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Code Issues Releases Wiki Activity

cgroup/cpuset: Enable update_tasks_cpumask() on top_cpuset

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[ Upstream commit ec5fbdfb99 ]

Previously, update_tasks_cpumask() is not supposed to be called with
top cpuset. With cpuset partition that takes CPUs away from the top
cpuset, adjusting the cpus_mask of the tasks in the top cpuset is
necessary. Percpu kthreads, however, are ignored.

Fixes: ee8dde0cd2 ("cpuset: Add new v2 cpuset.sched.partition flag")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Waiman Long 2022-09-01 16:57:36 -04:00 committed by Greg Kroah-Hartman
parent 771d8aa02d
commit 046803b74d
1 changed files with 11 additions and 7 deletions
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18
kernel/cgroup/cpuset.c
View file

@ -33,6 +33,7 @@
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/kmod.h>
#include <linux/kthread.h>
#include <linux/list.h>
#include <linux/mempolicy.h>
#include <linux/mm.h>
@ -1087,10 +1088,18 @@ static void update_tasks_cpumask(struct cpuset *cs)
{
struct css_task_iter it;
struct task_struct *task;
bool top_cs = cs == &top_cpuset;
css_task_iter_start(&cs->css, 0, &it);
while ((task = css_task_iter_next(&it)))
while ((task = css_task_iter_next(&it))) {
/*
* Percpu kthreads in top_cpuset are ignored
*/
if (top_cs && (task->flags & PF_KTHREAD) &&
kthread_is_per_cpu(task))
continue;
set_cpus_allowed_ptr(task, cs->effective_cpus);
}
css_task_iter_end(&it);
}
@ -2052,12 +2061,7 @@ static int update_prstate(struct cpuset *cs, int new_prs)
update_flag(CS_CPU_EXCLUSIVE, cs, 0);
}
/*
* Update cpumask of parent's tasks except when it is the top
* cpuset as some system daemons cannot be mapped to other CPUs.
*/
if (parent != &top_cpuset)
update_tasks_cpumask(parent);
update_tasks_cpumask(parent);
if (parent->child_ecpus_count)
update_sibling_cpumasks(parent, cs, &tmpmask);