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 73B71239E61 for ; Thu, 18 Sep 2025 07:03:00 +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=1758178980; cv=none; b=iELRqkAqnKGc+eHQFo7BdgNZahjjZaVVXwzGAwl6qLsRS/cg7She6cggxLLXtl4MaX4JSOCjmA9ud+lG5mSTOen4bU9uGLtJ9hwIGQGXQZCWLITUTFi/ygoC5D31+bvAcmiSyUF1j/G/yZhUim+8PbRDCk7Nva5+wZitND2u4MQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758178980; c=relaxed/simple; bh=t/tgrnSpQzBuhqeycgn8yPZpTHU7BCNR8cVDZenjmQY=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=o39Syev8XPDwaCQvMgj77XkbZTgA+LWkpnTQDaJt1qnuhq+FTvhuCJcItMASaXwSRMTf3gc1hc7M5CxxOSIbW8UvM897Omg3iK+IB4RKO45m0MMHlBMf8JBpRjQV5a/GmyQ+EmxmiWdaVwaLnpfxjrmDhjB1aMKMjUtRbv6lia4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=tXuN/uJU; 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="tXuN/uJU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6EB24C4CEF0; Thu, 18 Sep 2025 07:02:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1758178980; bh=t/tgrnSpQzBuhqeycgn8yPZpTHU7BCNR8cVDZenjmQY=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=tXuN/uJUuuNvcc7ZVLNWIzoXEkFQtWdLWmMeCTfnCccnTKsBs0iwiEyKn56Gp94H/ JSEEbTJb13l2hyQL+4UZryRiorR1vT2iRLCykabcImtdXx4BjsN+s02+odOr9R1I5M VW17wpRdaDA4wty2dGjTi9ELMEcc1GR/na5bfbuGwM7yMw3e0y8rZxMkkQvtxGG5ei kXW9SMbPe8GrWADMjsQmkaqvk3MWXad+1v8zg9Rz51eyazoZoYxhIe8+gIt5Wvh5PD vCtQn9A3FBeVWXnkNgtDuv505jfq5tHzKXB870ah5F55sSnwo5rToa2KRGB0SSNoZF 4v3znBGjH9SkA== Message-ID: <519340cb-a84d-4e0e-ab58-a5bf3562152d@kernel.org> Date: Thu, 18 Sep 2025 15:02:55 +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] f2fs: readahead node block in F2FS_GET_BLOCK_PRECACHE mode To: Yunji Kang , jaegeuk@kernel.org References: <20250917055217.39960-1-yunji0.kang@samsung.com> <000a01dc2858$7e50f460$7af2dd20$@samsung.com> Content-Language: en-US From: Chao Yu In-Reply-To: <000a01dc2858$7e50f460$7af2dd20$@samsung.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/18/25 12:55, 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 | 72.1ms | 29.2% | >>> | 10GB | 222.9ms | 149.5ms | 32.9% | >>> | 20GB | 446.2ms | 276.3ms | 38.1% | >>> +-----------+---------+---------+-----------+ >>> Tested on a 256GB mobile device with an SM8750 chipset. >>> >>> Reviewed-by: Sungjong Seo >>> Reviewed-by: Sunmin Jeong >>> Signed-off-by: Yunji Kang >>> --- >>> 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; >>> + >>> 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..50be167e5c59 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 || >> >> Does this change the logic for mode = LOOKUP_NODE_RA? >> >> Not sure, do you mean this? >> >> if ((i == level && level > 1) && >> (mode == LOOKUP_NODE_RA || >> (mode == LOOKUP_NODE_PRECACHE && >> offset[i - 1] % MAX_RA_NODE == 0))) >> >> Thanks, >> >>> + (mode == LOOKUP_NODE_PRECACHE && offset[i - 1] % >> MAX_RA_NODE == 0)) >>> + && 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]); > > I think the code has the same meaning. > The version you wrote looks more readable, so would it be okay if I change the patch with your code? Sure, please go ahead. > > Also, I did not change the logic for mode = LOOKUP_NODE_RA; I only added a condition for when readahead is performed. Oh, I see, I missed the parenthesis, sorry. Thanks, > > Thanks. >