6.6-stable review patch. If anyone has any objections, please let me know.
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From: Thomas Richter tmricht@linux.ibm.com
[ Upstream commit b286997e83dcf7b498329a66a8a22fc8a5bf50f0 ]
Event count value is initialized and set to zero in function paicrypt_start(). This function is called once per CPU when an event is started on that CPU. This leads to event count value being set to zero as many times as there are online CPUs. This is not necessary. The event count value is bound to the event and it is sufficient to initialize the event counter once at event creation time. This is done when the event structure is dynamicly allocated with __GFP_ZERO flag. This sets member count to zero.
Acked-by: Sumanth Korikkar sumanthk@linux.ibm.com Signed-off-by: Thomas Richter tmricht@linux.ibm.com Signed-off-by: Vasily Gorbik gor@linux.ibm.com Stable-dep-of: e9f3af02f639 ("s390/pai: fix sampling event removal for PMU device driver") Signed-off-by: Sasha Levin sashal@kernel.org --- arch/s390/kernel/perf_pai_crypto.c | 1 - arch/s390/kernel/perf_pai_ext.c | 1 - 2 files changed, 2 deletions(-)
diff --git a/arch/s390/kernel/perf_pai_crypto.c b/arch/s390/kernel/perf_pai_crypto.c index 4a4e914c283c8..0921cea849125 100644 --- a/arch/s390/kernel/perf_pai_crypto.c +++ b/arch/s390/kernel/perf_pai_crypto.c @@ -253,7 +253,6 @@ static void paicrypt_start(struct perf_event *event, int flags) if (!event->hw.last_tag) { event->hw.last_tag = 1; sum = paicrypt_getall(event); /* Get current value */ - local64_set(&event->count, 0); local64_set(&event->hw.prev_count, sum); } } diff --git a/arch/s390/kernel/perf_pai_ext.c b/arch/s390/kernel/perf_pai_ext.c index b5febe22d0546..ac32107167eac 100644 --- a/arch/s390/kernel/perf_pai_ext.c +++ b/arch/s390/kernel/perf_pai_ext.c @@ -327,7 +327,6 @@ static void paiext_start(struct perf_event *event, int flags) event->hw.last_tag = 1; sum = paiext_getall(event); /* Get current value */ local64_set(&event->hw.prev_count, sum); - local64_set(&event->count, 0); }
static int paiext_add(struct perf_event *event, int flags)