From patchwork Wed Aug 7 08:51:00 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qu Wenruo X-Patchwork-Id: 13756033 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.223.130]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2295B1CB325 for ; Wed, 7 Aug 2024 08:51:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.135.223.130 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723020671; cv=none; b=pwc/nksQ7kN27l6YSgFpmPCLL2xDH396ue8ZLwvinfyxFKeJpCgopwRS7P/7qHICF5o7j5IBt5D7Phv5k6e+55MsjvLh2MLw3xjrs6gzzmOYSa8HqVpAnxbVQhbBu3rkwr22lWzQZTBmLgihF7B4gw9oS8pvCfAK7JjEJVrkKUU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723020671; c=relaxed/simple; bh=uUuFkp0kHlR+NaE0BCIv7oYvGtf9rvuby4kJLl44j9U=; h=From:To:Subject:Date:Message-ID:MIME-Version; b=C8CbfmFKEBOx5JBSiinfo2NpBY2oiEggzLM+5rlWrYxRxtOQjoG1yjxavpXHUMP98asns6Cmj/+j9MglFECWhVjxtTUavp3cfRkeqtnWzdOTF/YQUoTAiLQbbYnqJ6XZi7nyRBYYkoPLL4UCJjohQSBcgjRD1uvk5x8MJtwKThA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com; spf=pass smtp.mailfrom=suse.com; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b=i0oGmr+E; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b=i0oGmr+E; arc=none smtp.client-ip=195.135.223.130 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="i0oGmr+E"; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="i0oGmr+E" Received: from imap1.dmz-prg2.suse.org (unknown [10.150.64.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 367BF21B89 for ; Wed, 7 Aug 2024 08:51:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1723020664; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=ahs0fznaiWbP+hDVRCXZE58cgz7VYoEfDE42U9ipsyE=; b=i0oGmr+EFPk9Zlv7UAQ+JN4G6nAng+kzxDI6Z4xxIvvfOzw51lmeC942Weh94rUu4FxFPO 544jJe1qh6CHO+3CDIz7vPJ7ZlE1u1ckN1zHLK0HnhLPSymAbOMoXi63mToHB3CLwmx6CA rGGfV7Vt/cC6WSe31xPDuI3jLWpnVHU= Authentication-Results: smtp-out1.suse.de; none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1723020664; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=ahs0fznaiWbP+hDVRCXZE58cgz7VYoEfDE42U9ipsyE=; b=i0oGmr+EFPk9Zlv7UAQ+JN4G6nAng+kzxDI6Z4xxIvvfOzw51lmeC942Weh94rUu4FxFPO 544jJe1qh6CHO+3CDIz7vPJ7ZlE1u1ckN1zHLK0HnhLPSymAbOMoXi63mToHB3CLwmx6CA rGGfV7Vt/cC6WSe31xPDuI3jLWpnVHU= Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id 592E013297 for ; Wed, 7 Aug 2024 08:51:03 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id +ckSBXc1s2b6fgAAD6G6ig (envelope-from ) for ; Wed, 07 Aug 2024 08:51:03 +0000 From: Qu Wenruo To: linux-btrfs@vger.kernel.org Subject: [PATCH] btrfs: refactor __extent_writepage_io() to do sector-by-sector submission Date: Wed, 7 Aug 2024 18:21:00 +0930 Message-ID: <9102c028537fbc1d94c4b092dd4a9940661bc58b.1723020573.git.wqu@suse.com> X-Mailer: git-send-email 2.45.2 Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spamd-Result: default: False [-2.80 / 50.00]; BAYES_HAM(-3.00)[100.00%]; MID_CONTAINS_FROM(1.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_MISSING_CHARSET(0.50)[]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; FUZZY_BLOCKED(0.00)[rspamd.com]; RCVD_VIA_SMTP_AUTH(0.00)[]; RCPT_COUNT_ONE(0.00)[1]; ARC_NA(0.00)[]; DKIM_SIGNED(0.00)[suse.com:s=susede1]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.com:email,imap1.dmz-prg2.suse.org:helo]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; MIME_TRACE(0.00)[0:+]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; TO_DN_NONE(0.00)[]; PREVIOUSLY_DELIVERED(0.00)[linux-btrfs@vger.kernel.org]; RCVD_TLS_ALL(0.00)[] X-Spam-Score: -2.80 X-Spam-Flag: NO X-Spam-Level: Unlike the bitmap usage inside raid56, for __extent_writepage_io() we handle the subpage submission not sector-by-sector, but for each dirty range we found. This is not a big deal normally, as normally the subpage complex code is already mostly optimized out. For the sake of consistency and for the future of subpage sector-perfect compression support, this patch does: - Extract the sector submission code into submit_one_sector() - Add the needed code to extract the dirty bitmap for subpage case - Use bitmap_and() to calculate the target sectors we need to submit For x86_64, the dirty bitmap will be fixed to 1, with the length of 1, so we're still doing the same workload per sector. For larger page sizes, the overhead will be a little larger, as previous we only need to do one extent_map lookup per-dirty-range, but now it will be one extent_map lookup per-sector. But that is the same frequency as x86_64, so we're just aligning the behavior to x86_64. Signed-off-by: Qu Wenruo Reviewed-by: Josef Bacik --- The plan of sector-perfect subpage compression is to introduce another bitmap, possibly inside bio_ctrl, to indicate which sectors do not need writeback submission (either inline, or async submission). So that __extent_writepage_io() can properly skip those ranges to support sector-perfect subpage compression. --- fs/btrfs/extent_io.c | 188 +++++++++++++++++-------------------------- fs/btrfs/subpage.c | 17 ++++ fs/btrfs/subpage.h | 3 + 3 files changed, 96 insertions(+), 112 deletions(-) diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 040c92541bc9..6acd763e8f26 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -1333,56 +1333,65 @@ static noinline_for_stack int writepage_delalloc(struct btrfs_inode *inode, } /* - * Find the first byte we need to write. + * Return 0 if we have submitted or queued the sector for submission. + * Return <0 for critical errors. * - * For subpage, one page can contain several sectors, and - * __extent_writepage_io() will just grab all extent maps in the page - * range and try to submit all non-inline/non-compressed extents. - * - * This is a big problem for subpage, we shouldn't re-submit already written - * data at all. - * This function will lookup subpage dirty bit to find which range we really - * need to submit. - * - * Return the next dirty range in [@start, @end). - * If no dirty range is found, @start will be page_offset(page) + PAGE_SIZE. + * Caller should make sure filepos < i_size and handle filepos >= i_size case. */ -static void find_next_dirty_byte(const struct btrfs_fs_info *fs_info, - struct folio *folio, u64 *start, u64 *end) +static int submit_one_sector(struct btrfs_inode *inode, + struct folio *folio, + u64 filepos, struct btrfs_bio_ctrl *bio_ctrl, + loff_t i_size) { - struct btrfs_subpage *subpage = folio_get_private(folio); - struct btrfs_subpage_info *spi = fs_info->subpage_info; - u64 orig_start = *start; - /* Declare as unsigned long so we can use bitmap ops */ - unsigned long flags; - int range_start_bit; - int range_end_bit; + struct btrfs_fs_info *fs_info = inode->root->fs_info; + struct extent_map *em; + u64 block_start; + u64 disk_bytenr; + u64 extent_offset; + u64 em_end; + u32 sectorsize = fs_info->sectorsize; - /* - * For regular sector size == page size case, since one page only - * contains one sector, we return the page offset directly. - */ - if (!btrfs_is_subpage(fs_info, folio->mapping)) { - *start = folio_pos(folio); - *end = folio_pos(folio) + folio_size(folio); - return; + ASSERT(IS_ALIGNED(filepos, sectorsize)); + + /* @filepos >= i_size case should be handled by the caller. */ + ASSERT(filepos < i_size); + + em = btrfs_get_extent(inode, NULL, filepos, sectorsize); + if (IS_ERR(em)) + return PTR_ERR_OR_ZERO(em); + + extent_offset = filepos - em->start; + em_end = extent_map_end(em); + ASSERT(filepos <= em_end); + ASSERT(IS_ALIGNED(em->start, fs_info->sectorsize)); + ASSERT(IS_ALIGNED(em->len, fs_info->sectorsize)); + + block_start = extent_map_block_start(em); + disk_bytenr = extent_map_block_start(em) + extent_offset; + + ASSERT(!extent_map_is_compressed(em)); + ASSERT(block_start != EXTENT_MAP_HOLE); + ASSERT(block_start != EXTENT_MAP_INLINE); + + free_extent_map(em); + em = NULL; + + btrfs_set_range_writeback(inode, filepos, filepos + sectorsize - 1); + if (!folio_test_writeback(folio)) { + btrfs_err(fs_info, + "folio %lu not writeback, cur %llu end %llu", + folio->index, filepos, filepos + sectorsize); } - - range_start_bit = spi->dirty_offset + - (offset_in_folio(folio, orig_start) >> - fs_info->sectorsize_bits); - - /* We should have the page locked, but just in case */ - spin_lock_irqsave(&subpage->lock, flags); - bitmap_next_set_region(subpage->bitmaps, &range_start_bit, &range_end_bit, - spi->dirty_offset + spi->bitmap_nr_bits); - spin_unlock_irqrestore(&subpage->lock, flags); - - range_start_bit -= spi->dirty_offset; - range_end_bit -= spi->dirty_offset; - - *start = folio_pos(folio) + range_start_bit * fs_info->sectorsize; - *end = folio_pos(folio) + range_end_bit * fs_info->sectorsize; + /* + * Although the PageDirty bit is cleared before entering this + * function, subpage dirty bit is not cleared. + * So clear subpage dirty bit here so next time we won't submit + * folio for range already written to disk. + */ + btrfs_folio_clear_dirty(fs_info, folio, filepos, sectorsize); + submit_extent_folio(bio_ctrl, disk_bytenr, folio, + sectorsize, filepos - folio_pos(folio)); + return 0; } /* @@ -1401,10 +1410,10 @@ static noinline_for_stack int __extent_writepage_io(struct btrfs_inode *inode, { struct btrfs_fs_info *fs_info = inode->root->fs_info; u64 cur = start; - u64 end = start + len - 1; - u64 extent_offset; - u64 block_start; - struct extent_map *em; + unsigned long dirty_bitmap = 1; + unsigned long range_bitmap = 0; + unsigned int bitmap_size = 1; + int bit; int ret = 0; int nr = 0; @@ -1419,18 +1428,23 @@ static noinline_for_stack int __extent_writepage_io(struct btrfs_inode *inode, return 1; } + if (btrfs_is_subpage(fs_info, inode->vfs_inode.i_mapping)) { + ASSERT(fs_info->subpage_info); + btrfs_get_subpage_dirty_bitmap(fs_info, folio, &dirty_bitmap); + bitmap_size = fs_info->subpage_info->bitmap_nr_bits; + } + for (cur = start; cur < start + len; cur += fs_info->sectorsize) + set_bit((cur - start) >> fs_info->sectorsize_bits, &range_bitmap); + bitmap_and(&dirty_bitmap, &dirty_bitmap, &range_bitmap, bitmap_size); + bio_ctrl->end_io_func = end_bbio_data_write; - while (cur <= end) { - u32 len = end - cur + 1; - u64 disk_bytenr; - u64 em_end; - u64 dirty_range_start = cur; - u64 dirty_range_end; - u32 iosize; + + for_each_set_bit(bit, &dirty_bitmap, bitmap_size) { + cur = folio_pos(folio) + (bit << fs_info->sectorsize_bits); if (cur >= i_size) { - btrfs_mark_ordered_io_finished(inode, folio, cur, len, - true); + btrfs_mark_ordered_io_finished(inode, folio, cur, + start + len - cur, true); /* * This range is beyond i_size, thus we don't need to * bother writing back. @@ -1439,63 +1453,13 @@ static noinline_for_stack int __extent_writepage_io(struct btrfs_inode *inode, * writeback the sectors with subpage dirty bits, * causing writeback without ordered extent. */ - btrfs_folio_clear_dirty(fs_info, folio, cur, len); + btrfs_folio_clear_dirty(fs_info, folio, cur, + start + len - cur); break; } - - find_next_dirty_byte(fs_info, folio, &dirty_range_start, - &dirty_range_end); - if (cur < dirty_range_start) { - cur = dirty_range_start; - continue; - } - - em = btrfs_get_extent(inode, NULL, cur, len); - if (IS_ERR(em)) { - ret = PTR_ERR_OR_ZERO(em); + ret = submit_one_sector(inode, folio, cur, bio_ctrl, i_size); + if (ret < 0) goto out_error; - } - - extent_offset = cur - em->start; - em_end = extent_map_end(em); - ASSERT(cur <= em_end); - ASSERT(cur < end); - ASSERT(IS_ALIGNED(em->start, fs_info->sectorsize)); - ASSERT(IS_ALIGNED(em->len, fs_info->sectorsize)); - - block_start = extent_map_block_start(em); - disk_bytenr = extent_map_block_start(em) + extent_offset; - - ASSERT(!extent_map_is_compressed(em)); - ASSERT(block_start != EXTENT_MAP_HOLE); - ASSERT(block_start != EXTENT_MAP_INLINE); - - /* - * Note that em_end from extent_map_end() and dirty_range_end from - * find_next_dirty_byte() are all exclusive - */ - iosize = min(min(em_end, end + 1), dirty_range_end) - cur; - free_extent_map(em); - em = NULL; - - btrfs_set_range_writeback(inode, cur, cur + iosize - 1); - if (!folio_test_writeback(folio)) { - btrfs_err(inode->root->fs_info, - "folio %lu not writeback, cur %llu end %llu", - folio->index, cur, end); - } - - /* - * Although the PageDirty bit is cleared before entering this - * function, subpage dirty bit is not cleared. - * So clear subpage dirty bit here so next time we won't submit - * folio for range already written to disk. - */ - btrfs_folio_clear_dirty(fs_info, folio, cur, iosize); - - submit_extent_folio(bio_ctrl, disk_bytenr, folio, - iosize, cur - folio_pos(folio)); - cur += iosize; nr++; } diff --git a/fs/btrfs/subpage.c b/fs/btrfs/subpage.c index 631d96f1e905..eea3b2c6bbc4 100644 --- a/fs/btrfs/subpage.c +++ b/fs/btrfs/subpage.c @@ -940,3 +940,20 @@ void __cold btrfs_subpage_dump_bitmap(const struct btrfs_fs_info *fs_info, subpage_info->bitmap_nr_bits, &ordered_bitmap, subpage_info->bitmap_nr_bits, &checked_bitmap); } + +void btrfs_get_subpage_dirty_bitmap(struct btrfs_fs_info *fs_info, + struct folio *folio, + unsigned long *ret_bitmap) +{ + struct btrfs_subpage_info *subpage_info = fs_info->subpage_info; + struct btrfs_subpage *subpage; + unsigned long flags; + + ASSERT(folio_test_private(folio) && folio_get_private(folio)); + ASSERT(subpage_info); + subpage = folio_get_private(folio); + + spin_lock_irqsave(&subpage->lock, flags); + GET_SUBPAGE_BITMAP(subpage, subpage_info, dirty, ret_bitmap); + spin_unlock_irqrestore(&subpage->lock, flags); +} diff --git a/fs/btrfs/subpage.h b/fs/btrfs/subpage.h index 5532cc4fac50..eee55e5a3952 100644 --- a/fs/btrfs/subpage.h +++ b/fs/btrfs/subpage.h @@ -175,6 +175,9 @@ void btrfs_folio_assert_not_dirty(const struct btrfs_fs_info *fs_info, struct folio *folio, u64 start, u32 len); void btrfs_folio_unlock_writer(struct btrfs_fs_info *fs_info, struct folio *folio, u64 start, u32 len); +void btrfs_get_subpage_dirty_bitmap(struct btrfs_fs_info *fs_info, + struct folio *folio, + unsigned long *ret_bitmap); void __cold btrfs_subpage_dump_bitmap(const struct btrfs_fs_info *fs_info, struct folio *folio, u64 start, u32 len);