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([2a09:80c0:192:0:5dac:bf3d:c41:c3e7]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-46fb4982b25sm246894965e9.7.2025.10.14.07.38.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 14 Oct 2025 07:38:07 -0700 (PDT) Message-ID: <2861a35d-4f8e-4ee1-bd11-b915580c9ce3@redhat.com> Date: Tue, 14 Oct 2025 16:38:05 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH -v2 1/2] mm: add spurious fault fixing support for huge pmd To: Lorenzo Stoakes , Huang Ying Cc: Catalin Marinas , Will Deacon , Andrew Morton , Vlastimil Babka , Zi Yan , Baolin Wang , Ryan Roberts , Yang Shi , "Christoph Lameter (Ampere)" , Dev Jain , Barry Song , Anshuman Khandual , Yicong Yang , Kefeng Wang , Kevin Brodsky , Yin Fengwei , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20251013092038.6963-1-ying.huang@linux.alibaba.com> <20251013092038.6963-2-ying.huang@linux.alibaba.com> <4c453dcc-2837-4f1a-905b-3462270f5e31@lucifer.local> From: David Hildenbrand Autocrypt: addr=david@redhat.com; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251014_073812_049305_095E708A X-CRM114-Status: GOOD ( 14.51 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org > > /* Skip spurious TLB flush for retried page fault */ > if (vmf->flags & FAULT_FLAG_TRIED) > goto unlock; > /* > * This is needed only for protection faults but the arch code > * is not yet telling us if this is a protection fault or not. > * This still avoids useless tlb flushes for .text page faults > * with threads. > */ > if (vmf->flags & FAULT_FLAG_WRITE) > flush_tlb_fix_spurious_fault(vmf->vma, vmf->address, > vmf->pte); > > > So I don't see why it's so egregious to have the equivalent here, or actually > ideally to abstract the code entirely. Let's definitely not duplicate such comments whereby one instance will end up bitrotting. When talking about spurious faults I assume the educated reader will usually find the right comments -- like you easily did :P However I agree that ... > > In commit b22cc9a9c7ff ("mm/rmap: convert "enum rmap_level" to "enum > pgtable_level"") David introduced: > > enum pgtable_level { > PGTABLE_LEVEL_PTE = 0, > PGTABLE_LEVEL_PMD, > PGTABLE_LEVEL_PUD, > PGTABLE_LEVEL_P4D, > PGTABLE_LEVEL_PGD, > }; > > Which allows for sensible abstraction. ... if there is an easier way to just unify the code and have the comments at a central place, even better. -- Cheers David / dhildenb