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| author | Alexander Shishkin <[email protected]> | 2017-09-06 16:08:11 +0000 |
|---|---|---|
| committer | Ingo Molnar <[email protected]> | 2017-09-29 08:06:45 +0000 |
| commit | 441430eb54a00586f95f1aefc48e0801bbd6a923 (patch) | |
| tree | 9e9bfffb3625e73466e63120ad9014980c97be46 /tools/perf/builtin-script.c | |
| parent | Merge tag 'acpi-4.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/ra... (diff) | |
| download | kernel-441430eb54a00586f95f1aefc48e0801bbd6a923.tar.gz kernel-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 <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
Diffstat (limited to 'tools/perf/builtin-script.c')
0 files changed, 0 insertions, 0 deletions