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Date: Thu, 28 Jul 2011 06:11:47 +0200 From: Eric Dumazet <eric.dumazet@...il.com> To: Christoph Hellwig <hch@...radead.org> Cc: Andi Kleen <andi@...stfloor.org>, Tim Chen <tim.c.chen@...ux.intel.com>, Al Viro <viro@...IV.linux.org.uk>, David Miller <davem@...emloft.net>, Matthew Wilcox <matthew@....cx>, Anton Blanchard <anton@...ba.org>, npiggin@...nel.dk, linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org, netdev <netdev@...r.kernel.org> Subject: [PATCH] vfs: conditionally call inode_wb_list_del() 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@...il.com> --- 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-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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