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Date: Wed, 3 Apr 2024 13:45:39 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Russell King <linux@armlinux.org.uk>, Catalin Marinas
 <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, Michael Ellerman
 <mpe@ellerman.id.au>, Nicholas Piggin <npiggin@gmail.com>, Christophe Leroy
 <christophe.leroy@csgroup.eu>, Paul Walmsley <paul.walmsley@sifive.com>,
 Palmer Dabbelt <palmer@dabbelt.com>, Albert Ou <aou@eecs.berkeley.edu>,
 Alexander Gordeev <agordeev@linux.ibm.com>, Gerald Schaefer
 <gerald.schaefer@linux.ibm.com>, Dave Hansen <dave.hansen@linux.intel.com>,
 Andy Lutomirski <luto@kernel.org>, Peter Zijlstra <peterz@infradead.org>,
 <x86@kernel.org>, <linux-arm-kernel@lists.infradead.org>,
 <linuxppc-dev@lists.ozlabs.org>, <linux-riscv@lists.infradead.org>,
 <linux-s390@vger.kernel.org>, <surenb@google.com>, <linux-mm@kvack.org>
Subject: Re: [PATCH v2 0/7] arch/mm/fault: accelerate pagefault when
 badaccess
Message-Id: <20240403134539.fde3a6c594f2d88409be30ed@linux-foundation.org>
In-Reply-To: <20240403083805.1818160-1-wangkefeng.wang@huawei.com>
References: <20240403083805.1818160-1-wangkefeng.wang@huawei.com>
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On Wed, 3 Apr 2024 16:37:58 +0800 Kefeng Wang <wangkefeng.wang@huawei.com> 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?