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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 94ADD80017 X-Rspam-User: X-Stat-Signature: nawjwj8r3wnd6ywitmjufpwi5axnpdbr X-HE-Tag: 1745917286-920178 X-HE-Meta: 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 gARzO4zZ 47/4BDg93SUy1r8a4/nzB9UVhQ6T3zEHaBmj2v5MNPynqS1dE0bhZqTYiX8nWA/OpkYMupfr1uXt1tMM7ljly4U31m4mv+mvd6cyLqYphEb+Pimn+WSJ8LnrYVl5WcMwqTq5RapvlotXNlwaI2OAcOIxIwLVTquhEL9S9oxtczRH5pcmoztOeehj1kkCzV5SPmczdeD2Emp9lqwlCX2vo53pb3yKwA2AlrKEg7m/mwbd30ChrHYH6iHN8OQ== 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 29/04/25 2:09 pm, Anshuman Khandual wrote: > > > On 4/29/25 10:53, Dev Jain wrote: >> Batch ptep_modify_prot_start/commit in preparation for optimizing mprotect. >> Architecture can override these helpers. >> >> Signed-off-by: Dev Jain >> --- >> include/linux/pgtable.h | 38 ++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 38 insertions(+) >> >> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h >> index b50447ef1c92..ed287289335f 100644 >> --- a/include/linux/pgtable.h >> +++ b/include/linux/pgtable.h >> @@ -891,6 +891,44 @@ static inline void wrprotect_ptes(struct mm_struct *mm, unsigned long addr, >> } >> #endif >> >> +/* See the comment for ptep_modify_prot_start */ >> +#ifndef modify_prot_start_ptes >> +static inline pte_t modify_prot_start_ptes(struct vm_area_struct *vma, >> + unsigned long addr, pte_t *ptep, unsigned int nr) >> +{ >> + pte_t pte, tmp_pte; >> + >> + pte = ptep_modify_prot_start(vma, addr, ptep); >> + while (--nr) { >> + ptep++; >> + addr += PAGE_SIZE; >> + tmp_pte = ptep_modify_prot_start(vma, addr, ptep); >> + if (pte_dirty(tmp_pte)) >> + pte = pte_mkdirty(pte); >> + if (pte_young(tmp_pte)) >> + pte = pte_mkyoung(pte); >> + } >> + return pte; >> +} >> +#endif >> + >> +/* See the comment for ptep_modify_prot_commit */ >> +#ifndef modify_prot_commit_ptes >> +static inline void modify_prot_commit_ptes(struct vm_area_struct *vma, unsigned long addr, >> + pte_t *ptep, pte_t old_pte, pte_t pte, unsigned int nr) >> +{ >> + for (;;) { >> + ptep_modify_prot_commit(vma, addr, ptep, old_pte, pte); >> + if (--nr == 0) >> + break; >> + ptep++; >> + addr += PAGE_SIZE; >> + old_pte = pte_next_pfn(old_pte); >> + pte = pte_next_pfn(pte); >> + } >> +} >> +#endif > > Is there any particular reason why the first loop here is while { } > based where as the second one is a for { } loop ? modify_prot_start_ptes follows the pattern of get_and_clear_full_ptes. modify_prot_commit_ptes follows the pattern of wrprotect_ptes. > >> + >> /* >> * On some architectures hardware does not set page access bit when accessing >> * memory page, it is responsibility of software setting this bit. It brings > > These helpers should be added with at least a single caller using them.