From 880ff1d92603789d132fa2aee2dd8d80e38705d3 Mon Sep 17 00:00:00 2001 From: Alexander Shishkin Date: Fri, 3 May 2019 11:55:35 +0300 Subject: [PATCH 0219/2944] ICX: perf/ring_buffer: Fix AUX software double buffering commit 26ae4f4406f88d82d79c85c11ac5fae18213cd38 upstream. 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 Signed-off-by: Alexander Shishkin Acked-by: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver 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 Signed-off-by: Shen, Xiaochen Signed-off-by: Jeffle Xu Acked-by: Joseph Qi Acked-by: Caspar Zhang --- kernel/events/ring_buffer.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c index 12f351b..34e1667 100644 --- a/kernel/events/ring_buffer.c +++ b/kernel/events/ring_buffer.c @@ -630,8 +630,7 @@ 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; -- 1.8.3.1