Le mercredi 27 juillet 2011 à 17:01 -0400, Christoph Hellwig a écrit :
> On Wed, Jul 27, 2011 at 10:59:57PM +0200, Andi Kleen wrote:
> > > Btw, I wonder if you should micro-optimize things a bit further by
> > > moving the unhashed checks from the deletion functions into the callers
> > > and thus save a function call for each of them.
> >
> > If the caller is in the same file modern gcc is able to do that automatically
> > if you're lucky enough ("partial inlining")
> >
> > I would not uglify the code for it.
>
> Depending on how you look at it the code might actually be a tad
> cleaner. One of called functions is outside of inode.c.
>
Thats right, thanks again for your valuable input Christoph.
The following is a clear win, since we avoid the call to external
function.
[PATCH] vfs: conditionally call inode_wb_list_del()
Some inodes (pipes, sockets, ...) are not in bdi writeback list.
evict() can avoid calling inode_wb_list_del() and its expensive spinlock
by checking inode i_wb_list being empty or not.
At this point, no other cpu/user can concurrently manipulate this inode
i_wb_list
Signed-off-by: Eric Dumazet <eric.dumazet@xxxxxxxxx>
---
fs/inode.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/fs/inode.c b/fs/inode.c
index d0c72ff..9dab13a 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -454,7 +454,9 @@ static void evict(struct inode *inode)
BUG_ON(!(inode->i_state & I_FREEING));
BUG_ON(!list_empty(&inode->i_lru));
- inode_wb_list_del(inode);
+ if (!list_empty(&inode->i_wb_list))
+ inode_wb_list_del(inode);
+
inode_sb_list_del(inode);
if (op->evict_inode) {
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
