X-Git-Url: http://git.monstr.eu/?a=blobdiff_plain;f=block%2Fblk-cgroup.c;h=575d7a2e7203b87a6df7b360cef002b143dc8a19;hb=2ea2086c223e3ae87cde85c3832b110aa6d7ec98;hp=7b06a5fa3cac2204f6278ed77d7371fba92ff6fc;hpb=8e8d9442d1139d05d0c3b83efa34c4b7693d2969;p=linux-2.6-microblaze.git

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 7b06a5fa3cac..575d7a2e7203 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -56,6 +56,8 @@ static LIST_HEAD(all_blkcgs);		/* protected by blkcg_pol_mutex */
 bool blkcg_debug_stats = false;
 static struct workqueue_struct *blkcg_punt_bio_wq;
 
+#define BLKG_DESTROY_BATCH_SIZE  64
+
 static bool blkcg_policy_enabled(struct request_queue *q,
 				 const struct blkcg_policy *pol)
 {
@@ -422,7 +424,9 @@ static void blkg_destroy(struct blkcg_gq *blkg)
 static void blkg_destroy_all(struct request_queue *q)
 {
 	struct blkcg_gq *blkg, *n;
+	int count = BLKG_DESTROY_BATCH_SIZE;
 
+restart:
 	spin_lock_irq(&q->queue_lock);
 	list_for_each_entry_safe(blkg, n, &q->blkg_list, q_node) {
 		struct blkcg *blkcg = blkg->blkcg;
@@ -430,6 +434,17 @@ static void blkg_destroy_all(struct request_queue *q)
 		spin_lock(&blkcg->lock);
 		blkg_destroy(blkg);
 		spin_unlock(&blkcg->lock);
+
+		/*
+		 * in order to avoid holding the spin lock for too long, release
+		 * it when a batch of blkgs are destroyed.
+		 */
+		if (!(--count)) {
+			count = BLKG_DESTROY_BATCH_SIZE;
+			spin_unlock_irq(&q->queue_lock);
+			cond_resched();
+			goto restart;
+		}
 	}
 
 	q->root_blkg = NULL;