From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6215FC433F5 for ; Mon, 28 Mar 2022 10:55:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240401AbiC1K53 (ORCPT ); Mon, 28 Mar 2022 06:57:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55332 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240386AbiC1K50 (ORCPT ); Mon, 28 Mar 2022 06:57:26 -0400 Received: from out30-57.freemail.mail.aliyun.com (out30-57.freemail.mail.aliyun.com [115.124.30.57]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CF01C24F1C; Mon, 28 Mar 2022 03:55:44 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R151e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04426;MF=hsiangkao@linux.alibaba.com;NM=1;PH=DS;RN=19;SR=0;TI=SMTPD_---0V8R4iF-_1648464938; Received: from B-P7TQMD6M-0146.local(mailfrom:hsiangkao@linux.alibaba.com fp:SMTPD_---0V8R4iF-_1648464938) by smtp.aliyun-inc.com(127.0.0.1); Mon, 28 Mar 2022 18:55:40 +0800 Date: Mon, 28 Mar 2022 18:55:38 +0800 From: Gao Xiang To: Jeffle Xu Cc: dhowells@redhat.com, linux-cachefs@redhat.com, xiang@kernel.org, chao@kernel.org, linux-erofs@lists.ozlabs.org, torvalds@linux-foundation.org, gregkh@linuxfoundation.org, willy@infradead.org, linux-fsdevel@vger.kernel.org, joseph.qi@linux.alibaba.com, bo.liu@linux.alibaba.com, tao.peng@linux.alibaba.com, gerry@linux.alibaba.com, eguan@linux.alibaba.com, linux-kernel@vger.kernel.org, luodaowen.backend@bytedance.com, tianzichen@kuaishou.com, fannaihao@baidu.com Subject: Re: [PATCH v6 21/22] erofs: implement fscache-based data readahead Message-ID: Mail-Followup-To: Jeffle Xu , dhowells@redhat.com, linux-cachefs@redhat.com, xiang@kernel.org, chao@kernel.org, linux-erofs@lists.ozlabs.org, torvalds@linux-foundation.org, gregkh@linuxfoundation.org, willy@infradead.org, linux-fsdevel@vger.kernel.org, joseph.qi@linux.alibaba.com, bo.liu@linux.alibaba.com, tao.peng@linux.alibaba.com, gerry@linux.alibaba.com, eguan@linux.alibaba.com, linux-kernel@vger.kernel.org, luodaowen.backend@bytedance.com, tianzichen@kuaishou.com, fannaihao@baidu.com References: <20220325122223.102958-1-jefflexu@linux.alibaba.com> <20220325122223.102958-22-jefflexu@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20220325122223.102958-22-jefflexu@linux.alibaba.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 25, 2022 at 08:22:22PM +0800, Jeffle Xu wrote: > Implements fscache-based data readahead. Also registers an individual > bdi for each erofs instance to enable readahead. > > Signed-off-by: Jeffle Xu > --- > fs/erofs/fscache.c | 114 +++++++++++++++++++++++++++++++++++++++++++++ > fs/erofs/super.c | 4 ++ > 2 files changed, 118 insertions(+) > > diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c > index cbb39657615e..589d1e7c2b1b 100644 > --- a/fs/erofs/fscache.c > +++ b/fs/erofs/fscache.c > @@ -191,12 +191,126 @@ static int erofs_fscache_readpage(struct file *file, struct page *page) > return ret; > } > > +static inline size_t erofs_fscache_calc_len(struct erofs_map_blocks *map, > + size_t len, size_t done) > +{ > + /* > + * 1) For CHUNK_BASED layout, the output m_la is rounded down to the > + * nearest chunk boundary, and the output m_llen actually starts from > + * the start of the containing chunk. > + * 2) For other cases, the output m_la is equal to o_la. > + */ > + size_t length = map->m_llen - (map->o_la - map->m_la); > + > + return min_t(size_t, length, len - done); This helper can be folded too. > +} > + > +static inline void erofs_fscache_unlock_folios(struct readahead_control *rac, > + size_t len) > +{ > + while (len) { > + struct folio *folio = readahead_folio(rac); > + > + len -= folio_size(folio); > + folio_mark_uptodate(folio); > + folio_unlock(folio); > + } > +} > + > +static void erofs_fscache_readahead(struct readahead_control *rac) > +{ > + struct inode *inode = rac->mapping->host; > + struct erofs_inode *vi = EROFS_I(inode); > + struct super_block *sb = inode->i_sb; > + size_t len, done = 0; > + loff_t start; > + int ret; > + > + if (erofs_inode_is_data_compressed(vi->datalayout)) { > + erofs_info(sb, "compressed layout not supported yet"); > + return; > + } Redundant check. > + > + if (!readahead_count(rac)) > + return; > + > + start = readahead_pos(rac); > + len = readahead_length(rac); > + > + do { > + struct erofs_map_blocks map; > + > + map.m_la = map.o_la = start + done; > + > + ret = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW); > + if (ret) > + return; > + > + /* Read-ahead Hole > + * Two cases will hit this: > + * 1) EOF. Imposibble in readahead routine; > + * 2) hole. Only CHUNK_BASED layout supports hole. > + */ /* * */ and typo `Imposibble'. Also I think this comment may not be useful though. > + if (!(map.m_flags & EROFS_MAP_MAPPED)) { > + struct iov_iter iter; > + loff_t offset = start + done; > + size_t count = erofs_fscache_calc_len(&map, len, done); > + > + iov_iter_xarray(&iter, READ, &rac->mapping->i_pages, offset, count); > + iov_iter_zero(count, &iter); > + > + erofs_fscache_unlock_folios(rac, count); > + ret = count; > + continue; > + } > + > + ret = erofs_fscache_get_map(&map, sb); > + if (ret) > + return; > + > + /* Read-ahead Inline */ > + if (map.m_flags & EROFS_MAP_META) { > + struct folio *folio = readahead_folio(rac); > + > + ret = erofs_fscache_readpage_inline(folio, &map); > + if (!ret) { > + folio_mark_uptodate(folio); > + ret = folio_size(folio); > + } > + > + folio_unlock(folio); > + continue; > + } > + > + /* Read-ahead No-inline */ > + if (vi->datalayout == EROFS_INODE_FLAT_PLAIN || > + vi->datalayout == EROFS_INODE_FLAT_INLINE || > + vi->datalayout == EROFS_INODE_CHUNK_BASED) { > + struct fscache_cookie *cookie = map.m_fscache->cookie; > + loff_t offset = start + done; > + size_t count = erofs_fscache_calc_len(&map, len, done); You could promote `offset' and `count' to the outer block. So another `offset' and `count' in !EROFS_MAP_MAPPED can be dropped then. Thanks, Gao Xiang From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1775CC433F5 for ; Mon, 28 Mar 2022 10:56:02 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4KRqPD4MJTz3c1p for ; Mon, 28 Mar 2022 21:56:00 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=linux.alibaba.com (client-ip=115.124.30.130; helo=out30-130.freemail.mail.aliyun.com; envelope-from=hsiangkao@linux.alibaba.com; receiver=) Received: from out30-130.freemail.mail.aliyun.com (out30-130.freemail.mail.aliyun.com [115.124.30.130]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4KRqP42Jtbz2ynj for ; Mon, 28 Mar 2022 21:55:49 +1100 (AEDT) X-Alimail-AntiSpam: AC=PASS; BC=-1|-1; BR=01201311R151e4; CH=green; DM=||false|; DS=||; FP=0|-1|-1|-1|0|-1|-1|-1; HT=e01e04426; MF=hsiangkao@linux.alibaba.com; NM=1; PH=DS; RN=19; SR=0; TI=SMTPD_---0V8R4iF-_1648464938; Received: from B-P7TQMD6M-0146.local(mailfrom:hsiangkao@linux.alibaba.com fp:SMTPD_---0V8R4iF-_1648464938) by smtp.aliyun-inc.com(127.0.0.1); Mon, 28 Mar 2022 18:55:40 +0800 Date: Mon, 28 Mar 2022 18:55:38 +0800 From: Gao Xiang To: Jeffle Xu Subject: Re: [PATCH v6 21/22] erofs: implement fscache-based data readahead Message-ID: Mail-Followup-To: Jeffle Xu , dhowells@redhat.com, linux-cachefs@redhat.com, xiang@kernel.org, chao@kernel.org, linux-erofs@lists.ozlabs.org, torvalds@linux-foundation.org, gregkh@linuxfoundation.org, willy@infradead.org, linux-fsdevel@vger.kernel.org, joseph.qi@linux.alibaba.com, bo.liu@linux.alibaba.com, tao.peng@linux.alibaba.com, gerry@linux.alibaba.com, eguan@linux.alibaba.com, linux-kernel@vger.kernel.org, luodaowen.backend@bytedance.com, tianzichen@kuaishou.com, fannaihao@baidu.com References: <20220325122223.102958-1-jefflexu@linux.alibaba.com> <20220325122223.102958-22-jefflexu@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20220325122223.102958-22-jefflexu@linux.alibaba.com> X-BeenThere: linux-erofs@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Development of Linux EROFS file system List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: tianzichen@kuaishou.com, linux-erofs@lists.ozlabs.org, fannaihao@baidu.com, willy@infradead.org, linux-kernel@vger.kernel.org, dhowells@redhat.com, joseph.qi@linux.alibaba.com, linux-cachefs@redhat.com, gregkh@linuxfoundation.org, linux-fsdevel@vger.kernel.org, luodaowen.backend@bytedance.com, gerry@linux.alibaba.com, torvalds@linux-foundation.org Errors-To: linux-erofs-bounces+linux-erofs=archiver.kernel.org@lists.ozlabs.org Sender: "Linux-erofs" On Fri, Mar 25, 2022 at 08:22:22PM +0800, Jeffle Xu wrote: > Implements fscache-based data readahead. Also registers an individual > bdi for each erofs instance to enable readahead. > > Signed-off-by: Jeffle Xu > --- > fs/erofs/fscache.c | 114 +++++++++++++++++++++++++++++++++++++++++++++ > fs/erofs/super.c | 4 ++ > 2 files changed, 118 insertions(+) > > diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c > index cbb39657615e..589d1e7c2b1b 100644 > --- a/fs/erofs/fscache.c > +++ b/fs/erofs/fscache.c > @@ -191,12 +191,126 @@ static int erofs_fscache_readpage(struct file *file, struct page *page) > return ret; > } > > +static inline size_t erofs_fscache_calc_len(struct erofs_map_blocks *map, > + size_t len, size_t done) > +{ > + /* > + * 1) For CHUNK_BASED layout, the output m_la is rounded down to the > + * nearest chunk boundary, and the output m_llen actually starts from > + * the start of the containing chunk. > + * 2) For other cases, the output m_la is equal to o_la. > + */ > + size_t length = map->m_llen - (map->o_la - map->m_la); > + > + return min_t(size_t, length, len - done); This helper can be folded too. > +} > + > +static inline void erofs_fscache_unlock_folios(struct readahead_control *rac, > + size_t len) > +{ > + while (len) { > + struct folio *folio = readahead_folio(rac); > + > + len -= folio_size(folio); > + folio_mark_uptodate(folio); > + folio_unlock(folio); > + } > +} > + > +static void erofs_fscache_readahead(struct readahead_control *rac) > +{ > + struct inode *inode = rac->mapping->host; > + struct erofs_inode *vi = EROFS_I(inode); > + struct super_block *sb = inode->i_sb; > + size_t len, done = 0; > + loff_t start; > + int ret; > + > + if (erofs_inode_is_data_compressed(vi->datalayout)) { > + erofs_info(sb, "compressed layout not supported yet"); > + return; > + } Redundant check. > + > + if (!readahead_count(rac)) > + return; > + > + start = readahead_pos(rac); > + len = readahead_length(rac); > + > + do { > + struct erofs_map_blocks map; > + > + map.m_la = map.o_la = start + done; > + > + ret = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW); > + if (ret) > + return; > + > + /* Read-ahead Hole > + * Two cases will hit this: > + * 1) EOF. Imposibble in readahead routine; > + * 2) hole. Only CHUNK_BASED layout supports hole. > + */ /* * */ and typo `Imposibble'. Also I think this comment may not be useful though. > + if (!(map.m_flags & EROFS_MAP_MAPPED)) { > + struct iov_iter iter; > + loff_t offset = start + done; > + size_t count = erofs_fscache_calc_len(&map, len, done); > + > + iov_iter_xarray(&iter, READ, &rac->mapping->i_pages, offset, count); > + iov_iter_zero(count, &iter); > + > + erofs_fscache_unlock_folios(rac, count); > + ret = count; > + continue; > + } > + > + ret = erofs_fscache_get_map(&map, sb); > + if (ret) > + return; > + > + /* Read-ahead Inline */ > + if (map.m_flags & EROFS_MAP_META) { > + struct folio *folio = readahead_folio(rac); > + > + ret = erofs_fscache_readpage_inline(folio, &map); > + if (!ret) { > + folio_mark_uptodate(folio); > + ret = folio_size(folio); > + } > + > + folio_unlock(folio); > + continue; > + } > + > + /* Read-ahead No-inline */ > + if (vi->datalayout == EROFS_INODE_FLAT_PLAIN || > + vi->datalayout == EROFS_INODE_FLAT_INLINE || > + vi->datalayout == EROFS_INODE_CHUNK_BASED) { > + struct fscache_cookie *cookie = map.m_fscache->cookie; > + loff_t offset = start + done; > + size_t count = erofs_fscache_calc_len(&map, len, done); You could promote `offset' and `count' to the outer block. So another `offset' and `count' in !EROFS_MAP_MAPPED can be dropped then. Thanks, Gao Xiang