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 4A4CB7484 for ; Sun, 7 Apr 2024 07:49:58 +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=1712476202; cv=none; b=tY7zIu0nEEq+5XbyVG0iaSMllmeHmG7WJxUhEmK5l3ZJ7gswHt9b3AdQkgyjAYCSFP1JCpMjLpzx/kg216i1YeRFxomTwrwS5IeLyIHoeDaMWt/l4KW/VEiXnJrvrgWrRauaBMcESydCuP+mcAiggebIhskr/Y8fnE7OO2qFqCU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712476202; c=relaxed/simple; bh=G2yXjWdg3pJnxsnntQWfuPvLSRSxp8WlVyEALB8Zy6M=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=lvO4gz1GHyKY+eoeh+YDEj0sPOAHXndVhUEYFhIAc+0SW5O/16VQVE54xWCofjD0SKeDY+8kzF9ou34HOXXI4feDaCj86E/KZ7n19nyKX03fMP1F8z5OLXwLnTsNBaeZnZSjIpFGwEAVEtvhxdNLepkYqJk9upbw35mOt2rSFp8= 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 [172.19.88.105]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4VC47C1yhVzwRPw; Sun, 7 Apr 2024 15:47:03 +0800 (CST) Received: from dggpemm100001.china.huawei.com (unknown [7.185.36.93]) by mail.maildlp.com (Postfix) with ESMTPS id 5A70414010C; Sun, 7 Apr 2024 15:49:55 +0800 (CST) Received: from [10.174.177.243] (10.174.177.243) by dggpemm100001.china.huawei.com (7.185.36.93) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.35; Sun, 7 Apr 2024 15:49:54 +0800 Message-ID: <4d45fffc-877a-4ad1-ad02-a33341e467e7@huawei.com> Date: Sun, 7 Apr 2024 15:49:53 +0800 Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 0/7] arch/mm/fault: accelerate pagefault when badaccess Content-Language: en-US To: Andrew Morton CC: Russell King , Catalin Marinas , Will Deacon , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexander Gordeev , Gerald Schaefer , Dave Hansen , Andy Lutomirski , Peter Zijlstra , , , , , , , References: <20240403083805.1818160-1-wangkefeng.wang@huawei.com> <20240403134539.fde3a6c594f2d88409be30ed@linux-foundation.org> From: Kefeng Wang In-Reply-To: <20240403134539.fde3a6c594f2d88409be30ed@linux-foundation.org> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggpemm100001.china.huawei.com (7.185.36.93) On 2024/4/4 4:45, Andrew Morton wrote: > On Wed, 3 Apr 2024 16:37:58 +0800 Kefeng Wang wrote: > >> After VMA lock-based page fault handling enabled, if bad access met >> under per-vma lock, it will fallback to mmap_lock-based handling, >> so it leads to unnessary mmap lock and vma find again. A test from >> lmbench shows 34% improve after this changes on arm64, >> >> lat_sig -P 1 prot lat_sig 0.29194 -> 0.19198 >> >> Only build test on other archs except arm64. > > Thanks. So we now want a bunch of architectures to runtime test this. Do > we have a selftest in place which will adequately do this? I don't find such selftest, and badaccess would lead to coredump, the performance should not affect most scene, so no selftest is acceptable. lmbench is easy to use to measure the performance.