cgroup, cpuset: don't use ss->pre_attach()

->pre_attach() is supposed to be called before migration, which is
observed during process migration but task migration does it the other
way around.  The only ->pre_attach() user is cpuset which can do the
same operaitons in ->can_attach().  Collapse cpuset_pre_attach() into
cpuset_can_attach().

-v2: Patch contamination from later patch removed.  Spotted by Paul
     Menage.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Paul Menage <paul@paulmenage.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
This commit is contained in:
Tejun Heo 2011-12-12 18:12:22 -08:00
parent bb9d97b6df
commit 94196f51c1

View File

@ -1370,6 +1370,15 @@ static int fmeter_getrate(struct fmeter *fmp)
return val;
}
/*
* Protected by cgroup_lock. The nodemasks must be stored globally because
* dynamically allocating them is not allowed in can_attach, and they must
* persist until attach.
*/
static cpumask_var_t cpus_attach;
static nodemask_t cpuset_attach_nodemask_from;
static nodemask_t cpuset_attach_nodemask_to;
/* Called by cgroups to determine if a cpuset is usable; cgroup_mutex held */
static int cpuset_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
struct cgroup_taskset *tset)
@ -1396,29 +1405,16 @@ static int cpuset_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
if ((ret = security_task_setscheduler(task)))
return ret;
}
return 0;
}
/*
* Protected by cgroup_lock. The nodemasks must be stored globally because
* dynamically allocating them is not allowed in pre_attach, and they must
* persist among pre_attach, and attach.
*/
static cpumask_var_t cpus_attach;
static nodemask_t cpuset_attach_nodemask_from;
static nodemask_t cpuset_attach_nodemask_to;
/* Set-up work for before attaching each task. */
static void cpuset_pre_attach(struct cgroup *cont)
{
struct cpuset *cs = cgroup_cs(cont);
/* prepare for attach */
if (cs == &top_cpuset)
cpumask_copy(cpus_attach, cpu_possible_mask);
else
guarantee_online_cpus(cs, cpus_attach);
guarantee_online_mems(cs, &cpuset_attach_nodemask_to);
return 0;
}
static void cpuset_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
@ -1904,7 +1900,6 @@ struct cgroup_subsys cpuset_subsys = {
.create = cpuset_create,
.destroy = cpuset_destroy,
.can_attach = cpuset_can_attach,
.pre_attach = cpuset_pre_attach,
.attach = cpuset_attach,
.populate = cpuset_populate,
.post_clone = cpuset_post_clone,