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 03398C433E1 for ; Tue, 2 Jun 2020 04:46:51 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id BC0D5206C3 for ; Tue, 2 Jun 2020 04:46:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="M4jXEj7u" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BC0D5206C3 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 64E808001A; Tue, 2 Jun 2020 00:46:50 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6252E80019; Tue, 2 Jun 2020 00:46:50 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 561CE8001A; Tue, 2 Jun 2020 00:46:50 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0101.hostedemail.com [216.40.44.101]) by kanga.kvack.org (Postfix) with ESMTP id 3C5B880019 for ; Tue, 2 Jun 2020 00:46:50 -0400 (EDT) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id F35AB3ABF for ; Tue, 2 Jun 2020 04:46:49 +0000 (UTC) X-FDA: 76883036538.23.bite12_1e7fd91c0234e Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin23.hostedemail.com (Postfix) with ESMTP id D8C3937606 for ; Tue, 2 Jun 2020 04:46:49 +0000 (UTC) X-HE-Tag: bite12_1e7fd91c0234e X-Filterd-Recvd-Size: 4186 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf26.hostedemail.com (Postfix) with ESMTP for ; Tue, 2 Jun 2020 04:46:49 +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 23C1E208A7; Tue, 2 Jun 2020 04:46:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591073208; bh=g3XWHNdAbx54FtZuh+HegMXlX/7YEraTB1gjBuA7m5w=; h=Date:From:To:Subject:In-Reply-To:From; b=M4jXEj7uPmmbxK/jOcYUYUy5B+eoRW0qk3jrMu7V+wIK+Dk/9X5zmcQAvdhM2KrHb 2QCbZJ1doUgJL/SAi4JG5BBuRBcS3IkUGIrxNmxmukLVszvWn2Tc+L7bhEErTiFUvd zIUNXdEfHrYBrI7RvMbAZ12tknSXgKJkMFAlaU6o= Date: Mon, 01 Jun 2020 21:46:47 -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 025/128] mm: move end_index check out of readahead loop Message-ID: <20200602044647.i0RBx6ur9%akpm@linux-foundation.org> In-Reply-To: <20200601214457.919c35648e96a2b46b573fe1@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Rspamd-Queue-Id: D8C3937606 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 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: move end_index check out of readahead loop By reducing nr_to_read, we can eliminate this check from inside the loop. Link: http://lkml.kernel.org/r/20200414150233.24495-13-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: John Hubbard 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: Joseph Qi Cc: Junxiao Bi Cc: Michal Hocko Cc: Zi Yan Cc: Johannes Thumshirn Cc: Miklos Szeredi Signed-off-by: Andrew Morton --- mm/readahead.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) --- a/mm/readahead.c~mm-move-end_index-check-out-of-readahead-loop +++ a/mm/readahead.c @@ -167,8 +167,6 @@ void __do_page_cache_readahead(struct ad unsigned long lookahead_size) { struct inode *inode = mapping->host; - struct page *page; - unsigned long end_index; /* The last page we want to read */ LIST_HEAD(page_pool); loff_t isize = i_size_read(inode); gfp_t gfp_mask = readahead_gfp_mask(mapping); @@ -178,22 +176,26 @@ void __do_page_cache_readahead(struct ad ._index = index, }; unsigned long i; + pgoff_t end_index; /* The last page we want to read */ if (isize == 0) return; - end_index = ((isize - 1) >> PAGE_SHIFT); + end_index = (isize - 1) >> PAGE_SHIFT; + if (index > end_index) + return; + /* Don't read past the page containing the last byte of the file */ + if (nr_to_read > end_index - index) + nr_to_read = end_index - index + 1; /* * Preallocate as many pages as we will need. */ for (i = 0; i < nr_to_read; i++) { - if (index + i > end_index) - break; + struct page *page = xa_load(&mapping->i_pages, index + i); BUG_ON(index + i != rac._index + rac._nr_pages); - page = xa_load(&mapping->i_pages, index + i); if (page && !xa_is_value(page)) { /* * Page already present? Kick off the current batch of _