From: "tip-bot2 for Peter Zijlstra" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Andi Kleen <ak@linux.intel.com>,
Kan Liang <kan.liang@linux.intel.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
x86 <x86@kernel.org>, LKML <linux-kernel@vger.kernel.org>
Subject: [tip: perf/core] perf/core: Fix endless multiplex timer
Date: Fri, 20 Mar 2020 12:58:01 -0000 [thread overview]
Message-ID: <158470908175.28353.4859180707604949658.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20200305123851.GX2596@hirez.programming.kicks-ass.net>
The following commit has been merged into the perf/core branch of tip:
Commit-ID: 90c91dfb86d0ff545bd329d3ddd72c147e2ae198
Gitweb: https://git.kernel.org/tip/90c91dfb86d0ff545bd329d3ddd72c147e2ae198
Author: Peter Zijlstra <peterz@infradead.org>
AuthorDate: Thu, 05 Mar 2020 13:38:51 +01:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Fri, 20 Mar 2020 13:06:22 +01:00
perf/core: Fix endless multiplex timer
Kan and Andi reported that we fail to kill rotation when the flexible
events go empty, but the context does not. XXX moar
Fixes: fd7d55172d1e ("perf/cgroups: Don't rotate events for cgroups unnecessarily")
Reported-by: Andi Kleen <ak@linux.intel.com>
Reported-by: Kan Liang <kan.liang@linux.intel.com>
Tested-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200305123851.GX2596@hirez.programming.kicks-ass.net
---
kernel/events/core.c | 20 ++++++++++++++------
1 file changed, 14 insertions(+), 6 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index ccf8d4f..b5a68d2 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -2291,6 +2291,7 @@ __perf_remove_from_context(struct perf_event *event,
if (!ctx->nr_events && ctx->is_active) {
ctx->is_active = 0;
+ ctx->rotate_necessary = 0;
if (ctx->task) {
WARN_ON_ONCE(cpuctx->task_ctx != ctx);
cpuctx->task_ctx = NULL;
@@ -3188,12 +3189,6 @@ static void ctx_sched_out(struct perf_event_context *ctx,
if (!ctx->nr_active || !(is_active & EVENT_ALL))
return;
- /*
- * If we had been multiplexing, no rotations are necessary, now no events
- * are active.
- */
- ctx->rotate_necessary = 0;
-
perf_pmu_disable(ctx->pmu);
if (is_active & EVENT_PINNED) {
list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
@@ -3203,6 +3198,13 @@ static void ctx_sched_out(struct perf_event_context *ctx,
if (is_active & EVENT_FLEXIBLE) {
list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
group_sched_out(event, cpuctx, ctx);
+
+ /*
+ * Since we cleared EVENT_FLEXIBLE, also clear
+ * rotate_necessary, is will be reset by
+ * ctx_flexible_sched_in() when needed.
+ */
+ ctx->rotate_necessary = 0;
}
perf_pmu_enable(ctx->pmu);
}
@@ -3985,6 +3987,12 @@ ctx_event_to_rotate(struct perf_event_context *ctx)
typeof(*event), group_node);
}
+ /*
+ * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in()
+ * finds there are unschedulable events, it will set it again.
+ */
+ ctx->rotate_necessary = 0;
+
return event;
}
next prev parent reply other threads:[~2020-03-20 12:58 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-03 20:28 [PATCH] perf/core: Fix endless multiplex timer kan.liang
2020-03-03 21:08 ` Peter Zijlstra
2020-03-04 1:40 ` Liang, Kan
2020-03-04 9:33 ` Peter Zijlstra
2020-03-04 14:20 ` Liang, Kan
2020-03-05 12:38 ` Peter Zijlstra
2020-03-05 17:56 ` Liang, Kan
2020-03-20 12:58 ` tip-bot2 for Peter Zijlstra [this message]
2020-08-06 18:11 ` [tip: perf/core] " Robin Murphy
2020-08-06 18:53 ` Greg KH
2020-08-06 20:40 ` Robin Murphy
2020-03-24 6:00 ` [perf/core] 92b1f046a2: BUG:kernel_NULL_pointer_dereference,address kernel test robot
2020-03-24 6:00 ` [perf/core] 92b1f046a2: BUG:kernel_NULL_pointer_dereference, address kernel test robot
2020-03-24 12:52 ` [perf/core] 92b1f046a2: BUG:kernel_NULL_pointer_dereference,address Liang, Kan
2020-03-24 12:52 ` [perf/core] 92b1f046a2: BUG:kernel_NULL_pointer_dereference, address Liang, Kan
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=158470908175.28353.4859180707604949658.tip-bot2@tip-bot2 \
--to=tip-bot2@linutronix.de \
--cc=ak@linux.intel.com \
--cc=kan.liang@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-tip-commits@vger.kernel.org \
--cc=peterz@infradead.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.