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=-15.7 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,URIBL_BLOCKED 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 78349C433F5 for ; Thu, 9 Sep 2021 01:10:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 56CDE61168 for ; Thu, 9 Sep 2021 01:10:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348949AbhIIBLP (ORCPT ); Wed, 8 Sep 2021 21:11:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:60432 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348941AbhIIBLO (ORCPT ); Wed, 8 Sep 2021 21:11:14 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 00C9261158; Thu, 9 Sep 2021 01:10:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1631149806; bh=Qi5g0WJd95Lld7Mm36JDS4ey+bIpL2U8i+LE+7t0DLI=; h=Date:From:To:Subject:In-Reply-To:From; b=tjX2+W5MSJQBvZaQvgy8Uog1sLFUictDCV5dS3QSpYfquLIZL36s3y3i02xB/No63 yVlJms9wjDsYwnF2SQTHwpfwnt9HbBRrjjVyezXnZ5n9mzKoqmLRTSamTsx+ocesqM 719qPO22gqbK8XhJuq/EEQCISXpRAsdCNZdUEqyk= Date: Wed, 08 Sep 2021 18:10:05 -0700 From: Andrew Morton To: akpm@linux-foundation.org, linux-mm@kvack.org, liuzixian4@huawei.com, mike.kravetz@oracle.com, mm-commits@vger.kernel.org, naoya.horiguchi@nec.com, stable@vger.kernel.org, torvalds@linux-foundation.org Subject: [patch 2/8] mm/hugetlb: initialize hugetlb_usage in mm_init Message-ID: <20210909011005.6UTH8UzKk%akpm@linux-foundation.org> In-Reply-To: <20210908180859.d523d4bb4ad8eec11c61500d@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org 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 @@ -1063,6 +1063,7 @@ 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; _