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=-2.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 A7D91C433F4 for ; Tue, 28 Aug 2018 11:20:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 60F262089D for ; Tue, 28 Aug 2018 11:20:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="BZHp6QbN" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 60F262089D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728062AbeH1PMB (ORCPT ); Tue, 28 Aug 2018 11:12:01 -0400 Received: from mail-pg1-f196.google.com ([209.85.215.196]:44842 "EHLO mail-pg1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727579AbeH1PMA (ORCPT ); Tue, 28 Aug 2018 11:12:00 -0400 Received: by mail-pg1-f196.google.com with SMTP id r1-v6so592281pgp.11; Tue, 28 Aug 2018 04:20:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=PqIy7bFKrUvh3N2mZhaZbdyHPW+hgwvBa4i30Nw8Ybc=; b=BZHp6QbN59dTJzQoscwjj/i43FAP0Gjci3ePWXPKsGC8C1C6frC6pwM7ZO9Og1acP6 kalOnMjZXknjI8Nx28NzpbS+Bf3PiNWazSfTSbEb5Tfl+239vryJxYCtq1UZm1KWzn0H LErHEmA5WLAWDKAGAxnCjAXNSt84PWxsr1fyECPVZJQ/WqwNnCqAHpj1BOcu3dssf1Xt ri+KTIc8FfxXuQLLx0wAF3iLM12t2IOTD2KNAaa3tt6ARchgJ8OtW2orWdvTnAmDuRT0 34rrzhoTIK0LlmWUaEsu/2lFprRk1Z7eQ/jprd4BLoyNtsG+l4id/94KNevuGHZiRKdN ojKA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=PqIy7bFKrUvh3N2mZhaZbdyHPW+hgwvBa4i30Nw8Ybc=; b=NxtFrsUVPRQrqKXvs1whjF8IngdGmrTJvhoPw9/9tf1RWS7EsvoUXXp6xEp1fNfhBK wyVIl/7ZEB0wyWq163wS0419tuSlLmDRW6YWIGjwN5nfE0LoDp9sFM9aQsXhleAleMIn 48mQ8KCFvzgJ4Zg0wQHwQVY3OGLU++LVO1E5G+kPnkQd/C77VwIVVigJO1fvVNWDB+Qn loH+JUWi3xyiKSYx8aIRKn/BgHXvsfWqW6Ku/CpiC77IklKmAWN2pyem99RIz5yTdCj6 4u+eiD0a0TZZca9GA/M6tvdH9QusKNeyOoNg1rR31mwMpXb6yJGI1HoiPaa0t+KuAuQo N6ag== X-Gm-Message-State: APzg51DWZsNozU2pcAo9kRm/VqJAHvITrzThyyir5epyHJmdskB1oaUB rjmunrvW5/HhQimIXYSH3TG279+M X-Google-Smtp-Source: ANB0Vda1rxfWQ20CAFltZX59amKlHwbHH1qDC49g8kZHwadojwF7gpVndoanEo69eLkZduJDG3UbpQ== X-Received: by 2002:a63:5751:: with SMTP id h17-v6mr1085425pgm.423.1535455249468; Tue, 28 Aug 2018 04:20:49 -0700 (PDT) Received: from roar.au.ibm.com (59-102-81-67.tpgi.com.au. [59.102.81.67]) by smtp.gmail.com with ESMTPSA id s3-v6sm3287917pgj.84.2018.08.28.04.20.45 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 28 Aug 2018 04:20:48 -0700 (PDT) From: Nicholas Piggin To: linux-mm@kvack.org Cc: Nicholas Piggin , linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Andrew Morton , Linus Torvalds Subject: [PATCH 1/3] mm/cow: don't bother write protectig already write-protected huge pages Date: Tue, 28 Aug 2018 21:20:32 +1000 Message-Id: <20180828112034.30875-2-npiggin@gmail.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180828112034.30875-1-npiggin@gmail.com> References: <20180828112034.30875-1-npiggin@gmail.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is the THP equivalent for 1b2de5d039c8 ("mm/cow: don't bother write protecting already write-protected pages"). Explicit hugetlb pages don't get the same treatment because they don't appear to have the right accessor functions. Signed-off-by: Nicholas Piggin --- mm/huge_memory.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 9592cbd8530a..d9bae12978ef 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -973,8 +973,11 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, mm_inc_nr_ptes(dst_mm); pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); - pmdp_set_wrprotect(src_mm, addr, src_pmd); - pmd = pmd_mkold(pmd_wrprotect(pmd)); + if (pmd_write(pmd)) { + pmdp_set_wrprotect(src_mm, addr, src_pmd); + pmd = pmd_wrprotect(pmd); + } + pmd = pmd_mkold(pmd); set_pmd_at(dst_mm, addr, dst_pmd, pmd); ret = 0; @@ -1064,8 +1067,11 @@ int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, /* No huge zero pud yet */ } - pudp_set_wrprotect(src_mm, addr, src_pud); - pud = pud_mkold(pud_wrprotect(pud)); + if (pud_write(pud)) { + pudp_set_wrprotect(src_mm, addr, src_pud); + pud = pud_wrprotect(pud); + } + pud = pud_mkold(pud); set_pud_at(dst_mm, addr, dst_pud, pud); ret = 0; -- 2.18.0