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 128CD16132A for ; Wed, 24 Sep 2025 07:58:42 +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=1758700723; cv=none; b=uQuMQB3thlHomQ/29PMB90TBh6QOzv6b3GHEc3laIcm4wnq6uIc1cXQfsOba8+81oYuXkeyxTvF6YMhb6dzYOJUwwDHQQSE0cKiJftk1M2GpXvKQyWIIe2h2hxOmmzsnglQg2MB+PTkBzw8tmYpGlLe4rDGBz9NMuzagdEG4fWk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758700723; c=relaxed/simple; bh=rHSxg4+4TSenEjSeMMvVprpOjHqvnCoRegMdDVjjUgQ=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=gnP35ZJ00yXZL/KObGuVJpCu4DsL4WbGlLzlzhn7j1knUvtzM71R57pCXwNfcJdYrXnkeLrNyX+lBRHtJG781utsT3MJ6ntLBiyRtWg2iFj+7Io+s6OK/XYge/m5+wnU7kHwkOIf3hKrjyYWT6E9T5FyU1zkGveB/E1k2ZfMNEM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=BbbXII8L; 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="BbbXII8L" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B0CDEC4CEE7; Wed, 24 Sep 2025 07:58:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1758700722; bh=rHSxg4+4TSenEjSeMMvVprpOjHqvnCoRegMdDVjjUgQ=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=BbbXII8LVVU1HEoc9RKzioSZaFq4mz5nRg5r1Ct/hCFWZALsg00YE0Q0KMXbI48DH RRsggo3mlKcuaBTpQ0yVUMBfNnrgpMZ6YD52RsPPpIb1SiskyMZuqnx+OuWB0cA0bj AAYpbY/5/pcO3ES3Aweozs5/bX9CBlyI5AD+VndfeeqJlWLfscBgvMXy53W9C2/Fg4 0tnh9YDBuUrrfHQkNFK6CfXBYKaNznP09/E1W8sECG/PnLXSSFz8wItSd7WoDMlgVN jzp/aG61AYBfFlyDoh0YYC4zTn5t+Dccelp3HYNFnDLak7BKoJ6At8QbRZVA9KSdbD 2gQr99zxC4wCg== Message-ID: <7d4dd633-8828-4d88-9160-2827c7a0bc83@kernel.org> Date: Wed, 24 Sep 2025 15:58:35 +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, jaegeuk@kernel.org, linux-kernel@vger.kernel.org, sj1557.seo@samsung.com, yunji0.kang@samsung.com Subject: Re: [f2fs-dev] [PATCH v3] f2fs: readahead node blocks in F2FS_GET_BLOCK_PRECACHE mode To: wangzijie , linux-f2fs-devel@lists.sourceforge.net References: <20250924065338.1359558-1-wangzijie1@honor.com> Content-Language: en-US From: Chao Yu In-Reply-To: <20250924065338.1359558-1-wangzijie1@honor.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/24/25 14:53, wangzijie wrote: >> 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, > > Hi Yunji and Chao, > I think so, we can directly use LOOKUP_NODE_RA for precache extents. > BTW, maybe there are more cases that LOOKUP_NODE_RA will be better? Like > defragment/compress(need to call __f2fs_cluster_blocks() ) ioctl.. Yeah, we can have a try to check the benefits. :) Thaks, > > >>> + >>> 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]);