() disables preemption and pagefaults for
historical reasons. The conversion to io_mapping_map_local_wc(), which
only disables migration, cannot be done wholesale because quite some call
sites need to be updated to accommodate with the changed semantics.
On PREEMPT_RT enabled kernels the io_mapping_map_atomic_wc() semantics are
problematic due to the implicit disabling of preemption which makes it
impossible to acquire 'sleeping' spinlocks within the mapped atomic
sections.
PREEMPT_RT replaces the preempt_disable() with a migrate_disable() for
more than a decade. It could be argued that this is a justification to do
this unconditionally, but PREEMPT_RT covers only a limited number of
architectures and it disables some functionality which limits the coverage
further.
Limit the replacement to PREEMPT_RT for now. This is also done
kmap_atomic().
Link: https://lkml.kernel.org/r/20230310162905.O57Pj7hh@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reported-by: Richard Weinberger <richard.weinberger@gmail.com>
Link: https://lore.kernel.org/CAFLxGvw0WMxaMqYqJ5WgvVSbKHq2D2xcXTOgMCpgq9nDC-MWTQ@mail.gmail.com
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Luis Chamberlain [Thu, 9 Mar 2023 23:05:45 +0000 (15:05 -0800)]
shmem: add support to ignore swap
In doing experimentations with shmem having the option to avoid swap
becomes a useful mechanism. One of the *raves* about brd over shmem is
you can avoid swap, but that's not really a good reason to use brd if we
can instead use shmem. Using brd has its own good reasons to exist, but
just because "tmpfs" doesn't let you do that is not a great reason to
avoid it if we can easily add support for it.
I don't add support for reconfiguring incompatible options, but if we
really wanted to we can add support for that.
To avoid swap we use mapping_set_unevictable() upon inode creation, and
put a WARN_ON_ONCE() stop-gap on writepages() for reclaim.
Link: https://lkml.kernel.org/r/20230309230545.2930737-7-mcgrof@kernel.org
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Acked-by: Christian Brauner <brauner@kernel.org>
Tested-by: Xin Hao <xhao@linux.alibaba.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Cc: Adam Manzanares <a.manzanares@samsung.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Luis Chamberlain [Thu, 9 Mar 2023 23:05:44 +0000 (15:05 -0800)]
shmem: update documentation
Update the docs to reflect a bit better why some folks prefer tmpfs over
ramfs and clarify a bit more about the difference between brd ramdisks.
While at it, add THP docs for tmpfs, both the mount options and the sysfs
file.
Link: https://lkml.kernel.org/r/20230309230545.2930737-6-mcgrof@kernel.org
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Tested-by: Xin Hao <xhao@linux.alibaba.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Cc: Adam Manzanares <a.manzanares@samsung.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Luis Chamberlain [Thu, 9 Mar 2023 23:05:43 +0000 (15:05 -0800)]
shmem: skip page split if we're not reclaiming
In theory when info->flags & VM_LOCKED we should not be getting
shem_writepage() called so we should be verifying this with a
WARN_ON_ONCE(). Since we should not be swapping then best to ensure we
also don't do the folio split earlier too. So just move the check early
to avoid folio splits in case its a dubious call.
We also have a similar early bail when !total_swap_pages so just move that
earlier to avoid the possible folio split in the same situation.
Link: https://lkml.kernel.org/r/20230309230545.2930737-5-mcgrof@kernel.org
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Tested-by: Xin Hao <xhao@linux.alibaba.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Cc: Adam Manzanares <a.manzanares@samsung.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Luis Chamberlain [Thu, 9 Mar 2023 23:05:42 +0000 (15:05 -0800)]
shmem: move reclaim check early on writepages()
i915_gem requires huge folios to be split when swapping. However we have
check for usage of writepages() to ensure it used only for swap purposes
later. Avoid the splits if we're not being called for reclaim, even if
they should in theory not happen.
This makes the conditions easier to follow on shem_writepage().
Link: https://lkml.kernel.org/r/20230309230545.2930737-4-mcgrof@kernel.org
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Tested-by: Xin Hao <xhao@linux.alibaba.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Cc: Adam Manzanares <a.manzanares@samsung.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Luis Chamberlain [Thu, 9 Mar 2023 23:05:41 +0000 (15:05 -0800)]
shmem: set shmem_writepage() variables early
shmem_writepage() sets up variables typically used *after* a possible huge
page split. However even if that does happen the address space mapping
should not change, and the inode does not change either. So it should be
safe to set that from the very beginning.
This commit makes no functional changes.
Link: https://lkml.kernel.org/r/20230309230545.2930737-3-mcgrof@kernel.org
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Tested-by: Xin Hao <xhao@linux.alibaba.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Cc: Adam Manzanares <a.manzanares@samsung.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Luis Chamberlain [Thu, 9 Mar 2023 23:05:40 +0000 (15:05 -0800)]
shmem: remove check for folio lock on writepage()
Patch series "tmpfs: add the option to disable swap", v2.
I'm doing this work as part of future experimentation with tmpfs and the
page cache, but given a common complaint found about tmpfs is the
innability to work without the page cache I figured this might be useful
to others. It turns out it is -- at least Christian Brauner indicates
systemd uses ramfs for a few use-cases because they don't want to use swap
and so having this option would let them move over to using tmpfs for
those small use cases, see systemd-creds(1).
To see if you hit swap:
mkswap /dev/nvme2n1
swapon /dev/nvme2n1
free -h
With swap - what we see today
=============================
mount -t tmpfs -o size=5G tmpfs /data-tmpfs/
dd if=/dev/urandom of=/data-tmpfs/5g-rand2 bs=1G count=5
free -h
total used free shared buff/cache available
Mem: 3.7Gi 2.6Gi 1.2Gi 2.2Gi 2.2Gi 1.2Gi
Swap: 99Gi 2.8Gi 97Gi
Without swap
=============
free -h
total used free shared buff/cache available
Mem: 3.7Gi 387Mi 3.4Gi 2.1Mi 57Mi 3.3Gi
Swap: 99Gi 0B 99Gi
mount -t tmpfs -o size=5G -o noswap tmpfs /data-tmpfs/
dd if=/dev/urandom of=/data-tmpfs/5g-rand2 bs=1G count=5
free -h
total used free shared buff/cache available
Mem: 3.7Gi 2.6Gi 1.2Gi 2.3Gi 2.3Gi 1.1Gi
Swap: 99Gi 21Mi 99Gi
The mix and match remount testing
=================================
# Cannot disable swap after it was first enabled:
mount -t tmpfs -o size=5G tmpfs /data-tmpfs/
mount -t tmpfs -o remount -o size=5G -o noswap tmpfs /data-tmpfs/
mount: /data-tmpfs: mount point not mounted or bad option.
dmesg(1) may have more information after failed mount system call.
dmesg -c
tmpfs: Cannot disable swap on remount
# Remount with the same noswap option is OK:
mount -t tmpfs -o size=5G -o noswap tmpfs /data-tmpfs/
mount -t tmpfs -o remount -o size=5G -o noswap tmpfs /data-tmpfs/
dmesg -c
# Trying to enable swap with a remount after it first disabled:
mount -t tmpfs -o size=5G -o noswap tmpfs /data-tmpfs/
mount -t tmpfs -o remount -o size=5G tmpfs /data-tmpfs/
mount: /data-tmpfs: mount point not mounted or bad option.
dmesg(1) may have more information after failed mount system call.
dmesg -c
tmpfs: Cannot enable swap on remount if it was disabled on first mount
This patch (of 6):
Matthew notes we should not need to check the folio lock on the
writepage() callback so remove it. This sanity check has been lingering
since linux-history days. We remove this as we tidy up the writepage()
callback to make things a bit clearer.
Link: https://lkml.kernel.org/r/20230309230545.2930737-1-mcgrof@kernel.org
Link: https://lkml.kernel.org/r/20230309230545.2930737-2-mcgrof@kernel.org
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Tested-by: Xin Hao <xhao@linux.alibaba.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Cc: Adam Manzanares <a.manzanares@samsung.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jingyu Wang [Thu, 9 Mar 2023 10:48:13 +0000 (18:48 +0800)]
mm/gup.c: fix typo in comments
Link: https://lkml.kernel.org/r/20230309104813.170309-1-jingyuwang_vip@163.com
Signed-off-by: Jingyu Wang <jingyuwang_vip@163.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>