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sched/fair: Reset NUMA fault locality after scan period update

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When updating the task scan period for NUMA locality checks,
update_task_scan_period() checks whether there were no faults or failed
migration on the last scan window, at which it prolongs the scan period.

However, p->numa_faults_locality, which is used to check for migration
failure and number of faults at the previous scan window is not cleared
after changing the scan period, which unintentionally increases
numa_scan_period up to numa_scan_period_max even when there were no
migration failures or no faults at previous scan.

Fix this by jumping to the out label on early exit at this case to
ensure p->numa_faults_locality is always cleared before returning.

Closes: https://lore.kernel.org/all/20250404095354.311156-1-qlsdnjs236@chungbuk.ac.kr/
Reported-by: Binwon Song <qlsdnjs236@chungbuk.ac.kr>
Signed-off-by: Eric Kim <seohyun.kim@outlook.kr>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/Message-ID:
This commit is contained in:
Eric Kim 2026-08-18 12:48:29 +09:00 committed by Peter Zijlstra
parent ef9293b3b7
commit e81ee06308
1 changed files with 5 additions and 2 deletions
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7
kernel/sched/fair.c
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@ -3514,7 +3514,7 @@ static void update_task_scan_period(struct task_struct *p,
p->mm->numa_next_scan = jiffies +
msecs_to_jiffies(p->numa_scan_period);
return;
goto out;
}
/*
@ -3558,7 +3558,10 @@ static void update_task_scan_period(struct task_struct *p,
p->numa_scan_period = clamp(p->numa_scan_period + diff,
task_scan_min(p), task_scan_max(p));
memset(p->numa_faults_locality, 0, sizeof(p->numa_faults_locality));
out:
memset(p->numa_faults_locality, 0,
sizeof(p->numa_faults_locality));
}
/*