From patchwork Wed Feb 19 21:00:50 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 11392475 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 00EE8109A for ; Wed, 19 Feb 2020 21:01:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D54452467C for ; Wed, 19 Feb 2020 21:01:25 +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="QAyJRxkc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728152AbgBSVBZ (ORCPT ); Wed, 19 Feb 2020 16:01:25 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:36170 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728081AbgBSVBO (ORCPT ); Wed, 19 Feb 2020 16:01:14 -0500 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=AKQIAD+CV6bMD4ebVqb2Pl7Yi9X7OosUM4taS8DkqDU=; b=QAyJRxkcJ0qFYdUlhIXy4+mSpF e5+qCIpSX5HiXDgrOQIQbQe1HOPpz2Eq8QNCgwjOEGmadMDjaO++xMzzSVceRCPuQAoc6Tl+d6V5e dmSrBTXyTNtKzG7+xtUdvS32EjUMteiGXgHVxylIBaDB9dhPAFdc2zEC22rL1/pS4OsWinJLNyOX/ +njQ996NBx79dZL9hdWy9fCBPiaPlolOxfWoGCLPwZF7HU8EBfeNvMA+5LcUUK8VK3DSgdmhdAw0X oVN1tqUr/j6OUd1gHaHjhmNYvEfeKetTcxFduGgXVHo/yRIwZCqGYkYB99En66BZXa3brMBQVoGLJ KgnVVXsw==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1j4WSv-0008Tu-3k; Wed, 19 Feb 2020 21:01:05 +0000 From: Matthew Wilcox To: linux-fsdevel@vger.kernel.org Cc: "Matthew Wilcox (Oracle)" , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-erofs@lists.ozlabs.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com, ocfs2-devel@oss.oracle.com, linux-xfs@vger.kernel.org Subject: [PATCH v7 11/24] mm: Move end_index check out of readahead loop Date: Wed, 19 Feb 2020 13:00:50 -0800 Message-Id: <20200219210103.32400-12-willy@infradead.org> X-Mailer: git-send-email 2.21.1 In-Reply-To: <20200219210103.32400-1-willy@infradead.org> References: <20200219210103.32400-1-willy@infradead.org> MIME-Version: 1.0 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org From: "Matthew Wilcox (Oracle)" By reducing nr_to_read, we can eliminate this check from inside the loop. Signed-off-by: Matthew Wilcox (Oracle) --- mm/readahead.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/mm/readahead.c b/mm/readahead.c index 07cdfbf00f4b..ace611f4bf05 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -166,8 +166,6 @@ 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); @@ -179,22 +177,27 @@ void __do_page_cache_readahead(struct address_space *mapping, ._nr_pages = 0, }; 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; + if (index + nr_to_read < index) + nr_to_read = ULONG_MAX - index + 1; + 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