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[2003:cb:c721:a000:7426:f6b4:82a3:c6ab]) by smtp.gmail.com with ESMTPSA id r5-20020a5d4985000000b00332d3b89561sm1764366wrq.97.2023.11.24.11.35.47 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 24 Nov 2023 11:35:49 -0800 (PST) Message-ID: Date: Fri, 24 Nov 2023 20:35:47 +0100 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC v2 05/27] mm: page_alloc: Add an arch hook to allow prep_new_page() to fail To: Alexandru Elisei , catalin.marinas@arm.com, will@kernel.org, oliver.upton@linux.dev, maz@kernel.org, james.morse@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, arnd@arndb.de, akpm@linux-foundation.org, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, mhiramat@kernel.org, rppt@kernel.org, hughd@google.com Cc: pcc@google.com, steven.price@arm.com, anshuman.khandual@arm.com, vincenzo.frascino@arm.com, eugenis@google.com, kcc@google.com, hyesoo.yu@samsung.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org References: <20231119165721.9849-1-alexandru.elisei@arm.com> <20231119165721.9849-6-alexandru.elisei@arm.com> From: David Hildenbrand Autocrypt: addr=david@redhat.com; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 19.11.23 17:56, Alexandru Elisei wrote: > Introduce arch_prep_new_page(), which will be used by arm64 to reserve tag > storage for an allocated page. Reserving tag storage can fail, for example, > if the tag storage page has a short pin on it, so allow prep_new_page() -> > arch_prep_new_page() to similarly fail. But what are the side-effects of this? How does the calling code recover? E.g., what if we need to populate a page into user space, but that particular page we allocated fails to be prepared? So we inject a signal into that poor process? -- Cheers, David / dhildenb