From c754fbbb1b6bf462c6ddba48b19f20adf2335cac Mon Sep 17 00:00:00 2001 From: Steven Whitehouse Date: Thu, 12 Dec 2013 10:47:59 +0000 Subject: GFS2: Use RCU/hlist_bl based hash for quotas Prior to this patch, GFS2 kept all the quotas for each super block in a single linked list. This is rather slow when there are large numbers of quotas. This patch introduces a hlist_bl based hash table, similar to the one used for glocks. The initial look up of the quota is now lockless in the case where it is already cached, although we still have to take the per quota spinlock in order to bump the ref count. Either way though, this is a big improvement on what was there before. The qd_lock and the per super block list is preserved, for the time being. However it is intended that since this is no longer used for its original role, it should be possible to shrink the number of items on that list in due course and remove the requirement to take qd_lock in qd_get. Signed-off-by: Steven Whitehouse Cc: Abhijith Das Cc: Paul E. McKenney --- fs/gfs2/incore.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'fs/gfs2/incore.h') diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h index a99f60c98845..59d99ec9d875 100644 --- a/fs/gfs2/incore.h +++ b/fs/gfs2/incore.h @@ -428,10 +428,13 @@ enum { }; struct gfs2_quota_data { + struct hlist_bl_node qd_hlist; struct list_head qd_list; struct kqid qd_id; + struct gfs2_sbd *qd_sbd; struct lockref qd_lockref; struct list_head qd_lru; + unsigned qd_hash; unsigned long qd_flags; /* QDF_... */ @@ -450,6 +453,7 @@ struct gfs2_quota_data { u64 qd_sync_gen; unsigned long qd_last_warn; + struct rcu_head qd_rcu; }; struct gfs2_trans { -- cgit v1.2.3-70-g09d2