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| author |   Alexander Shishkin <alexander.shishkin@linux.intel.com> | 2017-09-06 19:08:11 +0300 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2017-09-29 10:06:45 +0200 |
| commit | 441430eb54a00586f95f1aefc48e0801bbd6a923 (patch) | |
| tree | 9e9bfffb3625e73466e63120ad9014980c97be46 /tools | |
| parent | Merge tag 'acpi-4.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm (diff) | |
| download | linux-dev-441430eb54a00586f95f1aefc48e0801bbd6a923.tar.xz linux-dev-441430eb54a00586f95f1aefc48e0801bbd6a923.zip | |
perf/aux: Only update ->aux_wakeup in non-overwrite mode
The following commit:
d9a50b0256 ("perf/aux: Ensure aux_wakeup represents most recent wakeup index")
changed the AUX wakeup position calculation to rounddown(), which causes
a division-by-zero in AUX overwrite mode (aka "snapshot mode").
The zero denominator results from the fact that perf record doesn't set
aux_watermark to anything, in which case the kernel will set it to half
the AUX buffer size, but only for non-overwrite mode. In the overwrite
mode aux_watermark stays zero.
The good news is that, AUX overwrite mode, wakeups don't happen and
related bookkeeping is not relevant, so we can simply forego the whole
wakeup updates.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/20170906160811.16510-1-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'tools')
0 files changed, 0 insertions, 0 deletions