Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754717AbbKMKxa (ORCPT ); Fri, 13 Nov 2015 05:53:30 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:48718 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932603AbbKMKLN (ORCPT ); Fri, 13 Nov 2015 05:11:13 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Shaohua Li , Rik van Riel , Wu Fengguang , Mark Salyzyn , Riley Andrews , Will Deacon , Luis Henriques Subject: [PATCH 3.16.y-ckt 17/94] arm64: readahead: fault retry breaks mmap file read random detection Date: Fri, 13 Nov 2015 10:09:11 +0000 Message-Id: <1447409428-12178-18-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1447409428-12178-1-git-send-email-luis.henriques@canonical.com> References: <1447409428-12178-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2004 Lines: 53 3.16.7-ckt20 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Mark Salyzyn commit 569ba74a7ba69f46ce2950bf085b37fea2408385 upstream. This is the arm64 portion of commit 45cac65b0fcd ("readahead: fault retry breaks mmap file read random detection"), which was absent from the initial port and has since gone unnoticed. The original commit says: > .fault now can retry. The retry can break state machine of .fault. In > filemap_fault, if page is miss, ra->mmap_miss is increased. In the second > try, since the page is in page cache now, ra->mmap_miss is decreased. And > these are done in one fault, so we can't detect random mmap file access. > > Add a new flag to indicate .fault is tried once. In the second try, skip > ra->mmap_miss decreasing. The filemap_fault state machine is ok with it. With this change, Mark reports that: > Random read improves by 250%, sequential read improves by 40%, and > random write by 400% to an eMMC device with dm crypto wrapped around it. Cc: Shaohua Li Cc: Rik van Riel Cc: Wu Fengguang Signed-off-by: Mark Salyzyn Signed-off-by: Riley Andrews Signed-off-by: Will Deacon Signed-off-by: Luis Henriques --- arch/arm64/mm/fault.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index bcc965e2cce1..4e4a10df87c1 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -278,6 +278,7 @@ retry: * starvation. */ mm_flags &= ~FAULT_FLAG_ALLOW_RETRY; + mm_flags |= FAULT_FLAG_TRIED; goto retry; } } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/