commit 0158b83f7508851cda9e62c4b14678c5bd492cb2
author Peter Zijlstra <peterz@infradead.org> Fri Mar 11 15:23:46 2016 +0100
committer Ingo Molnar <mingo@kernel.org> Mon Mar 21 09:08:15 2016 +0100
tree 9011836bbf1e36c74eeba00b78c4ca52021f0b16
parent 1e02cd40f15190b78fcc6b3f50c952fb4028e9a5

perf/x86/ibs: Fix IBS throttle

When the IBS IRQ handler get a !0 return from perf_event_overflow;
meaning it should throttle the event, it only disables it, it doesn't
call perf_ibs_stop().

This confuses the state machine, as we'll use pmu::start() ->
perf_ibs_start() to unthrottle.

Tested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vince@deater.net>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: dvyukov@google.com
Cc: oleg@redhat.com
Cc: panand@redhat.com
Cc: sasha.levin@oracle.com
Link: http://lkml.kernel.org/r/20160311142346.GE6344@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/events/amd/ibs.c

diff --git a/arch/x86/events/amd/ibs.c b/arch/x86/events/amd/ibs.c
index 51087c2..7956d29 100644
--- a/arch/x86/events/amd/ibs.c
+++ b/arch/x86/events/amd/ibs.c
@@ -599,7 +599,7 @@
 	throttle = perf_event_overflow(event, &data, &regs);
 out:
 	if (throttle)
-		perf_ibs_disable_event(perf_ibs, hwc, *config);
+		perf_ibs_stop(event, 0);
 	else
 		perf_ibs_enable_event(perf_ibs, hwc, period >> 4);