From patchwork Thu Aug 3 06:33:29 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qu Wenruo X-Patchwork-Id: 13339288 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 72FD4C04A6A for ; Thu, 3 Aug 2023 06:33:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232755AbjHCGd5 (ORCPT ); Thu, 3 Aug 2023 02:33:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46016 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231674AbjHCGdz (ORCPT ); Thu, 3 Aug 2023 02:33:55 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 41D681706 for ; Wed, 2 Aug 2023 23:33:54 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 073F9219B7 for ; Thu, 3 Aug 2023 06:33:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1691044433; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ExJM3ITVtLsCodx9mjCHEfqPrTKGDzZfElD6esR7FFs=; b=JHyTKTsQigahReRVwpePbS9yxZ2V0lpZypvFfVRbtkkNBR6fjN9LuuDResYay3JPm2Wh27 bUkEBvTJsbm6+er1+BB56QzwCuGen71gCGojBjspVBIwbhtQHEaue87M17IRmjNDzoX4Tc kWC4HCl5MKG8ppQen4314j1Xpw64mIU= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id E63B6134B0 for ; Thu, 3 Aug 2023 06:33:51 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id MKSCK09Ky2SjGAAAMHmgww (envelope-from ) for ; Thu, 03 Aug 2023 06:33:51 +0000 From: Qu Wenruo To: linux-btrfs@vger.kernel.org Subject: [PATCH v2 1/5] btrfs: scrub: avoid unnecessary extent tree search preparing stripes Date: Thu, 3 Aug 2023 14:33:29 +0800 Message-ID: <4b64a2fb88ea924ccb531ed979011e71429682d8.1691044274.git.wqu@suse.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org Since commit e02ee89baa66 ("btrfs: scrub: switch scrub_simple_mirror() to scrub_stripe infrastructure"), scrub no longer re-use the same path for extent tree search. This can lead to unnecessary extent tree search, especially for the new stripe based scrub, as we have way more stripes to prepare. This patch would re-introduce a shared path for extent tree search, and properly release it when the block group is scrubbed. This change alone can improve scrub performance slightly by reducing the time spend preparing the stripe thus improving the queue depth. Before (with regression): Device r/s rkB/s rrqm/s %rrqm r_await rareq-sz aqu-sz %util nvme0n1p3 15578.00 993616.00 5.00 0.03 0.09 63.78 1.32 100.00 After (with this patch): nvme0n1p3 15875.00 1013328.00 12.00 0.08 0.08 63.83 1.35 100.00 Fixes: e02ee89baa66 ("btrfs: scrub: switch scrub_simple_mirror() to scrub_stripe infrastructure") Signed-off-by: Qu Wenruo --- fs/btrfs/scrub.c | 41 +++++++++++++++++++++++++++++------------ 1 file changed, 29 insertions(+), 12 deletions(-) diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index db076e12f442..d10afe94096f 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -175,6 +175,7 @@ struct scrub_ctx { struct scrub_stripe stripes[SCRUB_STRIPES_PER_SCTX]; struct scrub_stripe *raid56_data_stripes; struct btrfs_fs_info *fs_info; + struct btrfs_path extent_path; int first_free; int cur_stripe; atomic_t cancel_req; @@ -339,6 +340,8 @@ static noinline_for_stack struct scrub_ctx *scrub_setup_ctx( refcount_set(&sctx->refs, 1); sctx->is_dev_replace = is_dev_replace; sctx->fs_info = fs_info; + sctx->extent_path.search_commit_root = 1; + sctx->extent_path.skip_locking = 1; for (i = 0; i < SCRUB_STRIPES_PER_SCTX; i++) { int ret; @@ -1466,6 +1469,7 @@ static void scrub_stripe_reset_bitmaps(struct scrub_stripe *stripe) * Return <0 for error. */ static int scrub_find_fill_first_stripe(struct btrfs_block_group *bg, + struct btrfs_path *extent_path, struct btrfs_device *dev, u64 physical, int mirror_num, u64 logical_start, u32 logical_len, @@ -1475,7 +1479,6 @@ static int scrub_find_fill_first_stripe(struct btrfs_block_group *bg, struct btrfs_root *extent_root = btrfs_extent_root(fs_info, bg->start); struct btrfs_root *csum_root = btrfs_csum_root(fs_info, bg->start); const u64 logical_end = logical_start + logical_len; - struct btrfs_path path = { 0 }; u64 cur_logical = logical_start; u64 stripe_end; u64 extent_start; @@ -1491,14 +1494,13 @@ static int scrub_find_fill_first_stripe(struct btrfs_block_group *bg, /* The range must be inside the bg. */ ASSERT(logical_start >= bg->start && logical_end <= bg->start + bg->length); - path.search_commit_root = 1; - path.skip_locking = 1; - - ret = find_first_extent_item(extent_root, &path, logical_start, logical_len); + ret = find_first_extent_item(extent_root, extent_path, logical_start, + logical_len); /* Either error or not found. */ if (ret) goto out; - get_extent_info(&path, &extent_start, &extent_len, &extent_flags, &extent_gen); + get_extent_info(extent_path, &extent_start, &extent_len, &extent_flags, + &extent_gen); if (extent_flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) stripe->nr_meta_extents++; if (extent_flags & BTRFS_EXTENT_FLAG_DATA) @@ -1526,7 +1528,7 @@ static int scrub_find_fill_first_stripe(struct btrfs_block_group *bg, /* Fill the extent info for the remaining sectors. */ while (cur_logical <= stripe_end) { - ret = find_first_extent_item(extent_root, &path, cur_logical, + ret = find_first_extent_item(extent_root, extent_path, cur_logical, stripe_end - cur_logical + 1); if (ret < 0) goto out; @@ -1534,7 +1536,7 @@ static int scrub_find_fill_first_stripe(struct btrfs_block_group *bg, ret = 0; break; } - get_extent_info(&path, &extent_start, &extent_len, + get_extent_info(extent_path, &extent_start, &extent_len, &extent_flags, &extent_gen); if (extent_flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) stripe->nr_meta_extents++; @@ -1574,7 +1576,6 @@ static int scrub_find_fill_first_stripe(struct btrfs_block_group *bg, } set_bit(SCRUB_STRIPE_FLAG_INITIALIZED, &stripe->state); out: - btrfs_release_path(&path); return ret; } @@ -1764,8 +1765,9 @@ static int queue_scrub_stripe(struct scrub_ctx *sctx, struct btrfs_block_group * /* We can queue one stripe using the remaining slot. */ scrub_reset_stripe(stripe); - ret = scrub_find_fill_first_stripe(bg, dev, physical, mirror_num, - logical, length, stripe); + ret = scrub_find_fill_first_stripe(bg, &sctx->extent_path, dev, + physical, mirror_num, logical, + length, stripe); /* Either >0 as no more extents or <0 for error. */ if (ret) return ret; @@ -1783,6 +1785,7 @@ static int scrub_raid56_parity_stripe(struct scrub_ctx *sctx, struct btrfs_fs_info *fs_info = sctx->fs_info; struct btrfs_raid_bio *rbio; struct btrfs_io_context *bioc = NULL; + struct btrfs_path extent_path = { 0 }; struct bio *bio; struct scrub_stripe *stripe; bool all_empty = true; @@ -1793,6 +1796,14 @@ static int scrub_raid56_parity_stripe(struct scrub_ctx *sctx, ASSERT(sctx->raid56_data_stripes); + /* + * For data stripe search, we can not re-use the same extent path, as + * the data stripe bytenr may be smaller than previous extent. + * Thus we have to use our own extent path. + */ + extent_path.search_commit_root = 1; + extent_path.skip_locking = 1; + for (int i = 0; i < data_stripes; i++) { int stripe_index; int rot; @@ -1807,7 +1818,7 @@ static int scrub_raid56_parity_stripe(struct scrub_ctx *sctx, scrub_reset_stripe(stripe); set_bit(SCRUB_STRIPE_FLAG_NO_REPORT, &stripe->state); - ret = scrub_find_fill_first_stripe(bg, + ret = scrub_find_fill_first_stripe(bg, &extent_path, map->stripes[stripe_index].dev, physical, 1, full_stripe_start + btrfs_stripe_nr_to_offset(i), BTRFS_STRIPE_LEN, stripe); @@ -1935,6 +1946,7 @@ static int scrub_raid56_parity_stripe(struct scrub_ctx *sctx, bio_put(bio); btrfs_bio_counter_dec(fs_info); + btrfs_release_path(&extent_path); out: return ret; } @@ -2102,6 +2114,9 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx, u64 stripe_logical; int stop_loop = 0; + /* Extent_path should be probably released. */ + ASSERT(sctx->extent_path.nodes[0] == NULL); + scrub_blocked_if_needed(fs_info); if (sctx->is_dev_replace && @@ -2220,6 +2235,8 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx, ret2 = flush_scrub_stripes(sctx); if (!ret) ret = ret2; + btrfs_release_path(&sctx->extent_path); + if (sctx->raid56_data_stripes) { for (int i = 0; i < nr_data_stripes(map); i++) release_scrub_stripe(&sctx->raid56_data_stripes[i]);