From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 784B8334374; Fri, 21 Nov 2025 06:49:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763707790; cv=none; b=S1xrSFG04gAu+jiZJsy5iogMQRQ8ECsNTNcTpDQWzivEtxMSpeDkUZ6caWZ0ekI/Arg8+8Hx2V/HMQblPAlQPwimj3/ORz1kluEioVetiNm9/aBJ1rNZXG7oQ814fZtQy6KI9/HQlx2XqzumL1CS9+r9B8TNMsvJ0/ylsPcw1xc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763707790; c=relaxed/simple; bh=Oy/3exAGfxwDg3eFLTOEHnCYzIB8o5gq5VjqAAj6IGA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kcN9QezoJ7h/trzGpO6F4Tuw5h7szNcY0SVTD0iymkQEIb1jAxh0TyniawW/KbCAS68baTazBmG8fNcjqDdvakpZa3v2WtuEvT8VY1YsMrZly4iW3Zrg3hOtoOk47QMSok39UBoK8GaxS6Xv9ScfrsUXtGkVFNK7T3yvasZQXWQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=LfFscgXA; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="LfFscgXA" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=6Z2wSgy2zyNNpnV1+nFigOTTA+9f/wicUJMD/M0cv00=; b=LfFscgXAyljwTAzbKdofiwBSIr YWYUsofssn/tG0skiwGrltv9b8ePvZePS7jNfK4RiziTFvUhkQwfCVX/Lhj34YMREUQNJtx3cnCgo 7h6LtpoUjQ/SHzly93tP7y0XPAcX+U9M/upev6JqoLrk4y1DP9fa1XHxIggGAPOwcKCENGyKgCkoS l7IE7EycCTEb4p1yAlk1+4qtFZu0vsjCOPrWRmB2Rfq+uRivgN5cuIFXfFhaRUGjJTorUn1WlZCXR MePwiN9IDZ21Z1yUzef3f1Kaz1xYhy1CXVJqw8KHuyYeBDZBIBIgusRaoCC+kZf163AJiYgRPDfEr QKnUeDaw==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vMKxa-00000007wJZ-1QWX; Fri, 21 Nov 2025 06:49:34 +0000 Date: Thu, 20 Nov 2025 22:49:34 -0800 From: Christoph Hellwig To: Jaegeuk Kim Cc: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, Matthew Wilcox , Andrew Morton , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 1/2] f2fs: improve readahead for POSIX_FADV_WILLNEED Message-ID: References: <20251121014202.1969909-1-jaegeuk@kernel.org> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251121014202.1969909-1-jaegeuk@kernel.org> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Fri, Nov 21, 2025 at 01:42:01AM +0000, Jaegeuk Kim wrote: > This patch boosts readahead for POSIX_FADV_WILLNEED. How? That's not a good changelog. Also open coding the read-ahead logic is not a good idea. The only f2fs-specific bits are the compression check, and the extent precaching, but you surely should be able to share a read-ahead helper with common code instead of duplicating the logic. > > Signed-off-by: Jaegeuk Kim > --- > fs/f2fs/data.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++ > fs/f2fs/f2fs.h | 1 + > fs/f2fs/file.c | 9 +++++--- > 3 files changed, 68 insertions(+), 3 deletions(-) > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > index a0433c8a4d84..d95974d79fb3 100644 > --- a/fs/f2fs/data.c > +++ b/fs/f2fs/data.c > @@ -2710,6 +2710,67 @@ static void f2fs_readahead(struct readahead_control *rac) > f2fs_mpage_readpages(inode, rac, NULL); > } > > +int f2fs_readahead_pages(struct file *file, loff_t offset, loff_t len) > +{ > + struct inode *inode = file_inode(file); > + struct address_space *mapping = file->f_mapping; > + pgoff_t start_index = offset >> PAGE_SHIFT; > + loff_t endbyte = offset + len; > + pgoff_t end_index; > + unsigned long nrpages; > + unsigned long ra_pages = (16 * 1024 * 1024) / PAGE_SIZE; > + DEFINE_READAHEAD(ractl, NULL, &file->f_ra, mapping, start_index); > + > + if (!S_ISREG(inode->i_mode)) > + return -EOPNOTSUPP; > + > + /* Should be read only. */ > + if (!(file->f_mode & FMODE_READ)) > + return -EBADF; > + > + /* Do not support compressed file for large folio. */ > + if (f2fs_compressed_file(inode)) > + return -EINVAL; > + > + if (!mapping || len < 0) > + return -EINVAL; > + > + if (unlikely(!mapping->a_ops->read_folio && !mapping->a_ops->readahead)) > + return -EINVAL; > + > + /* Load extent cache at the first readahead. */ > + f2fs_precache_extents(inode); > + > + /* > + * Careful about overflows. Len == 0 means "as much as possible". Use > + * unsigned math because signed overflows are undefined and UBSan > + * complains. > + */ > + if (!len || endbyte > i_size_read(inode) || endbyte < len) > + endbyte = i_size_read(inode) - 1; > + else > + endbyte--; /* inclusive */ > + > + /* First and last PARTIAL page! */ > + end_index = endbyte >> PAGE_SHIFT; > + > + if (start_index > end_index) > + return 0; > + > + nrpages = end_index - start_index + 1; > + > + while (nrpages) { > + unsigned long this_chunk = min(nrpages, ra_pages); > + > + ractl.ra->ra_pages = this_chunk; > + > + page_cache_sync_ra(&ractl, this_chunk << 1); > + > + nrpages -= this_chunk; > + } > + return 0; > +} > + > int f2fs_encrypt_one_page(struct f2fs_io_info *fio) > { > struct inode *inode = fio_inode(fio); > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > index 3340db04a7c2..934287cc5624 100644 > --- a/fs/f2fs/f2fs.h > +++ b/fs/f2fs/f2fs.h > @@ -4047,6 +4047,7 @@ int f2fs_init_bio_entry_cache(void); > void f2fs_destroy_bio_entry_cache(void); > void f2fs_submit_read_bio(struct f2fs_sb_info *sbi, struct bio *bio, > enum page_type type); > +int f2fs_readahead_pages(struct file *file, loff_t offset, loff_t len); > int f2fs_init_write_merge_io(struct f2fs_sb_info *sbi); > void f2fs_submit_merged_write(struct f2fs_sb_info *sbi, enum page_type type); > void f2fs_submit_merged_write_cond(struct f2fs_sb_info *sbi, > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c > index d7047ca6b98d..b6f71efd6d2a 100644 > --- a/fs/f2fs/file.c > +++ b/fs/f2fs/file.c > @@ -5305,9 +5305,12 @@ static int f2fs_file_fadvise(struct file *filp, loff_t offset, loff_t len, > filp->f_mode &= ~FMODE_RANDOM; > spin_unlock(&filp->f_lock); > return 0; > - } else if (advice == POSIX_FADV_WILLNEED && offset == 0) { > - /* Load extent cache at the first readahead. */ > - f2fs_precache_extents(inode); > + } else if (advice == POSIX_FADV_WILLNEED) { > + if (offset == 0 && len == -1) { > + f2fs_precache_extents(inode); > + return 0; > + } > + return f2fs_readahead_pages(filp, offset, len); > } > > err = generic_fadvise(filp, offset, len, advice); > -- > 2.52.0.487.g5c8c507ade-goog > > ---end quoted text---