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 4B887289811 for ; Tue, 22 Jul 2025 11:25:04 +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=1753183507; cv=none; b=ko8AqMAm+eFtSsz33FUV5JS7sAPBa4Ao8phIF+TBJeQ6HxaqW2gx+rwWmH93nqyL9QL1I2fbdPhnqp9ptHuLw1In+FVV67F4cso3GW9RVZpqzBg9PyfGQcDTjKJAbC9I/ctC3rLbRsRKxIs1gi6vfPhJYkSMHAdPz8TZOTgFaDU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753183507; c=relaxed/simple; bh=CHS+1lDwG4RKhNRs4RdFSgLJwKj3ZZWuLF23+NulHjo=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=jKYemmRV6c8/pnVo/fpy7qKQim8ZOvUuDVYAlCGk3Ow/tDDDQe+QFDUhwcoUxF5EEyd9DrhB61JKv+WdGhmhKtKmiaQwN386gSHumSwXZdEGacSCI0oWGF5+xVYTbfWSTrZTAOH7++QvUuMtax4vYo/6ntrDv6raVSzZLSP59aM= 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 EBEB8152B; Tue, 22 Jul 2025 04:24:58 -0700 (PDT) Received: from [10.1.30.167] (XHFQ2J9959.cambridge.arm.com [10.1.30.167]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5C27A3F66E; Tue, 22 Jul 2025 04:25:01 -0700 (PDT) Message-ID: Date: Tue, 22 Jul 2025 12:25:00 +0100 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 v5 1/7] mm: Refactor MM_CP_PROT_NUMA skipping case into new function Content-Language: en-GB To: Dev Jain , akpm@linux-foundation.org Cc: 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, anshuman.khandual@arm.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, hughd@google.com, yang@os.amperecomputing.com, ziy@nvidia.com References: <20250718090244.21092-1-dev.jain@arm.com> <20250718090244.21092-2-dev.jain@arm.com> From: Ryan Roberts In-Reply-To: <20250718090244.21092-2-dev.jain@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 18/07/2025 10:02, Dev Jain wrote: > Reduce indentation by refactoring the prot_numa case into a new function. > No functional change intended. > > Signed-off-by: Dev Jain > --- > mm/mprotect.c | 101 +++++++++++++++++++++++++++----------------------- > 1 file changed, 55 insertions(+), 46 deletions(-) > > diff --git a/mm/mprotect.c b/mm/mprotect.c > index 88709c01177b..2a9c73bd0778 100644 > --- a/mm/mprotect.c > +++ b/mm/mprotect.c > @@ -83,6 +83,59 @@ bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr, > return pte_dirty(pte); > } > > +static bool prot_numa_skip(struct vm_area_struct *vma, unsigned long addr, > + pte_t oldpte, pte_t *pte, int target_node) > +{ > + struct folio *folio; > + bool toptier; > + int nid; > + > + /* Avoid TLB flush if possible */ > + if (pte_protnone(oldpte)) > + return true; > + > + folio = vm_normal_folio(vma, addr, oldpte); > + if (!folio) > + return true; > + > + if (folio_is_zone_device(folio) || folio_test_ksm(folio)) > + return true; > + > + /* Also skip shared copy-on-write pages */ > + if (is_cow_mapping(vma->vm_flags) && > + (folio_maybe_dma_pinned(folio) || folio_maybe_mapped_shared(folio))) > + return true; > + > + /* > + * While migration can move some dirty pages, > + * it cannot move them all from MIGRATE_ASYNC > + * context. > + */ > + if (folio_is_file_lru(folio) && folio_test_dirty(folio)) > + return true; > + > + /* > + * Don't mess with PTEs if page is already on the node > + * a single-threaded process is running on. > + */ > + nid = folio_nid(folio); > + if (target_node == nid) > + return true; > + > + toptier = node_is_toptier(nid); > + > + /* > + * Skip scanning top tier node if normal numa > + * balancing is disabled > + */ > + if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) && toptier) > + return true; > + > + if (folio_use_access_time(folio)) > + folio_xchg_access_time(folio, jiffies_to_msecs(jiffies)); Perhaps this bit should be kept in the original location? It's got nothing to do with determining if the pte should be skipped. Thanks, Ryan > + return false; > +} > + > static long change_pte_range(struct mmu_gather *tlb, > struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr, > unsigned long end, pgprot_t newprot, unsigned long cp_flags) > @@ -117,53 +170,9 @@ static long change_pte_range(struct mmu_gather *tlb, > * pages. See similar comment in change_huge_pmd. > */ > if (prot_numa) { > - struct folio *folio; > - int nid; > - bool toptier; > - > - /* Avoid TLB flush if possible */ > - if (pte_protnone(oldpte)) > - continue; > - > - folio = vm_normal_folio(vma, addr, oldpte); > - if (!folio || folio_is_zone_device(folio) || > - folio_test_ksm(folio)) > - continue; > - > - /* Also skip shared copy-on-write pages */ > - if (is_cow_mapping(vma->vm_flags) && > - (folio_maybe_dma_pinned(folio) || > - folio_maybe_mapped_shared(folio))) > - continue; > - > - /* > - * While migration can move some dirty pages, > - * it cannot move them all from MIGRATE_ASYNC > - * context. > - */ > - if (folio_is_file_lru(folio) && > - folio_test_dirty(folio)) > - continue; > - > - /* > - * Don't mess with PTEs if page is already on the node > - * a single-threaded process is running on. > - */ > - nid = folio_nid(folio); > - if (target_node == nid) > - continue; > - toptier = node_is_toptier(nid); > - > - /* > - * Skip scanning top tier node if normal numa > - * balancing is disabled > - */ > - if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) && > - toptier) > + if (prot_numa_skip(vma, addr, oldpte, pte, > + target_node)) > continue; > - if (folio_use_access_time(folio)) > - folio_xchg_access_time(folio, > - jiffies_to_msecs(jiffies)); > } > > oldpte = ptep_modify_prot_start(vma, addr, pte);