This is a note to let you know that I've just added the patch titled
s390/pai: initialize event count once at initialization
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
s390-pai-initialize-event-count-once-at-initializati.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 71020b7334f94ffa19b4d924dd00d987495c9acc
Author: Thomas Richter <tmricht@xxxxxxxxxxxxx>
Date: Wed Oct 11 12:09:30 2023 +0200
s390/pai: initialize event count once at initialization
[ 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@xxxxxxxxxxxxx>
Signed-off-by: Thomas Richter <tmricht@xxxxxxxxxxxxx>
Signed-off-by: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Stable-dep-of: e9f3af02f639 ("s390/pai: fix sampling event removal for PMU device driver")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
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)
