From patchwork Fri Aug 19 02:44:08 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: ethanlien X-Patchwork-Id: 12948246 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id ED1DFC00140 for ; Fri, 19 Aug 2022 02:44:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245005AbiHSCow (ORCPT ); Thu, 18 Aug 2022 22:44:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47754 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235620AbiHSCov (ORCPT ); Thu, 18 Aug 2022 22:44:51 -0400 Received: from synology.com (mail.synology.com [211.23.38.101]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 251249E2CE for ; Thu, 18 Aug 2022 19:44:50 -0700 (PDT) Received: from localhost.localdomain (unknown [10.17.45.240]) by synology.com (Postfix) with ESMTPA id 92BFE304E05C1; Fri, 19 Aug 2022 10:44:48 +0800 (CST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=synology.com; s=123; t=1660877088; bh=jpaNVO7yNJOJYEArErT2t4+7R2HV0RfknEOFy1PkReY=; h=From:To:Cc:Subject:Date; b=mu9nsvxGjtuhbeaaFNLAYbV7lynHVfrtaLDF9AvRGLxJeUlGs07WBiENJfKXYNhxP qotTZzT7OyhN+DkQHli+HmsGKYJGNR8bVnQwRut/KyQ4JE6k//BxRibnhm/mHXOwyA q51QkqZilDelz3gW6u+KEkcjfpw1654IkESeJ70Y= From: ethanlien To: linux-btrfs@vger.kernel.org, cunankimo@gmail.com Cc: Ethan Lien Subject: [PATCH v2] btrfs: remove unnecessary EXTENT_UPTODATE state in buffered I/O path Date: Fri, 19 Aug 2022 10:44:08 +0800 Message-Id: <20220819024408.9714-1-ethanlien@synology.com> X-Mailer: git-send-email 2.17.1 X-Synology-MCP-Status: no X-Synology-Spam-Flag: no X-Synology-Spam-Status: score=0, required 6, WHITELIST_FROM_ADDRESS 0 X-Synology-Virus-Status: no Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org From: Ethan Lien After we copied data to page cache in buffered I/O, we 1. Insert a EXTENT_UPTODATE state into inode's io_tree, by endio_readpage_release_extent(), set_extent_delalloc() or set_extent_defrag(). 2. Set page uptodate before we unlock the page. But the only place we check io_tree's EXTENT_UPTODATE state is in btrfs_do_readpage(). We know we enter btrfs_do_readpage() only when we have a non-uptodate page, so it is unnecessary to set EXTENT_UPTODATE. For example, when performing a buffered random read: fio --rw=randread --ioengine=libaio --direct=0 --numjobs=4 \ --filesize=32G --size=4G --bs=4k --name=job \ --filename=/mnt/file --name=job Then check how many extent_state in io_tree: cat /proc/slabinfo | grep btrfs_extent_state | awk '{print $2}' w/o this patch, we got 640567 btrfs_extent_state. w/ this patch, we got 204 btrfs_extent_state. Maintaining such a big tree brings overhead since every I/O needs to insert EXTENT_LOCKED, insert EXTENT_UPTODATE, then remove EXTENT_LOCKED. And in every insert or remove, we need to lock io_tree, do tree search, alloc or dealloc extent states. By removing unnecessary EXTENT_UPTODATE, we keep io_tree in a minimal size and reduce overhead when performing buffered I/O. Signed-off-by: Ethan Lien Reviewed-by: Robbie Ko Reviewed-by: Filipe Manana --- V2: Remove set_extent_uptodate() from btrfs_get_extent(), and when we found a inline extent, set page uptodate in btrfs_do_readpage(). fs/btrfs/extent-io-tree.h | 4 ++-- fs/btrfs/extent_io.c | 16 +--------------- fs/btrfs/inode.c | 2 -- 3 files changed, 3 insertions(+), 19 deletions(-) diff --git a/fs/btrfs/extent-io-tree.h b/fs/btrfs/extent-io-tree.h index c3eb52dbe61c..53ae849d0248 100644 --- a/fs/btrfs/extent-io-tree.h +++ b/fs/btrfs/extent-io-tree.h @@ -211,7 +211,7 @@ static inline int set_extent_delalloc(struct extent_io_tree *tree, u64 start, struct extent_state **cached_state) { return set_extent_bit(tree, start, end, - EXTENT_DELALLOC | EXTENT_UPTODATE | extra_bits, + EXTENT_DELALLOC | extra_bits, 0, NULL, cached_state, GFP_NOFS, NULL); } @@ -219,7 +219,7 @@ static inline int set_extent_defrag(struct extent_io_tree *tree, u64 start, u64 end, struct extent_state **cached_state) { return set_extent_bit(tree, start, end, - EXTENT_DELALLOC | EXTENT_UPTODATE | EXTENT_DEFRAG, + EXTENT_DELALLOC | EXTENT_DEFRAG, 0, NULL, cached_state, GFP_NOFS, NULL); } diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index bfae67c593c5..7e082770a088 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -2924,9 +2924,6 @@ static void endio_readpage_release_extent(struct processed_extent *processed, * Now we don't have range contiguous to the processed range, release * the processed range now. */ - if (processed->uptodate && tree->track_uptodate) - set_extent_uptodate(tree, processed->start, processed->end, - &cached, GFP_ATOMIC); unlock_extent_cached_atomic(tree, processed->start, processed->end, &cached); @@ -3718,20 +3715,9 @@ static int btrfs_do_readpage(struct page *page, struct extent_map **em_cached, continue; } /* the get_extent function already copied into the page */ - if (test_range_bit(tree, cur, cur_end, - EXTENT_UPTODATE, 1, NULL)) { - unlock_extent(tree, cur, cur + iosize - 1); - end_page_read(page, true, cur, iosize); - cur = cur + iosize; - pg_offset += iosize; - continue; - } - /* we have an inline extent but it didn't get marked up - * to date. Error out - */ if (block_start == EXTENT_MAP_INLINE) { unlock_extent(tree, cur, cur + iosize - 1); - end_page_read(page, false, cur, iosize); + end_page_read(page, true, cur, iosize); cur = cur + iosize; pg_offset += iosize; continue; diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index f0c97d25b4a0..639edbcce9fe 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -7031,8 +7031,6 @@ struct extent_map *btrfs_get_extent(struct btrfs_inode *inode, } flush_dcache_page(page); } - set_extent_uptodate(io_tree, em->start, - extent_map_end(em) - 1, NULL, GFP_NOFS); goto insert; } not_found: