From patchwork Tue Aug 31 22:42:50 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 504963 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS 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 588C7C432BE for ; Tue, 31 Aug 2021 22:42:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 324E261008 for ; Tue, 31 Aug 2021 22:42:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239894AbhHaWnr (ORCPT ); Tue, 31 Aug 2021 18:43:47 -0400 Received: from mail.kernel.org ([198.145.29.99]:43410 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229602AbhHaWnq (ORCPT ); Tue, 31 Aug 2021 18:43:46 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id B0B8060FF2; Tue, 31 Aug 2021 22:42:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1630449770; bh=JPaaH/lz1NiqWY8tspwvWTmAN1QHWj/poVs5KN/8N3c=; h=Date:From:To:Subject:From; b=AjWmw4YuvyEaWhT0m1QTjqG7mx9CgtA0x+yQRyGymxy4uUXuz0GDj/Fpeir/tlkOe Trl+HMpj3HHT6YFAVdtXGzi4FKVtXwxMdUJ2Gb2VjkvwfQaHJGrpgvvGMw8Fyrq2VC A6+mhS9fSWAYTJiLEJOEvfty87LuGxE0t6zppoas= Date: Tue, 31 Aug 2021 15:42:50 -0700 From: akpm@linux-foundation.org To: liuzixian4@huawei.com, mike.kravetz@oracle.com, mm-commits@vger.kernel.org, naoya.horiguchi@nec.com, stable@vger.kernel.org Subject: + mm-hugetlb-initialize-hugetlb_usage-in-mm_init.patch added to -mm tree Message-ID: <20210831224250.LRxYZi1vW%akpm@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch titled Subject: mm/hugetlb: initialize hugetlb_usage in mm_init has been added to the -mm tree. Its filename is mm-hugetlb-initialize-hugetlb_usage-in-mm_init.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-hugetlb-initialize-hugetlb_usage-in-mm_init.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-hugetlb-initialize-hugetlb_usage-in-mm_init.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Liu Zixian Subject: mm/hugetlb: initialize hugetlb_usage in mm_init After fork, the child process will get incorrect (2x) hugetlb_usage. If a process uses 5 2MB hugetlb pages in an anonymous mapping, HugetlbPages: 10240 kB and then forks, the child will show, HugetlbPages: 20480 kB The reason for double the amount is because hugetlb_usage will be copied from the parent and then increased when we copy page tables from parent to child. Child will have 2x actual usage. Fix this by adding hugetlb_count_init in mm_init. Link: https://lkml.kernel.org/r/20210826071742.877-1-liuzixian4@huawei.com Fixes: 5d317b2b6536 ("mm: hugetlb: proc: add HugetlbPages field to /proc/PID/status") Signed-off-by: Liu Zixian Reviewed-by: Naoya Horiguchi Reviewed-by: Mike Kravetz Cc: Signed-off-by: Andrew Morton --- include/linux/hugetlb.h | 9 +++++++++ kernel/fork.c | 1 + 2 files changed, 10 insertions(+) --- a/include/linux/hugetlb.h~mm-hugetlb-initialize-hugetlb_usage-in-mm_init +++ a/include/linux/hugetlb.h @@ -858,6 +858,11 @@ static inline spinlock_t *huge_pte_lockp void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm); +static inline void hugetlb_count_init(struct mm_struct *mm) +{ + atomic_long_set(&mm->hugetlb_usage, 0); +} + static inline void hugetlb_count_add(long l, struct mm_struct *mm) { atomic_long_add(l, &mm->hugetlb_usage); @@ -1042,6 +1047,10 @@ static inline spinlock_t *huge_pte_lockp return &mm->page_table_lock; } +static inline void hugetlb_count_init(struct mm_struct *mm) +{ +} + static inline void hugetlb_report_usage(struct seq_file *f, struct mm_struct *m) { } --- a/kernel/fork.c~mm-hugetlb-initialize-hugetlb_usage-in-mm_init +++ a/kernel/fork.c @@ -1052,6 +1052,7 @@ static struct mm_struct *mm_init(struct mm->pmd_huge_pte = NULL; #endif mm_init_uprobes_state(mm); + hugetlb_count_init(mm); if (current->mm) { mm->flags = current->mm->flags & MMF_INIT_MASK;