From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D75B7233159; Tue, 10 Dec 2024 02:25:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.187 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733797544; cv=none; b=gZ2tShAvM15Mo/QCwkQoAQWDVT94+PdiqLkTZCAv3rbLo/aaQ3BB7SACl/nLXQla/mKZPMd+NxbRx9JDitibbjNn34du+ZqZkzG31l5TRy7NmHWrVihDkpFBogirvmaZ5BAaw+HDsrWzbRSnD1sYVt9jQyXg+/Da3qfpOe8s9bU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733797544; c=relaxed/simple; bh=U1ZIGWbN5GTBVBOSCn+zZFDwiwb3aTnpStLINUF9ZaU=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=nVQEBA3tVktsGhaAnQQWHExPHL0hOQimJhx7KWF/821stLZk1QymRYVHHfmSMJEEg/XGvrNOn1Pmehmy5zD9p9D4KnIRY+tEXBukpJwClu00dD9H54C0mV8TpxS6Pt5noJgTK/AhvLOfMdb+v65QOWYU17VVFN0D8gZsHQoKG6A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.187 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.163.252]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4Y6jFb5bVNzhZX2; Tue, 10 Dec 2024 10:23:15 +0800 (CST) Received: from kwepemg200008.china.huawei.com (unknown [7.202.181.35]) by mail.maildlp.com (Postfix) with ESMTPS id ECCD8180357; Tue, 10 Dec 2024 10:25:38 +0800 (CST) Received: from [10.67.109.254] (10.67.109.254) by kwepemg200008.china.huawei.com (7.202.181.35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Tue, 10 Dec 2024 10:25:36 +0800 Message-ID: Date: Tue, 10 Dec 2024 10:25:35 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.2.0 Subject: Re: [PATCH 2/2] mm, rmap: handle anon_vma_fork() NULL check inline Content-Language: en-US To: Matthew Wilcox CC: , , , , , , , , , , , , References: <20241209132549.2878604-1-ruanjinjie@huawei.com> <20241209132549.2878604-3-ruanjinjie@huawei.com> From: Jinjie Ruan In-Reply-To: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To kwepemg200008.china.huawei.com (7.202.181.35) On 2024/12/9 21:35, Matthew Wilcox wrote: > On Mon, Dec 09, 2024 at 09:25:49PM +0800, Jinjie Ruan wrote: >> Check the anon_vma of pvma inline so we can avoid the function call >> overhead if the anon_vma is NULL. > > This really gets you 1% perf improvement? On what hardware? Yes，the total improvement of this two patches is about 1% on our last-generation arm64 server platform. During the test of Unixbench single-core process creation, the trace result shows that the two functions are frequently invoked, and a large number of check NULL and returned. > >