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=-16.8 required=3.0 tests=BAYES_00, 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 2A799C433DB for ; Fri, 15 Jan 2021 09:21:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D967823403 for ; Fri, 15 Jan 2021 09:21:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727036AbhAOJVO (ORCPT ); Fri, 15 Jan 2021 04:21:14 -0500 Received: from szxga06-in.huawei.com ([45.249.212.32]:10971 "EHLO szxga06-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726030AbhAOJVN (ORCPT ); Fri, 15 Jan 2021 04:21:13 -0500 Received: from DGGEMS401-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga06-in.huawei.com (SkyGuard) with ESMTP id 4DHFxl3l02zj6rd; Fri, 15 Jan 2021 17:19:39 +0800 (CST) Received: from huawei.com (10.175.104.175) by DGGEMS401-HUB.china.huawei.com (10.3.19.201) with Microsoft SMTP Server id 14.3.498.0; Fri, 15 Jan 2021 17:20:20 +0800 From: Miaohe Lin To: , CC: , , , Subject: [PATCH v2] mm/hugetlb: avoid unnecessary hugetlb_acct_memory() call Date: Fri, 15 Jan 2021 04:20:13 -0500 Message-ID: <20210115092013.61012-1-linmiaohe@huawei.com> X-Mailer: git-send-email 2.19.1 MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.104.175] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When gbl_reserve is 0, 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. Reviewed-by: David Hildenbrand Signed-off-by: Miaohe Lin --- mm/hugetlb.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 4f67f6b159c7..da064cb8fd53 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -3591,6 +3591,9 @@ static int hugetlb_acct_memory(struct hstate *h, long delta) { int ret = -ENOMEM; + if (!delta) + return 0; + spin_lock(&hugetlb_lock); /* * When cpuset is configured, it breaks the strict hugetlb page -- 2.19.1