perf sched timehist: Enlarge default 'comm_width'

Current default value is 20 but it's easily changed to a bigger value as
task has a long name and different tid and pid.  And it makes the output
not aligned.  So change it to have a large value as summary shows.

Committer notes:

Before:

  # perf sched record
  ^C
  # perf sched timehist
  <SNIP>
    40602.770537 [0001]  rcuos/2[29]               7.970      0.002      0.020
    40602.771512 [0003]  <idle>                    0.003      0.000      0.986
    40602.771586 [0001]  <idle>                    0.020      0.000      1.049
    40602.771606 [0001]  qemu-system-x86[3593/3510]      0.000      0.002      0.020
    40602.771629 [0003]  qemu-system-x86[3510]           0.000      0.003      0.116
    40602.771776 [0000]  <idle>                          0.001      0.000      1.892
  <SNIP>

After:

  # perf sched timehist
  <SNIP>
   40602.770537 [0001]  rcuos/2[29]                         7.970      0.002      0.020
   40602.771512 [0003]  <idle>                              0.003      0.000      0.986
   40602.771586 [0001]  <idle>                              0.020      0.000      1.049
   40602.771606 [0001]  qemu-system-x86[3593/3510]          0.000      0.002      0.020
   40602.771629 [0003]  qemu-system-x86[3510]               0.000      0.003      0.116
  <SNIP>

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20161222060350.17655-1-namhyung@kernel.org
[ Split from a larger patch ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf sched timehist: Honour 'comm_width' when aligning the headers

Current default value is 20, but that may change in the future, so make
places where we have 20 hardcoded use 'comm_width'.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20161222060350.17655-1-namhyung@kernel.org
[ Split from a larger patch ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf/x86: Fix overlap counter scheduling bug

Jiri reported the overlap scheduling exceeding its max stack.

Looking at the constraint that triggered this, it turns out the
overlap marker isn't needed.

The comment with EVENT_CONSTRAINT_OVERLAP states: "This is the case if
the counter mask of such an event is not a subset of any other counter
mask of a constraint with an equal or higher weight".

Esp. that latter part is of interest here I think, our overlapping mask
is 0x0e, that has 3 bits set and is the highest weight mask in on the
PMU, therefore it will be placed last. Can we still create a scenario
where we would need to rewind that?

The scenario for AMD Fam15h is we're having masks like:

0x3F -- 111111
0x38 -- 111000
0x07 -- 000111

0x09 -- 001001

And we mark 0x09 as overlapping, because it is not a direct subset of
0x38 or 0x07 and has less weight than either of those. This means we'll
first try and place the 0x09 event, then try and place 0x38/0x07 events.
Now imagine we have:

3 * 0x07 + 0x09

and the initial pick for the 0x09 event is counter 0, then we'll fail to
place all 0x07 events. So we'll pop back, try counter 4 for the 0x09
event, and then re-try all 0x07 events, which will now work.

The masks on the PMU in question are:

  0x01 - 0001
  0x03 - 0011
  0x0e - 1110
  0x0c - 1100

But since all the masks that have overlap (0xe -> {0xc,0x3}) and (0x3 ->
0x1) are of heavier weight, it should all work out.

Reported-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Liang Kan <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robert Richter <rric@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vince@deater.net>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/20161109155153.GQ3142@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>

perf/x86/pebs: Fix handling of PEBS buffer overflows

This patch solves a race condition between PEBS and the PMU handler.

In case multiple PEBS events are sampled at the same time,
it is possible to have GLOBAL_STATUS bit 62 set indicating
PEBS buffer overflow and also seeing at most 3 PEBS counters
having their bits set in the status register. This is a sign
that there was at least one PEBS record pending at the time
of the PMU interrupt. PEBS counters must only be processed
via the drain_pebs() calls, and not via the regular sample
processing loop coming after that the function, otherwise
phony regular samples may be generated in the sampling buffer
not marked with the EXACT tag.

Another possibility is to have one PEBS event and at least
one non-PEBS event whic hoverflows while PEBS has armed. In this
case, bit 62 of GLOBAL_STATUS will not be set, yet the overflow
status bit for the PEBS counter will be on Skylake.

To avoid this problem, we systematically ignore the PEBS-enabled
counters from the GLOBAL_STATUS mask and we always process PEBS
events via drain_pebs().

The problem manifested itself by having non-exact samples when
sampling only PEBS events, i.e., the PERF_SAMPLE_RECORD would
not have the EXACT flag set.

Note that this problem is only present on Skylake processor.
This fix is harmless on older processors.

Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1482395366-8992-1-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge tag 'perf-core-for-mingo-20161220' of git://git./linux/kernel/git/acme/linux into perf/urgent

Pull perf/core improvements and fixes:

New features:

 - Introduce 'perf sched timehist --idle', to analyse processes
   going to/from idle state (Namhyung Kim)

Fixes:

 - Allow 'perf record -u user' to continue when facing races with threads
   going away after having scanned them via /proc (Jiri Olsa)

 - Fix 'perf mem' --all-user/--all-kernel options (Jiri Olsa)

 - Support jumps with multiple arguments (Ravi Bangoria)

 - Fix jumps to before the function where they are located (Ravi Bangoria)

 - Fix lock-pi help string (Davidlohr Bueso)

 - Fix build of 'perf trace' in odd systems such as a RHEL PPC one (Jiri Olsa)

 - Do not overwrite valid build id in 'perf diff' (Kan Liang)

 - Don't throw error for zero length symbols, allowing the use of the TUI
   in PowerPC, where such symbols became more common recently (Ravi Bangoria)

Infrastructure changes:

 - Switch of samples/bpf/ to use tools/lib/bpf, removing libbpf
   duplication (Joe Stringer)

 - Move headers check into bash script (Jiri Olsa)

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

samples/bpf: Move open_raw_sock to separate header

This function was declared in libbpf.c and was the only remaining
function in this library, but has nothing to do with BPF. Shift it out
into a new header, sock_example.h, and include it from the relevant
samples.

Signed-off-by: Joe Stringer <joe@ovn.org>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/20161209024620.31660-8-joe@ovn.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

samples/bpf: Remove perf_event_open() declaration

This declaration was made in samples/bpf/libbpf.c for convenience, but
there's already one in tools/perf/perf-sys.h. Reuse that one.

Committer notes:

Testing it:

  $ make -j4 O=../build/v4.9.0-rc8+ samples/bpf/
  make[1]: Entering directory '/home/build/v4.9.0-rc8+'
    CHK     include/config/kernel.release
    GEN     ./Makefile
    CHK     include/generated/uapi/linux/version.h
    Using /home/acme/git/linux as source for kernel
    CHK     include/generated/utsrelease.h
    CHK     include/generated/timeconst.h
    CHK     include/generated/bounds.h
    CHK     include/generated/asm-offsets.h
    CALL    /home/acme/git/linux/scripts/checksyscalls.sh
    HOSTCC  samples/bpf/test_verifier.o
    HOSTCC  samples/bpf/libbpf.o
    HOSTCC  samples/bpf/../../tools/lib/bpf/bpf.o
    HOSTCC  samples/bpf/test_maps.o
    HOSTCC  samples/bpf/sock_example.o
    HOSTCC  samples/bpf/bpf_load.o
<SNIP>
    HOSTLD  samples/bpf/trace_event
    HOSTLD  samples/bpf/sampleip
    HOSTLD  samples/bpf/tc_l2_redirect
  make[1]: Leaving directory '/home/build/v4.9.0-rc8+'
  $

Also tested the offwaketime resulting from the rebuild, seems to work as
before.

Signed-off-by: Joe Stringer <joe@ovn.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/20161209024620.31660-7-joe@ovn.org
[ Use -I$(srctree)/tools/lib/ to support out of source code tree builds ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

samples/bpf: Be consistent with bpf_load_program bpf_insn parameter

Only one of the examples declare the bpf_insn bpf proggie as a const:

  $ grep 'struct bpf_insn [a-z]' samples/bpf/*.c
  samples/bpf/fds_example.c: static const struct bpf_insn insns[] = {
  samples/bpf/sock_example.c: struct bpf_insn prog[] = {
  samples/bpf/test_cgrp2_attach2.c: struct bpf_insn prog[] = {
  samples/bpf/test_cgrp2_attach.c: struct bpf_insn prog[] = {
  samples/bpf/test_cgrp2_sock.c: struct bpf_insn prog[] = {
  $

Which causes this warning:

  [root@f5065a7d6272 linux]# make -j4 O=/tmp/build/linux samples/bpf/
  <SNIP>
     HOSTCC  samples/bpf/fds_example.o
  /git/linux/samples/bpf/fds_example.c: In function 'bpf_prog_create':
  /git/linux/samples/bpf/fds_example.c:63:6: warning: passing argument 2 of 'bpf_load_program' discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
        insns, insns_cnt, "GPL", 0,
        ^~~~~
  In file included from /git/linux/samples/bpf/libbpf.h:5:0,
                   from /git/linux/samples/bpf/bpf_load.h:4,
                   from /git/linux/samples/bpf/fds_example.c:15:
  /git/linux/tools/lib/bpf/bpf.h:31:5: note: expected 'struct bpf_insn *' but argument is of type 'const struct bpf_insn *'
   int bpf_load_program(enum bpf_prog_type type, struct bpf_insn *insns,
       ^~~~~~~~~~~~~~~~
    HOSTCC  samples/bpf/sockex1_user.o

So just ditch that 'const' to reduce build noise, leaving changing the
bpf_load_program() bpf_insn parameter to const to a later patch, if deemed
adequate.

Cc: Joe Stringer <joe@ovn.org>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-1z5xee8n3oa66jf62bpv16ed@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools lib bpf: Add bpf_prog_{attach,detach}

Commit d8c5b17f2bc0 ("samples: bpf: add userspace example for attaching
eBPF programs to cgroups") added these functions to samples/libbpf, but
during this merge all of the samples libbpf functionality is shifting to
tools/lib/bpf. Shift these functions there.

Committer notes:

Use bzero + attr.FIELD = value instead of 'attr = { .FIELD = value, just
like the other wrapper calls to sys_bpf with bpf_attr to make this build
in older toolchais, such as the ones in CentOS 5 and 6.

Signed-off-by: Joe Stringer <joe@ovn.org>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-au2zvtsh55vqeo3v3uw7jr4c@git.kernel.org
Link: https://github.com/joestringer/linux/commit/353e6f298c3d0a92fa8bfa61ff898c5050261a12.patch
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

samples/bpf: Switch over to libbpf

Now that libbpf under tools/lib/bpf/* is synced with the version from
samples/bpf, we can get rid most of the libbpf library here.

Committer notes:

Built it in a docker fedora rawhide container and ran it in the f25 host, seems
to work just like it did before this patch, i.e. the switch to tools/lib/bpf/
doesn't seem to have introduced problems and Joe said he tested it with
all the entries in samples/bpf/ and other code he found:

  [root@f5065a7d6272 linux]# make -j4 O=/tmp/build/linux headers_install
  <SNIP>
  [root@f5065a7d6272 linux]# rm -rf /tmp/build/linux/samples/bpf/
  [root@f5065a7d6272 linux]# make -j4 O=/tmp/build/linux samples/bpf/
  make[1]: Entering directory '/tmp/build/linux'
    CHK     include/config/kernel.release
    HOSTCC  scripts/basic/fixdep
    GEN     ./Makefile
    CHK     include/generated/uapi/linux/version.h
    Using /git/linux as source for kernel
    CHK     include/generated/utsrelease.h
    HOSTCC  scripts/basic/bin2c
    HOSTCC  arch/x86/tools/relocs_32.o
    HOSTCC  arch/x86/tools/relocs_64.o
    LD      samples/bpf/built-in.o
  <SNIP>
    HOSTCC  samples/bpf/fds_example.o
    HOSTCC  samples/bpf/sockex1_user.o
  /git/linux/samples/bpf/fds_example.c: In function 'bpf_prog_create':
  /git/linux/samples/bpf/fds_example.c:63:6: warning: passing argument 2 of 'bpf_load_program' discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
        insns, insns_cnt, "GPL", 0,
        ^~~~~
  In file included from /git/linux/samples/bpf/libbpf.h:5:0,
                   from /git/linux/samples/bpf/bpf_load.h:4,
                   from /git/linux/samples/bpf/fds_example.c:15:
  /git/linux/tools/lib/bpf/bpf.h:31:5: note: expected 'struct bpf_insn *' but argument is of type 'const struct bpf_insn *'
   int bpf_load_program(enum bpf_prog_type type, struct bpf_insn *insns,
       ^~~~~~~~~~~~~~~~
    HOSTCC  samples/bpf/sockex2_user.o
  <SNIP>
    HOSTCC  samples/bpf/xdp_tx_iptunnel_user.o
  clang  -nostdinc -isystem /usr/lib/gcc/x86_64-redhat-linux/6.2.1/include -I/git/linux/arch/x86/include -I./arch/x86/include/generated/uapi -I./arch/x86/include/generated  -I/git/linux/include -I./include -I/git/linux/arch/x86/include/uapi -I/git/linux/include/uapi -I./include/generated/uapi -include /git/linux/include/linux/kconfig.h  \
  -D__KERNEL__ -D__ASM_SYSREG_H -Wno-unused-value -Wno-pointer-sign \
  -Wno-compare-distinct-pointer-types \
  -Wno-gnu-variable-sized-type-not-at-end \
  -Wno-address-of-packed-member -Wno-tautological-compare \
  -O2 -emit-llvm -c /git/linux/samples/bpf/sockex1_kern.c -o -| llc -march=bpf -filetype=obj -o samples/bpf/sockex1_kern.o
    HOSTLD  samples/bpf/tc_l2_redirect
  <SNIP>
    HOSTLD  samples/bpf/lwt_len_hist
    HOSTLD  samples/bpf/xdp_tx_iptunnel
  make[1]: Leaving directory '/tmp/build/linux'
  [root@f5065a7d6272 linux]#

And then, in the host:

  [root@jouet bpf]# mount | grep "docker.*devicemapper\/"
  /dev/mapper/docker-253:0-1705076-9bd8aa1e0af33adce89ff42090847868ca676932878942be53941a06ec5923f9 on /var/lib/docker/devicemapper/mnt/9bd8aa1e0af33adce89ff42090847868ca676932878942be53941a06ec5923f9 type xfs (rw,relatime,context="system_u:object_r:container_file_t:s0:c73,c276",nouuid,attr2,inode64,sunit=1024,swidth=1024,noquota)
  [root@jouet bpf]# cd /var/lib/docker/devicemapper/mnt/9bd8aa1e0af33adce89ff42090847868ca676932878942be53941a06ec5923f9/rootfs/tmp/build/linux/samples/bpf/
  [root@jouet bpf]# file offwaketime
  offwaketime: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=f423d171e0487b2f802b6a792657f0f3c8f6d155, not stripped
  [root@jouet bpf]# readelf -SW offwaketime
  offwaketime         offwaketime_kern.o  offwaketime_user.o
  [root@jouet bpf]# readelf -SW offwaketime_kern.o
  There are 11 section headers, starting at offset 0x700:

  Section Headers:
    [Nr] Name              Type            Address          Off    Size   ES Flg Lk Inf Al
    [ 0]                   NULL            0000000000000000 000000 000000 00      0   0  0
    [ 1] .strtab           STRTAB          0000000000000000 000658 0000a8 00      0   0  1
    [ 2] .text             PROGBITS        0000000000000000 000040 000000 00  AX  0   0  4
    [ 3] kprobe/try_to_wake_up PROGBITS        0000000000000000 000040 0000d8 00  AX  0   0  8
    [ 4] .relkprobe/try_to_wake_up REL             0000000000000000 0005a8 000020 10     10   3  8
    [ 5] tracepoint/sched/sched_switch PROGBITS        0000000000000000 000118 000318 00  AX  0   0  8
    [ 6] .reltracepoint/sched/sched_switch REL             0000000000000000 0005c8 000090 10     10   5  8
    [ 7] maps              PROGBITS        0000000000000000 000430 000050 00  WA  0   0  4
    [ 8] license           PROGBITS        0000000000000000 000480 000004 00  WA  0   0  1
    [ 9] version           PROGBITS        0000000000000000 000484 000004 00  WA  0   0  4
    [10] .symtab           SYMTAB          0000000000000000 000488 000120 18      1   4  8
  Key to Flags:
    W (write), A (alloc), X (execute), M (merge), S (strings)
    I (info), L (link order), G (group), T (TLS), E (exclude), x (unknown)
    O (extra OS processing required) o (OS specific), p (processor specific)
    [root@jouet bpf]# ./offwaketime | head -3
  qemu-system-x86;entry_SYSCALL_64_fastpath;sys_ppoll;do_sys_poll;poll_schedule_timeout;schedule_hrtimeout_range;schedule_hrtimeout_range_clock;schedule;__schedule;-;try_to_wake_up;hrtimer_wakeup;__hrtimer_run_queues;hrtimer_interrupt;local_apic_timer_interrupt;smp_apic_timer_interrupt;__irqentry_text_start;cpuidle_enter_state;cpuidle_enter;call_cpuidle;cpu_startup_entry;rest_init;start_kernel;x86_64_start_reservations;x86_64_start_kernel;start_cpu;;swapper/0 4
  firefox;entry_SYSCALL_64_fastpath;sys_poll;do_sys_poll;poll_schedule_timeout;schedule_hrtimeout_range;schedule_hrtimeout_range_clock;schedule;__schedule;-;try_to_wake_up;pollwake;__wake_up_common;__wake_up_sync_key;pipe_write;__vfs_write;vfs_write;sys_write;entry_SYSCALL_64_fastpath;;Timer 1
  swapper/2;start_cpu;start_secondary;cpu_startup_entry;schedule_preempt_disabled;schedule;__schedule;-;---;; 61
  [root@jouet bpf]#

Signed-off-by: Joe Stringer <joe@ovn.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: netdev@vger.kernel.org
Link: https://github.com/joestringer/linux/commit/5c40f54a52b1f437123c81e21873f4b4b1f9bd55.patch
Link: http://lkml.kernel.org/n/tip-xr8twtx7sjh5821g8qw47yxk@git.kernel.org
[ Use -I$(srctree)/tools/lib/ to support out of source code tree builds, as noticed by Wang Nan ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf diff: Do not overwrite valid build id

Fixes a perf diff regression issue which was introduced by commit
5baecbcd9c9a ("perf symbols: we can now read separate debug-info files
based on a build ID")

The binary name could be same when perf diff different binaries. Build
id is used to distinguish between them.
However, the previous patch assumes the same binary name has same build
id. So it overwrites the build id according to the binary name,
regardless of whether the build id is set or not.

Check the has_build_id in dso__load. If the build id is already set, use
it.

Before the fix:

  $ perf diff 1.perf.data 2.perf.data
  # Event 'cycles'
  #
  # Baseline    Delta  Shared Object     Symbol
  # ........  .......  ................  .............................
  #
    99.83%  -99.80%  tchain_edit       [.] f2
     0.12%  +99.81%  tchain_edit       [.] f3
     0.02%   -0.01%  [ixgbe]           [k] ixgbe_read_reg

  After the fix:
  $ perf diff 1.perf.data 2.perf.data
  # Event 'cycles'
  #
  # Baseline    Delta  Shared Object     Symbol
  # ........  .......  ................  .............................
  #
    99.83%   +0.10%  tchain_edit       [.] f3
     0.12%   -0.08%  tchain_edit       [.] f2

Signed-off-by: Kan Liang <kan.liang@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
CC: Dima Kogan <dima@secretsauce.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Fixes: 5baecbcd9c9a ("perf symbols: we can now read separate debug-info files based on a build ID")
Link: http://lkml.kernel.org/r/1481642984-13593-1-git-send-email-kan.liang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf annotate: Don't throw error for zero length symbols

'perf report --tui' exits with error when it finds a sample of zero
length symbol (i.e. addr == sym->start == sym->end). Actually these are
valid samples. Don't exit TUI and show report with such symbols.

Reported-and-Tested-by: Anton Blanchard <anton@samba.org>
Link: https://lkml.org/lkml/2016/10/8/189
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Chris Riyder <chris.ryder@arm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@kernel.org # v4.9+
Link: http://lkml.kernel.org/r/1479804050-5028-1-git-send-email-ravi.bangoria@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf bench futex: Fix lock-pi help string

Obvious copy/paste typo from the requeue program.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Davidlohr Bueso <dbueso@suse.de>
Link: http://lkml.kernel.org/r/1481830584-30909-1-git-send-email-dave@stgolabs.net
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf trace: Check if MAP_32BIT is defined (again)

There might be systems where MAP_32BIT is not defined, like some some
RHEL7 powerpc versions.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Kyle McMartin <kyle@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Fixes: 256763b01741 ("perf trace beauty mmap: Add more conditional defines")
Link: http://lkml.kernel.org/r/1481831814-23683-1-git-send-email-jolsa@kernel.org
[ Changed the Fixme cset to the one removing the conditional switch case for MAP_32BIT ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

samples/bpf: Make perf_event_read() static

While testing Joe's conversion of samples/bpf/ to use tools/lib/bpf/ I noticed
some warnings building samples/bpf/ on a Fedora Rawhide container, with
clang/llvm 3.9 I noticed this:

  [root@1e797fdfbf4f linux]# make -j4 O=/tmp/build/linux/ samples/bpf/
  make[1]: Entering directory '/tmp/build/linux'
    CHK     include/config/kernel.release
    GEN     ./Makefile
    CHK     include/generated/uapi/linux/version.h
    Using /git/linux as source for kernel
  <SNIP>
    HOSTCC  samples/bpf/trace_output_user.o
  /git/linux/samples/bpf/trace_output_user.c:64:6: warning: no previous
  prototype for 'perf_event_read' [-Wmissing-prototypes]
   void perf_event_read(print_fn fn)
        ^~~~~~~~~~~~~~~
    HOSTLD  samples/bpf/trace_output
  make[1]: Leaving directory '/tmp/build/linux'

Shut up the compiler by making that function static.

Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Joe Stringer <joe@ovn.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/20161215152927.GC6866@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

uprobes: Fix uprobes on MIPS, allow for a cache flush after ixol breakpoint creation

Commit:

  72e6ae285a1d ('ARM: 8043/1: uprobes need icache flush after xol write'

... has introduced an arch-specific method to ensure all caches are
flushed appropriately after an instruction is written to an XOL page.

However, when the XOL area is created and the out-of-line breakpoint
instruction is copied, caches are not flushed at all and stale data may
be found in icache.

Replace a simple copy_to_page() with arch_uprobe_copy_ixol() to allow
the arch to ensure all caches are updated accordingly.

This change fixes uprobes on MIPS InterAptiv (tested on Creator Ci40).

Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Victor Kamensky <victor.kamensky@linaro.org>
Cc: linux-mips@linux-mips.org
Link: http://lkml.kernel.org/r/1481625657-22850-1-git-send-email-marcin.nowakowski@imgtec.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

samples/bpf: Make samples more libbpf-centric

Switch all of the sample code to use the function names from
tools/lib/bpf so that they're consistent with that, and to declare their
own log buffers. This allow the next commit to be purely devoted to
getting rid of the duplicate library in samples/bpf.

Committer notes:

Testing it:

On a fedora rawhide container, with clang/llvm 3.9, sharing the host
linux kernel git tree:

  # make O=/tmp/build/linux/ headers_install
  # make O=/tmp/build/linux -C samples/bpf/

Since I forgot to make it privileged, just tested it outside the
container, using what it generated:

  # uname -a
  Linux jouet 4.9.0-rc8+ #1 SMP Mon Dec 12 11:20:49 BRT 2016 x86_64 x86_64 x86_64 GNU/Linux
  # cd /var/lib/docker/devicemapper/mnt/c43e09a53ff56c86a07baf79847f00e2cc2a17a1e2220e1adbf8cbc62734feda/rootfs/tmp/build/linux/samples/bpf/
  # ls -la offwaketime
  -rwxr-xr-x. 1 root root 24200 Dec 15 12:19 offwaketime
  # file offwaketime
  offwaketime: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=c940d3f127d5e66cdd680e42d885cb0b64f8a0e4, not stripped
  # readelf -SW offwaketime_kern.o  | grep PROGBITS
  [ 2] .text             PROGBITS        0000000000000000 000040 000000 00  AX  0   0  4
  [ 3] kprobe/try_to_wake_up PROGBITS        0000000000000000 000040 0000d8 00  AX  0   0  8
  [ 5] tracepoint/sched/sched_switch PROGBITS        0000000000000000 000118 000318 00  AX  0   0  8
  [ 7] maps              PROGBITS        0000000000000000 000430 000050 00  WA  0   0  4
  [ 8] license           PROGBITS        0000000000000000 000480 000004 00  WA  0   0  1
  [ 9] version           PROGBITS        0000000000000000 000484 000004 00  WA  0   0  4
  # ./offwaketime | head -5
  swapper/1;start_secondary;cpu_startup_entry;schedule_preempt_disabled;schedule;__schedule;-;---;; 106
  CPU 0/KVM;entry_SYSCALL_64_fastpath;sys_ioctl;do_vfs_ioctl;kvm_vcpu_ioctl;kvm_arch_vcpu_ioctl_run;kvm_vcpu_block;schedule;__schedule;-;try_to_wake_up;swake_up_locked;swake_up;apic_timer_expired;apic_timer_fn;__hrtimer_run_queues;hrtimer_interrupt;local_apic_timer_interrupt;smp_apic_timer_interrupt;__irqentry_text_start;cpuidle_enter;call_cpuidle;cpu_startup_entry;start_secondary;;swapper/3 2
  Compositor;entry_SYSCALL_64_fastpath;sys_futex;do_futex;futex_wait;futex_wait_queue_me;schedule;__schedule;-;try_to_wake_up;futex_requeue;do_futex;sys_futex;entry_SYSCALL_64_fastpath;;SoftwareVsyncTh 5
  firefox;entry_SYSCALL_64_fastpath;sys_poll;do_sys_poll;poll_schedule_timeout;schedule_hrtimeout_range;schedule_hrtimeout_range_clock;schedule;__schedule;-;try_to_wake_up;pollwake;__wake_up_common;__wake_up_sync_key;pipe_write;__vfs_write;vfs_write;sys_write;entry_SYSCALL_64_fastpath;;Timer 13
  JS Helper;entry_SYSCALL_64_fastpath;sys_futex;do_futex;futex_wait;futex_wait_queue_me;schedule;__schedule;-;try_to_wake_up;do_futex;sys_futex;entry_SYSCALL_64_fastpath;;firefox 2
  #

Signed-off-by: Joe Stringer <joe@ovn.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/20161214224342.12858-2-joe@ovn.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools lib bpf: Add flags to bpf_create_map()

Commit 6c905981743 ("bpf: pre-allocate hash map elements") introduces
map_flags to bpf_attr for BPF_MAP_CREATE command. Expose this new
parameter in libbpf.

By exposing it, users can access flags such as whether or not to
preallocate the map.

Signed-off-by: Joe Stringer <joe@ovn.org>
Acked-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Link: http://lkml.kernel.org/r/20161209024620.31660-4-joe@ovn.org
[ Added clarifying comment made by Wang Nan ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools lib bpf: use __u32 from linux/types.h

Fixes the following issue when building without access to 'u32' type:

./tools/lib/bpf/bpf.h:27:23: error: unknown type name ‘u32’

Signed-off-by: Joe Stringer <joe@ovn.org>
Acked-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Link: http://lkml.kernel.org/r/20161209024620.31660-3-joe@ovn.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools lib bpf: Sync {tools,}/include/uapi/linux/bpf.h

The tools version of this header is out of date; update it to the latest
version from the kernel headers.

Signed-off-by: Joe Stringer <joe@ovn.org>
Acked-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Link: http://lkml.kernel.org/r/20161209024620.31660-2-joe@ovn.org
[ Sync it harder, after merging with what was in net-next via perf/urgent via torvalds/master to get BPG_PROG_(AT|DE)TACH, etc ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf annotate: Fix jump target outside of function address range

If jump target is outside of function range, perf is not handling it
correctly. Especially when target address is lesser than function start
address, target offset will be negative. But, target address declared to
be unsigned, converts negative number into 2's complement. See below
example. Here target of 'jumpq' instruction at 34cf8 is 34ac0 which is
lesser than function start address(34cf0).

        34ac0 - 34cf0 = -0x230 = 0xfffffffffffffdd0

Objdump output:

  0000000000034cf0 <__sigaction>:
  __GI___sigaction():
    34cf0: lea    -0x20(%rdi),%eax
    34cf3: cmp    -bashx1,%eax
    34cf6: jbe    34d00 <__sigaction+0x10>
    34cf8: jmpq   34ac0 <__GI___libc_sigaction>
    34cfd: nopl   (%rax)
    34d00: mov    0x386161(%rip),%rax        # 3bae68 <_DYNAMIC+0x2e8>
    34d07: movl   -bashx16,%fs:(%rax)
    34d0e: mov    -bashxffffffff,%eax
    34d13: retq

perf annotate before applying patch:

  __GI___sigaction  /usr/lib64/libc-2.22.so
           lea    -0x20(%rdi),%eax
           cmp    -bashx1,%eax
        v  jbe    10
        v  jmpq   fffffffffffffdd0
           nop
    10:    mov    _DYNAMIC+0x2e8,%rax
           movl   -bashx16,%fs:(%rax)
           mov    -bashxffffffff,%eax
           retq

perf annotate after applying patch:

  __GI___sigaction  /usr/lib64/libc-2.22.so
           lea    -0x20(%rdi),%eax
           cmp    -bashx1,%eax
        v  jbe    10
        ^  jmpq   34ac0 <__GI___libc_sigaction>
           nop
    10:    mov    _DYNAMIC+0x2e8,%rax
           movl   -bashx16,%fs:(%rax)
           mov    -bashxffffffff,%eax
           retq

Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Chris Riyder <chris.ryder@arm.com>
Cc: Kim Phillips <kim.phillips@arm.com>
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Taeung Song <treeze.taeung@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1480953407-7605-3-git-send-email-ravi.bangoria@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf annotate: Support jump instruction with target as second operand

Architectures like PowerPC have jump instructions that includes a target
address as a second operand. For example, 'bne cr7,0xc0000000000f6154'.
Add support for such instruction in perf annotate.

objdump o/p:
  c0000000000f6140:   ld     r9,1032(r31)
  c0000000000f6144:   cmpdi  cr7,r9,0
  c0000000000f6148:   bne    cr7,0xc0000000000f6154
  c0000000000f614c:   ld     r9,2312(r30)
  c0000000000f6150:   std    r9,1032(r31)
  c0000000000f6154:   ld     r9,88(r31)

Corresponding perf annotate o/p:

Before patch:
         ld     r9,1032(r31)
         cmpdi  cr7,r9,0
      v  bne    3ffffffffff09f2c
         ld     r9,2312(r30)
         std    r9,1032(r31)
  74:    ld     r9,88(r31)

After patch:
         ld     r9,1032(r31)
         cmpdi  cr7,r9,0
      v  bne    74
         ld     r9,2312(r30)
         std    r9,1032(r31)
  74:    ld     r9,88(r31)

Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Chris Riyder <chris.ryder@arm.com>
Cc: Kim Phillips <kim.phillips@arm.com>
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Taeung Song <treeze.taeung@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1480953407-7605-2-git-send-email-ravi.bangoria@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf record: Force ignore_missing_thread for uid option

Enable perf_evsel::ignore_missing_thread for -u option to ignore
complete failure if any of the user's processes die between its
enumeration and time we open the event.

Committer notes:

While doing a 'make -j4 allmodconfig' we sometimes get into the race:

Before:

  # perf record -u acme
  Error:
  The sys_perf_event_open() syscall returned with 3 (No such process) for event (cycles:ppp).
  /bin/dmesg may provide additional information.
  No CONFIG_PERF_EVENTS=y kernel support configured?
  #

After:

  [root@jouet ~]# perf record -u acme
  WARNING: Ignored open failure for pid 9888
  WARNING: Ignored open failure for pid 18059
  [root@jouet ~]#

Which is an improvement, with the races not preventing the remaining threads
for the specified user from being monitored, but the message probably needs
further clarification.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1481538943-21874-6-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf evsel: Allow to ignore missing pid

Adding perf_evsel::ignore_missing_cpu_thread bool.

When set true, it allows perf to ignore error of missing pid of perf
event syscall.

We remove missing thread id from the thread_map, so the rest of the
processing like ioctl and mmap won't get disturbed with -1 fd.

The reason for supporting this is to ease up monitoring group of pids,
that 'disappear' before perf opens their event. This currently leads
perf to report error and exit and makes perf record's -u option unusable
under certain setup.

With this change we will allow this race and ignore such failure with
following warning:

  WARNING: Ignored open failure for pid 8605

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20161213074622.GA3084@krava
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf thread_map: Add thread_map__remove function

Add thread_map__remove function to remove thread from thread map.

Add automated test also.

Committer notes:

Testing it:

  # perf test "Remove thread map"
  39: Remove thread map                          : Ok
  # perf test -v "Remove thread map"
  39: Remove thread map                          :
  --- start ---
  test child forked, pid 4483
  2 threads: 4482, 4483
  1 thread: 4483
  0 thread:
  test child finished with 0
  ---- end ----
  Remove thread map: Ok
  #

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1481538943-21874-4-git-send-email-jolsa@kernel.org
[ Added stdlib.h, to get the free() declaration ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf evsel: Use variable instead of repeating lengthy FD macro

It's more readable and will ease up following patches.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1481538943-21874-3-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf mem: Fix --all-user/--all-kernel options

Removing extra '--' prefix.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Fixes: ad16511b0e40 ("perf mem: Add -U/-K (--all-user/--all-kernel) options")
Link: http://lkml.kernel.org/r/1481538943-21874-2-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf tools: Remove some needless __maybe_unused

I.e. those parameters/functions _are_ used, so ditch that misleading attribute.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-13cqtjh0yojg5gzvpq1zzpl0@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf sched timehist: Show callchains for idle stat

When --idle-hist option is used with --summary, it now shows idle stats
with callchains like below:

  Idle stats by callchain:
  CPU  0:   902.195 msec
  Idle time (msec)    Count Callchains
  ----------------  ------- --------------------------------------------------
           370.589       69 futex_wait_queue_me <- futex_wait <- do_futex <- sys_futex <- entry_SYSCALL_64_fastpath
           178.799       17 worker_thread <- kthread <- ret_from_fork
           128.352       17 schedule_timeout <- rcu_gp_kthread <- kthread <- ret_from_fork
           125.111       19 schedule_hrtimeout_range_clock <- schedule_hrtimeout_range <- poll_schedule_timeout <- do_select <- core_sys_select
            71.599       50 schedule_hrtimeout_range_clock <- schedule_hrtimeout_range <- poll_schedule_timeout <- do_sys_poll <- sys_poll
            23.146        1 rcu_gp_kthread <- kthread <- ret_from_fork
             4.510        1 schedule_hrtimeout_range_clock <- schedule_hrtimeout_range <- ep_poll <- sys_epoll_wait <- do_syscall_64
             0.085        1 schedule_hrtimeout_range_clock <- schedule_hrtimeout_range <- poll_schedule_timeout <- do_sys_poll <- do_restart_poll
  ...

Committer notes:

Extra testing:

  # uname -a
  Linux jouet 4.8.8-300.fc25.x86_64 #1 SMP Tue Nov 15 18:10:06 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

1) Run 'perf sched record -g'

2) Run 'perf sched timehist --idle --summary'

<SNIP>
  Idle stats by callchain:
  CPU  0: 13456.840 msec
  Idle time (msec) Count Callchains
  ---------------- ----- --------------------------------------------------
          5386.637  3283 schedule_hrtimeout_range_clock <- schedule_hrtimeout_range <- poll_schedule_timeout <- do_sys_poll <- sys_poll
          2750.238  2299 futex_wait_queue_me <- futex_wait <- do_futex <- sys_futex <- do_syscall_64
          1275.672  1287 schedule_hrtimeout_range_clock <- schedule_hrtimeout_range <- ep_poll <- sys_epoll_wait <- entry_SYSCALL_64_fastpath
           936.322   452 worker_thread <- kthread <- ret_from_fork
           741.311   385 rcu_nocb_kthread <- kthread <- ret_from_fork
           729.385   248 schedule_hrtimeout_range_clock <- schedule_hrtimeout_range <- poll_schedule_timeout <- do_sys_poll <- sys_ppoll
           365.386   229 irq_thread <- kthread <- ret_from_fork
           338.934   265 futex_wait_queue_me <- futex_wait <- do_futex <- sys_futex <- entry_SYSCALL_64_fastpath
           219.488   201 schedule_timeout <- rcu_gp_kthread <- kthread <- ret_from_fork
           186.839   410 schedule_hrtimeout_range_clock <- schedule_hrtimeout_range <- ep_poll <- sys_epoll_wait <- do_syscall_64
           142.541    59 kvm_vcpu_block <- kvm_arch_vcpu_ioctl_run <- kvm_vcpu_ioctl <- do_vfs_ioctl <- sys_ioctl
            83.887    92 smpboot_thread_fn <- kthread <- ret_from_fork
            62.722    96 do_exit <- do_group_exit <- 0x2a5594 <- entry_SYSCALL_64_fastpath
            47.894    83 pipe_wait <- pipe_read <- __vfs_read <- vfs_read <- sys_read
            46.554    61 rcu_gp_kthread <- kthread <- ret_from_fork
            34.337    21 schedule_timeout <- intel_fbc_work_fn <- process_one_work <- worker_thread <- kthread
            29.521    14 schedule_hrtimeout_range_clock <- schedule_hrtimeout_range <- poll_schedule_timeout <- do_select <- core_sys_select
            20.274    10 schedule_timeout <- io_schedule_timeout <- bit_wait_io <- __wait_on_bit <- out_of_line_wait_on_bit
            15.085    55 schedule_timeout <- unix_stream_read_generic <- unix_stream_recvmsg <- sock_recvmsg <- SYSC_recvfrom
<SNIP>

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20161208144755.16673-7-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf sched timehist: Add -I/--idle-hist option

The --idle-hist option is to analyze system idle state so which process
makes cpu to go idle.  If this option is specified, non-idle events will
be skipped and processes switching to/from idle will be shown.

This option is mostly useful when used with --summary(-only) option.  In
the idle-time summary view, idle time is accounted to previous thread
which is run before idle task.

The example output looks like following:

  Idle-time summary
                  comm parent sched-out idle-time min-idle avg-idle max-idle stddev migrations
                                (count)    (msec)   (msec)   (msec)   (msec)      %
  --------------------------------------------------------------------------------------------
        rcu_preempt[7]      2        95   550.872    0.011    5.798   23.146   7.63      0
       migration/1[16]      2         1    15.558   15.558   15.558   15.558   0.00      0
        khugepaged[39]      2         1     3.062    3.062    3.062    3.062   0.00      0
     kworker/0:1H[124]      2         2     4.728    0.611    2.364    4.116  74.12      0
  systemd-journal[167]      1         1     4.510    4.510    4.510    4.510   0.00      0
    kworker/u16:3[558]      2        13    74.737    0.080    5.749   12.960  21.96      0
   irq/34-iwlwifi[628]      2        21   118.403    0.032    5.638   23.990  24.00      0
    kworker/u17:0[673]      2         1     3.523    3.523    3.523    3.523   0.00      0
      dbus-daemon[722]      1         1     6.743    6.743    6.743    6.743   0.00      0
          ifplugd[741]      1         1    58.826   58.826   58.826   58.826   0.00      0
  wpa_supplicant[1490]      1         1    13.302   13.302   13.302   13.302   0.00      0
     wpa_actiond[1492]      1         2     4.064    0.168    2.032    3.896  91.72      0
         dockerd[1500]      1         1     0.055    0.055    0.055    0.055   0.00      0
  ...

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20161208144755.16673-6-namhyung@kernel.org
Link: http://lkml.kernel.org/r/20161213080632.19099-2-namhyung@kernel.org
[ Merged fix sent by Namhyumg, as posted in the second Link: tag ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf sched timehist: Skip non-idle events when necessary

Sometimes it only focuses on idle-related events like upcoming idle-hist
feature.  In this case we don't want to see other event to reduce noise.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20161208144755.16673-5-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf sched timehist: Save callchain when entering idle

In order to investigate the idleness reason, it is necessary to keep the
callchains when entering idle.  This can be identified by the
sched:sched_switch event having the next_pid field as 0.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20161208144755.16673-4-namhyung@kernel.org
Link: http://lkml.kernel.org/r/20161213080632.19099-1-namhyung@kernel.org
[ Merged fix from Namhyung, see second Link: tag ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf sched timehist: Introduce struct idle_time_data

The struct idle_time_data is to keep idle stats with callchains entering
to the idle task.  The normal thread_runtime calculation is done
transparently since it extends the struct thread_runtime.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20161208144755.16673-3-namhyung@kernel.org
[ Align struct field names ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf sched timehist: Split is_idle_sample()

The is_idle_sample() function actually does more than determining
whether sample come from idle task.  Split the callchain part into
save_task_callchain() to make it clearer.

Also checking prev_pid from trace data looks preferred than just
checking sample->pid since it's possible, although rare, to have invalid
0 pid/tid on scheduling an exiting task.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20161208144755.16673-2-namhyung@kernel.org
[ Remove some needless () in some return statements ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf tools: Move headers check into bash script

To make it nicer and easily maintainable.

Also moving the check into fixdep sub make, so its output is not
scattered around the build output.

Removing extra $$ from mman*.h checks.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1481030331-31944-5-git-send-email-jolsa@kernel.org
[ Use /bin/sh, and 'function check() {' -> 'check () {' to make it work with busybox, in Alpine Linux, for instance ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Merge tag 'docs-4.10' of git://git.lwn.net/linux

Pull documentation update from Jonathan Corbet:
 "These are the documentation changes for 4.10.

  It's another busy cycle for the docs tree, as the sphinx conversion
  continues. Highlights include:

   - Further work on PDF output, which remains a bit of a pain but
     should be more solid now.

   - Five more DocBook template files converted to Sphinx. Only 27 to
     go... Lots of plain-text files have also been converted and
     integrated.

   - Images in binary formats have been replaced with more
     source-friendly versions.

   - Various bits of organizational work, including the renaming of
     various files discussed at the kernel summit.

   - New documentation for the device_link mechanism.

  ... and, of course, lots of typo fixes and small updates"

* tag 'docs-4.10' of git://git.lwn.net/linux: (193 commits)
  dma-buf: Extract dma-buf.rst
  Update Documentation/00-INDEX
  docs: 00-INDEX: document directories/files with no docs
  docs: 00-INDEX: remove non-existing entries
  docs: 00-INDEX: add missing entries for documentation files/dirs
  docs: 00-INDEX: consolidate process/ and admin-guide/ description
  scripts: add a script to check if Documentation/00-INDEX is sane
  Docs: change sh -> awk in REPORTING-BUGS
  Documentation/core-api/device_link: Add initial documentation
  core-api: remove an unexpected unident
  ppc/idle: Add documentation for powersave=off
  Doc: Correct typo, "Introdution" => "Introduction"
  Documentation/atomic_ops.txt: convert to ReST markup
  Documentation/local_ops.txt: convert to ReST markup
  Documentation/assoc_array.txt: convert to ReST markup
  docs-rst: parse-headers.pl: cleanup the documentation
  docs-rst: fix media cleandocs target
  docs-rst: media/Makefile: reorganize the rules
  docs-rst: media: build SVG from graphviz files
  docs-rst: replace bayer.png by a SVG image
  ...

Merge branch 'akpm' (patches from Andrew)

Merge updates from Andrew Morton:

 - various misc bits

 - most of MM (quite a lot of MM material is awaiting the merge of
   linux-next dependencies)

 - kasan

 - printk updates

 - procfs updates

 - MAINTAINERS

 - /lib updates

 - checkpatch updates

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (123 commits)
  init: reduce rootwait polling interval time to 5ms
  binfmt_elf: use vmalloc() for allocation of vma_filesz
  checkpatch: don't emit unified-diff error for rename-only patches
  checkpatch: don't check c99 types like uint8_t under tools
  checkpatch: avoid multiple line dereferences
  checkpatch: don't check .pl files, improve absolute path commit log test
  scripts/checkpatch.pl: fix spelling
  checkpatch: don't try to get maintained status when --no-tree is given
  lib/ida: document locking requirements a bit better
  lib/rbtree.c: fix typo in comment of ____rb_erase_color
  lib/Kconfig.debug: make CONFIG_STRICT_DEVMEM depend on CONFIG_DEVMEM
  MAINTAINERS: add drm and drm/i915 irc channels
  MAINTAINERS: add "C:" for URI for chat where developers hang out
  MAINTAINERS: add drm and drm/i915 bug filing info
  MAINTAINERS: add "B:" for URI where to file bugs
  get_maintainer: look for arbitrary letter prefixes in sections
  printk: add Kconfig option to set default console loglevel
  printk/sound: handle more message headers
  printk/btrfs: handle more message headers
  printk/kdb: handle more message headers
  ...

treewide: Make remaining source files non-executable

.c and .h source files should not be executable, change
the permissions to 0644.

[ This would normally go through Andrew Morton, but his ancient
  patch-based toolchain doesn't do permission changes ]

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge branch 'irq-core-for-linus' of git://git./linux/kernel/git/tip/tip

Pull irq updates from Thomas Gleixner:
 "The irq department provides:

   - a major update to the auto affinity management code, which is used
     by multi-queue devices

   - move of the microblaze irq chip driver into the common driver code
     so it can be shared between microblaze, powerpc and MIPS

   - a series of updates to the ARM GICV3 interrupt controller

   - the usual pile of fixes and small improvements all over the place"

* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (25 commits)
  powerpc/virtex: Use generic xilinx irqchip driver
  irqchip/xilinx: Try to fall back if xlnx,kind-of-intr not provided
  irqchip/xilinx: Add support for parent intc
  irqchip/xilinx: Rename get_irq to xintc_get_irq
  irqchip/xilinx: Restructure and use jump label api
  irqchip/xilinx: Clean up print messages
  microblaze/irqchip: Move intc driver to irqchip
  ARM: virt: Select ARM_GIC_V3_ITS
  ARM: gic-v3-its: Add 32bit support to GICv3 ITS
  irqchip/gic-v3-its: Specialise readq and writeq accesses
  irqchip/gic-v3-its: Specialise flush_dcache operation
  irqchip/gic-v3-its: Narrow down Entry Size when used as a divider
  irqchip/gic-v3-its: Change unsigned types for AArch32 compatibility
  irqchip/gic-v3: Use nops macro for Cavium ThunderX erratum 23154
  irqchip/gic-v3: Convert arm64 GIC accessors to {read,write}_sysreg_s
  genirq/msi: Drop artificial PCI dependency
  irqchip/bcm7038-l1: Implement irq_cpu_offline() callback
  genirq/affinity: Use default affinity mask for reserved vectors
  genirq/affinity: Take reserved vectors into account when spreading irqs
  PCI: Remove the irq_affinity mask from struct pci_dev
  ...

Merge branch 'timers-core-for-linus' of git://git./linux/kernel/git/tip/tip

Pull timer updates from Thomas Gleixner:
 "The time/timekeeping/timer folks deliver with this update:

   - Fix a reintroduced signed/unsigned issue and cleanup the whole
     signed/unsigned mess in the timekeeping core so this wont happen
     accidentaly again.

   - Add a new trace clock based on boot time

   - Prevent injection of random sleep times when PM tracing abuses the
     RTC for storage

   - Make posix timers configurable for real tiny systems

   - Add tracepoints for the alarm timer subsystem so timer based
     suspend wakeups can be instrumented

   - The usual pile of fixes and updates to core and drivers"

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
  timekeeping: Use mul_u64_u32_shr() instead of open coding it
  timekeeping: Get rid of pointless typecasts
  timekeeping: Make the conversion call chain consistently unsigned
  timekeeping_Force_unsigned_clocksource_to_nanoseconds_conversion
  alarmtimer: Add tracepoints for alarm timers
  trace: Update documentation for mono, mono_raw and boot clock
  trace: Add an option for boot clock as trace clock
  timekeeping: Add a fast and NMI safe boot clock
  timekeeping/clocksource_cyc2ns: Document intended range limitation
  timekeeping: Ignore the bogus sleep time if pm_trace is enabled
  selftests/timers: Fix spelling mistake "Asyncrhonous" -> "Asynchronous"
  clocksource/drivers/bcm2835_timer: Unmap region obtained by of_iomap
  clocksource/drivers/arm_arch_timer: Map frame with of_io_request_and_map()
  arm64: dts: rockchip: Arch counter doesn't tick in system suspend
  clocksource/drivers/arm_arch_timer: Don't assume clock runs in suspend
  posix-timers: Make them configurable
  posix_cpu_timers: Move the add_device_randomness() call to a proper place
  timer: Move sys_alarm from timer.c to itimer.c
  ptp_clock: Allow for it to be optional
  Kconfig: Regenerate *.c_shipped files after previous changes
  ...

Merge branch 'smp-hotplug-for-linus' of git://git./linux/kernel/git/tip/tip

Pull smp hotplug updates from Thomas Gleixner:
 "This is the final round of converting the notifier mess to the state
  machine. The removal of the notifiers and the related infrastructure
  will happen around rc1, as there are conversions outstanding in other
  trees.

  The whole exercise removed about 2000 lines of code in total and in
  course of the conversion several dozen bugs got fixed. The new
  mechanism allows to test almost every hotplug step standalone, so
  usage sites can exercise all transitions extensively.

  There is more room for improvement, like integrating all the
  pointlessly different architecture mechanisms of synchronizing,
  setting cpus online etc into the core code"

* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (60 commits)
  tracing/rb: Init the CPU mask on allocation
  soc/fsl/qbman: Convert to hotplug state machine
  soc/fsl/qbman: Convert to hotplug state machine
  zram: Convert to hotplug state machine
  KVM/PPC/Book3S HV: Convert to hotplug state machine
  arm64/cpuinfo: Convert to hotplug state machine
  arm64/cpuinfo: Make hotplug notifier symmetric
  mm/compaction: Convert to hotplug state machine
  iommu/vt-d: Convert to hotplug state machine
  mm/zswap: Convert pool to hotplug state machine
  mm/zswap: Convert dst-mem to hotplug state machine
  mm/zsmalloc: Convert to hotplug state machine
  mm/vmstat: Convert to hotplug state machine
  mm/vmstat: Avoid on each online CPU loops
  mm/vmstat: Drop get_online_cpus() from init_cpu_node_state/vmstat_cpu_dead()
  tracing/rb: Convert to hotplug state machine
  oprofile/nmi timer: Convert to hotplug state machine
  net/iucv: Use explicit clean up labels in iucv_init()
  x86/pci/amd-bus: Convert to hotplug state machine
  x86/oprofile/nmi: Convert to hotplug state machine
  ...

init: reduce rootwait polling interval time to 5ms

For several devices, the rootwait time is sensitive because it directly
affects booting time.  The polling interval of rootwait is currently
100ms.  To save unnessesary waiting time, reduce the polling interval to
5 ms.

[akpm@linux-foundation.org: remove used-once #define]
Link: http://lkml.kernel.org/r/20161207060743.1728-1-js07.lee@samsung.com
Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

binfmt_elf: use vmalloc() for allocation of vma_filesz

We have observed page allocations failures of order 4 during core dump
while trying to allocate vma_filesz.  This results in a useless core
file of size 0.  To improve reliability use vmalloc().

Note that the vmalloc() allocation is bounded by sysctl_max_map_count,
which is 65,530 by default.  So with a 4k page size, and 8 bytes per
seg, this is a max of 128 pages or an order 7 allocation.  Other parts
of the core dump path, such as fill_files_note() are already using
vmalloc() for presumably similar reasons.

Link: http://lkml.kernel.org/r/1479745791-17611-1-git-send-email-jbaron@akamai.com
Signed-off-by: Jason Baron <jbaron@akamai.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

checkpatch: don't emit unified-diff error for rename-only patches

I generated a patch with `git format-patch` which checkpatch thinks is
invalid:

    $ ./scripts/checkpatch.pl lpc-dt/0006-mfd-dt-Move-syscon-bindings-to-syscon-subdirectory.patch
    WARNING: added, moved or deleted file(s), does MAINTAINERS need updating?
     Documentation/devicetree/bindings/mfd/{ => syscon}/aspeed-scu.txt         | 0

    ERROR: Does not appear to be a unified-diff format patch

    total: 1 errors, 1 warnings, 0 lines checked

    NOTE: For some of the reported defects, checkpatch may be able to
          mechanically convert to the typical style using --fix or --fix-inplace.

    lpc-dt/0006-mfd-dt-Move-syscon-bindings-to-syscon-subdirectory.patch has style problems, please review.

    NOTE: If any of the errors are false positives, please report
          them to the maintainer, see CHECKPATCH in MAINTAINERS.

The patch in question was all renames with no edits, giving 100%
similarity and thus no diff markers.

Set '$is_patch = 1;' in the add/remove/rename detection to avoid
generating spurious warnings.

Link: http://lkml.kernel.org/r/20161205232224.22685-1-andrew@aj.id.au
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Acked-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

checkpatch: don't check c99 types like uint8_t under tools

Tools contains user space code so uintX_t types are just fine.

Link: http://lkml.kernel.org/r/1479286379-853-1-git-send-email-tomas.winkler@intel.com
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Acked-by: Joe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

checkpatch: avoid multiple line dereferences

Code that puts a single dereferencing identifier on multiple lines like:

     struct_identifier->member[index].
member = <foo>;

is generally hard to follow.

Prefer that dereferencing identifiers be single line.

Link: http://lkml.kernel.org/r/e9c191ae3f41bedc8ffd5c0fbcc5a1cec1d1d2df.1478120869.git.joe@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

checkpatch: don't check .pl files, improve absolute path commit log test

perl files (*.pl) are mostly inappropriate to check coding styles so
exempt them from long line checks and various .[ch] file type tests.

And as well, only scan absolute paths in the commit log, not in the
patch.

Link: http://lkml.kernel.org/r/85b101d50acafe6c0261d9f7df283c827da52c4a.1477340110.git.joe@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/checkpatch.pl: fix spelling

s/preceeded/preceded/

Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

checkpatch: don't try to get maintained status when --no-tree is given

Fixes the following warning:

  Use of uninitialized value $root in concatenation (.) or string at /path/to/checkpatch.pl line 764.

Link: http://lkml.kernel.org/r/1476719709-16668-1-git-send-email-jerome.forissier@linaro.org
Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
Reviewed-by: Brian Norris <computersforpeace@gmail.com>
Acked-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/ida: document locking requirements a bit better

I wanted to wrap a bunch of ida_simple_get calls into their own locking,
until I dug around and read the original commit message.  Stuff like
this should imo be added to the kernel doc, let's do that.

Link: http://lkml.kernel.org/r/20161027072216.20411-1-daniel.vetter@ffwll.ch
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/rbtree.c: fix typo in comment of ____rb_erase_color

In Case 3 of `sibling == parent->rb_right':

Right rotation will not change color of sl and S in the diagram
(i.e. should not change "sl" to "Sl", "S" to "s")

In Case 3 of `sibling == parent->rb_left':

     (p)           (p)
     / \           / \
    S   N    -->  sr  N
   / \           /
  Sl  sr        S
               /
              Sl

  This is actually left rotation at "S", not right rotation.

In Case 4 of `sibling == parent->rb_left':

     (p)             (s)
     / \             / \
    S   N     -->   Sl  P
   / \                 / \
  sl (sr)            (sr) N

  This is actually right rotation at "(p)" + color flips, not left
  rotation + color flips.

Link: http://lkml.kernel.org/r/1472391115-3702-1-git-send-email-fykcee1@gmail.com
Signed-off-by: Jie Chen <fykcee1@gmail.com>
Cc: Wei Yang <weiyang@linux.vnet.ibm.com>
Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/Kconfig.debug: make CONFIG_STRICT_DEVMEM depend on CONFIG_DEVMEM

With CONFIG_DEVMEM not set, CONFIG_STRICT_DEVMEM will be useless even if
it is set =y, thus let's update the dependency in Kconfig.

Link: http://lkml.kernel.org/r/20161006051217.GA31027@dhcp-128-65.nay.redhat.com
Signed-off-by: Dave Young <dyoung@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

MAINTAINERS: add drm and drm/i915 irc channels

Link: http://lkml.kernel.org/r/1476966135-26943-4-git-send-email-jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

MAINTAINERS: add "C:" for URI for chat where developers hang out

Make it easier to find the developer chat for the subsystem or driver.

Link: http://lkml.kernel.org/r/1476966135-26943-3-git-send-email-jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

MAINTAINERS: add drm and drm/i915 bug filing info

Link: http://lkml.kernel.org/r/1476966135-26943-2-git-send-email-jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

MAINTAINERS: add "B:" for URI where to file bugs

Different subsystems and drivers have different preferences for where to
file bugs and what information to include.  Add "B:" entry for
specifying the URI for the bug tracker directly, a web page for detailed
info on filing bugs, or a mailto: URI.

Link: http://lkml.kernel.org/r/1476966135-26943-1-git-send-email-jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Acked-by: Daniel Vetter <daniel@ffwll.ch>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

get_maintainer: look for arbitrary letter prefixes in sections

Jani Nikula proposes patches to add a few new letter prefixes for "B:"
bug reporting and "C:" maintainer chatting to the various sections of
MAINTAINERS.

Add a generic mechanism to get_maintainer.pl to find sections that have
any combination of "[A-Z]" letter prefix types in a section.

Link: http://lkml.kernel.org/r/1477332323.1984.8.camel@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Airlie <airlied@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

printk: add Kconfig option to set default console loglevel

Add a configuration option to set the default console loglevel.  This
is, as before, still possible to override at runtime through bootargs
(loglevel=<x>), sysrq and /proc/printk.

There are cases where adding additional arguments on the commandline is
impractical, and changing the default for the kernel when being built
makes more sense.  Provide such a method here, for those who choose to
do so.

Also, while touching this code, clarify the difference between
MESSAGE_LOGLEVEL_DEFAULT and CONSOLE_LOGLEVEL_DEFAULT.

Link: http://lkml.kernel.org/r/1479676829-30031-1-git-send-email-olof@lixom.net
Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

printk/sound: handle more message headers

Commit 4bcc595ccd80 ("printk: reinstate KERN_CONT for printing
continuation lines") allows to define more message headers for a single
message.  The motivation is that continuous lines might get mixed.
Therefore it make sense to define the right log level for every piece of
a cont line.

This patch allows to copy only the real message level.  We should ignore
KERN_CONT because <filename:line> is added for each message.  By other
words, we want to know where each piece of the line comes from.

[pmladek@suse.com: fix a check of the valid message level]
Link: http://lkml.kernel.org/r/20161111183444.GE2145@dhcp128.suse.cz
Link: http://lkml.kernel.org/r/1478695291-12169-5-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Joe Perches <joe@perches.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <jbacik@fb.com>
Cc: David Sterba <dsterba@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

printk/btrfs: handle more message headers

Commit 4bcc595ccd80 ("printk: reinstate KERN_CONT for printing
continuation lines") allows to define more message headers for a single
message.  The motivation is that continuous lines might get mixed.
Therefore it make sense to define the right log level for every piece of
a cont line.

The current btrfs_printk() macros do not support continuous lines at the
moment.  But better be prepared for a custom messages and avoid
potential "lvl" buffer overflow.

This patch iterates over the entire message header.  It is interested
only into the message level like the original code.

This patch also introduces PRINTK_MAX_SINGLE_HEADER_LEN.  Three bytes
are enough for the message level header at the moment.  But it used to
be three, see the commit 04d2c8c83d0e ("printk: convert the format for
KERN_<LEVEL> to a 2 byte pattern").

Also I fixed the default ratelimit level.  It looked very strange when it
was different from the default log level.

[pmladek@suse.com: Fix a check of the valid message level]
Link: http://lkml.kernel.org/r/20161111183236.GD2145@dhcp128.suse.cz
Link: http://lkml.kernel.org/r/1478695291-12169-4-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: David Sterba <dsterba@suse.com>
Cc: Joe Perches <joe@perches.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <jbacik@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

printk/kdb: handle more message headers

Commit 4bcc595ccd80 ("printk: reinstate KERN_CONT for printing
continuation lines") allows to define more message headers for a single
message.  The motivation is that continuous lines might get mixed.
Therefore it make sense to define the right log level for every piece of
a cont line.

This patch introduces printk_skip_headers() that will skip all headers
and uses it in the kdb code instead of printk_skip_level().

This approach helps to fix other printk_skip_level() users
independently.

Link: http://lkml.kernel.org/r/1478695291-12169-3-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Joe Perches <joe@perches.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <jbacik@fb.com>
Cc: David Sterba <dsterba@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

printk/NMI: handle continuous lines and missing newline

Commit 4bcc595ccd80 ("printk: reinstate KERN_CONT for printing
continuation lines") added back KERN_CONT message header.  As a result
it might appear in the middle of the line when the parts are squashed
via the temporary NMI buffer.

A reasonable solution seems to be to split the text in the NNI temporary
not only by newlines but also by the message headers.

Another solution would be to filter out KERN_CONT when writing to the
temporary buffer.  But this would complicate the lockless handling.
Also it would not solve problems with a missing newline that was there
even before the KERN_CONT stuff.

This patch moves the temporary buffer handling into separate function.
I played with it and it seems that using the char pointers make the code
easier to read.

Also it prints the final newline as a continuous line.

Finally, it moves handling of the s->len overflow into the paranoid
check.  And allows to recover from the disaster.

Link: http://lkml.kernel.org/r/1478695291-12169-2-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Joe Perches <joe@perches.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <jbacik@fb.com>
Cc: David Sterba <dsterba@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

printk/NMI: fix up handling of the full nmi log buffer

vsnprintf() adds the trailing '\0' but it does not count it into the
number of printed characters.  The result is that there is one byte less
space for the real characters in the buffer.

The broken check for the free space might cause that we will repeatedly
try to print 1 character into the buffer, never reach the full buffer,
and do not count the messages as missed.

Also vsnprintf() returns the number of characters that would be printed
if the buffer was big enough.  As a result, s->len might be bigger than
the size of the buffer[*].  And the printk() function might return
bigger len than it really printed.  Both problems are fixed by using
vscnprintf() instead.

Note that I though about increasing the number of missed messages even
when the message was shrunken.  But it made the code even more
complicated.  I think that it is not worth it.  Shrunken messages are
usually easy to recognize.  And it should be a corner case.

[*] The overflown s->len value is crazy and unexpected.  I "made a
mistake" and reported this situation as an internal error when fixed
handling of PR_CONT headers in some other patch.

Link: http://lkml.kernel.org/r/20161208174912.GA17042@linux.suse
Signed-off-by: Petr Mladek <pmladek@suse.com>
CcL Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Chris Mason <clm@fb.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Josef Bacik <jbacik@fb.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Takashi Iwai <tiwai@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

compiler-gcc.h: use "proved" instead of "proofed"

Link: http://lkml.kernel.org/r/1477894241.1103202.772260161.1B0A5995@webmail.messagingengine.com
Signed-off-by: Benjamin Peterson <bp@benjamin.pe>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

hung_task: decrement sysctl_hung_task_warnings only if it is positive

Since sysctl_hung_task_warnings == -1 is allowed (infinite warnings),
commit 48a6d64edadb ("hung_task: allow hung_task_panic when
hung_task_warnings is 0") should decrement it only when it is not -1.

This prevents the kernel from ceasing warnings after the first
4294967295 ;)

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: John Siddle <jsiddle@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/proc: calculate /proc/* and /proc/*/task/* nlink at init time

Runtime nlink calculation works but meh.  I don't know how to do it at
compile time, but I know how to do it at init time.

Shift "2+" part into init time as a bonus.

Link: http://lkml.kernel.org/r/20161122195549.GB29812@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/proc/base.c: save decrement during lookup/readdir in /proc/$PID

Comparison for "<" works equally well as comparison for "<=" but one
SUB/LEA is saved (no, it is not optimised away, at least here).

Link: http://lkml.kernel.org/r/20161122195143.GA29812@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/proc/array.c: slightly improve render_sigset_t

format_decode and vsnprintf occasionally show up in perf top, so I went
looking for places that might not need the full printf power.  With the
help of kprobes, I gathered some statistics on which format strings we
mostly pass to vsnprintf.  On a trivial desktop workload, I hit "%x" 25%
of the time, so something apparently reads /proc/pid/status (which does
5*16 printf("%x") calls) a lot.

With this patch, reading /proc/pid/status is 30% faster according to
this microbenchmark:

char buf[4096];
int i, fd;
for (i = 0; i < 10000; ++i) {
fd = open("/proc/self/status", O_RDONLY);
read(fd, buf, sizeof(buf));
close(fd);
}

Link: http://lkml.kernel.org/r/1474410485-1305-1-git-send-email-linux@rasmusvillemoes.dk
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Andrei Vagin <avagin@openvz.org>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc: tweak comments about 2 stage open and everything

Some comments were obsoleted since commit 05c0ae21c034 ("try a saner
locking for pde_opener...").

Some new comments added.

Some confusing comments replaced with equally confusing ones.

Link: http://lkml.kernel.org/r/20161029160231.GD1246@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc: kmalloc struct pde_opener

kzalloc is too much, half of the fields will be reinitialized anyway.

If proc file doesn't have ->release hook (some still do not), clearing
is unnecessary because it will be freed immediately.

Link: http://lkml.kernel.org/r/20161029155747.GC1246@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc: fix type of struct pde_opener::closing field

struct pde_opener::closing is boolean.

Link: http://lkml.kernel.org/r/20161029155439.GB1246@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc: just list_del() struct pde_opener

list_del_init() is too much, structure will be freed in three lines
anyway.

Link: http://lkml.kernel.org/r/20161029155313.GA1246@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc: make struct struct map_files_info::len unsigned int

Linux doesn't support 4GB+ filenames in /proc, so unsigned long is too
much.

MOV r64, r/m64 is larger than MOV r32, r/m32.

Link: http://lkml.kernel.org/r/20161029161123.GG1246@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc: make struct pid_entry::len unsigned

"unsigned int" is better on x86_64 because it most of the time it
autoexpands to 64-bit value while "int" requires MOVSX instruction.

Link: http://lkml.kernel.org/r/20161029160810.GF1246@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc: report no_new_privs state

Similar to being able to examine if a process has been correctly
confined with seccomp, the state of no_new_privs is equally interesting,
so this adds it to /proc/$pid/status.

Link: http://lkml.kernel.org/r/20161103214041.GA58566@beast
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Jann Horn <jann@thejh.net>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Rodrigo Freire <rfreire@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Robert Ho <robert.hu@intel.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "Richard W.M. Jones" <rjones@redhat.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/percpu.c: fix panic triggered by BUG_ON() falsely

As shown by pcpu_build_alloc_info(), the number of units within a percpu
group is deduced by rounding up the number of CPUs within the group to
@upa boundary/ Therefore, the number of CPUs isn't equal to the units's
if it isn't aligned to @upa normally.  However, pcpu_page_first_chunk()
uses BUG_ON() to assert that one number is equal to the other roughly,
so a panic is maybe triggered by the BUG_ON() incorrectly.

In order to fix this issue, the number of CPUs is rounded up then
compared with units's and the BUG_ON() is replaced with a warning and
return of an error code as well, to keep system alive as much as
possible.

Link: http://lkml.kernel.org/r/57FCF07C.2020103@zoho.com
Signed-off-by: zijun_hu <zijun_hu@htc.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kasan: turn on -fsanitize-address-use-after-scope

In the upcoming gcc7 release, the -fsanitize=kernel-address option at
first implied new -fsanitize-address-use-after-scope option.  This would
cause link errors on older kernels because they don't have two new
functions required for use-after-scope support.  Therefore, gcc7 changed
default to -fno-sanitize-address-use-after-scope.

Now the kernel has everything required for that feature since commit
828347f8f9a5 ("kasan: support use-after-scope detection").  So, to make it
work, we just have to enable use-after-scope in CFLAGS.

Link: http://lkml.kernel.org/r/1481207977-28654-1-git-send-email-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kasan: eliminate long stalls during quarantine reduction

Currently we dedicate 1/32 of RAM for quarantine and then reduce it by
1/4 of total quarantine size.  This can be a significant amount of
memory.  For example, with 4GB of RAM total quarantine size is 128MB and
it is reduced by 32MB at a time.  With 128GB of RAM total quarantine
size is 4GB and it is reduced by 1GB.  This leads to several problems:

 - freeing 1GB can take tens of seconds, causes rcu stall warnings and
   just introduces unexpected long delays at random places
 - if kmalloc() is called under a mutex, other threads stall on that
   mutex while a thread reduces quarantine
 - threads wait on quarantine_lock while one thread grabs a large batch
   of objects to evict
 - we walk the uncached list of object to free twice which makes all of
   the above worse
 - when a thread frees objects, they are already not accounted against
   global_quarantine.bytes; as the result we can have quarantine_size
   bytes in quarantine + unbounded amount of memory in large batches in
   threads that are in process of freeing

Reduce size of quarantine in smaller batches to reduce the delays.  The
only reason to reduce it in batches is amortization of overheads, the
new batch size of 1MB should be well enough to amortize spinlock
lock/unlock and few function calls.

Plus organize quarantine as a FIFO array of batches.  This allows to not
walk the list in quarantine_reduce() under quarantine_lock, which in
turn reduces contention and is just faster.

This improves performance of heavy load (syzkaller fuzzing) by ~20% with
4 CPUs and 32GB of RAM.  Also this eliminates frequent (every 5 sec)
drops of CPU consumption from ~400% to ~100% (one thread reduces
quarantine while others are waiting on a mutex).

Some reference numbers:
1. Machine with 4 CPUs and 4GB of memory. Quarantine size 128MB.
   Currently we free 32MB at at time.
   With new code we free 1MB at a time (1024 batches, ~128 are used).
2. Machine with 32 CPUs and 128GB of memory. Quarantine size 4GB.
   Currently we free 1GB at at time.
   With new code we free 8MB at a time (1024 batches, ~512 are used).
3. Machine with 4096 CPUs and 1TB of memory. Quarantine size 32GB.
   Currently we free 8GB at at time.
   With new code we free 4MB at a time (16K batches, ~8K are used).

Link: http://lkml.kernel.org/r/1478756952-18695-1-git-send-email-dvyukov@google.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kasan: support panic_on_warn

If user sets panic_on_warn, he wants kernel to panic if there is
anything barely wrong with the kernel.  KASAN-detected errors are
definitely not less benign than an arbitrary kernel WARNING.

Panic after KASAN errors if panic_on_warn is set.

We use this for continuous fuzzing where we want kernel to stop and
reboot on any error.

Link: http://lkml.kernel.org/r/1476694764-31986-1-git-send-email-dvyukov@google.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: make transparent hugepage size public

Test programs want to know the size of a transparent hugepage.  While it
is commonly the same as the size of a hugetlbfs page (shown as
Hugepagesize in /proc/meminfo), that is not always so: powerpc
implements transparent hugepages in a different way from hugetlbfs
pages, so it's coincidence when their sizes are the same; and x86 and
others can support more than one hugetlbfs page size.

Add /sys/kernel/mm/transparent_hugepage/hpage_pmd_size to show the THP
size in bytes - it's the same for Anonymous and Shmem hugepages.  Call
it hpage_pmd_size (after HPAGE_PMD_SIZE) rather than hpage_size, in case
some transparent support for pud and pgd pages is added later.

Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1612052200290.13021@eggly.anvils
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Greg Thelen <gthelen@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: add cond_resched() in gather_pte_stats()

The other pagetable walks in task_mmu.c have a cond_resched() after
walking their ptes: add a cond_resched() in gather_pte_stats() too, for
reading /proc/<id>/numa_maps.  Only pagemap_pmd_range() has a
cond_resched() in its (unusually expensive) pmd_trans_huge case: more
should probably be added, but leave them unchanged for now.

Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1612052157400.13021@eggly.anvils
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: add three more cond_resched() in swapoff

Add a cond_resched() in the unuse_pmd_range() loop (so as to call it
even when pmd none or trans_huge, like zap_pmd_range() does); and in the
unuse_mm() loop (since that might skip over many vmas).  shmem_unuse()
and radix_tree_locate_item() look good enough already.

Those were the obvious places, but in fact the stalls came from
find_next_to_unuse(), which sometimes scans through many unused entries.
Apply scan_swap_map()'s LATENCY_LIMIT of 256 there too; and only go off
to test frontswap_map when a used entry is found.

Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1612052155140.13021@eggly.anvils
Signed-off-by: Hugh Dickins <hughd@google.com>
Reported-by: Eric Dumazet <edumazet@google.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm, page_alloc: keep pcp count and list contents in sync if struct page is corrupted

Vlastimil Babka pointed out that commit 479f854a207c ("mm, page_alloc:
defer debugging checks of pages allocated from the PCP") will allow the
per-cpu list counter to be out of sync with the per-cpu list contents if
a struct page is corrupted.

The consequence is an infinite loop if the per-cpu lists get fully
drained by free_pcppages_bulk because all the lists are empty but the
count is positive.  The infinite loop occurs here

                do {
                        batch_free++;
                        if (++migratetype == MIGRATE_PCPTYPES)
                                migratetype = 0;
                        list = &pcp->lists[migratetype];
                } while (list_empty(list));

What the user sees is a bad page warning followed by a soft lockup with
interrupts disabled in free_pcppages_bulk().

This patch keeps the accounting in sync.

Fixes: 479f854a207c ("mm, page_alloc: defer debugging checks of pages allocated from the PCP")
Link: http://lkml.kernel.org/r/20161202112951.23346-2-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: <stable@vger.kernel.org> [4.7+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm, rmap: handle anon_vma_prepare() common case inline

anon_vma_prepare() is mostly a large "if (unlikely(...))" block, as the
expected common case is that an anon_vma already exists.  We could turn
the condition around and return 0, but it also makes sense to do it
inline and avoid a call for the common case.

Bloat-o-meter naturally shows that inlining the check has some code size
costs:

add/remove: 1/1 grow/shrink: 4/0 up/down: 475/-373 (102)
function                                     old     new   delta
__anon_vma_prepare                             -     359    +359
handle_mm_fault                             2744    2796     +52
hugetlb_cow                                 1146    1170     +24
hugetlb_fault                               2123    2145     +22
wp_page_copy                                1469    1487     +18
anon_vma_prepare                             373       -    -373

Checking the asm however confirms that the hot paths now avoid a call,
which is moved away.

[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/20161116074005.22768-1-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm, debug: print raw struct page data in __dump_page()

__dump_page() is used when a page metadata inconsistency is detected,
either by standard runtime checks, or extra checks in CONFIG_DEBUG_VM
builds.  It prints some of the relevant metadata, but not the whole
struct page, which is based on unions and interpretation is dependent on
the context.

This means that sometimes e.g.  a VM_BUG_ON_PAGE() checks certain field,
which is however not printed by __dump_page() and the resulting bug
report may then lack clues that could help in determining the root
cause.  This patch solves the problem by simply printing the whole
struct page word by word, so no part is missing, but the interpretation
of the data is left to developers.  This is similar to e.g.  x86_64 raw
stack dumps.

Example output:

 page:ffffea00000475c0 count:1 mapcount:0 mapping:          (null) index:0x0
 flags: 0x100000000000400(reserved)
 raw: 0100000000000400 0000000000000000 0000000000000000 00000001ffffffff
 raw: ffffea00000475e0 ffffea00000475e0 0000000000000000 0000000000000000
 page dumped because: VM_BUG_ON_PAGE(1)

[aryabinin@virtuozzo.com: suggested print_hex_dump()]
Link: http://lkml.kernel.org/r/2ff83214-70fe-741e-bf05-fe4a4073ec3e@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: THP page cache support for ppc64

Add arch specific callback in the generic THP page cache code that will
deposit and withdarw preallocated page table.  Archs like ppc64 use this
preallocated table to store the hash pte slot information.

Testing:
kernel build of the patch series on tmpfs mounted with option huge=always

The related thp stat:
thp_fault_alloc 72939
thp_fault_fallback 60547
thp_collapse_alloc 603
thp_collapse_alloc_failed 0
thp_file_alloc 253763
thp_file_mapped 4251
thp_split_page 51518
thp_split_page_failed 1
thp_deferred_split_page 73566
thp_split_pmd 665
thp_zero_page_alloc 3
thp_zero_page_alloc_failed 0

[akpm@linux-foundation.org: remove unneeded parentheses, per Kirill]
Link: http://lkml.kernel.org/r/20161113150025.17942-2-aneesh.kumar@linux.vnet.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: move vma_is_anonymous check within pmd_move_must_withdraw

Independent of whether the vma is for anonymous memory, some arches like
ppc64 would like to override pmd_move_must_withdraw().

One option is to encapsulate the vma_is_anonymous() check for general
architectures inside pmd_move_must_withdraw() so that is always called
and architectures that need unconditional overriding can override this
function.  ppc64 needs to override the function when the MMU is
configured to use hash PTE's.

[bsingharora@gmail.com: reworked changelog]
Link: http://lkml.kernel.org/r/20161113150025.17942-1-aneesh.kumar@linux.vnet.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: add preempt points into __purge_vmap_area_lazy()

Use cond_resched_lock to avoid holding the vmap_area_lock for a
potentially long time and thus creating bad latencies for various
workloads.

[hch: split from a larger patch by Joel, wrote the crappy changelog]
Link: http://lkml.kernel.org/r/1479474236-4139-11-git-send-email-hch@lst.de
Signed-off-by: Joel Fernandes <joelaf@google.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Jisheng Zhang <jszhang@marvell.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: John Dias <joaodias@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: turn vmap_purge_lock into a mutex

The purge_lock spinlock causes high latencies with non RT kernel.  This
has been reported multiple times on lkml [1] [2] and affects
applications like audio.

This patch replaces it with a mutex to allow preemption while holding
the lock.

Thanks to Joel Fernandes for the detailed report and analysis as well as
an earlier attempt at fixing this issue.

[1] http://lists.openwall.net/linux-kernel/2016/03/23/29
[2] https://lkml.org/lkml/2016/10/9/59

Link: http://lkml.kernel.org/r/1479474236-4139-10-git-send-email-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Jisheng Zhang <jszhang@marvell.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: John Dias <joaodias@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: mark all calls into the vmalloc subsystem as potentially sleeping

We will take a sleeping lock in later in this series, so this adds the
proper safeguards.

Link: http://lkml.kernel.org/r/1479474236-4139-9-git-send-email-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Jisheng Zhang <jszhang@marvell.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: John Dias <joaodias@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

x86/ldt: use vfree_atomic() to free ldt entries

vfree() is going to use sleeping lock.  free_ldt_struct() may be called
with disabled preemption, therefore we must use vfree_atomic() here.

E.g. call trace:
vfree()
free_ldt_struct()
destroy_context_ldt()
__mmdrop()
finish_task_switch()
schedule_tail()
ret_from_fork()

Link: http://lkml.kernel.org/r/1479474236-4139-7-git-send-email-hch@lst.de
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Jisheng Zhang <jszhang@marvell.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: John Dias <joaodias@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/fork: use vfree_atomic() to free thread stack

vfree() is going to use sleeping lock.  Thread stack freed in atomic
context, therefore we must use vfree_atomic() here.

Link: http://lkml.kernel.org/r/1479474236-4139-6-git-send-email-hch@lst.de
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Jisheng Zhang <jszhang@marvell.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: John Dias <joaodias@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: add vfree_atomic()

We are going to use sleeping lock for freeing vmap.  However some
vfree() users want to free memory from atomic (but not from interrupt)
context.  For this we add vfree_atomic() - deferred variation of vfree()
which can be used in any atomic context (except NMIs).

[akpm@linux-foundation.org: tweak comment grammar]
[aryabinin@virtuozzo.com: use raw_cpu_ptr() instead of this_cpu_ptr()]
Link: http://lkml.kernel.org/r/1481553981-3856-1-git-send-email-aryabinin@virtuozzo.com
Link: http://lkml.kernel.org/r/1479474236-4139-5-git-send-email-hch@lst.de
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Jisheng Zhang <jszhang@marvell.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: John Dias <joaodias@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: refactor __purge_vmap_area_lazy()

Move the purge_lock synchronization to the callers, move the call to
purge_fragmented_blocks_allcpus at the beginning of the function to the
callers that need it, move the force_flush behavior to the caller that
needs it, and pass start and end by value instead of by reference.

No change in behavior.

Link: http://lkml.kernel.org/r/1479474236-4139-4-git-send-email-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Jisheng Zhang <jszhang@marvell.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: John Dias <joaodias@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: remove free_unmap_vmap_area_addr()

Just inline it into the only caller.

Link: http://lkml.kernel.org/r/1479474236-4139-3-git-send-email-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Jisheng Zhang <jszhang@marvell.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: John Dias <joaodias@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: remove free_unmap_vmap_area_noflush()

Patch series "reduce latency in __purge_vmap_area_lazy", v2.

This patch (of 10):

Sort out the long lock hold times in __purge_vmap_area_lazy.  It is
based on a patch from Joel.

Inline free_unmap_vmap_area_noflush() it into the only caller.

Link: http://lkml.kernel.org/r/1479474236-4139-2-git-send-email-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Jisheng Zhang <jszhang@marvell.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: John Dias <joaodias@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: workingset: update shadow limit to reflect bigger active list

Since commit 59dc76b0d4df ("mm: vmscan: reduce size of inactive file
list") the size of the active file list is no longer limited to half of
memory.  Increase the shadow node limit accordingly to avoid throwing
out shadow entries that might still result in eligible refaults.

The exact size of the active list now depends on the overall size of the
page cache, but converges toward taking up most of the space:

In mm/vmscan.c::inactive_list_is_low(),

 * total     target    max
 * memory    ratio     inactive
 * -------------------------------------
 *   10MB       1         5MB
 *  100MB       1        50MB
 *    1GB       3       250MB
 *   10GB      10       0.9GB
 *  100GB      31         3GB
 *    1TB     101        10GB
 *   10TB     320        32GB

It would be possible to apply the same precise ratios when determining
the limit for radix tree nodes containing shadow entries, but since it
is merely an approximation of the oldest refault distances in the wild
and the code also makes assumptions about the node population density,
keep it simple and always target the full cache size.

While at it, clarify the comment and the formula for memory footprint.

Link: http://lkml.kernel.org/r/20161117214701.29000-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: workingset: restore refault tracking for single-page files

Shadow entries in the page cache used to be accounted behind the radix
tree implementation's back in the upper bits of node->count, and the
radix tree code extending a single-entry tree with a shadow entry in
root->rnode would corrupt that counter.  As a result, we could not put
shadow entries at index 0 if the tree didn't have any other entries, and
that means no refault detection for any single-page file.

Now that the shadow entries are tracked natively in the radix tree's
exceptional counter, this is no longer necessary.  Extending and
shrinking the tree from and to single entries in root->rnode now does
the right thing when the entry is exceptional, remove that limitation.

Link: http://lkml.kernel.org/r/20161117193244.GF23430@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <mawilcox@linuxonhyperv.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: workingset: move shadow entry tracking to radix tree exceptional tracking

Currently, we track the shadow entries in the page cache in the upper
bits of the radix_tree_node->count, behind the back of the radix tree
implementation.  Because the radix tree code has no awareness of them,
we rely on random subtleties throughout the implementation (such as the
node->count != 1 check in the shrinking code, which is meant to exclude
multi-entry nodes but also happens to skip nodes with only one shadow
entry, as that's accounted in the upper bits).  This is error prone and
has, in fact, caused the bug fixed in d3798ae8c6f3 ("mm: filemap: don't
plant shadow entries without radix tree node").

To remove these subtleties, this patch moves shadow entry tracking from
the upper bits of node->count to the existing counter for exceptional
entries.  node->count goes back to being a simple counter of valid
entries in the tree node and can be shrunk to a single byte.

This vastly simplifies the page cache code.  All accounting happens
natively inside the radix tree implementation, and maintaining the LRU
linkage of shadow nodes is consolidated into a single function in the
workingset code that is called for leaf nodes affected by a change in
the page cache tree.

This also removes the last user of the __radix_delete_node() return
value.  Eliminate it.

Link: http://lkml.kernel.org/r/20161117193211.GE23430@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <mawilcox@linuxonhyperv.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib: radix-tree: update callback for changing leaf nodes

Support handing __radix_tree_replace() a callback that gets invoked for
all leaf nodes that change or get freed as a result of the slot
replacement, to assist users tracking nodes with node->private_list.

This prepares for putting page cache shadow entries into the radix tree
root again and drastically simplifying the shadow tracking.

Link: http://lkml.kernel.org/r/20161117193134.GD23430@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Suggested-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <mawilcox@linuxonhyperv.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>