From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 589C61552FD for ; Wed, 24 Sep 2025 06:34:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758695660; cv=none; b=IcI2LxMHUtHFHOSs75bwf72p3aRU8AcO+zMCEHDWj6MnoXSJOiaemjfq68N6yRSw/MMTMr6DxvyaHb+jE1ni/VY/Vm+dYsEbl/OKFPzUe4AQjEo9at88rU37t8VA/JIl24p6t0jusVYHhTtfsbWifclnP3/0wv/5WV7pZYu7NcQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758695660; c=relaxed/simple; bh=n+fob0a/KleEhL3/yk1pmNFL67AabGNBDwLx7nDdKXg=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=ldDVgsqZYPpaL9wSMqxi8/pKNW8ni7gCjSLoHWx4amuVlujJLTNgjy+K2p8JXBZUDp5C9jh9IdEO0J4ccaXkD1dkpvfFNdGvIKTfLEaH+nHE02IB3TIkMKJcGVQcoWUagfcS1X5Ny0Z6x7L5STZrnvS6+rB9MoplmujOlp4msfw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Jh3ptc5M; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Jh3ptc5M" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2EE91C4CEE7; Wed, 24 Sep 2025 06:34:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1758695659; bh=n+fob0a/KleEhL3/yk1pmNFL67AabGNBDwLx7nDdKXg=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=Jh3ptc5MDKfNd29lg4+XyQtcDxf3MKkosBFwUtADKV4ALckS1TQ1GtMXLS53JX+2d sRv4KWLGQEIRuGzZueURU6rSw+w7aJDAM1eKgFKdrQLcpKI5zcah+6jeYYvSzWFakH kMwfBAIeInZeVAVaZHU+4IvnZP8i1SlJaQCKwjWR61cRxDrcF18Ciz+Zs7I2LmAGN2 PF6T3A9WYsLm4T6BuTMdHu5dbcFRlCtlPH+mD85mKSaYWOROkKDrc5YL40nTGAxlcc nqyrIga+WoLJq1Ul7np72mydkFTDRT5KOGegMu3ggxyOYLQp6Z8RhiFPjHnNCEJ6Wq k4UXmPXt60ipA== Message-ID: Date: Wed, 24 Sep 2025 14:34:15 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: chao@kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, Sungjong Seo , Sunmin Jeong Subject: Re: [PATCH v3] f2fs: readahead node blocks in F2FS_GET_BLOCK_PRECACHE mode To: Yunji Kang , jaegeuk@kernel.org References: <20250924055831.250805-1-yunji0.kang@samsung.com> Content-Language: en-US From: Chao Yu In-Reply-To: <20250924055831.250805-1-yunji0.kang@samsung.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/24/25 13:58, Yunji Kang wrote: > In f2fs_precache_extents(), For large files, It requires reading many > node blocks. Instead of reading each node block with synchronous I/O, > this patch applies readahead so that node blocks can be fetched in > advance. > > It reduces the overhead of repeated sync reads and improves efficiency > when precaching extents of large files. > > I created a file with the same largest extent and executed the test. > For this experiment, I set the file's largest extent with an offset of 0 > and a size of 1GB. I configured the remaining area with 100MB extents. > > 5GB test file: > dd if=/dev/urandom of=test1 bs=1m count=5120 > cp test1 test2 > fsync test1 > dd if=test1 of=test2 bs=1m skip=1024 seek=1024 count=100 conv=notrunc > dd if=test1 of=test2 bs=1m skip=1224 seek=1224 count=100 conv=notrunc > ... > dd if=test1 of=test2 bs=1m skip=5024 seek=5024 count=100 conv=notrunc > reboot > > I also created 10GB and 20GB files with large extents using the same > method. > > ioctl(F2FS_IOC_PRECACHE_EXTENTS) test results are as follows: > +-----------+---------+---------+-----------+ > | File size | Before | After | Reduction | > +-----------+---------+---------+-----------+ > | 5GB | 101.8ms | 37.0ms | 72.1% | > | 10GB | 222.9ms | 56.0ms | 74.9% | > | 20GB | 446.2ms | 116.4ms | 73.9% | > +-----------+---------+---------+-----------+ > Tested on a 256GB mobile device with an SM8750 chipset. > > Reviewed-by: Sungjong Seo > Reviewed-by: Sunmin Jeong > Signed-off-by: Yunji Kang > --- > v2: > - Modify the readahead condition check routine for better code > readability. > - Update the title from 'node block' to 'node blocks'. > > v3: > - Bug fix to allow more node pages to be readahead. > - Updated with test results. > > fs/f2fs/data.c | 3 +++ > fs/f2fs/f2fs.h | 1 + > fs/f2fs/node.c | 4 +++- > 3 files changed, 7 insertions(+), 1 deletion(-) > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > index 7961e0ddfca3..ab3117e3b24a 100644 > --- a/fs/f2fs/data.c > +++ b/fs/f2fs/data.c > @@ -1572,6 +1572,9 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map, int flag) > pgofs = (pgoff_t)map->m_lblk; > end = pgofs + maxblocks; > > + if (flag == F2FS_GET_BLOCK_PRECACHE) > + mode = LOOKUP_NODE_PRECACHE; If trigger condition of LOOKUP_NODE_RA and LOOKUP_NODE_PRECACHE is the same, What about? if (flag == F2FS_GET_BLOCK_PRECACHE) mode = LOOKUP_NODE_RA; Thanks, > + > next_dnode: > if (map->m_may_create) { > if (f2fs_lfs_mode(sbi)) > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > index 9d3bc9633c1d..3ce41528d48e 100644 > --- a/fs/f2fs/f2fs.h > +++ b/fs/f2fs/f2fs.h > @@ -651,6 +651,7 @@ enum { > * look up a node with readahead called > * by get_data_block. > */ > + LOOKUP_NODE_PRECACHE, /* look up a node for F2FS_GET_BLOCK_PRECACHE */ > }; > > #define DEFAULT_RETRY_IO_COUNT 8 /* maximum retry read IO or flush count */ > diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c > index 4254db453b2d..63e9ee7ab911 100644 > --- a/fs/f2fs/node.c > +++ b/fs/f2fs/node.c > @@ -860,7 +860,9 @@ int f2fs_get_dnode_of_data(struct dnode_of_data *dn, pgoff_t index, int mode) > set_nid(parent, offset[i - 1], nids[i], i == 1); > f2fs_alloc_nid_done(sbi, nids[i]); > done = true; > - } else if (mode == LOOKUP_NODE_RA && i == level && level > 1) { > + } else if ((mode == LOOKUP_NODE_RA || > + (mode == LOOKUP_NODE_PRECACHE)) > + && i == level && level > 1) { > nfolio[i] = f2fs_get_node_folio_ra(parent, offset[i - 1]); > if (IS_ERR(nfolio[i])) { > err = PTR_ERR(nfolio[i]);