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  1. 12 8月, 2014 5 次提交
  3. 02 8月, 2014 1 次提交
  5. 31 7月, 2014 2 次提交
    • A
      perf symbols: Make sure --symfs usage includes the path separator · 972f393b
      由 Arnaldo Carvalho de Melo 提交于 
      Minchan reported that perf failed to load vmlinux if --symfs argument
doesn't end with '/' character.

Fix it by making sure that the '/' path separator is used when composing
pathnames with a --symfs provided directory name.
Reported-by: NMinchan Kim <minchan@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-8n4s6b6zvsez5ktanw006125@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      972f393b
    • A
      perf evlist: Don't run workload if not told to · 5f1c4225
      由 Arnaldo Carvalho de Melo 提交于 
      The perf_evlist__prepare_workload() method works by forking and then
waiting on a fd that must be written to to allow the workload to be
exec()ed.

But if the tool calling it fails to, say, set up the events with which
it wants to sample the workload for, it will not call
perf_evlist__start_workload(), but even in this case the workload ended
up running:

  [acme@zoo linux]$ trace /bin/echo workload ends up running, it should not...
  Couldn't mmap the events: Operation not permitted
  workload ends up running, it should not...
  [acme@zoo linux]$

So check if at least one byte was written before letting exec() be
called.

Now the expected behaviour:

  [acme@zoo linux]$ trace /bin/echo workload ends up running, it should not...
  Couldn't mmap the events: Operation not permitted
  [acme@zoo linux]$
Acked-by: NJiri Olsa <jolsa@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-oh1ixo8m74rf295a05gfjw8b@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      5f1c4225
  7. 30 7月, 2014 2 次提交
  9. 28 7月, 2014 10 次提交
  11. 27 7月, 2014 2 次提交
    • L
      Fix gcc-4.9.0 miscompilation of load_balance() in scheduler · 2062afb4
      由 Linus Torvalds 提交于 
      Michel Dänzer and a couple of other people reported inexplicable random
oopses in the scheduler, and the cause turns out to be gcc mis-compiling
the load_balance() function when debugging is enabled.  The gcc bug
apparently goes back to gcc-4.5, but slight optimization changes means
that it now showed up as a problem in 4.9.0 and 4.9.1.

The instruction scheduling problem causes gcc to schedule a spill
operation to before the stack frame has been created, which in turn can
corrupt the spilled value if an interrupt comes in.  There may be other
effects of this bug too, but that's the code generation problem seen in
Michel's case.

This is fixed in current gcc HEAD, but the workaround as suggested by
Markus Trippelsdorf is pretty simple: use -fno-var-tracking-assignments
when compiling the kernel, which disables the gcc code that causes the
problem.  This can result in slightly worse debug information for
variable accesses, but that is infinitely preferable to actual code
generation problems.

Doing this unconditionally (not just for CONFIG_DEBUG_INFO) also allows
non-debug builds to verify that the debug build would be identical: we
can do

    export GCC_COMPARE_DEBUG=1

to make gcc internally verify that the result of the build is
independent of the "-g" flag (it will make the compiler build everything
twice, toggling the debug flag, and compare the results).

Without the "-fno-var-tracking-assignments" option, the build would fail
(even with 4.8.3 that didn't show the actual stack frame bug) with a gcc
compare failure.

See also gcc bugzilla:

  https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61801Reported-by: NMichel Dänzer <michel@daenzer.net>
Suggested-by: NMarkus Trippelsdorf <markus@trippelsdorf.de>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: stable@kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      2062afb4
    • H
      mm: fix direct reclaim writeback regression · 8bdd6380
      由 Hugh Dickins 提交于 
      Shortly before 3.16-rc1, Dave Jones reported:

  WARNING: CPU: 3 PID: 19721 at fs/xfs/xfs_aops.c:971
           xfs_vm_writepage+0x5ce/0x630 [xfs]()
  CPU: 3 PID: 19721 Comm: trinity-c61 Not tainted 3.15.0+ #3
  Call Trace:
    xfs_vm_writepage+0x5ce/0x630 [xfs]
    shrink_page_list+0x8f9/0xb90
    shrink_inactive_list+0x253/0x510
    shrink_lruvec+0x563/0x6c0
    shrink_zone+0x3b/0x100
    shrink_zones+0x1f1/0x3c0
    try_to_free_pages+0x164/0x380
    __alloc_pages_nodemask+0x822/0xc90
    alloc_pages_vma+0xaf/0x1c0
    handle_mm_fault+0xa31/0xc50
  etc.

 970   if (WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) ==
 971                   PF_MEMALLOC))

I did not respond at the time, because a glance at the PageDirty block
in shrink_page_list() quickly shows that this is impossible: we don't do
writeback on file pages (other than tmpfs) from direct reclaim nowadays.
Dave was hallucinating, but it would have been disrespectful to say so.

However, my own /var/log/messages now shows similar complaints

  WARNING: CPU: 1 PID: 28814 at fs/ext4/inode.c:1881 ext4_writepage+0xa7/0x38b()
  WARNING: CPU: 0 PID: 27347 at fs/ext4/inode.c:1764 ext4_writepage+0xa7/0x38b()

from stressing some mmotm trees during July.

Could a dirty xfs or ext4 file page somehow get marked PageSwapBacked,
so fail shrink_page_list()'s page_is_file_cache() test, and so proceed
to mapping->a_ops->writepage()?

Yes, 3.16-rc1's commit 68711a74 ("mm, migration: add destination
page freeing callback") has provided such a way to compaction: if
migrating a SwapBacked page fails, its newpage may be put back on the
list for later use with PageSwapBacked still set, and nothing will clear
it.

Whether that can do anything worse than issue WARN_ON_ONCEs, and get
some statistics wrong, is unclear: easier to fix than to think through
the consequences.

Fixing it here, before the put_new_page(), addresses the bug directly,
but is probably the worst place to fix it.  Page migration is doing too
many parts of the job on too many levels: fixing it in
move_to_new_page() to complement its SetPageSwapBacked would be
preferable, except why is it (and newpage->mapping and newpage->index)
done there, rather than down in migrate_page_move_mapping(), once we are
sure of success? Not a cleanup to get into right now, especially not
with memcg cleanups coming in 3.17.
Reported-by: NDave Jones <davej@redhat.com>
Signed-off-by: NHugh Dickins <hughd@google.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      8bdd6380
  13. 26 7月, 2014 13 次提交
  15. 25 7月, 2014 5 次提交
    • J
      perf record: Store PERF_RECORD_FINISHED_ROUND only for nonempty rounds · dcabb507
      由 Jiri Olsa 提交于 
      Currently we store PERF_RECORD_FINISHED_ROUND event each time
we go throught mmap buffers no matter if it contains any data,
which is useless.

Forcing the PERF_RECORD_FINISHED_ROUND event to be stored any
time we finished the round AND wrote at least one event.
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Acked-by: NAdrian Hunter <adrian.hunter@intel.com>
Acked-by: NDavid Ahern <dsahern@gmail.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jean Pihet <jean.pihet@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1406300177-31805-19-git-send-email-jolsa@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      dcabb507
    • J
      perf record: Always force PERF_RECORD_FINISHED_ROUND event · 33bf7481
      由 Jiri Olsa 提交于 
      The PERF_RECORD_FINISHED_ROUND synthetic record governs queue flushing
in reporting, so it needs to be stored for any kind of event.

The lack of such periodic flushing made the tools use more memory than
needed, as the reordering was being done only after processing all
events.  This was the case when no tracepoints were in the mix.

Forcing the PERF_RECORD_FINISHED_ROUND event to be stored for all event
types.
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Acked-by: NAdrian Hunter <adrian.hunter@intel.com>
Acked-by: NDavid Ahern <dsahern@gmail.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jean Pihet <jean.pihet@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1406300177-31805-18-git-send-email-jolsa@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      33bf7481
    • A
      perf inject: Add --kallsyms parameter · a7a2b8b4
      由 Adrian Hunter 提交于 
      Let perf inject take --kallsyms parameter the same as perf script and
perf report do.

That is needed for decoding Instruction Trace data using a copy of
/proc/kcore for the kernel object because the kallsyms path is used to
locate that copy.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1406035081-14301-30-git-send-email-adrian.hunter@intel.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      a7a2b8b4
    • A
      perf tools: Expose 'addr' functions so they can be reused · 9b0d2d87
      由 Adrian Hunter 提交于 
      Move some functions and functionality related to the use of
'addr' out of builtin-script so they can be reused.

The moved functions are: is_bts_event() and sample_addr_correlates_sym()
and a new function perf_event__preprocess_sample_addr() is created from
bits of print_sample_addr().

perf_event__preprocess_sample_addr() is the equivalent of
perf_event__preprocess_sample() but for 'addr' instead of 'ip'.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1406035081-14301-31-git-send-email-adrian.hunter@intel.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      9b0d2d87
    • H
      x86: Merge tag 'ras_urgent' into x86/urgent · bf72f5de
      由 H. Peter Anvin 提交于 
      Promote one fix for 3.16

This fix was necessary after

9c15a24b ("x86/mce: Improve mcheck_init_device() error handling")

went in. What this patch did was, among others, check the return value
of misc_register and exit early if it encountered an error. Original
code sloppily didn't do that.

However,

        cef12ee5 ("xen/mce: Add mcelog support for Xen platform")

made it so that xen's init routine xen_late_init_mcelog runs first. This
was needed for the xen mcelog device which is supposed to be independent
from the baremetal one.

Initially it was reported that misc_register() fails often on xen and
that's why it needed fixing. However, it is *supposed* to fail by
design, when running in dom0 so that the xen mcelog device file gets
registered first.

And *then* you need the notifier *not* unregistered on the error path so
that the timer does get deleted properly in the CPU hotplug notifier.

Btw, this fix is needed also on baremetal in the unlikely event that
misc_register(&mce_chrdev_device) fails there too.

I was unsure whether to rush it in now and decided to delay it to 3.17.
However, xen people wanted it promoted as it breaks xen when doing cpu
hotplug there. So, after a bit of simmering in tip/master for initial
smoke testing, let's move it to 3.16. It fixes a semi-regression which
got introduced in 3.16 so no need for stable tagging.

tip/x86/ras contains that exact same commit but we can't remove it
there as it is not the last one. It won't cause any merge issues, as I
confirmed locally but I should state here the special situation of this
one fix explicitly anyway.

Thanks.
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
      bf72f5de