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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C4987C433E1 for ; Tue, 2 Jun 2020 04:46:32 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 7F241207FB for ; Tue, 2 Jun 2020 04:46:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="heEztUhy" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7F241207FB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 27E4B280006; Tue, 2 Jun 2020 00:46:32 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 254FA80016; Tue, 2 Jun 2020 00:46:32 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 19152280006; Tue, 2 Jun 2020 00:46:32 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0002.hostedemail.com [216.40.44.2]) by kanga.kvack.org (Postfix) with ESMTP id 0017180016 for ; Tue, 2 Jun 2020 00:46:31 -0400 (EDT) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id B817E181AEF0B for ; Tue, 2 Jun 2020 04:46:31 +0000 (UTC) X-FDA: 76883035782.30.lead05_1bd369a2e782b Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin30.hostedemail.com (Postfix) with ESMTP id 9A3D6180B3C83 for ; Tue, 2 Jun 2020 04:46:31 +0000 (UTC) X-HE-Tag: lead05_1bd369a2e782b X-Filterd-Recvd-Size: 12798 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf07.hostedemail.com (Postfix) with ESMTP for ; Tue, 2 Jun 2020 04:46:31 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AC12520842; Tue, 2 Jun 2020 04:46:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591073190; bh=AS7FIRCnAKlHjhAAzL45Yy5u8ntWIAj72mdpB+GEI6o=; h=Date:From:To:Subject:In-Reply-To:From; b=heEztUhy6Ewy2sB/s8aikVuEAMpJ76xgOQd2NoYg0mFjSjzFTkuHGbVRBYQfGu+hO YjP7XMUaTvmp13hXNXNJmO08JQnNykaIUR2uuZLqQ5a9FgPVqHp78SNBCWXtXNAwXE GP6mXiLDv2Jf3+Ceo7b6ppo/dzW1ifalHedZ8Cx0= Date: Mon, 01 Jun 2020 21:46:29 -0700 From: Andrew Morton To: akpm@linux-foundation.org, darrick.wong@oracle.com, dchinner@redhat.com, ebiggers@google.com, gaoxiang25@huawei.com, hch@lst.de, jaegeuk@kernel.org, jhubbard@nvidia.com, johannes.thumshirn@wdc.com, joseph.qi@linux.alibaba.com, junxiao.bi@oracle.com, linux-mm@kvack.org, mhocko@suse.com, mm-commits@vger.kernel.org, mszeredi@redhat.com, torvalds@linux-foundation.org, william.kucharski@oracle.com, willy@infradead.org, xiyou.wangcong@gmail.com, yuchao0@huawei.com, ziy@nvidia.com Subject: [patch 020/128] mm: rename various 'offset' parameters to 'index' Message-ID: <20200602044629.RpFoeOQI6%akpm@linux-foundation.org> In-Reply-To: <20200601214457.919c35648e96a2b46b573fe1@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Rspamd-Queue-Id: 9A3D6180B3C83 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: "Matthew Wilcox (Oracle)" Subject: mm: rename various 'offset' parameters to 'index' The word 'offset' is used ambiguously to mean 'byte offset within a page', 'byte offset from the start of the file' and 'page offset from the start of the file'. Use 'index' to mean 'page offset from the start of the file' throughout the readahead code. Link: http://lkml.kernel.org/r/20200414150233.24495-8-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Zi Yan Reviewed-by: William Kucharski Cc: Chao Yu Cc: Christoph Hellwig Cc: Cong Wang Cc: Darrick J. Wong Cc: Dave Chinner Cc: Eric Biggers Cc: Gao Xiang Cc: Jaegeuk Kim Cc: John Hubbard Cc: Joseph Qi Cc: Junxiao Bi Cc: Michal Hocko Cc: Johannes Thumshirn Cc: Miklos Szeredi Signed-off-by: Andrew Morton --- mm/readahead.c | 86 ++++++++++++++++++++++------------------------- 1 file changed, 42 insertions(+), 44 deletions(-) --- a/mm/readahead.c~mm-rename-various-offset-parameters-to-index +++ a/mm/readahead.c @@ -156,7 +156,7 @@ out: * We really don't want to intermingle reads and writes like that. */ void __do_page_cache_readahead(struct address_space *mapping, - struct file *filp, pgoff_t offset, unsigned long nr_to_read, + struct file *filp, pgoff_t index, unsigned long nr_to_read, unsigned long lookahead_size) { struct inode *inode = mapping->host; @@ -180,7 +180,7 @@ void __do_page_cache_readahead(struct ad * Preallocate as many pages as we will need. */ for (page_idx = 0; page_idx < nr_to_read; page_idx++) { - pgoff_t page_offset = offset + page_idx; + pgoff_t page_offset = index + page_idx; if (page_offset > end_index) break; @@ -219,7 +219,7 @@ void __do_page_cache_readahead(struct ad * memory at once. */ void force_page_cache_readahead(struct address_space *mapping, - struct file *filp, pgoff_t offset, unsigned long nr_to_read) + struct file *filp, pgoff_t index, unsigned long nr_to_read) { struct backing_dev_info *bdi = inode_to_bdi(mapping->host); struct file_ra_state *ra = &filp->f_ra; @@ -239,9 +239,9 @@ void force_page_cache_readahead(struct a if (this_chunk > nr_to_read) this_chunk = nr_to_read; - __do_page_cache_readahead(mapping, filp, offset, this_chunk, 0); + __do_page_cache_readahead(mapping, filp, index, this_chunk, 0); - offset += this_chunk; + index += this_chunk; nr_to_read -= this_chunk; } } @@ -322,21 +322,21 @@ static unsigned long get_next_ra_size(st */ /* - * Count contiguously cached pages from @offset-1 to @offset-@max, + * Count contiguously cached pages from @index-1 to @index-@max, * this count is a conservative estimation of * - length of the sequential read sequence, or * - thrashing threshold in memory tight systems */ static pgoff_t count_history_pages(struct address_space *mapping, - pgoff_t offset, unsigned long max) + pgoff_t index, unsigned long max) { pgoff_t head; rcu_read_lock(); - head = page_cache_prev_miss(mapping, offset - 1, max); + head = page_cache_prev_miss(mapping, index - 1, max); rcu_read_unlock(); - return offset - 1 - head; + return index - 1 - head; } /* @@ -344,13 +344,13 @@ static pgoff_t count_history_pages(struc */ static int try_context_readahead(struct address_space *mapping, struct file_ra_state *ra, - pgoff_t offset, + pgoff_t index, unsigned long req_size, unsigned long max) { pgoff_t size; - size = count_history_pages(mapping, offset, max); + size = count_history_pages(mapping, index, max); /* * not enough history pages: @@ -363,10 +363,10 @@ static int try_context_readahead(struct * starts from beginning of file: * it is a strong indication of long-run stream (or whole-file-read) */ - if (size >= offset) + if (size >= index) size *= 2; - ra->start = offset; + ra->start = index; ra->size = min(size + req_size, max); ra->async_size = 1; @@ -378,13 +378,13 @@ static int try_context_readahead(struct */ static void ondemand_readahead(struct address_space *mapping, struct file_ra_state *ra, struct file *filp, - bool hit_readahead_marker, pgoff_t offset, + bool hit_readahead_marker, pgoff_t index, unsigned long req_size) { struct backing_dev_info *bdi = inode_to_bdi(mapping->host); unsigned long max_pages = ra->ra_pages; unsigned long add_pages; - pgoff_t prev_offset; + pgoff_t prev_index; /* * If the request exceeds the readahead window, allow the read to @@ -396,15 +396,15 @@ static void ondemand_readahead(struct ad /* * start of file */ - if (!offset) + if (!index) goto initial_readahead; /* - * It's the expected callback offset, assume sequential access. + * It's the expected callback index, assume sequential access. * Ramp up sizes, and push forward the readahead window. */ - if ((offset == (ra->start + ra->size - ra->async_size) || - offset == (ra->start + ra->size))) { + if ((index == (ra->start + ra->size - ra->async_size) || + index == (ra->start + ra->size))) { ra->start += ra->size; ra->size = get_next_ra_size(ra, max_pages); ra->async_size = ra->size; @@ -421,14 +421,14 @@ static void ondemand_readahead(struct ad pgoff_t start; rcu_read_lock(); - start = page_cache_next_miss(mapping, offset + 1, max_pages); + start = page_cache_next_miss(mapping, index + 1, max_pages); rcu_read_unlock(); - if (!start || start - offset > max_pages) + if (!start || start - index > max_pages) return; ra->start = start; - ra->size = start - offset; /* old async_size */ + ra->size = start - index; /* old async_size */ ra->size += req_size; ra->size = get_next_ra_size(ra, max_pages); ra->async_size = ra->size; @@ -443,29 +443,29 @@ static void ondemand_readahead(struct ad /* * sequential cache miss - * trivial case: (offset - prev_offset) == 1 - * unaligned reads: (offset - prev_offset) == 0 + * trivial case: (index - prev_index) == 1 + * unaligned reads: (index - prev_index) == 0 */ - prev_offset = (unsigned long long)ra->prev_pos >> PAGE_SHIFT; - if (offset - prev_offset <= 1UL) + prev_index = (unsigned long long)ra->prev_pos >> PAGE_SHIFT; + if (index - prev_index <= 1UL) goto initial_readahead; /* * Query the page cache and look for the traces(cached history pages) * that a sequential stream would leave behind. */ - if (try_context_readahead(mapping, ra, offset, req_size, max_pages)) + if (try_context_readahead(mapping, ra, index, req_size, max_pages)) goto readit; /* * standalone, small random read * Read as is, and do not pollute the readahead state. */ - __do_page_cache_readahead(mapping, filp, offset, req_size, 0); + __do_page_cache_readahead(mapping, filp, index, req_size, 0); return; initial_readahead: - ra->start = offset; + ra->start = index; ra->size = get_init_ra_size(req_size, max_pages); ra->async_size = ra->size > req_size ? ra->size - req_size : ra->size; @@ -476,7 +476,7 @@ readit: * the resulted next readahead window into the current one. * Take care of maximum IO pages as above. */ - if (offset == ra->start && ra->size == ra->async_size) { + if (index == ra->start && ra->size == ra->async_size) { add_pages = get_next_ra_size(ra, max_pages); if (ra->size + add_pages <= max_pages) { ra->async_size = add_pages; @@ -495,9 +495,8 @@ readit: * @mapping: address_space which holds the pagecache and I/O vectors * @ra: file_ra_state which holds the readahead state * @filp: passed on to ->readpage() and ->readpages() - * @offset: start offset into @mapping, in pagecache page-sized units - * @req_size: hint: total size of the read which the caller is performing in - * pagecache pages + * @index: Index of first page to be read. + * @req_count: Total number of pages being read by the caller. * * page_cache_sync_readahead() should be called when a cache miss happened: * it will submit the read. The readahead logic may decide to piggyback more @@ -506,7 +505,7 @@ readit: */ void page_cache_sync_readahead(struct address_space *mapping, struct file_ra_state *ra, struct file *filp, - pgoff_t offset, unsigned long req_size) + pgoff_t index, unsigned long req_count) { /* no read-ahead */ if (!ra->ra_pages) @@ -517,12 +516,12 @@ void page_cache_sync_readahead(struct ad /* be dumb */ if (filp && (filp->f_mode & FMODE_RANDOM)) { - force_page_cache_readahead(mapping, filp, offset, req_size); + force_page_cache_readahead(mapping, filp, index, req_count); return; } /* do read-ahead */ - ondemand_readahead(mapping, ra, filp, false, offset, req_size); + ondemand_readahead(mapping, ra, filp, false, index, req_count); } EXPORT_SYMBOL_GPL(page_cache_sync_readahead); @@ -531,21 +530,20 @@ EXPORT_SYMBOL_GPL(page_cache_sync_readah * @mapping: address_space which holds the pagecache and I/O vectors * @ra: file_ra_state which holds the readahead state * @filp: passed on to ->readpage() and ->readpages() - * @page: the page at @offset which has the PG_readahead flag set - * @offset: start offset into @mapping, in pagecache page-sized units - * @req_size: hint: total size of the read which the caller is performing in - * pagecache pages + * @page: The page at @index which triggered the readahead call. + * @index: Index of first page to be read. + * @req_count: Total number of pages being read by the caller. * * page_cache_async_readahead() should be called when a page is used which - * has the PG_readahead flag; this is a marker to suggest that the application + * is marked as PageReadahead; this is a marker to suggest that the application * has used up enough of the readahead window that we should start pulling in * more pages. */ void page_cache_async_readahead(struct address_space *mapping, struct file_ra_state *ra, struct file *filp, - struct page *page, pgoff_t offset, - unsigned long req_size) + struct page *page, pgoff_t index, + unsigned long req_count) { /* no read-ahead */ if (!ra->ra_pages) @@ -569,7 +567,7 @@ page_cache_async_readahead(struct addres return; /* do read-ahead */ - ondemand_readahead(mapping, ra, filp, true, offset, req_size); + ondemand_readahead(mapping, ra, filp, true, index, req_count); } EXPORT_SYMBOL_GPL(page_cache_async_readahead); _