From: Marco Elver <elver@google.com>
To: elver@google.com, Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
Waiman Long <longman@redhat.com>,
Boqun Feng <boqun.feng@gmail.com>
Cc: "Paul E. McKenney" <paulmck@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Mark Rutland <mark.rutland@arm.com>,
Dmitry Vyukov <dvyukov@google.com>,
kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org
Subject: [PATCH v2 1/5] time/sched_clock: Swap update_clock_read_data() latch writes
Date: Mon, 4 Nov 2024 16:43:05 +0100 [thread overview]
Message-ID: <20241104161910.780003-2-elver@google.com> (raw)
In-Reply-To: <20241104161910.780003-1-elver@google.com>
Swap the writes to the odd and even copies to make the writer critical
section look like all other seqcount_latch writers.
Signed-off-by: Marco Elver <elver@google.com>
---
v2:
* New patch.
---
kernel/time/sched_clock.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c
index 68d6c1190ac7..85595fcf6aa2 100644
--- a/kernel/time/sched_clock.c
+++ b/kernel/time/sched_clock.c
@@ -119,9 +119,6 @@ unsigned long long notrace sched_clock(void)
*/
static void update_clock_read_data(struct clock_read_data *rd)
{
- /* update the backup (odd) copy with the new data */
- cd.read_data[1] = *rd;
-
/* steer readers towards the odd copy */
raw_write_seqcount_latch(&cd.seq);
@@ -130,6 +127,9 @@ static void update_clock_read_data(struct clock_read_data *rd)
/* switch readers back to the even copy */
raw_write_seqcount_latch(&cd.seq);
+
+ /* update the backup (odd) copy with the new data */
+ cd.read_data[1] = *rd;
}
/*
--
2.47.0.163.g1226f6d8fa-goog
next prev parent reply other threads:[~2024-11-04 16:19 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-11-04 15:43 [PATCH v2 0/5] kcsan, seqlock: Support seqcount_latch_t Marco Elver
2024-11-04 15:43 ` Marco Elver [this message]
2024-11-06 10:47 ` [tip: locking/core] time/sched_clock: Swap update_clock_read_data() latch writes tip-bot2 for Marco Elver
2024-11-04 15:43 ` [PATCH v2 2/5] time/sched_clock: Broaden sched_clock()'s instrumentation coverage Marco Elver
2024-11-05 9:22 ` Marco Elver
2024-11-05 9:35 ` Peter Zijlstra
2024-11-06 10:47 ` [tip: locking/core] " tip-bot2 for Marco Elver
2024-11-04 15:43 ` [PATCH v2 3/5] kcsan, seqlock: Support seqcount_latch_t Marco Elver
2024-11-06 10:47 ` [tip: locking/core] " tip-bot2 for Marco Elver
2024-11-04 15:43 ` [PATCH v2 4/5] seqlock, treewide: Switch to non-raw seqcount_latch interface Marco Elver
2024-11-06 10:47 ` [tip: locking/core] " tip-bot2 for Marco Elver
2024-11-04 15:43 ` [PATCH v2 5/5] kcsan, seqlock: Fix incorrect assumption in read_seqbegin() Marco Elver
2024-11-05 9:13 ` Peter Zijlstra
2024-11-05 9:28 ` Marco Elver
2024-11-05 9:34 ` Peter Zijlstra
2024-11-05 9:41 ` Peter Zijlstra
2024-11-05 9:50 ` Marco Elver
2024-11-06 10:47 ` [tip: locking/core] " tip-bot2 for Marco Elver
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