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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 90FA4ECAAD5 for ; Sat, 27 Aug 2022 02:18:49 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 145206B0074; Fri, 26 Aug 2022 22:18:49 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0F5916B0075; Fri, 26 Aug 2022 22:18:49 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EFE9E940007; Fri, 26 Aug 2022 22:18:48 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id DDA976B0074 for ; Fri, 26 Aug 2022 22:18:48 -0400 (EDT) Received: from smtpin31.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id A729C1A0F0C for ; Sat, 27 Aug 2022 02:18:48 +0000 (UTC) X-FDA: 79843764336.31.05291C4 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by imf05.hostedemail.com (Postfix) with ESMTP id D3EEF10002F for ; Sat, 27 Aug 2022 02:18:47 +0000 (UTC) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.54]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4MF0hF1rX6zGpHJ; Sat, 27 Aug 2022 10:17:01 +0800 (CST) Received: from [10.174.177.76] (10.174.177.76) by canpemm500002.china.huawei.com (7.192.104.244) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Sat, 27 Aug 2022 10:18:43 +0800 Subject: Re: [PATCH 08/10] hugetlb: remove unneeded SetHPageVmemmapOptimized() To: Muchun Song CC: Andrew Morton , Mike Kravetz , Muchun Song , Linux MM , References: <20220826092422.39591-1-linmiaohe@huawei.com> <20220826092422.39591-9-linmiaohe@huawei.com> From: Miaohe Lin Message-ID: Date: Sat, 27 Aug 2022 10:18:43 +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: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.177.76] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1661566728; a=rsa-sha256; cv=none; b=BzQah2CE7HR1JJh5HavJj4fa1UrZS8YTRlD1UwP9ySC+ypMSqDi3anrKFzzsxO93SgVrNk mKx9+mf54N8q2+GrTrnVYxcqFptk/buxhJgD5KuykRUUHgbFd7vwHdFLbuEs4jMes76bmc Bs5WaJV0Ua6NfpIn6Ep3z48EUMUc5y8= ARC-Authentication-Results: i=1; imf05.hostedemail.com; dkim=none; spf=pass (imf05.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.189 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1661566728; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=L7wcRLzsiM9XqP7f5d7XjHclwseTNrKw6q00tS8s390=; b=nK43dDsPps04ltA6c1ydfnZLX3+ObEPdCod6eLbwZMz9G8X29no+Sb5ZUoExCiRqgqX0bV 9ql8PjaLc/eSyhKn0OGtbD44D/u8p5129ewG7G0vpjK35N3SZtY4qKqaAcS5MRdMytnQMQ y+ntVXUX9A14pAm/d9Q2eLNo3lbWFgA= X-Rspam-User: Authentication-Results: imf05.hostedemail.com; dkim=none; spf=pass (imf05.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.189 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com X-Rspamd-Server: rspam08 X-Stat-Signature: xqmgipm4zh4b3hsyrguka1u6p7m3wdik X-Rspamd-Queue-Id: D3EEF10002F X-HE-Tag: 1661566727-558160 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: On 2022/8/27 9:35, Muchun Song wrote: > > >> On Aug 26, 2022, at 17:24, Miaohe Lin wrote: >> >> If code reaches here, it's guaranteed that HPageVmemmapOptimized is set >> for the hugetlb page (or VM_BUG_ON_PAGE() will complain about it). It's > > Hi Miaohe, > > Right. > >> unnecessary to set it again. > > No, I suppose you didn’t test this patch since it does not work. The > HPageVmemmapOptimized is cleared in the above code of line > (set_page_private(page, 0)). So NAck. Sorry, I missed that and thanks for pointing this out. Does this code deserves a comment like below? diff --git a/mm/hugetlb.c b/mm/hugetlb.c index d0617d64d718..3374c1d2b52e 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1522,6 +1522,10 @@ static void add_hugetlb_page(struct hstate *h, struct page *page, set_compound_page_dtor(page, HUGETLB_PAGE_DTOR); set_page_private(page, 0); + /* + * We have to set HPageVmemmapOptimized again as above + * set_page_private(page, 0) cleared it. + */ SetHPageVmemmapOptimized(page); /* Thanks, Miaohe Lin