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-rw-r--r--kernel/cpuset.c59
1 files changed, 13 insertions, 46 deletions
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index a09ac2b9a66..1010cc61931 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -964,7 +964,6 @@ static void cpuset_change_task_nodemask(struct task_struct *tsk,
{
bool need_loop;
-repeat:
/*
* Allow tasks that have access to memory reserves because they have
* been OOM killed to get memory anywhere.
@@ -983,45 +982,19 @@ repeat:
*/
need_loop = task_has_mempolicy(tsk) ||
!nodes_intersects(*newmems, tsk->mems_allowed);
- nodes_or(tsk->mems_allowed, tsk->mems_allowed, *newmems);
- mpol_rebind_task(tsk, newmems, MPOL_REBIND_STEP1);
- /*
- * ensure checking ->mems_allowed_change_disable after setting all new
- * allowed nodes.
- *
- * the read-side task can see an nodemask with new allowed nodes and
- * old allowed nodes. and if it allocates page when cpuset clears newly
- * disallowed ones continuous, it can see the new allowed bits.
- *
- * And if setting all new allowed nodes is after the checking, setting
- * all new allowed nodes and clearing newly disallowed ones will be done
- * continuous, and the read-side task may find no node to alloc page.
- */
- smp_mb();
+ if (need_loop)
+ write_seqcount_begin(&tsk->mems_allowed_seq);
- /*
- * Allocation of memory is very fast, we needn't sleep when waiting
- * for the read-side.
- */
- while (need_loop && ACCESS_ONCE(tsk->mems_allowed_change_disable)) {
- task_unlock(tsk);
- if (!task_curr(tsk))
- yield();
- goto repeat;
- }
-
- /*
- * ensure checking ->mems_allowed_change_disable before clearing all new
- * disallowed nodes.
- *
- * if clearing newly disallowed bits before the checking, the read-side
- * task may find no node to alloc page.
- */
- smp_mb();
+ nodes_or(tsk->mems_allowed, tsk->mems_allowed, *newmems);
+ mpol_rebind_task(tsk, newmems, MPOL_REBIND_STEP1);
mpol_rebind_task(tsk, newmems, MPOL_REBIND_STEP2);
tsk->mems_allowed = *newmems;
+
+ if (need_loop)
+ write_seqcount_end(&tsk->mems_allowed_seq);
+
task_unlock(tsk);
}
@@ -1399,8 +1372,7 @@ 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)
+static int cpuset_can_attach(struct cgroup *cgrp, struct cgroup_taskset *tset)
{
struct cpuset *cs = cgroup_cs(cgrp);
struct task_struct *task;
@@ -1436,8 +1408,7 @@ static int cpuset_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
return 0;
}
-static void cpuset_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
- struct cgroup_taskset *tset)
+static void cpuset_attach(struct cgroup *cgrp, struct cgroup_taskset *tset)
{
struct mm_struct *mm;
struct task_struct *task;
@@ -1833,8 +1804,7 @@ static int cpuset_populate(struct cgroup_subsys *ss, struct cgroup *cont)
* (and likewise for mems) to the new cgroup. Called with cgroup_mutex
* held.
*/
-static void cpuset_post_clone(struct cgroup_subsys *ss,
- struct cgroup *cgroup)
+static void cpuset_post_clone(struct cgroup *cgroup)
{
struct cgroup *parent, *child;
struct cpuset *cs, *parent_cs;
@@ -1857,13 +1827,10 @@ static void cpuset_post_clone(struct cgroup_subsys *ss,
/*
* cpuset_create - create a cpuset
- * ss: cpuset cgroup subsystem
* cont: control group that the new cpuset will be part of
*/
-static struct cgroup_subsys_state *cpuset_create(
- struct cgroup_subsys *ss,
- struct cgroup *cont)
+static struct cgroup_subsys_state *cpuset_create(struct cgroup *cont)
{
struct cpuset *cs;
struct cpuset *parent;
@@ -1902,7 +1869,7 @@ static struct cgroup_subsys_state *cpuset_create(
* will call async_rebuild_sched_domains().
*/
-static void cpuset_destroy(struct cgroup_subsys *ss, struct cgroup *cont)
+static void cpuset_destroy(struct cgroup *cont)
{
struct cpuset *cs = cgroup_cs(cont);