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From: Lance Yang In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 47B22120006 X-Stat-Signature: k94y5ftsesz1n5gg63osh7qs6mzjxnqb X-HE-Tag: 1762525079-614705 X-HE-Meta: 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 EnrSE1Rz 2WCUIgPQ+CefFHYuBpR0NW5H+wMC4OIcC1TcuP04g9V4Vmm/NE/cfxrBV33Ga88ocU8owgbmRip7WjRzq47PlNv0s9hUwxSpMbJPLeUt2zDRtTCNXRUzfP8RY7gySfco4muttXWUhGj8VaWdEDEriM0hNPZcLu89zGTiA3ohiB3ixp1JLiqgUpfvXlPmI9yZpZIVH5mgZ4meG+l9emrLXDQSPku0xlhc6HQnj0zwQa1opOj/MGwm6vNhV5EF1gR44CtWrKzDsSOS5URKMGy/fOZHdiP4Nm7WxwBsAndJQDwJVvxUUHfLH2cMYcCwONrg2FzmwdKJXgh586f8= 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 2025/11/7 20:50, Arnd Bergmann wrote: > On Fri, Nov 7, 2025, at 12:44, Lance Yang wrote: >> From: Lance Yang >> On Fri, 7 Nov 2025 17:59:22 +0800, Huacai Chen wrote: >>> >>> */ >>> static inline pte_t *__pte_alloc_one_kernel_noprof(struct mm_struct *mm) >>> { >>> - struct ptdesc *ptdesc = pagetable_alloc_noprof(GFP_PGTABLE_KERNEL & >>> - ~__GFP_HIGHMEM, 0); >>> + struct ptdesc *ptdesc = pagetable_alloc_noprof(GFP_PGTABLE_KERNEL, 0); >> >> I looked into the history and it seems you are right. This defensive pattern >> was likely introduced by Vishal Moola in commit c787ae5[1]. > > Right, so not even so long ago, so we need to make sure we agree > on a direction and don't send opposite patches in the name of > cleanups. Yes, better to get on the same page now than to have conflicting cleanups down the line ;) > >> After this cleanup, would it make sense to add a BUILD_BUG_ON() somewhere >> to check that __GFP_HIGHMEM is not present in GFP_PGTABLE_KERNEL and >> GFP_PGTABLE_USER? This would prevent any future regression ;) >> >> Just a thought ... > > I think we can go either way here, but I'd tend towards not > adding more checks but instead removing any mention of __GFP_HIGHMEM > that we can show is either pointless or can be avoided, with Makes sense to me :) > the goal of having only a small number of actual highmem > allocations remaining in places we do care about (normal > page cache, zram, possibly huge pages). Right! That's the ideal end state. Making the code cleaner and the intention clearer ;p Cheers, Lance