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=unavailable 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 7FC8FC433E0 for ; Wed, 24 Feb 2021 20:08:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 394DD64F1B for ; Wed, 24 Feb 2021 20:08:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234905AbhBXUIS (ORCPT ); Wed, 24 Feb 2021 15:08:18 -0500 Received: from mail.kernel.org ([198.145.29.99]:59764 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235098AbhBXUHj (ORCPT ); Wed, 24 Feb 2021 15:07:39 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 786B564EC4; Wed, 24 Feb 2021 20:06:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1614197218; bh=KpeBFR/dGOJBi1Oh10U6eRZSUVrBkCx1AFX7PM/uvEY=; h=Date:From:To:Subject:In-Reply-To:From; b=yKSHnlS+wXLplcNYbCfxIfoHXwf1k4bYdGNDebtR6+HZ//Q0EKj4zmbaxXPk8Y8qn pgnimL0UN378C/Tcijaxk+DlVTyhljlm/e++dNyG2LsoQipzy00kWsI5eivKEcVHcN fEVfUqjdEIbUksue+YfJqwk4ERKK8eyehYFdBn2c= Date: Wed, 24 Feb 2021 12:06:57 -0800 From: Andrew Morton To: akpm@linux-foundation.org, david@redhat.com, linmiaohe@huawei.com, linux-mm@kvack.org, mike.kravetz@oracle.com, mm-commits@vger.kernel.org, osalvador@suse.de, torvalds@linux-foundation.org Subject: [patch 115/173] mm/hugetlb: avoid unnecessary hugetlb_acct_memory() call Message-ID: <20210224200657.oU6qkHah9%akpm@linux-foundation.org> In-Reply-To: <20210224115824.1e289a6895087f10c41dd8d6@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: Miaohe Lin Subject: mm/hugetlb: avoid unnecessary hugetlb_acct_memory() call When reservation accounting remains unchanged, hugetlb_acct_memory() will do nothing except holding and releasing hugetlb_lock. We should avoid this unnecessary hugetlb_lock lock/unlock cycle which is happening on 'most' hugetlb munmap operations by check delta against 0 at the beginning of hugetlb_acct_memory. Link: https://lkml.kernel.org/r/20210115092013.61012-1-linmiaohe@huawei.com Signed-off-by: Miaohe Lin Reviewed-by: David Hildenbrand Reviewed-by: Oscar Salvador Cc: Mike Kravetz Signed-off-by: Andrew Morton --- mm/hugetlb.c | 3 +++ 1 file changed, 3 insertions(+) --- a/mm/hugetlb.c~mm-hugetlb-avoid-unnecessary-hugetlb_acct_memory-call +++ a/mm/hugetlb.c @@ -3591,6 +3591,9 @@ static int hugetlb_acct_memory(struct hs { int ret = -ENOMEM; + if (!delta) + return 0; + spin_lock(&hugetlb_lock); /* * When cpuset is configured, it breaks the strict hugetlb page _