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[2620:137:e000::1:20]) by mx.google.com with ESMTP id k8-20020a170902c40800b001b9c7300823si2049827plk.221.2023.07.27.16.12.13; Thu, 27 Jul 2023 16:12:26 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=UaeO1yW6; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232086AbjG0V3s (ORCPT + 99 others); Thu, 27 Jul 2023 17:29:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52718 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229765AbjG0V3p (ORCPT ); Thu, 27 Jul 2023 17:29:45 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D4923E47 for ; Thu, 27 Jul 2023 14:28:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1690493337; 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=3V6q8K76IOW6dvze9Iao5sragyvrE9hiergd1FJ9CnQ=; b=UaeO1yW6QgE/pRoiqzWWrdZt0XM+bYv4bkFaBuPah1cTt6TwV32MFI5tb1MT9gOUd421WV qWT2MPqkq41xZJRK14yFTz9oadKKGCrJeQvjOUkhh1YEz0G4dWGqCOxafaxTdLNDQnssDv agwKHJFxAOtWofjBcVC8OdIc94TkmhI= Received: from mimecast-mx02.redhat.com (66.187.233.73 [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-16-1ckDkazHPumtGeeYi-ezOg-1; Thu, 27 Jul 2023 17:28:53 -0400 X-MC-Unique: 1ckDkazHPumtGeeYi-ezOg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 2E0FA3810D42; Thu, 27 Jul 2023 21:28:53 +0000 (UTC) Received: from t14s.redhat.com (unknown [10.39.192.55]) by smtp.corp.redhat.com (Postfix) with ESMTP id 41E6C40C2063; Thu, 27 Jul 2023 21:28:50 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, David Hildenbrand , Andrew Morton , Linus Torvalds , liubo , Peter Xu , Matthew Wilcox , Hugh Dickins , Jason Gunthorpe , John Hubbard , stable@vger.kernel.org Subject: [PATCH v1 1/4] smaps: Fix the abnormal memory statistics obtained through /proc/pid/smaps Date: Thu, 27 Jul 2023 23:28:42 +0200 Message-ID: <20230727212845.135673-2-david@redhat.com> In-Reply-To: <20230727212845.135673-1-david@redhat.com> References: <20230727212845.135673-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H4,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1772617253063035659 X-GMAIL-MSGID: 1772617253063035659 From: liubo In commit 474098edac26 ("mm/gup: replace FOLL_NUMA by gup_can_follow_protnone()"), FOLL_NUMA was removed and replaced by the gup_can_follow_protnone interface. However, for the case where the user-mode process uses transparent huge pages, when analyzing the memory usage through /proc/pid/smaps_rollup, the obtained memory usage is not consistent with the RSS in /proc/pid/status. Related examples are as follows: cat /proc/15427/status VmRSS: 20973024 kB RssAnon: 20971616 kB RssFile: 1408 kB RssShmem: 0 kB cat /proc/15427/smaps_rollup 00400000-7ffcc372d000 ---p 00000000 00:00 0 [rollup] Rss: 14419432 kB Pss: 14418079 kB Pss_Dirty: 14418016 kB Pss_Anon: 14418016 kB Pss_File: 63 kB Pss_Shmem: 0 kB Anonymous: 14418016 kB LazyFree: 0 kB AnonHugePages: 14417920 kB The root cause is that the traversal In the page table, the number of pages obtained by smaps_pmd_entry does not include the pages corresponding to PROTNONE,resulting in a different situation. Therefore, when obtaining pages through the follow_trans_huge_pmd interface, add the FOLL_FORCE flag to count the pages corresponding to PROTNONE to solve the above problem. Signed-off-by: liubo Cc: stable@vger.kernel.org Fixes: 474098edac26 ("mm/gup: replace FOLL_NUMA by gup_can_follow_protnone()") Signed-off-by: David Hildenbrand # AKPM fixups, cc stable Signed-off-by: David Hildenbrand --- fs/proc/task_mmu.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index c1e6531cb02a..7075ce11dc7d 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -571,8 +571,12 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr, bool migration = false; if (pmd_present(*pmd)) { - /* FOLL_DUMP will return -EFAULT on huge zero page */ - page = follow_trans_huge_pmd(vma, addr, pmd, FOLL_DUMP); + /* + * FOLL_DUMP will return -EFAULT on huge zero page + * FOLL_FORCE follow a PROT_NONE mapped page + */ + page = follow_trans_huge_pmd(vma, addr, pmd, + FOLL_DUMP | FOLL_FORCE); } else if (unlikely(thp_migration_supported() && is_swap_pmd(*pmd))) { swp_entry_t entry = pmd_to_swp_entry(*pmd); From patchwork Thu Jul 27 21:28:43 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 127208 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:918b:0:b0:3e4:2afc:c1 with SMTP id s11csp37220vqg; Thu, 27 Jul 2023 15:06:50 -0700 (PDT) X-Google-Smtp-Source: APBJJlFhfTmFokI6PVOQSL4cEoVV94V200HFgYof1cgvEjyjOVn6wZ3T3N+iwiL0ezhxJ72r6rUP X-Received: by 2002:a2e:88ce:0:b0:2b9:4418:b46e with SMTP id a14-20020a2e88ce000000b002b94418b46emr237516ljk.21.1690495609943; Thu, 27 Jul 2023 15:06:49 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1690495609; cv=none; d=google.com; s=arc-20160816; b=oZ082szF9uphW38p8EmZtgJ/4mNUzsByoJT7YwTxhyK1sZNJFM/F3AVb6VMGetA4zl c4u96P3snwea0J21QNsLOgPR5NKPH3Ah0MAfaJeoKa+JNlSPzByFwtXJ2TfyXHiPghbp 5NK5F3RwydUsYSzYDj/sb3G4z04j26OVqV8Nyx224tuF7sLQ6eTQm6Wj6z4ff8eJOqbw +vhxGAp4kabsf+9gdR4WoQi0rjGg5ueBaZTo3Ez8HbiN/9BJ4ObwV1uzQfNf7SmdXX4/ NWT6AvM+nbYyBuY0LG3B3RY4TSO0BxEjLLMPubKhJ3TTR7mWTaGkNLx0Dxrs7JwkXshj bh5A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=NHdYsiNqqxFFYOyFZT8N/uUoLYdRyRl4LhGdK5bhGpM=; fh=i2xka5O4sIhq1fON2X/zWAmhKqmUDKbi5QldKXT0naQ=; b=eafW3TG7xJn75HV90GJ6xMQPIi+8N4leS9/txu0d7CLNrRMA1sxtNSDJpQDlsUh6Tx R307SJ0JHVC/Q2Tm+FFq38KkfkVI9YYvCv2MS++Ng+NHYPORjJftj87ItJM7kDfLeTE4 TXDkbNOqo2RixNyBr/bGbXTqGPRDnSHTxkvyNDDnF06vjneaIz1zCMUgooX8dQgkzsGV yLyoiHcuSxRw92WtqpbVe3FsOYvumCNmPyoI5WAFt7eY/gmHrOYdqT447nj7CRAXOap5 FV+YL/evv30Zm0PbVSbLUGnHGTFeDYjcprPA5f7gVoqMMF0nAeAMnhiDAWJBdPfUI6xK VLlQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b="U/h5LvTx"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id m21-20020a1709066d1500b00992071c984fsi1528294ejr.954.2023.07.27.15.06.25; Thu, 27 Jul 2023 15:06:49 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b="U/h5LvTx"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232127AbjG0Vaj (ORCPT + 99 others); Thu, 27 Jul 2023 17:30:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52878 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232260AbjG0VaZ (ORCPT ); Thu, 27 Jul 2023 17:30:25 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1D90D198A for ; Thu, 27 Jul 2023 14:29:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1690493339; 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=NHdYsiNqqxFFYOyFZT8N/uUoLYdRyRl4LhGdK5bhGpM=; b=U/h5LvTxWsyY4eHnC0udW1fJNSAsv5faxZEuPYE/0JV1G61QS2yBLYccsVo/BcM3tb9j+w yP6Jm/sjhUyk3F6Ppe/s3g9RXcgsNvM4B+moZuEwlFLfV9Jo98oEFkxd6tyizJRXTh5Mb4 9iKZdMQ43zbVre+xvTI3Da+gsdzFHH8= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-554-F0H8AQw3M0yhKgh2HgjDcA-1; Thu, 27 Jul 2023 17:28:56 -0400 X-MC-Unique: F0H8AQw3M0yhKgh2HgjDcA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 50B76104458B; Thu, 27 Jul 2023 21:28:55 +0000 (UTC) Received: from t14s.redhat.com (unknown [10.39.192.55]) by smtp.corp.redhat.com (Postfix) with ESMTP id 67C2B40C2063; Thu, 27 Jul 2023 21:28:53 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, David Hildenbrand , Andrew Morton , Linus Torvalds , liubo , Peter Xu , Matthew Wilcox , Hugh Dickins , Jason Gunthorpe , John Hubbard , stable@vger.kernel.org Subject: [PATCH v1 2/4] mm/gup: Make follow_page() succeed again on PROT_NONE PTEs/PMDs Date: Thu, 27 Jul 2023 23:28:43 +0200 Message-ID: <20230727212845.135673-3-david@redhat.com> In-Reply-To: <20230727212845.135673-1-david@redhat.com> References: <20230727212845.135673-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H4,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE, T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1772613124903527453 X-GMAIL-MSGID: 1772613124903527453 We accidentally enforced PROT_NONE PTE/PMD permission checks for follow_page() like we do for get_user_pages() and friends. That was undesired, because follow_page() is usually only used to lookup a currently mapped page, not to actually access it. Further, follow_page() does not actually trigger fault handling, but instead simply fails. Let's restore that behavior by conditionally setting FOLL_FORCE if FOLL_WRITE is not set. This way, for example KSM and migration code will no longer fail on PROT_NONE mapped PTEs/PMDS. Handling this internally doesn't require us to add any new FOLL_FORCE usage outside of GUP code. While at it, refuse to accept FOLL_FORCE: we don't even perform VMA permission checks like in check_vma_flags(), so especially FOLL_FORCE|FOLL_WRITE would be dodgy. This issue was identified by code inspection. We'll add some documentation regarding FOLL_FORCE next. Reported-by: Peter Xu Fixes: 474098edac26 ("mm/gup: replace FOLL_NUMA by gup_can_follow_protnone()") Cc: Signed-off-by: David Hildenbrand --- mm/gup.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/mm/gup.c b/mm/gup.c index 2493ffa10f4b..da9a5cc096ac 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -841,9 +841,17 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address, if (vma_is_secretmem(vma)) return NULL; - if (WARN_ON_ONCE(foll_flags & FOLL_PIN)) + if (WARN_ON_ONCE(foll_flags & (FOLL_PIN | FOLL_FORCE))) return NULL; + /* + * Traditionally, follow_page() succeeded on PROT_NONE-mapped pages + * but failed follow_page(FOLL_WRITE) on R/O-mapped pages. Let's + * keep these semantics by setting FOLL_FORCE if FOLL_WRITE is not set. + */ + if (!(foll_flags & FOLL_WRITE)) + foll_flags |= FOLL_FORCE; + page = follow_page_mask(vma, address, foll_flags, &ctx); if (ctx.pgmap) put_dev_pagemap(ctx.pgmap); From patchwork Thu Jul 27 21:28:44 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 127215 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:918b:0:b0:3e4:2afc:c1 with SMTP id s11csp41305vqg; Thu, 27 Jul 2023 15:15:49 -0700 (PDT) X-Google-Smtp-Source: APBJJlGefQi2thb+dwhMoG81y+E90CDVYhxGDePbQDztc70tvfI34R5kZX38rjSSAQz4/QT4k4sB X-Received: by 2002:a17:903:1d1:b0:1a9:40d5:b0ae with SMTP id e17-20020a17090301d100b001a940d5b0aemr594629plh.12.1690496148925; Thu, 27 Jul 2023 15:15:48 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1690496148; cv=none; d=google.com; s=arc-20160816; b=cW3sVegmUiEe6nIMORskAoIhFAIbGakrK1to+GF5HDsFhrCALpSRgvsHEqW+v7OmJI N2G9fh/RCnhgYiIVIdFa2qz1i4nIW1eVTOF2mVSlpsmQ7Zq6ncwHxwaI1etdL851QPEs i2RK4yu05FhvNRkzJgx80YxZ5PTfSYlzkc/sQGP4HYMDgnDpTCaJ2N//bqBDauG19pFM ZHxAXV0Kfkh3aWd5THrsDO88TvcPe0Mu9TI972OMgiMDIvjmf7YMFWAau4YrvsYq3arV Xrq8CZiB8BDnaMnC22MU7N4msCP/ARPJXOMR2R9TfKU0Hl/VUquowQU571lTH5jde3vZ l9aA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=Gg+vYFf2MUM715aNnpsI37yVDyYtQwBsTVNC7NmhATc=; fh=7Rgwgprh6RG9EUsex42/VTSquO8kknsMsxso4zkcjrY=; b=0DqBJD8mc8uALtDryumPl3xivcLHU9zY4oDar/Ka6nBvgYePwAFvViYO+yvL+mEXnu eGXEV2iBHelT6EokllfiS4eZlpGlWICtxaoPX7Y5JFRLf6YqCitsGvRHApGohjXvUCTD VsRtQOM0L88yxh60iKKfzaFi9wKa+xkcPCRifDjKPdOnO8gKQ+nWrc4BapLEdG3xqseq +tr/7PBqEJrMioRJOZcsWxHHgElm3Af+Jdkdl4HPQ8Y7oW7JVuR2J3+WuUc5qmErOAci 3vTXHYMUu7Z7q5OwlJy9K20WOWC94uN1jMvcIlSFAUIBbeB6IChtdLulII8f9EbGK2Zv qYhQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=aHuPhlKK; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id g12-20020a170902c98c00b001bb2ef676c4si1821819plc.202.2023.07.27.15.15.36; Thu, 27 Jul 2023 15:15:48 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=aHuPhlKK; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230106AbjG0Vag (ORCPT + 99 others); Thu, 27 Jul 2023 17:30:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52892 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230231AbjG0VaY (ORCPT ); Thu, 27 Jul 2023 17:30:24 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7CA4419BF for ; Thu, 27 Jul 2023 14:29:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1690493341; 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=Gg+vYFf2MUM715aNnpsI37yVDyYtQwBsTVNC7NmhATc=; b=aHuPhlKKbrDbKy1cg/mJXooRQ+2/ikLLxttMfZU9DPvA+v0s+iXqPRJGNxwwiB0eK/yg/M mS9OJrdlOs9fHQYC3OMsU0fhj9ufv+eSZc0u3/uir4Xok9k335rF/kv7U1rPy1dFWhrC+7 5XzJCP0iwOm/a6Z45h97wk7TZb3HqRU= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-359-RlyUAFoMPPO8N1iA8aE7qw-1; Thu, 27 Jul 2023 17:28:58 -0400 X-MC-Unique: RlyUAFoMPPO8N1iA8aE7qw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 924CC805951; Thu, 27 Jul 2023 21:28:57 +0000 (UTC) Received: from t14s.redhat.com (unknown [10.39.192.55]) by smtp.corp.redhat.com (Postfix) with ESMTP id 91ABF40C2063; Thu, 27 Jul 2023 21:28:55 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, David Hildenbrand , Andrew Morton , Linus Torvalds , liubo , Peter Xu , Matthew Wilcox , Hugh Dickins , Jason Gunthorpe , John Hubbard Subject: [PATCH v1 3/4] smaps: use vm_normal_page_pmd() instead of follow_trans_huge_pmd() Date: Thu, 27 Jul 2023 23:28:44 +0200 Message-ID: <20230727212845.135673-4-david@redhat.com> In-Reply-To: <20230727212845.135673-1-david@redhat.com> References: <20230727212845.135673-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H4,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1772613689707209087 X-GMAIL-MSGID: 1772613689707209087 We really shouldn't be using a GUP-internal helper if it can be avoided, and avoiding the FOLL_FORCE here is certainly desirable. Similar to smaps_pte_entry() that uses vm_normal_page(), let's use vm_normal_page_pmd() -- that didn't exist back when we introduced that code -- that similarly refuses to return the huge zeropage. Signed-off-by: David Hildenbrand --- fs/proc/task_mmu.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 7075ce11dc7d..b8ea270bf68b 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -571,12 +571,7 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr, bool migration = false; if (pmd_present(*pmd)) { - /* - * FOLL_DUMP will return -EFAULT on huge zero page - * FOLL_FORCE follow a PROT_NONE mapped page - */ - page = follow_trans_huge_pmd(vma, addr, pmd, - FOLL_DUMP | FOLL_FORCE); + page = vm_normal_page_pmd(vma, addr, *pmd); } else if (unlikely(thp_migration_supported() && is_swap_pmd(*pmd))) { swp_entry_t entry = pmd_to_swp_entry(*pmd); From patchwork Thu Jul 27 21:28:45 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 127221 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:918b:0:b0:3e4:2afc:c1 with SMTP id s11csp43537vqg; Thu, 27 Jul 2023 15:21:09 -0700 (PDT) X-Google-Smtp-Source: APBJJlE5Oq0JKYKwCmaYzNsspTKivsLRHFLGE9j1cfnEqnFw88DznHaT8hfqFRUmik148SXx564K X-Received: by 2002:a17:903:2443:b0:1b6:6f12:502e with SMTP id l3-20020a170903244300b001b66f12502emr649537pls.49.1690496468838; Thu, 27 Jul 2023 15:21:08 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1690496468; cv=none; d=google.com; s=arc-20160816; b=uqmr+F1YjkcvRtbclUwE7N9+wEr4djZq0ba4j5Wfh77oMRBbmlSxNQqs5NMcyWB6T0 tlW5sGMif8bv0zr00g4/8C890TgwXcBNVa7m0nrKtT+hlQhc/YR3eaPhvC+RUNAXB7Xx NY6+WePunAKnJ2g/8N+1v8/fL/u0vaFCMJnBRko3OmdCWbO77f97Qa6doed4gXlu39yq Ta1ITapGB95iVZGxQrONauTjaiu4I6Y42641rWhFsy7NCK9X/p30Whv96VKFImVsplKK fypsccYgiqEdEHXEILFSjvgyeRxMdkXNMCFeE7++WAxh6ml1P6aOTBfvbAzIuQNaB6zq dadg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=jGnguQzUAnXSgoEJGq4aUCEYI9GBqFjghH3nhnid2s4=; fh=7Rgwgprh6RG9EUsex42/VTSquO8kknsMsxso4zkcjrY=; b=Q6uWpwnZBtSoveAYRHXABDsde3tiHrlQxZwfjEK7j7LdQU7G99Mbb3z1MQCA0m5mvV jj3YaX19CEu9I/2Zz4suzPzOIFvZVx3ftBPN0aKdL8Iab1LIo0f3VFLzy7kV40dvTVtu k0+LZ4+0bi8VdKWdAWA2aSNSY8D2tKPFgp2FKriqJ3yDoHLhQXszHXYWQ+X4xUcKXJJH SnakigeUuPYbrwF3hk0WWp3kNRdH6H0mABQSZP2KepfC837wiU+XBBxjuwE1ffsexz6X P6UInk+7DhXcc+rMis4aZ9LDkEVXzz7Fo6X/StXHWsH9BfAf9Enevhwv5yx8xsBK50j2 F+wA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=CE1+m84T; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id d9-20020a170903230900b0019c354055d0si1926506plh.304.2023.07.27.15.20.45; Thu, 27 Jul 2023 15:21:08 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=CE1+m84T; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232168AbjG0Vam (ORCPT + 99 others); Thu, 27 Jul 2023 17:30:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52944 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230453AbjG0Vab (ORCPT ); Thu, 27 Jul 2023 17:30:31 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A4D1C1BC6 for ; Thu, 27 Jul 2023 14:29:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1690493344; 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=jGnguQzUAnXSgoEJGq4aUCEYI9GBqFjghH3nhnid2s4=; b=CE1+m84ToiW7szkkYKChwaKkelUv97ANi7OafUT1aZ8TbNrqKlVepk77xMxrRNZgZwD409 O0Jr5x4f8/q1CbQu/jqiuYDiJlN6z0AX81eggi4Es9ZUSOW/TUBLz93aogqSrpi98+5L/w zoSi9eQdzysFicemscszbjdPnHlSr/s= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-49-u7XBChHRONmnMfoWeq8OoQ-1; Thu, 27 Jul 2023 17:29:00 -0400 X-MC-Unique: u7XBChHRONmnMfoWeq8OoQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id C80A3856F66; Thu, 27 Jul 2023 21:28:59 +0000 (UTC) Received: from t14s.redhat.com (unknown [10.39.192.55]) by smtp.corp.redhat.com (Postfix) with ESMTP id CDA6240C2063; Thu, 27 Jul 2023 21:28:57 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, David Hildenbrand , Andrew Morton , Linus Torvalds , liubo , Peter Xu , Matthew Wilcox , Hugh Dickins , Jason Gunthorpe , John Hubbard Subject: [PATCH v1 4/4] mm/gup: document FOLL_FORCE behavior Date: Thu, 27 Jul 2023 23:28:45 +0200 Message-ID: <20230727212845.135673-5-david@redhat.com> In-Reply-To: <20230727212845.135673-1-david@redhat.com> References: <20230727212845.135673-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H4,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1772614025216924048 X-GMAIL-MSGID: 1772614025216924048 As suggested by Peter, let's document FOLL_FORCE handling and make it clear that without FOLL_FORCE, we will always trigger NUMA-hinting faults when stumbling over a PROT_NONE-mapped PTE. Also add a comment regarding follow_page() and its interaction with FOLL_FORCE. Let's place the doc next to the definition, where it certainly can't be missed. Signed-off-by: David Hildenbrand --- include/linux/mm_types.h | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 2fa6fcc740a1..96cf78686c29 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -1243,7 +1243,30 @@ enum { FOLL_GET = 1 << 1, /* give error on hole if it would be zero */ FOLL_DUMP = 1 << 2, - /* get_user_pages read/write w/o permission */ + /* + * Make get_user_pages() and friends ignore some VMA+PTE permissions. + * + * This flag should primarily only be used by ptrace and some + * GUP-internal functionality, such as for mlock handling. + * + * Without this flag, these functions always trigger page faults + * (such as NUMA hinting faults) when stumbling over a + * PROT_NONE-mapped PTE. + * + * !FOLL_WRITE: succeed even if the PTE is PROT_NONE + * * Rejected if the VMA is currently not readable and it cannot + * become readable + * + * FOLL_WRITE: succeed even if the PTE is not writable. + * * Rejected if the VMA is currently not writable and + * * it is a hugetlb mapping + * * it is not a COW mapping that could become writable + * + * Note: follow_page() does not accept FOLL_FORCE. Historically, + * follow_page() behaved similar to FOLL_FORCE without FOLL_WRITE: + * succeed even if the PTE is PROT_NONE and FOLL_WRITE is not set. + * However, VMA permissions are not checked. + */ FOLL_FORCE = 1 << 3, /* * if a disk transfer is needed, start the IO and return without waiting