From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: [PATCH] vfs: conditionally call inode_wb_list_del() Date: Thu, 28 Jul 2011 06:11:47 +0200 Message-ID: <1311826307.2697.19.camel@edumazet-laptop> References: <1311633550.2576.33.camel@schen9-DESK> <20110725225154.GD22133@ZenIV.linux.org.uk> <1311636178.2576.34.camel@schen9-DESK> <1311660013.2996.6.camel@edumazet-laptop> <1311668466.2355.12.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <20110726090357.GA13013@infradead.org> <1311672994.2355.17.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <1311780065.2356.18.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <20110727204415.GA13308@infradead.org> <20110727205957.GC8006@one.firstfloor.org> <20110727210104.GA9066@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Andi Kleen , Tim Chen , Al Viro , David Miller , Matthew Wilcox , Anton Blanchard , npiggin@kernel.dk, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, netdev To: Christoph Hellwig Return-path: In-Reply-To: <20110727210104.GA9066@infradead.org> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Le mercredi 27 juillet 2011 =C3=A0 17:01 -0400, Christoph Hellwig a =C3= =A9crit : > 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 b= y > > > moving the unhashed checks from the deletion functions into the c= allers > > > and thus save a function call for each of them. > >=20 > > If the caller is in the same file modern gcc is able to do that aut= omatically > > if you're lucky enough ("partial inlining") > >=20 > > I would not uglify the code for it. >=20 > Depending on how you look at it the code might actually be a tad > cleaner. One of called functions is outside of inode.c. >=20 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 spinloc= k 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 --- 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)); =20 - inode_wb_list_del(inode); + if (!list_empty(&inode->i_wb_list)) + inode_wb_list_del(inode); + inode_sb_list_del(inode); =20 if (op->evict_inode) { -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel= " in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html