From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 6DCFE2E64A for ; Thu, 6 Feb 2025 13:08:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738847285; cv=none; b=KeHoZmvAuP3q6eltMXztNKaV5mm0KtDVeZP6/MTDdz+qssb65jVFiVMVLSuLMIRZF3K0sY0WJBpeAyPSxK+5ADqvpIR0SSWWWLwBeNzMKPCRxCDTPTirQWeQWjaPzEArtEAJRa4AI8tDb50Du4/aG3FEMuqa72JKupvN9iE83+k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738847285; c=relaxed/simple; bh=Q4ZLYNJR1J2T4kWWCavLPGtusojVZbuFW4D5XjA/H40=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=cU1Dk6Ym1VJOZgeEPrvxXV1MAdmAPuG6bv0P3yd6wsYf7uakPCHp0KT+M59m6gF3VFy0+go9ju5Vh507/VffeyoRn47rEVpZGhoIGj2SoTGLkg44cCkZfHrG4wL3VmWj6E55jg8xooLIOKwQptltmiKyfvYnqNIkEWRijD3aW8Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C82F8FEC; Thu, 6 Feb 2025 05:08:25 -0800 (PST) Received: from [10.57.80.166] (unknown [10.57.80.166]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id AB8383F5A1; Thu, 6 Feb 2025 05:07:59 -0800 (PST) Message-ID: Date: Thu, 6 Feb 2025 13:07:32 +0000 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1 05/16] mm/page_table_check: Batch-check pmds/puds just like ptes Content-Language: en-GB To: Anshuman Khandual , Catalin Marinas , Will Deacon , Muchun Song , Pasha Tatashin , Andrew Morton , Uladzislau Rezki , Christoph Hellwig , Mark Rutland , Ard Biesheuvel , Dev Jain , Alexandre Ghiti , Steve Capper , Kevin Brodsky Cc: linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20250205151003.88959-1-ryan.roberts@arm.com> <20250205151003.88959-6-ryan.roberts@arm.com> From: Ryan Roberts In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 06/02/2025 10:55, Anshuman Khandual wrote: > On 2/5/25 20:39, Ryan Roberts wrote: >> Convert page_table_check_p[mu]d_set(...) to >> page_table_check_p[mu]ds_set(..., nr) to allow checking a contiguous set >> of pmds/puds in single batch. We retain page_table_check_p[mu]d_set(...) >> as macros that call new batch functions with nr=1 for compatibility. >> >> arm64 is about to reorganise its pte/pmd/pud helpers to reuse more code >> and to allow the implementation for huge_pte to more efficiently set >> ptes/pmds/puds in batches. We need these batch-helpers to make the >> refactoring possible. > > A very small nit. > > Although this justification here is reasonable enough but not sure if > platform specific requirements, need to be spelled out in such detail > for a generic MM change. Personally I find the "why" to be the most useful part of a commit log. I'd prefer to leave it in unless any mm people complain. > >> >> Signed-off-by: Ryan Roberts >> --- > > Regardless, LGTM. > > Reviewed-by: Anshuman Khandual Thanks! > >> include/linux/page_table_check.h | 30 +++++++++++++++++----------- >> mm/page_table_check.c | 34 +++++++++++++++++++------------- >> 2 files changed, 38 insertions(+), 26 deletions(-) >> >> diff --git a/include/linux/page_table_check.h b/include/linux/page_table_check.h >> index 6722941c7cb8..289620d4aad3 100644 >> --- a/include/linux/page_table_check.h >> +++ b/include/linux/page_table_check.h >> @@ -19,8 +19,10 @@ void __page_table_check_pmd_clear(struct mm_struct *mm, pmd_t pmd); >> void __page_table_check_pud_clear(struct mm_struct *mm, pud_t pud); >> void __page_table_check_ptes_set(struct mm_struct *mm, pte_t *ptep, pte_t pte, >> unsigned int nr); >> -void __page_table_check_pmd_set(struct mm_struct *mm, pmd_t *pmdp, pmd_t pmd); >> -void __page_table_check_pud_set(struct mm_struct *mm, pud_t *pudp, pud_t pud); >> +void __page_table_check_pmds_set(struct mm_struct *mm, pmd_t *pmdp, pmd_t pmd, >> + unsigned int nr); >> +void __page_table_check_puds_set(struct mm_struct *mm, pud_t *pudp, pud_t pud, >> + unsigned int nr); >> void __page_table_check_pte_clear_range(struct mm_struct *mm, >> unsigned long addr, >> pmd_t pmd); >> @@ -74,22 +76,22 @@ static inline void page_table_check_ptes_set(struct mm_struct *mm, >> __page_table_check_ptes_set(mm, ptep, pte, nr); >> } >> >> -static inline void page_table_check_pmd_set(struct mm_struct *mm, pmd_t *pmdp, >> - pmd_t pmd) >> +static inline void page_table_check_pmds_set(struct mm_struct *mm, >> + pmd_t *pmdp, pmd_t pmd, unsigned int nr) >> { >> if (static_branch_likely(&page_table_check_disabled)) >> return; >> >> - __page_table_check_pmd_set(mm, pmdp, pmd); >> + __page_table_check_pmds_set(mm, pmdp, pmd, nr); >> } >> >> -static inline void page_table_check_pud_set(struct mm_struct *mm, pud_t *pudp, >> - pud_t pud) >> +static inline void page_table_check_puds_set(struct mm_struct *mm, >> + pud_t *pudp, pud_t pud, unsigned int nr) >> { >> if (static_branch_likely(&page_table_check_disabled)) >> return; >> >> - __page_table_check_pud_set(mm, pudp, pud); >> + __page_table_check_puds_set(mm, pudp, pud, nr); >> } >> >> static inline void page_table_check_pte_clear_range(struct mm_struct *mm, >> @@ -129,13 +131,13 @@ static inline void page_table_check_ptes_set(struct mm_struct *mm, >> { >> } >> >> -static inline void page_table_check_pmd_set(struct mm_struct *mm, pmd_t *pmdp, >> - pmd_t pmd) >> +static inline void page_table_check_pmds_set(struct mm_struct *mm, >> + pmd_t *pmdp, pmd_t pmd, unsigned int nr) >> { >> } >> >> -static inline void page_table_check_pud_set(struct mm_struct *mm, pud_t *pudp, >> - pud_t pud) >> +static inline void page_table_check_puds_set(struct mm_struct *mm, >> + pud_t *pudp, pud_t pud, unsigned int nr) >> { >> } >> >> @@ -146,4 +148,8 @@ static inline void page_table_check_pte_clear_range(struct mm_struct *mm, >> } >> >> #endif /* CONFIG_PAGE_TABLE_CHECK */ >> + >> +#define page_table_check_pmd_set(mm, pmdp, pmd) page_table_check_pmds_set(mm, pmdp, pmd, 1) >> +#define page_table_check_pud_set(mm, pudp, pud) page_table_check_puds_set(mm, pudp, pud, 1) >> + >> #endif /* __LINUX_PAGE_TABLE_CHECK_H */ >> diff --git a/mm/page_table_check.c b/mm/page_table_check.c >> index 509c6ef8de40..dae4a7d776b3 100644 >> --- a/mm/page_table_check.c >> +++ b/mm/page_table_check.c >> @@ -234,33 +234,39 @@ static inline void page_table_check_pmd_flags(pmd_t pmd) >> WARN_ON_ONCE(swap_cached_writable(pmd_to_swp_entry(pmd))); >> } >> >> -void __page_table_check_pmd_set(struct mm_struct *mm, pmd_t *pmdp, pmd_t pmd) >> +void __page_table_check_pmds_set(struct mm_struct *mm, pmd_t *pmdp, pmd_t pmd, >> + unsigned int nr) >> { >> + unsigned int i; >> + unsigned long stride = PMD_SIZE >> PAGE_SHIFT; >> + >> if (&init_mm == mm) >> return; >> >> page_table_check_pmd_flags(pmd); >> >> - __page_table_check_pmd_clear(mm, *pmdp); >> - if (pmd_user_accessible_page(pmd)) { >> - page_table_check_set(pmd_pfn(pmd), PMD_SIZE >> PAGE_SHIFT, >> - pmd_write(pmd)); >> - } >> + for (i = 0; i < nr; i++) >> + __page_table_check_pmd_clear(mm, *(pmdp + i)); >> + if (pmd_user_accessible_page(pmd)) >> + page_table_check_set(pmd_pfn(pmd), stride * nr, pmd_write(pmd)); >> } >> -EXPORT_SYMBOL(__page_table_check_pmd_set); >> +EXPORT_SYMBOL(__page_table_check_pmds_set); >> >> -void __page_table_check_pud_set(struct mm_struct *mm, pud_t *pudp, pud_t pud) >> +void __page_table_check_puds_set(struct mm_struct *mm, pud_t *pudp, pud_t pud, >> + unsigned int nr) >> { >> + unsigned int i; >> + unsigned long stride = PUD_SIZE >> PAGE_SHIFT; >> + >> if (&init_mm == mm) >> return; >> >> - __page_table_check_pud_clear(mm, *pudp); >> - if (pud_user_accessible_page(pud)) { >> - page_table_check_set(pud_pfn(pud), PUD_SIZE >> PAGE_SHIFT, >> - pud_write(pud)); >> - } >> + for (i = 0; i < nr; i++) >> + __page_table_check_pud_clear(mm, *(pudp + i)); >> + if (pud_user_accessible_page(pud)) >> + page_table_check_set(pud_pfn(pud), stride * nr, pud_write(pud)); >> } >> -EXPORT_SYMBOL(__page_table_check_pud_set); >> +EXPORT_SYMBOL(__page_table_check_puds_set); >> >> void __page_table_check_pte_clear_range(struct mm_struct *mm, >> unsigned long addr,