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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 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 X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 39E0D18000F X-Stat-Signature: k59ha7uz767as33i5q7jexzhoa9tyups X-Rspam-User: X-HE-Tag: 1700854553-305912 X-HE-Meta: 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 L7puA/1t IUZrFWYSVoU4NUse4h+yMTKNTJ6kvqVX9jycaukUTScbjnDRHnmsV0/QXpIT1Uo6GQ2ZPaX5aFeF/yVaKLCeugIOcv17JYfZ4yw/tPM0y7O4DYTf7gF7Et5ClJZmBlBd+7CoFh2vIUqKphSE1gSBih9fRfjY8VdrG7I1sdgyqrc755VXM4t46xpcSapUWNYHW3RO72zeTTDYivR1sSpkdoyLmPwcHx6fAWNbVxdvfPd9fImaH33m8ftivMeNOTiuzbEPqlVBuWXvxrLVfcvyk06+pHKBh9pixUJGbbMFcZ/wtESnzTTAYuvplzSN+Pf/3V75NbcRCGdZC0ZGnWszOeb58FgTqlpf3QoZtsyapowSEfAW60VnzENpP8A== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000005, 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 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