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authorPaul Jackson <pj@sgi.com>2006-03-24 03:16:11 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-24 07:33:24 -0800
commit151a44202d097ae8b1bbaa6d8d2f97df30e3cd1e (patch)
tree3752bba902e73001443bb75f40495cc3a1d24f54 /kernel
parent8488bc359d674baf710992e4b641513ea5ebd212 (diff)
downloadlinux-sh-151a44202d097ae8b1bbaa6d8d2f97df30e3cd1e.tar.gz
[PATCH] cpuset: don't need to mark cpuset_mems_generation atomic
Drop the atomic_t marking on the cpuset static global cpuset_mems_generation. Since all access to it is guarded by the global manage_mutex, there is no need for further serialization of this value. Signed-off-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/cpuset.c19
1 files changed, 11 insertions, 8 deletions
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index bc4131141230..702928664f42 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -149,7 +149,7 @@ static inline int is_spread_slab(const struct cpuset *cs)
}
/*
- * Increment this atomic integer everytime any cpuset changes its
+ * Increment this integer everytime any cpuset changes its
* mems_allowed value. Users of cpusets can track this generation
* number, and avoid having to lock and reload mems_allowed unless
* the cpuset they're using changes generation.
@@ -163,8 +163,11 @@ static inline int is_spread_slab(const struct cpuset *cs)
* on every visit to __alloc_pages(), to efficiently check whether
* its current->cpuset->mems_allowed has changed, requiring an update
* of its current->mems_allowed.
+ *
+ * Since cpuset_mems_generation is guarded by manage_mutex,
+ * there is no need to mark it atomic.
*/
-static atomic_t cpuset_mems_generation = ATOMIC_INIT(1);
+static int cpuset_mems_generation;
static struct cpuset top_cpuset = {
.flags = ((1 << CS_CPU_EXCLUSIVE) | (1 << CS_MEM_EXCLUSIVE)),
@@ -877,7 +880,7 @@ static int update_nodemask(struct cpuset *cs, char *buf)
mutex_lock(&callback_mutex);
cs->mems_allowed = trialcs.mems_allowed;
- cs->mems_generation = atomic_inc_return(&cpuset_mems_generation);
+ cs->mems_generation = cpuset_mems_generation++;
mutex_unlock(&callback_mutex);
set_cpuset_being_rebound(cs); /* causes mpol_copy() rebind */
@@ -1270,11 +1273,11 @@ static ssize_t cpuset_common_file_write(struct file *file, const char __user *us
break;
case FILE_SPREAD_PAGE:
retval = update_flag(CS_SPREAD_PAGE, cs, buffer);
- cs->mems_generation = atomic_inc_return(&cpuset_mems_generation);
+ cs->mems_generation = cpuset_mems_generation++;
break;
case FILE_SPREAD_SLAB:
retval = update_flag(CS_SPREAD_SLAB, cs, buffer);
- cs->mems_generation = atomic_inc_return(&cpuset_mems_generation);
+ cs->mems_generation = cpuset_mems_generation++;
break;
case FILE_TASKLIST:
retval = attach_task(cs, buffer, &pathbuf);
@@ -1823,7 +1826,7 @@ static long cpuset_create(struct cpuset *parent, const char *name, int mode)
atomic_set(&cs->count, 0);
INIT_LIST_HEAD(&cs->sibling);
INIT_LIST_HEAD(&cs->children);
- cs->mems_generation = atomic_inc_return(&cpuset_mems_generation);
+ cs->mems_generation = cpuset_mems_generation++;
fmeter_init(&cs->fmeter);
cs->parent = parent;
@@ -1913,7 +1916,7 @@ int __init cpuset_init_early(void)
struct task_struct *tsk = current;
tsk->cpuset = &top_cpuset;
- tsk->cpuset->mems_generation = atomic_inc_return(&cpuset_mems_generation);
+ tsk->cpuset->mems_generation = cpuset_mems_generation++;
return 0;
}
@@ -1932,7 +1935,7 @@ int __init cpuset_init(void)
top_cpuset.mems_allowed = NODE_MASK_ALL;
fmeter_init(&top_cpuset.fmeter);
- top_cpuset.mems_generation = atomic_inc_return(&cpuset_mems_generation);
+ top_cpuset.mems_generation = cpuset_mems_generation++;
init_task.cpuset = &top_cpuset;