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=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 F3718C4167B for ; Tue, 8 Dec 2020 02:52:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B839523998 for ; Tue, 8 Dec 2020 02:52:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728320AbgLHCv6 (ORCPT ); Mon, 7 Dec 2020 21:51:58 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:23182 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728052AbgLHCv6 (ORCPT ); Mon, 7 Dec 2020 21:51:58 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1607395831; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=y3Z2K8nRRfGkaf6Txv+p5jeGljoBTJFR0t93dd3Zx9U=; b=Gs6LxJ2QSDCr+xI9/nONJy0WglY4dWPG09VWE85sSNiEQh5I3VsCKcG7nc8/rs+LEMV4d6 MioP/HH5l9OanjwSRh9y4hoTqKPiaorDqjZVaLyTEm0VW0lqGRzHkj3+EE3Ux0FtpIZ2G/ aNRjLklv0hPN57H2x2q+1bxv5wFrb3g= Received: from mail-qt1-f200.google.com (mail-qt1-f200.google.com [209.85.160.200]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-249-wWiW8vdAPIySeKZ0wJgLyQ-1; Mon, 07 Dec 2020 21:50:29 -0500 X-MC-Unique: wWiW8vdAPIySeKZ0wJgLyQ-1 Received: by mail-qt1-f200.google.com with SMTP id i1so8398443qtw.4 for ; Mon, 07 Dec 2020 18:50:29 -0800 (PST) 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:mime-version:content-transfer-encoding; bh=y3Z2K8nRRfGkaf6Txv+p5jeGljoBTJFR0t93dd3Zx9U=; b=fYf3LH3OtoMxpw/X0MfA5HycYLX96VPFn7PNaULDxFNcn/mEX4kld0vIng0JTXpd5C om2gHoYF4OmtS7Ye2UwxPRws/unOQRKy6bB6WR/hVKwRXJ3AEGgQmBvFugRdm8+V33xR PlPuxiyquKd8swpiGiVR6tqszyPBKKlCqWPNmRH5XMpOerSxPvlwJ/3LgfpW50SkfrxO yXfNOqkMmnME/H4S3Wm+YcF/aAARjyIi9sQpobeSOtUqyvr4R8XFl6GbgFoKoiJyN/VV upH8i0KhwVC4ZELiDAm/4gWq8dmH+2MqLTgR2Jx9ApEZ54PbwD1e/LvDd4rPuLRVj+OF Hx2Q== X-Gm-Message-State: AOAM5301TTuPIqaLDgcVKZXJm3UnxTayXbUVlLEVO8mxtLBdzJyukCEX lAngr3fEdaC387eUEmOjcwvCcLylHVj6rumqIl9zmCT1J90WTW5wLJQToXDdsJt4glrG0CDmNaM 18tuQHCaNxFutdrLxRyfzzzjyzzWLD6HkLx/T5mZoyRho1NlyMODxtL8Nqwfsdw3dfHg8aLIhkQ == X-Received: by 2002:a0c:c405:: with SMTP id r5mr16720991qvi.4.1607395828993; Mon, 07 Dec 2020 18:50:28 -0800 (PST) X-Google-Smtp-Source: ABdhPJzHzUEslTZ1FZEWzJNu0W0qlP5gzOXXVxFImV3fi6ypeqsM2vcqg63+0O0dcsbZ71OFP2qwyQ== X-Received: by 2002:a0c:c405:: with SMTP id r5mr16720969qvi.4.1607395828714; Mon, 07 Dec 2020 18:50:28 -0800 (PST) Received: from localhost.localdomain ([142.126.83.202]) by smtp.gmail.com with ESMTPSA id a28sm2632766qtm.80.2020.12.07.18.50.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Dec 2020 18:50:28 -0800 (PST) From: Peter Xu To: linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: Andrea Arcangeli , peterx@redhat.com, "Kirill A . Shutemov" , Andrew Morton Subject: [PATCH 3/3] mm: Introduce ZAP_FLAG_SKIP_SWAP Date: Mon, 7 Dec 2020 21:50:22 -0500 Message-Id: <20201208025022.8234-4-peterx@redhat.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20201208025022.8234-1-peterx@redhat.com> References: <20201208025022.8234-1-peterx@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Firstly, the comment in zap_pte_range() is misleading because it checks against details rather than check_mappings, so it's against what the code did. Meanwhile, it's confusing too on not explaining why passing in the details pointer would mean to skip all swap entries. New user of zap_details could very possibly miss this fact if they don't read deep until zap_pte_range() because there's no comment at zap_details talking about it at all, so swap entries could be errornously skipped without being noticed. This partly reverts 3e8715fdc03e ("mm: drop zap_details::check_swap_entries"), but introduce ZAP_FLAG_SKIP_SWAP flag, which means the opposite of previous "details" parameter: the caller should explicitly set this to skip swap entries, otherwise swap entries will always be considered (which is still the major case here). Cc: Kirill A. Shutemov Signed-off-by: Peter Xu --- include/linux/mm.h | 12 ++++++++++++ mm/memory.c | 8 +++++--- 2 files changed, 17 insertions(+), 3 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 7ed4352ec84f..16631ee5eb9d 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1622,6 +1622,8 @@ extern void user_shm_unlock(size_t, struct user_struct *); /* Whether to check page->mapping when zapping */ #define ZAP_FLAG_CHECK_MAPPING BIT(0) +/* Whether to skip zapping swap entries */ +#define ZAP_FLAG_SKIP_SWAP BIT(1) /* * Parameter block passed down to zap_pte_range in exceptional cases. @@ -1644,6 +1646,16 @@ zap_check_mapping_skip(struct zap_details *details, struct page *page) return details->zap_mapping != page_rmapping(page); } +/* Return true if skip swap entries, false otherwise */ +static inline bool +zap_skip_swap(struct zap_details *details) +{ + if (!details) + return false; + + return details->zap_flags & ZAP_FLAG_SKIP_SWAP; +} + struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, pte_t pte); struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr, diff --git a/mm/memory.c b/mm/memory.c index 20a8ba05c334..c9945f3c374d 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1262,8 +1262,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, continue; } - /* If details->check_mapping, we leave swap entries. */ - if (unlikely(details)) + if (unlikely(zap_skip_swap(details))) continue; if (!non_swap_entry(entry)) @@ -3159,7 +3158,10 @@ void unmap_mapping_pages(struct address_space *mapping, pgoff_t start, pgoff_t nr, bool even_cows) { pgoff_t first_index = start, last_index = start + nr - 1; - struct zap_details details = { .zap_mapping = mapping }; + struct zap_details details = { + .zap_mapping = mapping, + .zap_flags = ZAP_FLAG_SKIP_SWAP, + }; if (!even_cows) details.zap_flags |= ZAP_FLAG_CHECK_MAPPING; -- 2.26.2