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b=umnW21h9/XnH7XSpLYW9KZ4S/xlKkkdzV1m8oq5Rkh0Amq/72/y/pnsKpRxabxu7V q6tfiBxdfIuq2UU5fh9f7hYOLRr9urF7vG6S5Ii7j3XkiFYEUnh5t+s+XF1jGzYgWa sIgYz+Box1fhiUSQu04Lc6Jc4LIMMPdP7B+RrH3GKdC3HQ8E0/RPRfO3q312Cz05iQ BsRwmDAwfspMG4tcSa4w/erMBbw0vLOJba6hlRGduXnomH4tarzmcwbOkR2zCzQ23f /J5qUJ858GGaB+2gB9qNj1kx5Jn4Qk7LUZKBNjldL2BOJjp85XmmNSQ14OQW2aCEvc cwe0v1ZRVj8Dw== Message-ID: Date: Mon, 11 May 2026 15:51:28 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 09/22] mm/page_alloc: don't overload migratetype in find_suitable_fallback() Content-Language: en-US To: Brendan Jackman , Borislav Petkov , Dave Hansen , Peter Zijlstra , Andrew Morton , David Hildenbrand , Wei Xu , Johannes Weiner , Zi Yan , Lorenzo Stoakes Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, x86@kernel.org, rppt@kernel.org, Sumit Garg , derkling@google.com, reijiw@google.com, Will Deacon , rientjes@google.com, "Kalyazin, Nikita" , patrick.roy@linux.dev, "Itazuri, Takahiro" , Andy Lutomirski , David Kaplan , Thomas Gleixner , Yosry Ahmed References: <20260320-page_alloc-unmapped-v2-0-28bf1bd54f41@google.com> <20260320-page_alloc-unmapped-v2-9-28bf1bd54f41@google.com> From: "Vlastimil Babka (SUSE)" In-Reply-To: <20260320-page_alloc-unmapped-v2-9-28bf1bd54f41@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Queue-Id: 87F4140007 X-Rspamd-Server: rspam04 X-Stat-Signature: sk1871d4hsqcq1ebnz6od6a8qq66u9bt X-HE-Tag: 1778507495-722258 X-HE-Meta: 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 FQwuv8Ue xrocYoNj9NdXRbopK9/Y6/Dd8cgHg5aEzSblRqnpkdfv5ohe0sU5FoKfGbLjYSDPjbUEfSKEi7TMFMvNTgNXiFE09wkoEbaXdjeQd3yixkaQ6xYfeWYJo0ISvSTnHzRf3usl3PtahZk5HMwfLfwFrdWu1uvWdX9P8JXhsKKgjTv+dAKGaKTBc2Ao+D1KO95Z0Ml9Z6AdK1BByiD+IP02Rlf0Ch2cgLcBQlvhWlLZVUQ3mBTSlZmMR9XZxVZ0X17gFojPkcB7pqQmvnbyXL1lGDf4iS4Y5marJjiGsN0cL5PotVgMKYi/+eKA7TdVBFh2QPJVLMieL7VVxHFKDMzNHbyGNBKtOq7qwNLxES8c7lP2upF0R6VA1aAUBwiz7WTWwHjMR Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 3/20/26 19:23, Brendan Jackman wrote: > This function currently returns a signed integer that encodes status > in-band, as negative numbers, along with a migratetype. > > This function is about to be updated to a mode where this in-band > signaling no longer makes sense. Therefore, switch to a more > explicit/verbose style that encodes the status and migratetype > separately. > > In the spirit of making things more explicit, also create an enum to > avoid using magic integer literals with special meanings. This enables > documenting the values at their definition instead of in one of the > callers. > > Signed-off-by: Brendan Jackman Reviewed-by: Vlastimil Babka (SUSE)