github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-07-27 17:47:41 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

sched/cache: Fix checking active load balance by only considering the CFS task

Browse Source 
The currently running task cur may not be a CFS task, such as
an RT or Deadline task. For non-CFS tasks, the task_util(cur)
utilization average is not maintained, so this might pass a
stale or meaningless value to can_migrate_llc().

Check if the task is CFS before getting its task_util().

This bug was reported by sashiko.

Fixes: 714059f79f ("sched/cache: Handle moving single tasks to/from their preferred LLC")
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/f9161133cf040d286dca11344a112c5ef2a5253d.1778703694.git.tim.c.chen@linux.intel.com
This commit is contained in:
Chen Yu 2026-05-13 13:39:22 -07:00 committed by Peter Zijlstra
parent 03755348b8
commit d6b9afab44
1 changed files with 3 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
kernel/sched/fair.c
View File

@ -10509,7 +10509,8 @@ alb_break_llc(struct lb_env *env)
/*
* All tasks prefer to stay on their current CPU.
* Do not pull a task from its preferred CPU if:
* 1. It is the only task running there(not too imbalance); OR
* 1. It is the only task running and does not exceed
* imbalance allowance; OR
* 2. Migrating it away from its preferred LLC would violate
* the cache-aware scheduling policy.
*/
@ -10522,7 +10523,7 @@ alb_break_llc(struct lb_env *env)
return true;
cur = rcu_dereference_all(env->src_rq->curr);
if (cur)
if (cur && cur->sched_class == &fair_sched_class)
util = task_util(cur);
if (can_migrate_llc(env->src_cpu, env->dst_cpu,