[tip:perf/urgent] perf/x86/ibs: Fix IBS throttle

[tip-bot for Peter Zijlstra]

Commit-ID:  0158b83f7508851cda9e62c4b14678c5bd492cb2
Gitweb:     http://git.kernel.org/tip/0158b83f7508851cda9e62c4b14678c5bd492cb2
Author:     Peter Zijlstra <pet...@infradead.org>
AuthorDate: Fri, 11 Mar 2016 15:23:46 +0100
Committer:  Ingo Molnar <mi...@kernel.org>
CommitDate: Mon, 21 Mar 2016 09:08:15 +0100

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 <b...@alien8.de>
Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Cc: Alexander Shishkin <alexander.shish...@linux.intel.com>
Cc: Andy Lutomirski <l...@amacapital.net>
Cc: Arnaldo Carvalho de Melo <a...@redhat.com>
Cc: Brian Gerst <brge...@gmail.com>
Cc: David Ahern <dsah...@gmail.com>
Cc: Denys Vlasenko <dvlas...@redhat.com>
Cc: H. Peter Anvin <h...@zytor.com>
Cc: Jiri Olsa <jo...@redhat.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Namhyung Kim <namhy...@kernel.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Stephane Eranian <eran...@google.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Vince Weaver <vi...@deater.net>
Cc: Vince Weaver <vincent.wea...@maine.edu>
Cc: dvyu...@google.com
Cc: o...@redhat.com
Cc: pan...@redhat.com
Cc: sasha.le...@oracle.com
Link: 
http://lkml.kernel.org/r/20160311142346.ge6...@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mi...@kernel.org>
---
 arch/x86/events/amd/ibs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

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 @@ static int perf_ibs_handle_irq(struct perf_ibs *perf_ibs, 
struct pt_regs *iregs)
        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);