Reduce cpuset.c write_lock_irq() to read_lock()
cpuset.c:update_nodemask() uses a write_lock_irq() on tasklist_lock to
block concurrent forks; a read_lock() suffices and is less intrusive.
Signed-off-by: Paul Menage<menage@google.com>
Acked-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 4c49188..824b1c0 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -981,10 +981,10 @@
mmarray = kmalloc(ntasks * sizeof(*mmarray), GFP_KERNEL);
if (!mmarray)
goto done;
- write_lock_irq(&tasklist_lock); /* block fork */
+ read_lock(&tasklist_lock); /* block fork */
if (atomic_read(&cs->count) <= ntasks)
break; /* got enough */
- write_unlock_irq(&tasklist_lock); /* try again */
+ read_unlock(&tasklist_lock); /* try again */
kfree(mmarray);
}
@@ -1006,7 +1006,7 @@
continue;
mmarray[n++] = mm;
} while_each_thread(g, p);
- write_unlock_irq(&tasklist_lock);
+ read_unlock(&tasklist_lock);
/*
* Now that we've dropped the tasklist spinlock, we can