linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH] blk-cgroup: Initialize ioc->cgroup_changed at ioc creation time
@ 2011-05-23 14:55 Vivek Goyal
  2011-05-23 17:35 ` Jens Axboe
  0 siblings, 1 reply; 2+ messages in thread
From: Vivek Goyal @ 2011-05-23 14:55 UTC (permalink / raw)
  To: Jens Axboe, linux kernel mailing list; +Cc: Paul Bolle

If we don't explicitly initialize it to zero, CFQ might think that
cgroup of ioc has changed and it generates lots of unnecessary calls
to call_for_each_cic(changed_cgroup). Fix it.

cfq_get_io_context()
  cfq_ioc_set_cgroup()
     call_for_each_cic(ioc, changed_cgroup)

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
---
 block/blk-ioc.c |    3 +++
 1 file changed, 3 insertions(+)

Index: linux-2.6-block/block/blk-ioc.c
===================================================================
--- linux-2.6-block.orig/block/blk-ioc.c	2011-03-08 09:40:58.057296008 -0500
+++ linux-2.6-block/block/blk-ioc.c	2011-05-23 10:33:51.875994035 -0400
@@ -96,6 +96,9 @@ struct io_context *alloc_io_context(gfp_
 		INIT_RADIX_TREE(&ret->radix_root, GFP_ATOMIC | __GFP_HIGH);
 		INIT_HLIST_HEAD(&ret->cic_list);
 		ret->ioc_data = NULL;
+#if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)
+		ret->cgroup_changed = 0;
+#endif
 	}
 
 	return ret;

^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH] blk-cgroup: Initialize ioc->cgroup_changed at ioc creation time
  2011-05-23 14:55 [PATCH] blk-cgroup: Initialize ioc->cgroup_changed at ioc creation time Vivek Goyal
@ 2011-05-23 17:35 ` Jens Axboe
  0 siblings, 0 replies; 2+ messages in thread
From: Jens Axboe @ 2011-05-23 17:35 UTC (permalink / raw)
  To: Vivek Goyal; +Cc: linux kernel mailing list, Paul Bolle

On 2011-05-23 16:55, Vivek Goyal wrote:
> If we don't explicitly initialize it to zero, CFQ might think that
> cgroup of ioc has changed and it generates lots of unnecessary calls
> to call_for_each_cic(changed_cgroup). Fix it.
> 
> cfq_get_io_context()
>   cfq_ioc_set_cgroup()
>      call_for_each_cic(ioc, changed_cgroup)

Thanks Vivek, applied.

-- 
Jens Axboe


^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2011-05-23 17:36 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2011-05-23 14:55 [PATCH] blk-cgroup: Initialize ioc->cgroup_changed at ioc creation time Vivek Goyal
2011-05-23 17:35 ` Jens Axboe

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).