From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CC934C4338F for ; Wed, 28 Jul 2021 19:18:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B129960F9B for ; Wed, 28 Jul 2021 19:18:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229542AbhG1TSG (ORCPT ); Wed, 28 Jul 2021 15:18:06 -0400 Received: from mail.kernel.org ([198.145.29.99]:33722 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230333AbhG1TSG (ORCPT ); Wed, 28 Jul 2021 15:18:06 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 6F08860F46; Wed, 28 Jul 2021 19:18:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1627499884; bh=/CDHdtfpzYBVz6l06R6h3LDvRs3N2JhZlBOTijs8Mdg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=GucY9WbMG6NcqEAdfyKsTCk8GJypCuQypN0OK4rsMA7W/SWvm1eb0YlxXyM27B9in dpDykT7Z3eke0KFQYWRSHGh21HIqKtCTOzslFQ7d3ZJ5cwdvb1UyB4YNLRJuNUH/Ow n2US2Ca8OwNdY7T0LVj8JZ7Wevx2I48eelW7JTb68eDv5i+y3JT+IRrw0wg3rIbMeb Tqbh7pR1DgL46DFHgmDJ+2OLPD3yt5/tYJOJSW7L7x36IPOki1hJuNya+DUDUhom08 New0H/MjTUtA3b/4kXRG0RtBJmqHfnvfWWfo4f3MHCYS4t6gsmbsTVWzNsbmr6NG3H gzrP0RqPpNCWg== Date: Wed, 28 Jul 2021 12:18:03 -0700 From: "Darrick J. Wong" To: Allison Henderson Cc: linux-xfs@vger.kernel.org Subject: Re: [PATCH v22 10/16] RFC xfs: Skip flip flags for delayed attrs Message-ID: <20210728191803.GD3601443@magnolia> References: <20210727062053.11129-1-allison.henderson@oracle.com> <20210727062053.11129-11-allison.henderson@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210727062053.11129-11-allison.henderson@oracle.com> Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Mon, Jul 26, 2021 at 11:20:47PM -0700, Allison Henderson wrote: > This is a clean up patch that skips the flip flag logic for delayed attr > renames. Since the log replay keeps the inode locked, we do not need to > worry about race windows with attr lookups. So we can skip over > flipping the flag and the extra transaction roll for it > > RFC: In the last review, folks asked for some performance analysis, so I > did a few perf captures with and with out this patch. What I found was > that there wasnt very much difference at all between having the patch or > not having it. Of the time we do spend in the affected code, the > percentage is small. Most of the time we spend about %0.03 of the time > in this function, with or with out the patch. Occasionally we get a > 0.02%, though not often. So I think this starts to challenge needing > this patch at all. This patch was requested some number of reviews ago, > be perhaps in light of the findings, it may no longer be of interest. > > 0.03% 0.00% fsstress [xfs] [k] xfs_attr_set_iter > > Keep it or drop it? > > Signed-off-by: Allison Henderson > Reviewed-by: Darrick J. Wong /me hates it when he notices things after review... :/ > --- > fs/xfs/libxfs/xfs_attr.c | 51 +++++++++++++++++++++++++------------------ > fs/xfs/libxfs/xfs_attr_leaf.c | 3 ++- > 2 files changed, 32 insertions(+), 22 deletions(-) > > diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c > index 11d8081..eee219c6 100644 > --- a/fs/xfs/libxfs/xfs_attr.c > +++ b/fs/xfs/libxfs/xfs_attr.c > @@ -355,6 +355,7 @@ xfs_attr_set_iter( > struct xfs_inode *dp = args->dp; > struct xfs_buf *bp = NULL; > int forkoff, error = 0; > + struct xfs_mount *mp = args->dp->i_mount; > > /* State machine switch */ > switch (dac->dela_state) { > @@ -476,16 +477,21 @@ xfs_attr_set_iter( > * In a separate transaction, set the incomplete flag on the > * "old" attr and clear the incomplete flag on the "new" attr. > */ > - error = xfs_attr3_leaf_flipflags(args); > - if (error) > - return error; > - /* > - * Commit the flag value change and start the next trans in > - * series. > - */ > - dac->dela_state = XFS_DAS_FLIP_LFLAG; > - trace_xfs_attr_set_iter_return(dac->dela_state, args->dp); > - return -EAGAIN; > + if (!xfs_hasdelattr(mp)) { More nitpicking: this should be gated directly on the log incompat feature check, not the LARP knob... if (!xfs_sb_version_haslogxattrs(&mp->m_sb)) { > + error = xfs_attr3_leaf_flipflags(args); > + if (error) > + return error; > + /* > + * Commit the flag value change and start the next trans > + * in series. > + */ > + dac->dela_state = XFS_DAS_FLIP_LFLAG; > + trace_xfs_attr_set_iter_return(dac->dela_state, > + args->dp); > + return -EAGAIN; > + } > + > + /* fallthrough */ > case XFS_DAS_FLIP_LFLAG: > /* > * Dismantle the "old" attribute/value pair by removing a > @@ -587,17 +593,21 @@ xfs_attr_set_iter( > * In a separate transaction, set the incomplete flag on the > * "old" attr and clear the incomplete flag on the "new" attr. > */ > - error = xfs_attr3_leaf_flipflags(args); > - if (error) > - goto out; > - /* > - * Commit the flag value change and start the next trans in > - * series > - */ > - dac->dela_state = XFS_DAS_FLIP_NFLAG; > - trace_xfs_attr_set_iter_return(dac->dela_state, args->dp); > - return -EAGAIN; > + if (!xfs_hasdelattr(mp)) { ...and here... > + error = xfs_attr3_leaf_flipflags(args); > + if (error) > + goto out; > + /* > + * Commit the flag value change and start the next trans > + * in series > + */ > + dac->dela_state = XFS_DAS_FLIP_NFLAG; > + trace_xfs_attr_set_iter_return(dac->dela_state, > + args->dp); > + return -EAGAIN; > + } > > + /* fallthrough */ > case XFS_DAS_FLIP_NFLAG: > /* > * Dismantle the "old" attribute/value pair by removing a > @@ -1241,7 +1251,6 @@ xfs_attr_node_addname_clear_incomplete( > * Re-find the "old" attribute entry after any split ops. The INCOMPLETE > * flag means that we will find the "old" attr, not the "new" one. > */ > - args->attr_filter |= XFS_ATTR_INCOMPLETE; Why is this removed from the query arguments? If we're going to skip the INCOMPLETE flag dance, I would have thought that you'd change the XFS_DAS_CLR_FLAG case to omit xfs_attr_node_addname_clear_incomplete if the logged xattr feature is set? > state = xfs_da_state_alloc(args); > state->inleaf = 0; > error = xfs_da3_node_lookup_int(state, &retval); > diff --git a/fs/xfs/libxfs/xfs_attr_leaf.c b/fs/xfs/libxfs/xfs_attr_leaf.c > index b910bd2..a9116ee 100644 > --- a/fs/xfs/libxfs/xfs_attr_leaf.c > +++ b/fs/xfs/libxfs/xfs_attr_leaf.c > @@ -1482,7 +1482,8 @@ xfs_attr3_leaf_add_work( > if (tmp) > entry->flags |= XFS_ATTR_LOCAL; > if (args->op_flags & XFS_DA_OP_RENAME) { > - entry->flags |= XFS_ATTR_INCOMPLETE; > + if (!xfs_hasdelattr(mp)) Same change here as above. --D > + entry->flags |= XFS_ATTR_INCOMPLETE; > if ((args->blkno2 == args->blkno) && > (args->index2 <= args->index)) { > args->index2++; > -- > 2.7.4 >