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 51F5C1D5CC7 for ; Thu, 18 Sep 2025 02:09:55 +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=1758161396; cv=none; b=ZnMRqXLEZ19Opq802tVJ00fyQ0PXgr3VaRqWIeRTPomm1pGMwMhqg21dEJw7rLdSA5ShEOMfB42ZgpE0NhTYLNlFA425R/NAo9WcR/4fCqPlK+w/AqOPI94sIOh0HGdbe20KWGHiQQq99bscCrF6ScbkdNAOeUdabx5sH2vCfcY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758161396; c=relaxed/simple; bh=2Gl5VQpe3Kr+g9GDcpIm9On2t4jBVt6mmEX/BU/mrAQ=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=XNLZNysgv4x41ZSnNhwYY0/kDuLuRs7Y70QILS1xYoR2g61gRlI6AbPhy1OByJW4ATbZbJkJ3k8KTWvDS3o2IvhKwtAvp2J00uuLneFl9Dtk3SodfeQZ+UY/iNvwHDVBFxYKy17vXPgZaclXCavVsnbViWuI/SwYGsu+tEtEQrk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=R2NuQrgG; 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="R2NuQrgG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3C7ECC4CEE7; Thu, 18 Sep 2025 02:09:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1758161395; bh=2Gl5VQpe3Kr+g9GDcpIm9On2t4jBVt6mmEX/BU/mrAQ=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=R2NuQrgG+QMzce/tITsqLa0Na5y4kjZ33KcJWmNYXIVY2FUAGfWMv9leQVENng3w/ odID7xGRQNs63cwejiO4nbEczpaNN7KMh0b/oz8fZwOKntzpRPuMEbga16J9gwHngj 4KKKLj+9YJaS1FTcORm91f+cfHW2DGGNsRr5MzmR8JR+GGVQKQubJwXuTkkkiYOmzK oRVakjICOEwmmVUpMEFGxroAk23EHoMMf+Nn6EE5wkoSfM3XyQnzVAUH2yU1M/7M9i k/cWfoyh22+k1RGC9VuGIYhwfihItEfPN6eZnxHoePXyPC28g7dXSV5qBbmTqYbZcY fakeP8kGfxlOQ== Message-ID: Date: Thu, 18 Sep 2025 10:09:48 +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> Content-Language: en-US From: Chao Yu In-Reply-To: <20250917055217.39960-1-yunji0.kang@samsung.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/17/25 13:52, 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]);