diff options
| author | Chen Yu <yu.c.chen@intel.com> | 2026-05-13 13:39:27 -0700 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2026-05-18 21:33:18 +0200 |
| commit | c99b8593b060931c5a0a4b701689f8d6a2c00dbf (patch) | |
| tree | 4f05894491916ef8b1ab920903ca76710e8ea56e | |
| parent | a7660ce1590fc1316a44cc2af53a07a21dfc25da (diff) | |
sched/cache: Fix stale preferred_llc for a new task
On fork without CLONE_VM, the child gets a new mm,
the parent's preferred_llc value is stale for the
child.
Fix this by resetting the task's preferred_llc to -1.
This bug was reported by sashiko.
Fixes: 47d8696b95f7 ("sched/cache: Assign preferred LLC ID to processes")
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
Co-developed-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/0ec7309d0e24ede97656754d1505b7490403d966.1778703694.git.tim.c.chen@linux.intel.com
| -rw-r--r-- | kernel/sched/fair.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index c249caea3862..2614315a25e0 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1914,6 +1914,11 @@ void init_sched_mm(struct task_struct *p) init_task_work(work, task_cache_work); work->next = work; + /* + * Reset new task's preference to avoid + * polluting account_llc_enqueue(). + */ + p->preferred_llc = -1; } #else /* CONFIG_SCHED_CACHE */ |