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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 A8FC4C433DB for ; Fri, 15 Jan 2021 09:44:21 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 1860B2339D for ; Fri, 15 Jan 2021 09:44:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1860B2339D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 8BE908D014B; Fri, 15 Jan 2021 04:44:20 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 8482C8D0023; Fri, 15 Jan 2021 04:44:20 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 738678D014B; Fri, 15 Jan 2021 04:44:20 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0206.hostedemail.com [216.40.44.206]) by kanga.kvack.org (Postfix) with ESMTP id 5B5408D0023 for ; Fri, 15 Jan 2021 04:44:20 -0500 (EST) Received: from smtpin01.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 298CE1807C6DE for ; Fri, 15 Jan 2021 09:44:20 +0000 (UTC) X-FDA: 77707523880.01.juice54_081164c2752e Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin01.hostedemail.com (Postfix) with ESMTP id 0659110054F1D for ; Fri, 15 Jan 2021 09:44:20 +0000 (UTC) X-HE-Tag: juice54_081164c2752e X-Filterd-Recvd-Size: 2269 Received: from szxga04-in.huawei.com (szxga04-in.huawei.com [45.249.212.190]) by imf13.hostedemail.com (Postfix) with ESMTP for ; Fri, 15 Jan 2021 09:44:19 +0000 (UTC) Received: from DGGEMS411-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4DHGSV2jP3zl4qj; Fri, 15 Jan 2021 17:42:50 +0800 (CST) Received: from [10.174.176.197] (10.174.176.197) by DGGEMS411-HUB.china.huawei.com (10.3.19.211) with Microsoft SMTP Server id 14.3.498.0; Fri, 15 Jan 2021 17:44:08 +0800 Subject: Re: [PATCH v2] mm/hugetlb: avoid unnecessary hugetlb_acct_memory() call To: Oscar Salvador , Andrew Morton CC: , , , References: <20210115092013.61012-1-linmiaohe@huawei.com> <20210115092849.GC4092@linux> From: Miaohe Lin Message-ID: <8f7b7e94-f803-11e4-6fc8-f510e01d2305@huawei.com> Date: Fri, 15 Jan 2021 17:44:08 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <20210115092849.GC4092@linux> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.176.197] X-CFilter-Loop: Reflected X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hi: On 2021/1/15 17:28, Oscar Salvador wrote: > On Fri, Jan 15, 2021 at 04:20:13AM -0500, Miaohe Lin wrote: >> 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 > > I would avoid mentioning gbl_reserve as not all callers use it, and focus > on what delta means: > > "When reservation accounting remains unchanged..", but anyway: Sounds good. Maybe Andrew could kindly do this if this patch is picked up ? > > Reviewed-by: Oscar Salvador > > Many thanks for your review.