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DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1782625451; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Hh2gd/qWylLtYWmFXLrDcR+MvqoGGuVJgOfm4/cNwnU=; b=UbSaXfGFeBZY8DWvD4BZijtH1P+LU+jU7J+yZCcXnK6fzLcMgDZfFgvUOZ6QoZ+3q31NgQ RuPz+1jUO6Q6d6PczVunELVw6rDH7vqb9rxNAFzlsoaC8oCQBa633o30AfId7jm4PvZ3jj dW1Of102EdtUGtUOHDuvE8cA1aDtamw= From: Lance Yang To: dev.jain@arm.com Cc: lance.yang@linux.dev, linmiaohe@huawei.com, muchun.song@linux.dev, osalvador@suse.de, akpm@linux-foundation.org, ljs@kernel.org, david@kernel.org, liam@infradead.org, riel@surriel.com, vbabka@kernel.org, harry@kernel.org, jannh@google.com, kas@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, rcampbell@nvidia.com, apopple@nvidia.com, ziy@nvidia.com, matthew.brost@intel.com, joshua.hahnjy@gmail.com, rakie.kim@sk.com, byungchul@sk.com, gourry@gourry.net, ying.huang@linux.alibaba.com, mel@csn.ul.ie, nao.horiguchi@gmail.com, ak@linux.intel.com, j-nomura@ce.jp.nec.com, pfalcato@suse.de, dave.hansen@intel.com, tglx@kernel.org, jpoimboe@kernel.org, ryan.roberts@arm.com, anshuman.khandual@arm.com, stable@vger.kernel.org Subject: Re: [PATCH 4/5] mm/page_vma_mapped: use huge_ptep_get() for hugetlb Date: Sun, 28 Jun 2026 13:44:02 +0800 Message-Id: <20260628054402.76978-1-lance.yang@linux.dev> In-Reply-To: <82395f5a-31d4-406b-b7ec-10d1a9d067d4@arm.com> References: <82395f5a-31d4-406b-b7ec-10d1a9d067d4@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 91AA140003 X-Rspam-User: X-Stat-Signature: qk8x7tsyhuiuhyx5dj7znkxeudabpfyo X-HE-Tag: 1782625453-654880 X-HE-Meta: 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 rTBihPx9 KVed2FNcszcWC+gKoI7PSg8aI5ZvJqtUpfoQxj4EJDVS1D2gzcCbqbGzBz347CUy3n/T9Wbhoiglo3QWmMqBmdG7pSMOptnU8GlYk5pU9WMFb1jRW1nbmzHlS2nSoy6W5CukwweERWGnRV7wuqkcfJmlmkNopiXhG1l5MH3HvzOzgRQBlizSi4V56vjTtZr3F+njhQ0m2OqC0nTQzaUUV8hyKQC4EWd5i9jMgWbAlPpGl/J3xpbM0+s6/UrnE11FWsOJSufICWQMjI1aJbOlNGtQHknxSaKVmNctdZ7KsKwqDPv2MLmWV13M4qFGsEOu6Lkz1MlQXcbQ9jM0= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sat, Jun 27, 2026 at 12:43:31PM +0530, Dev Jain wrote: > > >On 26/06/26 10:16 pm, Lance Yang wrote: [...] >> >> Just thinking out loud: given that huge_ptep_get() already assumes that >> addr matches the huge pte, at least on arm64, would it make sense to >> have a small hugetlb wrapper around it that takes hstate and aligns >> the address before calling the arch helper? >> >> Might make the rule clearer, and a bit harder to get wrong again :) > >Are you suggesting something like: Yes, that's what I had in mind :) thanks! >diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h >index fdb7bdf7645c..xxxxxxxxxxxx 100644 >--- a/include/linux/hugetlb.h >+++ b/include/linux/hugetlb.h >@@ -825,6 +825,15 @@ static inline struct folio *filemap_lock_hugetlb_folio(struct hstate *h, > > #include Maybe worth spelling out the rule as well: For arch helpers that use addr, huge_ptep_get() assumes addr is the address for the hugetlb entry ptep points to. arm64 already makes that assumption. Callers where addr may not be hugepage-aligned should use hugetlb_ptep_get() instead. >+static inline pte_t hugetlb_ptep_get(struct vm_area_struct *vma, >+ unsigned long addr, pte_t *ptep) >+{ >+ struct hstate *h = hstate_vma(vma); >+ >+ return huge_ptep_get(vma->vm_mm, addr & huge_page_mask(h), ptep); >+} >+ > #ifndef is_hugepage_only_range > static inline int is_hugepage_only_range(struct mm_struct *mm, > unsigned long addr, unsigned long len) >diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c >index 18e1d341f463..xxxxxxxxxxxx 100644 >--- a/mm/page_vma_mapped.c >+++ b/mm/page_vma_mapped.c >@@ -110,8 +110,7 @@ static bool check_pte(struct page_vma_mapped_walk *pvmw, unsigned long pte_nr) > pte_t ptent; > > if (is_vm_hugetlb_page(pvmw->vma)) >- ptent = huge_ptep_get(pvmw->vma->vm_mm, pvmw->address, >- pvmw->pte); >+ ptent = hugetlb_ptep_get(pvmw->vma, pvmw->address, pvmw->pte); > else > ptent = ptep_get(pvmw->pte); [...] Cheers, Lance