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=-9.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 08739C4332D for ; Fri, 20 Mar 2020 14:39:26 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3B6F520724 for ; Fri, 20 Mar 2020 14:39:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="nxesXJP7" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3B6F520724 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linux-erofs-bounces+linux-erofs=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 48kRHb0z19zDrNw for ; Sat, 21 Mar 2020 01:39:23 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=infradead.org (client-ip=2607:7c80:54:e::133; helo=bombadil.infradead.org; envelope-from=willy@infradead.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=bombadil.20170209 header.b=nxesXJP7; dkim-atps=neutral Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) (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 48kQwK2R0NzDsMM for ; Sat, 21 Mar 2020 01:22:41 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=pdWSzME62UL+uO1yH93k0e9uf35TIExoaTsL2owlX54=; b=nxesXJP7ft9mGfzchH1MIKZfLV ruJHCYKTXN+OH4e4bbMluolVkYWROV4AZIQi1/y4y0BsswAR7xTJBh4/mAgJHSz3vMNVcJw0rOgAe 1nmdB9zdFZ88m/Ugpd8jOqsjJIo1VWXsbI9YX+TG9qH6ybYIITOR0/Vxp/bbYFK5RhpuTSaqr7i+E d15wyn5YBpKS1pep4G6KEJrCE/VtwNKG0xyY3ZOR49k4U22JiIX/i2cXRU33+C7ueKMc9G/JweZdZ pRHrXMvXfP58amDDUif7hgr19IlPklmnVQM5FjE4fTe33XaheOFzBFuJt3JoHAFbp2ZU/I4nx79BS rjLU7M6Q==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jFIXh-0000iK-Jm; Fri, 20 Mar 2020 14:22:33 +0000 From: Matthew Wilcox To: Andrew Morton Subject: [PATCH v9 12/25] mm: Move end_index check out of readahead loop Date: Fri, 20 Mar 2020 07:22:18 -0700 Message-Id: <20200320142231.2402-13-willy@infradead.org> X-Mailer: git-send-email 2.21.1 In-Reply-To: <20200320142231.2402-1-willy@infradead.org> References: <20200320142231.2402-1-willy@infradead.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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: linux-xfs@vger.kernel.org, William Kucharski , John Hubbard , linux-kernel@vger.kernel.org, "Matthew Wilcox \(Oracle\)" , linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com, linux-mm@kvack.org, ocfs2-devel@oss.oracle.com, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-erofs@lists.ozlabs.org, linux-btrfs@vger.kernel.org Errors-To: linux-erofs-bounces+linux-erofs=archiver.kernel.org@lists.ozlabs.org Sender: "Linux-erofs" From: "Matthew Wilcox (Oracle)" By reducing nr_to_read, we can eliminate this check from inside the loop. Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: John Hubbard Reviewed-by: William Kucharski --- mm/readahead.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/mm/readahead.c b/mm/readahead.c index d01531ef9f3c..a37b68f66233 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -167,8 +167,6 @@ void __do_page_cache_readahead(struct address_space *mapping, 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 +176,29 @@ void __do_page_cache_readahead(struct address_space *mapping, ._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; + /* Avoid wrapping to the beginning of the file */ + if (index + nr_to_read < index) + nr_to_read = ULONG_MAX - index + 1; + /* Don't read past the page containing the last byte of the file */ + if (index + nr_to_read >= end_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 -- 2.25.1