From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id DABAEC48260 for ; Tue, 13 Feb 2024 16:48:58 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 72CE26B0096; Tue, 13 Feb 2024 11:48:58 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 6B6C26B0098; Tue, 13 Feb 2024 11:48:58 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 557C76B009A; Tue, 13 Feb 2024 11:48:58 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 42F706B0096 for ; Tue, 13 Feb 2024 11:48:58 -0500 (EST) Received: from smtpin22.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 054E6C0C89 for ; Tue, 13 Feb 2024 16:48:57 +0000 (UTC) X-FDA: 81787365156.22.C2B0B68 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf19.hostedemail.com (Postfix) with ESMTP id 05F951A001B for ; Tue, 13 Feb 2024 16:48:55 +0000 (UTC) Authentication-Results: imf19.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf19.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1707842936; h=from:from:sender: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=S5Qgd2h/TB4YoTN8C/XsFotDC25mSZ09EG/vV9H4ldM=; b=vqaqP4MHIJIgFAnujEfHaNtXG8P3SCtd/O9a8+X7WlYXJN4/nUFaBA6ShYzIlls7kO2ovy tjmjVpyz7IeXfc2MArYLrWNI1nzHQa5sGnjrtYpkP76GeDnpYStKSs6P72GqWx9a1e+1xZ k/2fSDv1FmfKmgUECGrsUWdoZEgEy94= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf19.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1707842936; a=rsa-sha256; cv=none; b=Amu08SyjsrXCC6XPo/Mi34AN0oYL1sW2jIwVxEH/0eRXhO72lL3LRKWefQf12ap6yNpXph KGIRw0BImvLDl9zRfPPld+OovtzWSCzlOhXiCha7gQzAzihOzyHJgkD3qAZYzPCJSyEMCS rNcNYQaQ9OJe77zgxkrApe+K8nMUOs0= 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 4E6F9DA7; Tue, 13 Feb 2024 08:49:36 -0800 (PST) Received: from [10.1.36.184] (XHFQ2J9959.cambridge.arm.com [10.1.36.184]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4EA173F5A1; Tue, 13 Feb 2024 08:48:51 -0800 (PST) Message-ID: Date: Tue, 13 Feb 2024 16:48:50 +0000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 21/25] arm64/mm: Implement new [get_and_]clear_full_ptes() batch APIs Content-Language: en-GB To: Mark Rutland Cc: Catalin Marinas , Will Deacon , Ard Biesheuvel , Marc Zyngier , James Morse , Andrey Ryabinin , Andrew Morton , Matthew Wilcox , David Hildenbrand , Kefeng Wang , John Hubbard , Zi Yan , Barry Song <21cnbao@gmail.com>, Alistair Popple , Yang Shi , Nicholas Piggin , Christophe Leroy , "Aneesh Kumar K.V" , "Naveen N. Rao" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , linux-arm-kernel@lists.infradead.org, x86@kernel.org, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20240202080756.1453939-1-ryan.roberts@arm.com> <20240202080756.1453939-22-ryan.roberts@arm.com> From: Ryan Roberts In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 05F951A001B X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: kqwho6bb3r5dsqucawubeegiiic6f5qh X-HE-Tag: 1707842935-782916 X-HE-Meta: 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 QLc2RimF JHBTTH1eBBhMHLy2OqkFVISyi0tMmb6pfV6PurjDgv5P19jiKhn6V0Z9anLDOQYgBJBIUFznTdBZ16/Pg1Z+5y0wfqYDXQOkh4I2ZcTeTR1Bt6wZ3BpWw07+t6q79hilji29tRHwzZNXWQWZjhrmFzr68nkMFMK2TiBCYQknlrGtjlukR6VNxbS5MeqskosxdT+E349tKVq7Kn+R0kSPTtOZ9b3V1O4dg+FXrQDgoG5qIESgKX6DucSrWZg2wOa46MXIwAMo6YP8yyC2ZgMXyWb1cstAsUuXTC8wL/V3YC/uEcZ37Mk27A5ZOxDAsSS5jbzsz/z5/IfPKKEUO+N4PxxHcbOmjW+QjlE0C 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 13/02/2024 16:43, Mark Rutland wrote: > On Fri, Feb 02, 2024 at 08:07:52AM +0000, Ryan Roberts wrote: >> Optimize the contpte implementation to fix some of the >> exit/munmap/dontneed performance regression introduced by the initial >> contpte commit. Subsequent patches will solve it entirely. >> >> During exit(), munmap() or madvise(MADV_DONTNEED), mappings must be >> cleared. Previously this was done 1 PTE at a time. But the core-mm >> supports batched clear via the new [get_and_]clear_full_ptes() APIs. So >> let's implement those APIs and for fully covered contpte mappings, we no >> longer need to unfold the contpte. This significantly reduces unfolding >> operations, reducing the number of tlbis that must be issued. >> >> Tested-by: John Hubbard >> Signed-off-by: Ryan Roberts >> --- >> arch/arm64/include/asm/pgtable.h | 67 ++++++++++++++++++++++++++++++++ >> arch/arm64/mm/contpte.c | 17 ++++++++ >> 2 files changed, 84 insertions(+) >> >> diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h >> index c07f0d563733..ad04adb7b87f 100644 >> --- a/arch/arm64/include/asm/pgtable.h >> +++ b/arch/arm64/include/asm/pgtable.h >> @@ -965,6 +965,37 @@ static inline pte_t __ptep_get_and_clear(struct mm_struct *mm, >> return pte; >> } >> >> +static inline void __clear_full_ptes(struct mm_struct *mm, unsigned long addr, >> + pte_t *ptep, unsigned int nr, int full) >> +{ >> + for (;;) { >> + __ptep_get_and_clear(mm, addr, ptep); >> + if (--nr == 0) >> + break; >> + ptep++; >> + addr += PAGE_SIZE; >> + } >> +} > > The loop construct is a bit odd; can't this be: I found it a little odd at first, but its avoiding the ptep and addr increments the last time through the loop. Its the preferred pattern for these functions in core-mm. See default set_ptes(), wrprotect_ptes(), clear_full_ptes() in include/linux/pgtable.h. So I'd prefer to leave it as is so that we match them. What do you think? > > while (nr--) { > __ptep_get_and_clear(mm, addr, ptep); > ptep++; > addr += PAGE_SIZE; > } > > ... or: > > do { > __ptep_get_and_clear(mm, addr, ptep); > ptep++; > addr += PAGE_SIZE; > } while (--nr); > > ... ? > > Otherwise, this looks good to me. > > Mark. > >> + >> +static inline pte_t __get_and_clear_full_ptes(struct mm_struct *mm, >> + unsigned long addr, pte_t *ptep, >> + unsigned int nr, int full) >> +{ >> + pte_t pte, tmp_pte; >> + >> + pte = __ptep_get_and_clear(mm, addr, ptep); >> + while (--nr) { >> + ptep++; >> + addr += PAGE_SIZE; >> + tmp_pte = __ptep_get_and_clear(mm, addr, ptep); >> + if (pte_dirty(tmp_pte)) >> + pte = pte_mkdirty(pte); >> + if (pte_young(tmp_pte)) >> + pte = pte_mkyoung(pte); >> + } >> + return pte; >> +} >> + >> #ifdef CONFIG_TRANSPARENT_HUGEPAGE >> #define __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR >> static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm, >> @@ -1167,6 +1198,11 @@ extern pte_t contpte_ptep_get(pte_t *ptep, pte_t orig_pte); >> extern pte_t contpte_ptep_get_lockless(pte_t *orig_ptep); >> extern void contpte_set_ptes(struct mm_struct *mm, unsigned long addr, >> pte_t *ptep, pte_t pte, unsigned int nr); >> +extern void contpte_clear_full_ptes(struct mm_struct *mm, unsigned long addr, >> + pte_t *ptep, unsigned int nr, int full); >> +extern pte_t contpte_get_and_clear_full_ptes(struct mm_struct *mm, >> + unsigned long addr, pte_t *ptep, >> + unsigned int nr, int full); >> extern int contpte_ptep_test_and_clear_young(struct vm_area_struct *vma, >> unsigned long addr, pte_t *ptep); >> extern int contpte_ptep_clear_flush_young(struct vm_area_struct *vma, >> @@ -1254,6 +1290,35 @@ static inline void pte_clear(struct mm_struct *mm, >> __pte_clear(mm, addr, ptep); >> } >> >> +#define clear_full_ptes clear_full_ptes >> +static inline void clear_full_ptes(struct mm_struct *mm, unsigned long addr, >> + pte_t *ptep, unsigned int nr, int full) >> +{ >> + if (likely(nr == 1)) { >> + contpte_try_unfold(mm, addr, ptep, __ptep_get(ptep)); >> + __clear_full_ptes(mm, addr, ptep, nr, full); >> + } else { >> + contpte_clear_full_ptes(mm, addr, ptep, nr, full); >> + } >> +} >> + >> +#define get_and_clear_full_ptes get_and_clear_full_ptes >> +static inline pte_t get_and_clear_full_ptes(struct mm_struct *mm, >> + unsigned long addr, pte_t *ptep, >> + unsigned int nr, int full) >> +{ >> + pte_t pte; >> + >> + if (likely(nr == 1)) { >> + contpte_try_unfold(mm, addr, ptep, __ptep_get(ptep)); >> + pte = __get_and_clear_full_ptes(mm, addr, ptep, nr, full); >> + } else { >> + pte = contpte_get_and_clear_full_ptes(mm, addr, ptep, nr, full); >> + } >> + >> + return pte; >> +} >> + >> #define __HAVE_ARCH_PTEP_GET_AND_CLEAR >> static inline pte_t ptep_get_and_clear(struct mm_struct *mm, >> unsigned long addr, pte_t *ptep) >> @@ -1338,6 +1403,8 @@ static inline int ptep_set_access_flags(struct vm_area_struct *vma, >> #define set_pte __set_pte >> #define set_ptes __set_ptes >> #define pte_clear __pte_clear >> +#define clear_full_ptes __clear_full_ptes >> +#define get_and_clear_full_ptes __get_and_clear_full_ptes >> #define __HAVE_ARCH_PTEP_GET_AND_CLEAR >> #define ptep_get_and_clear __ptep_get_and_clear >> #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG >> diff --git a/arch/arm64/mm/contpte.c b/arch/arm64/mm/contpte.c >> index c85e64baf03b..80346108450b 100644 >> --- a/arch/arm64/mm/contpte.c >> +++ b/arch/arm64/mm/contpte.c >> @@ -207,6 +207,23 @@ void contpte_set_ptes(struct mm_struct *mm, unsigned long addr, >> } >> EXPORT_SYMBOL(contpte_set_ptes); >> >> +void contpte_clear_full_ptes(struct mm_struct *mm, unsigned long addr, >> + pte_t *ptep, unsigned int nr, int full) >> +{ >> + contpte_try_unfold_partial(mm, addr, ptep, nr); >> + __clear_full_ptes(mm, addr, ptep, nr, full); >> +} >> +EXPORT_SYMBOL(contpte_clear_full_ptes); >> + >> +pte_t contpte_get_and_clear_full_ptes(struct mm_struct *mm, >> + unsigned long addr, pte_t *ptep, >> + unsigned int nr, int full) >> +{ >> + contpte_try_unfold_partial(mm, addr, ptep, nr); >> + return __get_and_clear_full_ptes(mm, addr, ptep, nr, full); >> +} >> +EXPORT_SYMBOL(contpte_get_and_clear_full_ptes); >> + >> int contpte_ptep_test_and_clear_young(struct vm_area_struct *vma, >> unsigned long addr, pte_t *ptep) >> { >> -- >> 2.25.1 >>