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authorArnd Bergmann <arnd@arndb.de>2012-01-09 16:16:29 +0000
committerArnd Bergmann <arnd@arndb.de>2012-01-09 16:16:29 +0000
commitdcf7ec5ee62a78123057a1e286c88ca739717409 (patch)
treefa3f19434638a942ba66d236dde4d9aaadf8b370 /kernel/cpuset.c
parent15db3e823c3246e3bd31fe454f5c8927eb85caf2 (diff)
parent142f2101a86ade2d6c9dfbedf82e1b5b31c8fce6 (diff)
Merge branch 'samsung/driver' into next/drivers
Conflicts: arch/arm/mach-mxs/include/mach/common.h Pull in previous samsung conflict merges and do a trivial merge of an mxs double-add conflict. Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'kernel/cpuset.c')
-rw-r--r--kernel/cpuset.c29
1 files changed, 24 insertions, 5 deletions
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 9fe58c46a42..0b1712dba58 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -123,6 +123,19 @@ static inline struct cpuset *task_cs(struct task_struct *task)
struct cpuset, css);
}
+#ifdef CONFIG_NUMA
+static inline bool task_has_mempolicy(struct task_struct *task)
+{
+ return task->mempolicy;
+}
+#else
+static inline bool task_has_mempolicy(struct task_struct *task)
+{
+ return false;
+}
+#endif
+
+
/* bits in struct cpuset flags field */
typedef enum {
CS_CPU_EXCLUSIVE,
@@ -949,7 +962,7 @@ static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from,
static void cpuset_change_task_nodemask(struct task_struct *tsk,
nodemask_t *newmems)
{
- bool masks_disjoint = !nodes_intersects(*newmems, tsk->mems_allowed);
+ bool need_loop;
repeat:
/*
@@ -962,6 +975,14 @@ repeat:
return;
task_lock(tsk);
+ /*
+ * Determine if a loop is necessary if another thread is doing
+ * get_mems_allowed(). If at least one node remains unchanged and
+ * tsk does not have a mempolicy, then an empty nodemask will not be
+ * possible when mems_allowed is larger than a word.
+ */
+ 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);
@@ -981,11 +1002,9 @@ repeat:
/*
* Allocation of memory is very fast, we needn't sleep when waiting
- * for the read-side. No wait is necessary, however, if at least one
- * node remains unchanged.
+ * for the read-side.
*/
- while (masks_disjoint &&
- ACCESS_ONCE(tsk->mems_allowed_change_disable)) {
+ while (need_loop && ACCESS_ONCE(tsk->mems_allowed_change_disable)) {
task_unlock(tsk);
if (!task_curr(tsk))
yield();