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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 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-Originating-IP: [10.174.177.243] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggpemm100001.china.huawei.com (7.185.36.93) X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: D3C8C100007 X-Stat-Signature: rykxb54ces6u1xeezr3383zoqkf11qs3 X-HE-Tag: 1712476199-480247 X-HE-Meta: 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 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: List-Subscribe: List-Unsubscribe: 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.