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=-19.0 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 ED387C4332B for ; Fri, 15 Jan 2021 17:11:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BB61F2333E for ; Fri, 15 Jan 2021 17:11:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733110AbhAORLC (ORCPT ); Fri, 15 Jan 2021 12:11:02 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:52169 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729599AbhAORLB (ORCPT ); Fri, 15 Jan 2021 12:11:01 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1610730573; 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=zJk71zqOOD6fILHtrWgSqq8ioKD+WcJBLRfGm+Kflhs=; b=Mg9xWOnrLA4uJjvP9tfWRS84j3IVDQl9PFmSga/PYmfbNlY5FZrcfYv2j3bzGJq59bB3IR 5GyXz5KV2bQdBlmurEMLngzrzQCLrgzBsaVuKOWktg5WrOst5I97SMxuoXqRRgSOG2ASjM BgxhaesofWWMDMNN7KZlI9oAuDhEskA= Received: from mail-qk1-f197.google.com (mail-qk1-f197.google.com [209.85.222.197]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-515-2Otgv2JbN3q00mafNMC5vg-1; Fri, 15 Jan 2021 12:09:32 -0500 X-MC-Unique: 2Otgv2JbN3q00mafNMC5vg-1 Received: by mail-qk1-f197.google.com with SMTP id p21so8620990qke.6 for ; Fri, 15 Jan 2021 09:09:32 -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=zJk71zqOOD6fILHtrWgSqq8ioKD+WcJBLRfGm+Kflhs=; b=ia1KnWcqWi3fE1AYzK8xHrVLddXwmGTygh5CKUBuuyvz1NfZPoPxEJgXc0i9sFZKog a55GbLnvNilEQTJaotdtLqh3Cz1eGCbgth/d+5m57S8GqAXq6YfkuVBNVkk2k+B3yVin 3vzoR4mkMfSZ8JuUHqmk9psH2U+14ZN5l5FqawGhVBHeizrn/P5a4Lkrc0Fm3rCXcoZO 8FW+Nj6afuAb8xbKIH8ekvoPD0JjWjHq7Y/3oNq9ZxmuQ/mvolV8HKBO48cJc3Gm6pF9 GMQc8FX+eHN4B013rVp25e8PscvI549veiaW5cc++CPzgBADaj58zicdpJ/GF572NrhR Qe8Q== X-Gm-Message-State: AOAM532R1J6/SzeQ+xVBqTjHfZhoxTesm9Ud0fIYhJXvDAfKQpNwl92y LhCUCcM3K/R4k6rb4pOTGqRxwgGMWIcvW8Pb6NhIai3dlf0FNrucnH3HPkjynfC9VCh/SAI9uXD q20oUnEXpw1oH6eU7B3wvlHlC6NSpp5BXt79RPcwp85hObZyu0Lq3oDe6uEtgBMK+8VSC/qhAYA == X-Received: by 2002:ad4:58c2:: with SMTP id dh2mr13333741qvb.4.1610730571926; Fri, 15 Jan 2021 09:09:31 -0800 (PST) X-Google-Smtp-Source: ABdhPJx/ZGLVCHpITAQmxUytH5fcvrbscIS0jfSoJpLhoJN9VFYKioBq4OLm6JnuowYdUKczUKfJBw== X-Received: by 2002:ad4:58c2:: with SMTP id dh2mr13333709qvb.4.1610730571685; Fri, 15 Jan 2021 09:09:31 -0800 (PST) Received: from localhost.localdomain ([142.126.83.202]) by smtp.gmail.com with ESMTPSA id d123sm5187840qke.95.2021.01.15.09.09.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 15 Jan 2021 09:09:30 -0800 (PST) From: Peter Xu To: linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: Mike Rapoport , Mike Kravetz , peterx@redhat.com, Jerome Glisse , "Kirill A . Shutemov" , Hugh Dickins , Axel Rasmussen , Matthew Wilcox , Andrew Morton , Andrea Arcangeli , Nadav Amit Subject: [PATCH RFC 11/30] mm: Introduce ZAP_FLAG_SKIP_SWAP Date: Fri, 15 Jan 2021 12:08:48 -0500 Message-Id: <20210115170907.24498-12-peterx@redhat.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210115170907.24498-1-peterx@redhat.com> References: <20210115170907.24498-1-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 2380e1df6a49..0b1d04404275 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1632,6 +1632,8 @@ 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. @@ -1654,6 +1656,16 @@ 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 43d8641dbe18..873b2515e187 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1268,8 +1268,7 @@ 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)) @@ -3168,7 +3167,10 @@ 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