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a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1745916002; 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=WDoi6k7sqtgxQYJqKHtEcH9BVLqdMs88OozTGG6SCcE=; b=jrlOxpGw1Nb2iz0EGpVS4BIMv9O4F4I5pNSTDkplz7m9QAzn9Xv05PdPmElt7pTDLPVIJW Ug3mQdcWpwRjr5O60MkRkYN1ThUiKYBEwQG8qq3+knFO4SK580dF8mkOBWtNE4JCG+2/A1 +grprjqgRqn8QpkZRr7meQSHCxmFaSY= 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 D69421515; Tue, 29 Apr 2025 01:39:53 -0700 (PDT) Received: from [10.163.52.122] (unknown [10.163.52.122]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 97EBB3F66E; Tue, 29 Apr 2025 01:39:50 -0700 (PDT) Message-ID: <93411699-2e36-4a4e-bc3a-3efeb8e2260b@arm.com> Date: Tue, 29 Apr 2025 14:09:46 +0530 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 3/7] mm: Add batched versions of ptep_modify_prot_start/commit To: Dev Jain , akpm@linux-foundation.org Cc: ryan.roberts@arm.com, david@redhat.com, willy@infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, catalin.marinas@arm.com, will@kernel.org, Liam.Howlett@oracle.com, lorenzo.stoakes@oracle.com, vbabka@suse.cz, jannh@google.com, peterx@redhat.com, joey.gouly@arm.com, ioworker0@gmail.com, baohua@kernel.org, kevin.brodsky@arm.com, quic_zhenhuah@quicinc.com, christophe.leroy@csgroup.eu, yangyicong@hisilicon.com, linux-arm-kernel@lists.infradead.org, namit@vmware.com, hughd@google.com, yang@os.amperecomputing.com, ziy@nvidia.com References: <20250429052336.18912-1-dev.jain@arm.com> <20250429052336.18912-4-dev.jain@arm.com> Content-Language: en-US From: Anshuman Khandual In-Reply-To: <20250429052336.18912-4-dev.jain@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: A868A1A000D X-Stat-Signature: tyhz6c9udtdhqkgyp5qxk4x9ejqnrm9c X-Rspam-User: X-HE-Tag: 1745916001-459241 X-HE-Meta: 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 2e/xNtHX cPSJbI5X4gzewJB4xqSC/FcDpNYDewvbc6ju4vdP7vXiLnTaYNqCcmvSbGaLlcbC/diK4xYovgGn1uALUjVdpvhJURH2vzrQCevPc/lVny4Fxi6PfN4y7/uRdJyiAhDtOixOdmsgKV3KOKmZYZvAdchBl7zgS1AEN0kB2fYSyoTQIh64+IxfksDvzt9WjbMtfLJMAFiOWbaHD710Ld0fHPEjWLgKkmy7bLSwYFUetYhu3AKin/DxntE3wpA== 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 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 ? > + > /* > * 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.