github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-05-12 16:18:45 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity

tick/nohz: Fix inverted return value in check_tick_dependency() fast path

Browse Source 
Commit 56534673ce ("tick/nohz: Optimize check_tick_dependency() with
early return") added a fast path that returns !val when the tick_stop
tracepoint is disabled.

This is inverted: the slow path returns true when a dependency IS found
(val != 0), but !val returns true when val is zero (no dependency).  The
result is that can_stop_full_tick() sees "dependency found" when there are
none, and the tick never stops on nohz_full CPUs.

Fix this by returning !!val instead of !val, matching the slow-path semantics.

Fixes: 56534673ce ("tick/nohz: Optimize check_tick_dependency() with early return")
Signed-off-by: Josh Snyder <josh@code406.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Assisted-by: Claude:claude-opus-4-6
Link: https://patch.msgid.link/20260402-fix-idle-tick2-v1-1-eecb589649d3@code406.com
This commit is contained in:
Josh Snyder 2026-04-02 16:23:38 -07:00 committed by Thomas Gleixner
parent 591cd656a1
commit 82b915051d
1 changed files with 1 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
kernel/time/tick-sched.c
View File

@ -345,7 +345,7 @@ static bool check_tick_dependency(atomic_t *dep)
int val = atomic_read(dep);
if (likely(!tracepoint_enabled(tick_stop)))
return !val;
return !!val;
if (val & TICK_DEP_MASK_POSIX_TIMER) {
trace_tick_stop(0, TICK_DEP_MASK_POSIX_TIMER);