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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1A996C44500 for ; Thu, 22 Jan 2026 09:19:28 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7C4BC6B0128; Thu, 22 Jan 2026 04:19:27 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 7725D6B0129; Thu, 22 Jan 2026 04:19:27 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 69EC46B012A; Thu, 22 Jan 2026 04:19:27 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 53D876B0128 for ; Thu, 22 Jan 2026 04:19:27 -0500 (EST) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 0D1E3160182 for ; Thu, 22 Jan 2026 09:19:27 +0000 (UTC) X-FDA: 84359051574.23.9A4DADE Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf17.hostedemail.com (Postfix) with ESMTP id D5B0E40004 for ; Thu, 22 Jan 2026 09:19:24 +0000 (UTC) Authentication-Results: imf17.hostedemail.com; dkim=none; spf=pass (imf17.hostedemail.com: domain of dev.jain@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=dev.jain@arm.com; dmarc=pass (policy=none) header.from=arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1769073565; 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=oDNFwaPGoX3waIMP5rZJNqCBjlJdC/yYu221+ARpHC8=; b=ZUP5Q59iHiA7ILlX338FoKMwwhwuuwV8b7nLqAFWoA+oJ1Oc6xR9UTjhWZLDQ8KJszpS44 kIwckknutTN+fmt0ia1kWmrGfWdzlyNVvnVyVSPLeX8v2YcYpOshAUw4NmJApcxhKfEN47 C/0LD6VmcTqcjWmYLs4xJG6urgvO2Cc= ARC-Authentication-Results: i=1; imf17.hostedemail.com; dkim=none; spf=pass (imf17.hostedemail.com: domain of dev.jain@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=dev.jain@arm.com; dmarc=pass (policy=none) header.from=arm.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1769073565; a=rsa-sha256; cv=none; b=0KDTYE0G8Ag2z1pEZQVB4TeOUaadP98OeBIBobSZTNtg3FT43M+cdyOAN0Dknu0yPige/0 wHs/Qa25HzpYQspp/oeBiOUh9nKpWv1kpSBdVQjAlgEw9rXscKkKUtbrc4HYOrQCW9vz+9 x7RlG+8k18n/eKCVb4r0uDy1AiJK5Qo= 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 238651476; Thu, 22 Jan 2026 01:19:17 -0800 (PST) Received: from [10.164.18.63] (MacBook-Pro.blr.arm.com [10.164.18.63]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 35CAB3F632; Thu, 22 Jan 2026 01:19:19 -0800 (PST) Message-ID: <5639693a-a89a-47c8-978e-1aab59268413@arm.com> Date: Thu, 22 Jan 2026 14:49:17 +0530 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH V3 4/5] mm/khugepaged: use enum scan_result for result variables and return types To: Shivank Garg , Andrew Morton , David Hildenbrand , Lorenzo Stoakes Cc: Zi Yan , Baolin Wang , "Liam R . Howlett" , Nico Pache , Ryan Roberts , Barry Song , Lance Yang , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20260118192253.9263-4-shivankg@amd.com> <20260118192253.9263-12-shivankg@amd.com> Content-Language: en-US From: Dev Jain In-Reply-To: <20260118192253.9263-12-shivankg@amd.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Queue-Id: D5B0E40004 X-Rspamd-Server: rspam07 X-Stat-Signature: ypsndpn66yojdgw9zo9qr1k8npz5ra81 X-HE-Tag: 1769073564-807355 X-HE-Meta: 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 VDEUzSBv BoQpP3t/ZJ47GvAeffZuDxq/AyWWgIOK+CWGt1M9Y6aqDY/3V1k6dS1WAv6vK0gLWoVNCgvKJ2+tL7u0v5meOt0c7rEOmvye/EMmpNnFpYr4uReLsQKY2qpn8TVmXf5xWKShlZTpBmL0O12Uxjesrn3doudnYJxRl9oOIdxNRr0H6Lfs0BaIrbjHoCuxLRD0O3Oiu4oUz+FS5mTK7XhLjTjU0RDrf86oOBCcmfN+PhIKqGNW8Nkh14M/bjjIF+BguSqgLUWp4N5jZNxYkGYgyNYCdid0T+UkEWWZdxz/OEtuGw9bOByLUdeaWMlw8xYbtx0iNqIMzLjeburZZGALqHkcdlA== 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 19/01/26 12:52 am, Shivank Garg wrote: > Convert result variables and return types from int to enum scan_result > throughout khugepaged code. This improves type safety and code clarity > by making the intent explicit. > > No functional change. > > Reviewed-by: Zi Yan > Signed-off-by: Shivank Garg Reviewed-by: Dev Jain > --- > mm/khugepaged.c | 99 +++++++++++++++++++++++-------------------------- > 1 file changed, 46 insertions(+), 53 deletions(-) > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index 17f3f0043368..1667abae6d8d 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -537,17 +537,16 @@ static void release_pte_pages(pte_t *pte, pte_t *_pte, > } > } > > -static int __collapse_huge_page_isolate(struct vm_area_struct *vma, > - unsigned long start_addr, > - pte_t *pte, > - struct collapse_control *cc, > - struct list_head *compound_pagelist) > +static enum scan_result __collapse_huge_page_isolate(struct vm_area_struct *vma, > + unsigned long start_addr, pte_t *pte, struct collapse_control *cc, > + struct list_head *compound_pagelist) > { > struct page *page = NULL; > struct folio *folio = NULL; > unsigned long addr = start_addr; > pte_t *_pte; > - int none_or_zero = 0, shared = 0, result = SCAN_FAIL, referenced = 0; > + int none_or_zero = 0, shared = 0, referenced = 0; > + enum scan_result result = SCAN_FAIL; > > for (_pte = pte; _pte < pte + HPAGE_PMD_NR; > _pte++, addr += PAGE_SIZE) { > @@ -780,13 +779,13 @@ static void __collapse_huge_page_copy_failed(pte_t *pte, > * @ptl: lock on raw pages' PTEs > * @compound_pagelist: list that stores compound pages > */ > -static int __collapse_huge_page_copy(pte_t *pte, struct folio *folio, > +static enum scan_result __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) > { > unsigned int i; > - int result = SCAN_SUCCEED; > + enum scan_result result = SCAN_SUCCEED; > > /* > * Copying pages' contents is subject to memory poison at any iteration. > @@ -898,10 +897,8 @@ static int hpage_collapse_find_target_node(struct collapse_control *cc) > * Returns enum scan_result value. > */ > > -static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address, > - bool expect_anon, > - struct vm_area_struct **vmap, > - struct collapse_control *cc) > +static enum scan_result hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address, > + bool expect_anon, struct vm_area_struct **vmap, struct collapse_control *cc) > { > struct vm_area_struct *vma; > enum tva_type type = cc->is_khugepaged ? TVA_KHUGEPAGED : > @@ -930,7 +927,7 @@ static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address, > return SCAN_SUCCEED; > } > > -static inline int check_pmd_state(pmd_t *pmd) > +static inline enum scan_result check_pmd_state(pmd_t *pmd) > { > pmd_t pmde = pmdp_get_lockless(pmd); > > @@ -953,9 +950,8 @@ static inline int check_pmd_state(pmd_t *pmd) > return SCAN_SUCCEED; > } > > -static int find_pmd_or_thp_or_none(struct mm_struct *mm, > - unsigned long address, > - pmd_t **pmd) > +static enum scan_result find_pmd_or_thp_or_none(struct mm_struct *mm, > + unsigned long address, pmd_t **pmd) > { > *pmd = mm_find_pmd(mm, address); > if (!*pmd) > @@ -964,12 +960,11 @@ static int find_pmd_or_thp_or_none(struct mm_struct *mm, > return check_pmd_state(*pmd); > } > > -static int check_pmd_still_valid(struct mm_struct *mm, > - unsigned long address, > - pmd_t *pmd) > +static enum scan_result check_pmd_still_valid(struct mm_struct *mm, > + unsigned long address, pmd_t *pmd) > { > pmd_t *new_pmd; > - int result = find_pmd_or_thp_or_none(mm, address, &new_pmd); > + enum scan_result result = find_pmd_or_thp_or_none(mm, address, &new_pmd); > > if (result != SCAN_SUCCEED) > return result; > @@ -985,15 +980,14 @@ static int check_pmd_still_valid(struct mm_struct *mm, > * Called and returns without pte mapped or spinlocks held. > * Returns result: if not SCAN_SUCCEED, mmap_lock has been released. > */ > -static int __collapse_huge_page_swapin(struct mm_struct *mm, > - struct vm_area_struct *vma, > - unsigned long start_addr, pmd_t *pmd, > - int referenced) > +static enum scan_result __collapse_huge_page_swapin(struct mm_struct *mm, > + struct vm_area_struct *vma, unsigned long start_addr, pmd_t *pmd, > + int referenced) > { > int swapped_in = 0; > vm_fault_t ret = 0; > unsigned long addr, end = start_addr + (HPAGE_PMD_NR * PAGE_SIZE); > - int result; > + enum scan_result result; > pte_t *pte = NULL; > spinlock_t *ptl; > > @@ -1062,8 +1056,8 @@ static int __collapse_huge_page_swapin(struct mm_struct *mm, > return result; > } > > -static int alloc_charge_folio(struct folio **foliop, struct mm_struct *mm, > - struct collapse_control *cc) > +static enum scan_result alloc_charge_folio(struct folio **foliop, struct mm_struct *mm, > + struct collapse_control *cc) > { > gfp_t gfp = (cc->is_khugepaged ? alloc_hugepage_khugepaged_gfpmask() : > GFP_TRANSHUGE); > @@ -1090,9 +1084,8 @@ static int alloc_charge_folio(struct folio **foliop, struct mm_struct *mm, > return SCAN_SUCCEED; > } > > -static int collapse_huge_page(struct mm_struct *mm, unsigned long address, > - int referenced, int unmapped, > - struct collapse_control *cc) > +static enum scan_result collapse_huge_page(struct mm_struct *mm, unsigned long address, > + int referenced, int unmapped, struct collapse_control *cc) > { > LIST_HEAD(compound_pagelist); > pmd_t *pmd, _pmd; > @@ -1100,7 +1093,7 @@ static int collapse_huge_page(struct mm_struct *mm, unsigned long address, > pgtable_t pgtable; > struct folio *folio; > spinlock_t *pmd_ptl, *pte_ptl; > - int result = SCAN_FAIL; > + enum scan_result result = SCAN_FAIL; > struct vm_area_struct *vma; > struct mmu_notifier_range range; > > @@ -1246,15 +1239,14 @@ static int collapse_huge_page(struct mm_struct *mm, unsigned long address, > return result; > } > > -static int hpage_collapse_scan_pmd(struct mm_struct *mm, > - struct vm_area_struct *vma, > - unsigned long start_addr, bool *mmap_locked, > - struct collapse_control *cc) > +static enum scan_result hpage_collapse_scan_pmd(struct mm_struct *mm, > + struct vm_area_struct *vma, unsigned long start_addr, bool *mmap_locked, > + struct collapse_control *cc) > { > pmd_t *pmd; > pte_t *pte, *_pte; > - int result = SCAN_FAIL, referenced = 0; > - int none_or_zero = 0, shared = 0; > + int none_or_zero = 0, shared = 0, referenced = 0; > + enum scan_result result = SCAN_FAIL; > struct page *page = NULL; > struct folio *folio = NULL; > unsigned long addr; > @@ -1441,8 +1433,8 @@ static void collect_mm_slot(struct mm_slot *slot) > } > > /* folio must be locked, and mmap_lock must be held */ > -static int set_huge_pmd(struct vm_area_struct *vma, unsigned long addr, > - pmd_t *pmdp, struct folio *folio, struct page *page) > +static enum scan_result set_huge_pmd(struct vm_area_struct *vma, unsigned long addr, > + pmd_t *pmdp, struct folio *folio, struct page *page) > { > struct mm_struct *mm = vma->vm_mm; > struct vm_fault vmf = { > @@ -1477,10 +1469,11 @@ static int set_huge_pmd(struct vm_area_struct *vma, unsigned long addr, > return SCAN_SUCCEED; > } > > -static int try_collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr, > +static enum scan_result try_collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr, > bool install_pmd) > { > - int nr_mapped_ptes = 0, result = SCAN_FAIL; > + enum scan_result result = SCAN_FAIL; > + int nr_mapped_ptes = 0; > unsigned int nr_batch_ptes; > struct mmu_notifier_range range; > bool notified = false; > @@ -1862,9 +1855,8 @@ static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff) > * + unlock old pages > * + unlock and free huge page; > */ > -static int collapse_file(struct mm_struct *mm, unsigned long addr, > - struct file *file, pgoff_t start, > - struct collapse_control *cc) > +static enum scan_result collapse_file(struct mm_struct *mm, unsigned long addr, > + struct file *file, pgoff_t start, struct collapse_control *cc) > { > struct address_space *mapping = file->f_mapping; > struct page *dst; > @@ -1872,7 +1864,8 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr, > pgoff_t index = 0, end = start + HPAGE_PMD_NR; > LIST_HEAD(pagelist); > XA_STATE_ORDER(xas, &mapping->i_pages, start, HPAGE_PMD_ORDER); > - int nr_none = 0, result = SCAN_SUCCEED; > + enum scan_result result = SCAN_SUCCEED; > + int nr_none = 0; > bool is_shmem = shmem_file(file); > > VM_BUG_ON(!IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) && !is_shmem); > @@ -2293,16 +2286,15 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr, > return result; > } > > -static int hpage_collapse_scan_file(struct mm_struct *mm, unsigned long addr, > - struct file *file, pgoff_t start, > - struct collapse_control *cc) > +static enum scan_result hpage_collapse_scan_file(struct mm_struct *mm, unsigned long addr, > + struct file *file, pgoff_t start, struct collapse_control *cc) > { > struct folio *folio = NULL; > struct address_space *mapping = file->f_mapping; > XA_STATE(xas, &mapping->i_pages, start); > int present, swap; > int node = NUMA_NO_NODE; > - int result = SCAN_SUCCEED; > + enum scan_result result = SCAN_SUCCEED; > > present = 0; > swap = 0; > @@ -2400,7 +2392,7 @@ static int hpage_collapse_scan_file(struct mm_struct *mm, unsigned long addr, > return result; > } > > -static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result, > +static unsigned int khugepaged_scan_mm_slot(unsigned int pages, enum scan_result *result, > struct collapse_control *cc) > __releases(&khugepaged_mm_lock) > __acquires(&khugepaged_mm_lock) > @@ -2562,7 +2554,7 @@ static void khugepaged_do_scan(struct collapse_control *cc) > unsigned int progress = 0, pass_through_head = 0; > unsigned int pages = READ_ONCE(khugepaged_pages_to_scan); > bool wait = true; > - int result = SCAN_SUCCEED; > + enum scan_result result = SCAN_SUCCEED; > > lru_add_drain_all(); > > @@ -2775,7 +2767,8 @@ int madvise_collapse(struct vm_area_struct *vma, unsigned long start, > struct collapse_control *cc; > struct mm_struct *mm = vma->vm_mm; > unsigned long hstart, hend, addr; > - int thps = 0, last_fail = SCAN_FAIL; > + enum scan_result last_fail = SCAN_FAIL; > + int thps = 0; > bool mmap_locked = true; > > BUG_ON(vma->vm_start > start); > @@ -2796,7 +2789,7 @@ int madvise_collapse(struct vm_area_struct *vma, unsigned long start, > hend = end & HPAGE_PMD_MASK; > > for (addr = hstart; addr < hend; addr += HPAGE_PMD_SIZE) { > - int result = SCAN_FAIL; > + enum scan_result result = SCAN_FAIL; > bool triggered_wb = false; > > retry: