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 A88B5433B3 for ; Fri, 10 Jan 2025 06:38:51 +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=1736491133; cv=none; b=PnSTadomMFbvPZMmT8bNXvHuujqKNmAntQZF623Y1SE1r+UaGgVzR7bouQy2B9ZeCKa9fu6eP8iF1FfiaoOhT7/pwmPTDRfRHrC9KoQ1z/yzay/kZCEumNzfhmxeHi1/Z1WgnZsxtNfr6F6AUG2t6caEHz646ag48K1mdCBFN9g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736491133; c=relaxed/simple; bh=RxScvZh0VLUrAMBvdyHb8+N93F/m/8ii/nYgvtOHJzo=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=gyJxfirQRMrIN00QdUYU6kJB2BRAp0dvDi34jFwlqSo5ZvcHDSu+uknmvIS4DNeR8vyk0v9T/Jcwk+tysUo+4n1UWRmmcOWwskrBY0vCoVWaj4w5yLvJOCfwTJ6/6Lnwjmfbkx/IuRvoTLubXW4qkx6hmrYNSi/zM51sWfeGm2w= 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 3C4561477; Thu, 9 Jan 2025 22:39:19 -0800 (PST) Received: from [10.162.42.21] (K4MQJ0H1H2.blr.arm.com [10.162.42.21]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 16B353F673; Thu, 9 Jan 2025 22:38:38 -0800 (PST) Message-ID: <042059ee-e0c0-4182-bafd-851655c1ad4f@arm.com> Date: Fri, 10 Jan 2025 12:08:35 +0530 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: [RFC 07/11] khugepaged: generalize __collapse_huge_page_* for mTHP support To: Nico Pache , linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: ryan.roberts@arm.com, anshuman.khandual@arm.com, catalin.marinas@arm.com, cl@gentwo.org, vbabka@suse.cz, mhocko@suse.com, apopple@nvidia.com, dave.hansen@linux.intel.com, will@kernel.org, baohua@kernel.org, jack@suse.cz, srivatsa@csail.mit.edu, haowenchao22@gmail.com, hughd@google.com, aneesh.kumar@kernel.org, yang@os.amperecomputing.com, peterx@redhat.com, ioworker0@gmail.com, wangkefeng.wang@huawei.com, ziy@nvidia.com, jglisse@google.com, surenb@google.com, vishal.moola@gmail.com, zokeefe@google.com, zhengqi.arch@bytedance.com, jhubbard@nvidia.com, 21cnbao@gmail.com, willy@infradead.org, kirill.shutemov@linux.intel.com, david@redhat.com, aarcange@redhat.com, raquini@redhat.com, sunnanyong@huawei.com, usamaarif642@gmail.com, audra@redhat.com, akpm@linux-foundation.org References: <20250108233128.14484-1-npache@redhat.com> <20250108233128.14484-8-npache@redhat.com> Content-Language: en-US From: Dev Jain In-Reply-To: <20250108233128.14484-8-npache@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 09/01/25 5:01 am, Nico Pache wrote: > generalize the order of the __collapse_huge_page_* functions > to support future mTHP collapse. > > No functional changes in this patch. > > Signed-off-by: Nico Pache > --- > mm/khugepaged.c | 36 +++++++++++++++++++----------------- > 1 file changed, 19 insertions(+), 17 deletions(-) > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index 6daf3a943a1a..9eb161b04ee4 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -565,7 +565,8 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma, > unsigned long address, > pte_t *pte, > struct collapse_control *cc, > - struct list_head *compound_pagelist) > + struct list_head *compound_pagelist, > + u8 order) > { > struct page *page = NULL; > struct folio *folio = NULL; > @@ -573,7 +574,7 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma, > int none_or_zero = 0, shared = 0, result = SCAN_FAIL, referenced = 0; > bool writable = false; > > - for (_pte = pte; _pte < pte + HPAGE_PMD_NR; > + for (_pte = pte; _pte < pte + (1 << order); > _pte++, address += PAGE_SIZE) { > pte_t pteval = ptep_get(_pte); > if (pte_none(pteval) || (pte_present(pteval) && > @@ -711,14 +712,15 @@ static void __collapse_huge_page_copy_succeeded(pte_t *pte, > struct vm_area_struct *vma, > unsigned long address, > spinlock_t *ptl, > - struct list_head *compound_pagelist) > + struct list_head *compound_pagelist, > + u8 order) > { > struct folio *src, *tmp; > pte_t *_pte; > pte_t pteval; > > - for (_pte = pte; _pte < pte + HPAGE_PMD_NR; > - _pte++, address += PAGE_SIZE) { > + for (_pte = pte; _pte < pte + (1 << order); > + _pte++, address += PAGE_SIZE) { > pteval = ptep_get(_pte); > if (pte_none(pteval) || is_zero_pfn(pte_pfn(pteval))) { > add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1); > @@ -764,7 +766,8 @@ static void __collapse_huge_page_copy_failed(pte_t *pte, > pmd_t *pmd, > pmd_t orig_pmd, > struct vm_area_struct *vma, > - struct list_head *compound_pagelist) > + struct list_head *compound_pagelist, > + u8 order) > { > spinlock_t *pmd_ptl; > > @@ -781,7 +784,7 @@ static void __collapse_huge_page_copy_failed(pte_t *pte, > * Release both raw and compound pages isolated > * in __collapse_huge_page_isolate. > */ > - release_pte_pages(pte, pte + HPAGE_PMD_NR, compound_pagelist); > + release_pte_pages(pte, pte + (1 << order), compound_pagelist); > } > > /* > @@ -802,7 +805,7 @@ static void __collapse_huge_page_copy_failed(pte_t *pte, > static int __collapse_huge_page_copy(pte_t *pte, struct folio *folio, > pmd_t *pmd, pmd_t orig_pmd, struct vm_area_struct *vma, > unsigned long address, spinlock_t *ptl, > - struct list_head *compound_pagelist) > + struct list_head *compound_pagelist, u8 order) > { > unsigned int i; > int result = SCAN_SUCCEED; > @@ -810,7 +813,7 @@ static int __collapse_huge_page_copy(pte_t *pte, struct folio *folio, > /* > * Copying pages' contents is subject to memory poison at any iteration. > */ > - for (i = 0; i < HPAGE_PMD_NR; i++) { > + for (i = 0; i < (1 << order); i++) { > pte_t pteval = ptep_get(pte + i); > struct page *page = folio_page(folio, i); > unsigned long src_addr = address + i * PAGE_SIZE; > @@ -829,10 +832,10 @@ static int __collapse_huge_page_copy(pte_t *pte, struct folio *folio, > > if (likely(result == SCAN_SUCCEED)) > __collapse_huge_page_copy_succeeded(pte, vma, address, ptl, > - compound_pagelist); > + compound_pagelist, order); > else > __collapse_huge_page_copy_failed(pte, pmd, orig_pmd, vma, > - compound_pagelist); > + compound_pagelist, order); > > return result; > } > @@ -996,11 +999,11 @@ static int check_pmd_still_valid(struct mm_struct *mm, > static int __collapse_huge_page_swapin(struct mm_struct *mm, > struct vm_area_struct *vma, > unsigned long haddr, pmd_t *pmd, > - int referenced) > + int referenced, u8 order) > { I had dropped 'h' from haddr because the address won't be huge-aligned after mTHP support. > int swapped_in = 0; > vm_fault_t ret = 0; > - unsigned long address, end = haddr + (HPAGE_PMD_NR * PAGE_SIZE); > + unsigned long address, end = haddr + ((1 << order) * PAGE_SIZE); Better to write PAGE_SIZE << order, as Matthew had noted in my patch :)