[tip: locking/core] sched: Avoid signed comparison of preempt_count() in __cant_migrate()
"tip-bot2 for Boqun Feng" <[email protected]>
| Newsgroups | gmane.linux.kernel |
|---|---|
| Message-ID | <178622210558.442315.2431817868495969988.tip-bot2@tip-bot2> |
The following commit has been merged into the locking/core branch of tip: Commit-ID: 31f35d04a29a7554bb3b9ad827dd37c2942e31d4 Gitweb: https://git.kernel.org/tip/31f35d04a29a7554bb3b9ad827dd37c2942e31d4 Author: Boqun Feng <[email protected]> AuthorDate: Tue, 04 Aug 2026 09:14:31 -07:00 Committer: Peter Zijlstra <[email protected]> CommitterDate: Sat, 08 Aug 2026 22:44:08 +02:00 sched: Avoid signed comparison of preempt_count() in __cant_migrate() Currently preempt_count() is always a non-negative int on all archs (PREEMPT_NEED_RESCHED archs will mask out the MSB when returning preempt_count()), hence the checking in __cant_migrate() is in fact just checking whether preempt_count() is 0 or not. In a future change, we are going to use all the 32 bits of preempt_count(), which would make negative int values possible from preempt_count(). Therefore convert the "> 0" comparison into a zero check to prepare for the future change. No functional changes are intended. Signed-off-by: Boqun Feng <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Link: https://patch.msgid.link/[email protected] --- kernel/sched/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index aa116da..9b3f176 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -9241,7 +9241,7 @@ void __cant_migrate(const char *file, int line) if (!IS_ENABLED(CONFIG_PREEMPT_COUNT)) return; - if (preempt_count() > 0) + if (preempt_count()) return; if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)