forked from Minki/linux
cgroup, cpuset: replace cpuset_post_attach_flush() with cgroup_subsys->post_attach callback
Since e93ad19d05
("cpuset: make mm migration asynchronous"), cpuset
kicks off asynchronous NUMA node migration if necessary during task
migration and flushes it from cpuset_post_attach_flush() which is
called at the end of __cgroup_procs_write(). This is to avoid
performing migration with cgroup_threadgroup_rwsem write-locked which
can lead to deadlock through dependency on kworker creation.
memcg has a similar issue with charge moving, so let's convert it to
an official callback rather than the current one-off cpuset specific
function. This patch adds cgroup_subsys->post_attach callback and
makes cpuset register cpuset_post_attach_flush() as its ->post_attach.
The conversion is mostly one-to-one except that the new callback is
called under cgroup_mutex. This is to guarantee that no other
migration operations are started before ->post_attach callbacks are
finished. cgroup_mutex is one of the outermost mutex in the system
and has never been and shouldn't be a problem. We can add specialized
synchronization around __cgroup_procs_write() but I don't think
there's any noticeable benefit.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org> # 4.4+ prerequisite for the next patch
This commit is contained in:
parent
bcc981e9ed
commit
5cf1cacb49
@ -444,6 +444,7 @@ struct cgroup_subsys {
|
||||
int (*can_attach)(struct cgroup_taskset *tset);
|
||||
void (*cancel_attach)(struct cgroup_taskset *tset);
|
||||
void (*attach)(struct cgroup_taskset *tset);
|
||||
void (*post_attach)(void);
|
||||
int (*can_fork)(struct task_struct *task);
|
||||
void (*cancel_fork)(struct task_struct *task);
|
||||
void (*fork)(struct task_struct *task);
|
||||
|
@ -137,8 +137,6 @@ static inline void set_mems_allowed(nodemask_t nodemask)
|
||||
task_unlock(current);
|
||||
}
|
||||
|
||||
extern void cpuset_post_attach_flush(void);
|
||||
|
||||
#else /* !CONFIG_CPUSETS */
|
||||
|
||||
static inline bool cpusets_enabled(void) { return false; }
|
||||
@ -245,10 +243,6 @@ static inline bool read_mems_allowed_retry(unsigned int seq)
|
||||
return false;
|
||||
}
|
||||
|
||||
static inline void cpuset_post_attach_flush(void)
|
||||
{
|
||||
}
|
||||
|
||||
#endif /* !CONFIG_CPUSETS */
|
||||
|
||||
#endif /* _LINUX_CPUSET_H */
|
||||
|
@ -2825,9 +2825,10 @@ static ssize_t __cgroup_procs_write(struct kernfs_open_file *of, char *buf,
|
||||
size_t nbytes, loff_t off, bool threadgroup)
|
||||
{
|
||||
struct task_struct *tsk;
|
||||
struct cgroup_subsys *ss;
|
||||
struct cgroup *cgrp;
|
||||
pid_t pid;
|
||||
int ret;
|
||||
int ssid, ret;
|
||||
|
||||
if (kstrtoint(strstrip(buf), 0, &pid) || pid < 0)
|
||||
return -EINVAL;
|
||||
@ -2875,8 +2876,10 @@ out_unlock_rcu:
|
||||
rcu_read_unlock();
|
||||
out_unlock_threadgroup:
|
||||
percpu_up_write(&cgroup_threadgroup_rwsem);
|
||||
for_each_subsys(ss, ssid)
|
||||
if (ss->post_attach)
|
||||
ss->post_attach();
|
||||
cgroup_kn_unlock(of->kn);
|
||||
cpuset_post_attach_flush();
|
||||
return ret ?: nbytes;
|
||||
}
|
||||
|
||||
|
@ -58,7 +58,6 @@
|
||||
#include <asm/uaccess.h>
|
||||
#include <linux/atomic.h>
|
||||
#include <linux/mutex.h>
|
||||
#include <linux/workqueue.h>
|
||||
#include <linux/cgroup.h>
|
||||
#include <linux/wait.h>
|
||||
|
||||
@ -1016,7 +1015,7 @@ static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from,
|
||||
}
|
||||
}
|
||||
|
||||
void cpuset_post_attach_flush(void)
|
||||
static void cpuset_post_attach(void)
|
||||
{
|
||||
flush_workqueue(cpuset_migrate_mm_wq);
|
||||
}
|
||||
@ -2087,6 +2086,7 @@ struct cgroup_subsys cpuset_cgrp_subsys = {
|
||||
.can_attach = cpuset_can_attach,
|
||||
.cancel_attach = cpuset_cancel_attach,
|
||||
.attach = cpuset_attach,
|
||||
.post_attach = cpuset_post_attach,
|
||||
.bind = cpuset_bind,
|
||||
.legacy_cftypes = files,
|
||||
.early_init = true,
|
||||
|
Loading…
Reference in New Issue
Block a user