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| author | Guopeng Zhang <zhangguopeng@kylinos.cn> | 2026-05-09 13:20:31 +0300 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2026-05-11 23:27:14 +0300 |
| commit | 5dd74441cbf42c22e874450eb6a6bbb19390a216 (patch) | |
| tree | 31bc5f42d6ba5c41002bd389a152e75b6f6aacc7 /include | |
| parent | 4a39eda5fdd867fc39f3c039714dd432cee00268 (diff) | |
| download | linux-5dd74441cbf42c22e874450eb6a6bbb19390a216.tar.xz | |
cgroup/cpuset: Reserve DL bandwidth only for root-domain moves
cpuset_can_attach() currently adds the bandwidth of all migrating
SCHED_DEADLINE tasks to sum_migrate_dl_bw. If the source and destination
cpuset effective CPU masks do not overlap, the whole sum is then
reserved in the destination root domain.
set_cpus_allowed_dl(), however, subtracts bandwidth from the source
root domain only when the affinity change really moves the task between
root domains. A DL task can move between cpusets that are still in the
same root domain, so including that task in sum_migrate_dl_bw can reserve
destination bandwidth without a matching source-side subtraction.
Share the root-domain move test with set_cpus_allowed_dl(). Keep
nr_migrate_dl_tasks counting all migrating deadline tasks for cpuset DL
task accounting, but add to sum_migrate_dl_bw only for tasks that need a
root-domain bandwidth move. Keep using the destination cpuset effective
CPU mask and leave the broader can_attach()/attach() transaction model
unchanged.
Fixes: 2ef269ef1ac0 ("cgroup/cpuset: Free DL BW in case can_attach() fails")
Cc: stable@vger.kernel.org # v6.10+
Signed-off-by: Guopeng Zhang <zhangguopeng@kylinos.cn>
Reviewed-by: Waiman Long <longman@redhat.com>
Acked-by: Juri Lelli <juri.lelli@redhat.com>
Tested-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/sched/deadline.h | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/include/linux/sched/deadline.h b/include/linux/sched/deadline.h index 1198138cb839..273538200a44 100644 --- a/include/linux/sched/deadline.h +++ b/include/linux/sched/deadline.h @@ -33,6 +33,15 @@ struct root_domain; extern void dl_add_task_root_domain(struct task_struct *p); extern void dl_clear_root_domain(struct root_domain *rd); extern void dl_clear_root_domain_cpu(int cpu); +/* + * Return whether moving DL task @p to @new_mask requires moving DL + * bandwidth accounting between root domains. This helper is specific to + * DL bandwidth move accounting semantics and is shared by + * cpuset_can_attach() and set_cpus_allowed_dl() so both paths use the + * same source root-domain test. + */ +extern bool dl_task_needs_bw_move(struct task_struct *p, + const struct cpumask *new_mask); extern u64 dl_cookie; extern bool dl_bw_visited(int cpu, u64 cookie); |