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perf/x86/intel: Avoid spamming kernel log for BTS buffer failure 

It's unnecessary to excessively spam the kernel log anytime the BTS buffer
cannot be allocated, so make this allocation __GFP_NOWARN.

The user probably will want to at least find some artifact that the
allocation has failed in the past, probably due to fragmentation because
of its large size, when it's not allocated at bootstrap.  Thus, add a
WARN_ONCE() so something is left behind for them to understand why perf
commnads that require PEBS is not working properly.

Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1406301600460.26302@chino.kir.corp.google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
hifive-unleashed-5.1
David Rientjes 2014-06-30 16:04:08 -07:00 committed by Ingo Molnar
parent 338b522ca4
commit 4485154138
1 changed files with 4 additions and 2 deletions
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6
arch/x86/kernel/cpu/perf_event_intel_ds.c
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@ -311,9 +311,11 @@ static int alloc_bts_buffer(int cpu)
if (!x86_pmu.bts)
return 0;
buffer = kzalloc_node(BTS_BUFFER_SIZE, GFP_KERNEL, node);
if (unlikely(!buffer))
buffer = kzalloc_node(BTS_BUFFER_SIZE, GFP_KERNEL | __GFP_NOWARN, node);
if (unlikely(!buffer)) {
WARN_ONCE(1, "%s: BTS buffer allocation failure\n", __func__);
return -ENOMEM;
}
max = BTS_BUFFER_SIZE / BTS_RECORD_SIZE;
thresh = max / 16;