path: root/fs/fs-writeback.c
diff options
authorNick Piggin <npiggin@suse.de>2010-10-23 06:55:17 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2010-10-25 21:26:09 -0400
commit9e38d86ff2d8a8db99570e982230861046df32b5 (patch)
tree7ea2ceea24a4e070259a4585b2748c9e2c070ee0 /fs/fs-writeback.c
parentcffbc8aa334f55c9ed42d25202eb3ebf3a97c195 (diff)
fs: Implement lazy LRU updates for inodes
Convert the inode LRU to use lazy updates to reduce lock and cacheline traffic. We avoid moving inodes around in the LRU list during iget/iput operations so these frequent operations don't need to access the LRUs. Instead, we defer the refcount checks to reclaim-time and use a per-inode state flag, I_REFERENCED, to tell reclaim that iget has touched the inode in the past. This means that only reclaim should be touching the LRU with any frequency, hence significantly reducing lock acquisitions and the amount contention on LRU updates. This also removes the inode_in_use list, which means we now only have one list for tracking the inode LRU status. This makes it much simpler to split out the LRU list operations under it's own lock. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/fs-writeback.c')
1 files changed, 4 insertions, 7 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index f04d04af84f..e8f65290e83 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -408,16 +408,13 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
* completion.
- } else if (atomic_read(&inode->i_count)) {
- /*
- * The inode is clean, inuse
- */
- list_move(&inode->i_list, &inode_in_use);
} else {
- * The inode is clean, unused
+ * The inode is clean. At this point we either have
+ * a reference to the inode or it's on it's way out.
+ * No need to add it back to the LRU.
- list_move(&inode->i_list, &inode_unused);
+ list_del_init(&inode->i_list);