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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Queue-Id: D016680013 X-Stat-Signature: uwksfd74kcaztnthjguyz634coxf5r1s X-Rspamd-Server: rspam04 X-HE-Tag: 1750086185-706114 X-HE-Meta: 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 +hycAQRW 1iQoonLYoXIdefuG3MgKv8tqMrkr2bOnCLE9AovzLPpFakt9FnZ5V3lYx+cKI4JbwU8BgztOLzu3BJCpoqRmbOE02VwHzJZi51AvpwUNgRMozQLxzq9mLfA3etuXiIp8/92JMYD39cxe93xRbt4ctFeMxleBz/a7rVYo60BHALU/MifSyxOOZVtUeuXvRZypq2CpComJlh+8N0tIR/Pm6+NFVxmKbBa5tucx5WfXhS9Vc9Nufcp6CzYLg2S4xn6W+E11D X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, 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 6/16/25 07:50, Peter Zijlstra wrote: > On Mon, Jun 16, 2025 at 07:44:13AM -0700, Dave Hansen wrote: >> To me, that's deserving of an ARCH_HAS_FOO bit that we can set on the >> x86 side that then cajoles the core mm/ code to use the fancy new >> clear_pages_resched() implementation. > Note that we should only set this bit with either full or lazy > preemption selected. Haven't checked the patch-set to see if that > constraint is already taken care of. There is a check in the C code for preempt_model_preemptible(). So as long as there was something like: config SOMETHING_PAGE_CLEARING def_bool y depends on ARCH_HAS_WHATEVER_PAGE_CLEARING depends on !HIGHMEM Then the check for HIGHMEM and the specific architecture support could be along the lines of: static void clear_pages_resched(void *addr, int npages) { int i, remaining; if (!IS_ENABLED(SOMETHING_PAGE_CLEARING) || preempt_model_preemptible()) { clear_pages(addr, npages); goto out; } ... which would also remove the #ifdef CONFIG_HIGHMEM in there now.