diff options
authorAlexander Shishkin <alexander.shishkin@linux.intel.com>2019-05-03 11:55:35 +0300
committerIngo Molnar <mingo@kernel.org>2019-05-03 12:46:10 +0200
commit26ae4f4406f88d82d79c85c11ac5fae18213cd38 (patch)
parent221856b16e8e92619b0b99ec7d798a34be051d74 (diff)
perf/ring_buffer: Fix AUX software double buffering
This recent commit: 5768402fd9c6e87 ("perf/ring_buffer: Use high order allocations for AUX buffers optimistically") overlooked the fact that the previous one page granularity of the AUX buffer provided an implicit double buffering capability to the PMU driver, which went away when the entire buffer became one high-order page. Always make the full-trace mode AUX allocation at least two-part to preserve the previous behavior and allow the implicit double buffering to continue. Reported-by: Ammy Yi <ammy.yi@intel.com> Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: adrian.hunter@intel.com Fixes: 5768402fd9c6e87 ("perf/ring_buffer: Use high order allocations for AUX buffers optimistically") Link: http://lkml.kernel.org/r/20190503085536.24119-2-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
1 files changed, 1 insertions, 2 deletions
diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index 5eedb49a65ea..674b35383491 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -610,8 +610,7 @@ int rb_alloc_aux(struct ring_buffer *rb, struct perf_event *event,
* PMU requests more than one contiguous chunks of memory
* for SW double buffering
- if ((event->pmu->capabilities & PERF_PMU_CAP_AUX_SW_DOUBLEBUF) &&
- !overwrite) {
+ if (!overwrite) {
if (!max_order)
return -EINVAL;