fork: remove use of percpu_counter_sum_all

This effectively reverts the change made in commit f689054aace2
("percpu_counter: add percpu_counter_sum_all interface") as the
race condition percpu_counter_sum_all() was invented to avoid is
now handled directly in percpu_counter_sum() and nobody needs to
care about summing racing with cpu unplug anymore.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

diff --git a/kernel/fork.c b/kernel/fork.c
index f68954d05e89dce1f7d430610322fff0a3a379f1..bcc3085e79ef47852c921e4e976f60ec1a491102 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -755,11 +755,6 @@ static void check_mm(struct mm_struct *mm)
        for (i = 0; i < NR_MM_COUNTERS; i++) {
                long x = percpu_counter_sum(&mm->rss_stat[i]);
 
-               if (likely(!x))
-                       continue;
-
-               /* Making sure this is not due to race with CPU offlining. */
-               x = percpu_counter_sum_all(&mm->rss_stat[i]);
                if (unlikely(x))
                        pr_alert("BUG: Bad rss-counter state mm:%p type:%s val:%ld\n",
                                 mm, resident_page_types[i], x);