From: Corrado Zoccolo <czoccolo@gmail.com>
Date: Wed, 9 Dec 2009 19:56:04 +0000 (+0100)
Subject: cfq-iosched: commenting non-obvious initialization
X-Git-Tag: v2.6.33-rc1~76^2~3
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=edc71131c4dc6cc73e2a24aa0a7a79cfce738f12;p=karo-tx-linux.git

cfq-iosched: commenting non-obvious initialization

Added a comment to explain the initialization of last_delayed_sync.

Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 98b15b98b85d..69ecee7f4ad4 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -3759,6 +3759,10 @@ static void *cfq_init_queue(struct request_queue *q)
 	cfqd->cfq_latency = 1;
 	cfqd->cfq_group_isolation = 0;
 	cfqd->hw_tag = -1;
+	/*
+	 * we optimistically start assuming sync ops weren't delayed in last
+	 * second, in order to have larger depth for async operations.
+	 */
 	cfqd->last_delayed_sync = jiffies - HZ;
 	INIT_RCU_HEAD(&cfqd->rcu);
 	return cfqd;