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s=arc-20220608; d=hostedemail.com; t=1773127875; a=rsa-sha256; cv=none; b=nEIZeSApmipIQDcsVl6dPrFvqXkUpkGD6g4PVtYQTl4/nLmSQ2z+p+9ZxsoGwFBbSPhSIK 3HXDA8cnV4igq2V7dkmQk5vFLMka1qYTYZ0z4x/bBW8eozCXETjLmhITgWEop8KhzFnaHq mCIMZGya9rpU9PhSROVhf6tIzSiCFKw= ARC-Authentication-Results: i=1; imf03.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf03.hostedemail.com: domain of dev.jain@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=dev.jain@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 4534216A3; Tue, 10 Mar 2026 00:31:08 -0700 (PDT) Received: from a080796.blr.arm.com (a080796.arm.com [10.164.21.51]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 8EA0F3F73B; Tue, 10 Mar 2026 00:31:05 -0700 (PDT) From: Dev Jain To: akpm@linux-foundation.org, axelrasmussen@google.com, yuanchu@google.com, david@kernel.org, hughd@google.com, chrisl@kernel.org, kasong@tencent.com Cc: weixugc@google.com, ljs@kernel.org, Liam.Howlett@oracle.com, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, riel@surriel.com, harry.yoo@oracle.com, jannh@google.com, pfalcato@suse.de, baolin.wang@linux.alibaba.com, shikemeng@huaweicloud.com, nphamcs@gmail.com, bhe@redhat.com, baohua@kernel.org, youngjun.park@lge.com, ziy@nvidia.com, kas@kernel.org, willy@infradead.org, yuzhao@google.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, ryan.roberts@arm.com, anshuman.khandual@arm.com, Dev Jain Subject: [PATCH 3/9] mm/rmap: refactor lazyfree unmap commit path to commit_ttu_lazyfree_folio() Date: Tue, 10 Mar 2026 13:00:07 +0530 Message-Id: <20260310073013.4069309-4-dev.jain@arm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260310073013.4069309-1-dev.jain@arm.com> References: <20260310073013.4069309-1-dev.jain@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 8821820006 X-Stat-Signature: 3wtaswz9w5pdsh5f48km7d85qgbx5jek X-Rspam-User: X-HE-Tag: 1773127875-568371 X-HE-Meta: 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 BuNvgrWV JiPTSIoOac1Xo1JE1Rgr6rPsy6AEeMWknQDKr1r3ViI5UGA388aWjPyZqmg8K0977BmJAKlPwN68skjFz24p4IOQGL9IB2SAYx2jNeyWt1ZzOrassqAzPU4dyVHJYfpPXbxw8KbqXLsrkYOnhP4lhfOvQTDIf5qKJpR1mYmvVHXwgY3mLXhtxA+H3SF0L1qq8ZgL/KyLWXKCNfetKRALT35r8qWfbY68Z7BSb0s9zCn1P+3Q= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Clean up the code by refactoring the post-pte-clearing path of lazyfree folio unmapping, into commit_ttu_lazyfree_folio(). No functional change is intended. Signed-off-by: Dev Jain --- mm/rmap.c | 93 ++++++++++++++++++++++++++++++++----------------------- 1 file changed, 54 insertions(+), 39 deletions(-) diff --git a/mm/rmap.c b/mm/rmap.c index 1fa020edd954a..a61978141ee3f 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1966,6 +1966,57 @@ static inline unsigned int folio_unmap_pte_batch(struct folio *folio, FPB_RESPECT_WRITE | FPB_RESPECT_SOFT_DIRTY); } +static inline int commit_ttu_lazyfree_folio(struct vm_area_struct *vma, + struct folio *folio, unsigned long address, pte_t *ptep, + pte_t pteval, long nr_pages) +{ + struct mm_struct *mm = vma->vm_mm; + int ref_count, map_count; + + /* + * Synchronize with gup_pte_range(): + * - clear PTE; barrier; read refcount + * - inc refcount; barrier; read PTE + */ + smp_mb(); + + ref_count = folio_ref_count(folio); + map_count = folio_mapcount(folio); + + /* + * Order reads for page refcount and dirty flag + * (see comments in __remove_mapping()). + */ + smp_rmb(); + + if (folio_test_dirty(folio) && !(vma->vm_flags & VM_DROPPABLE)) { + /* + * redirtied either using the page table or a previously + * obtained GUP reference. + */ + set_ptes(mm, address, ptep, pteval, nr_pages); + folio_set_swapbacked(folio); + return 1; + } + + if (ref_count != 1 + map_count) { + /* + * Additional reference. Could be a GUP reference or any + * speculative reference. GUP users must mark the folio + * dirty if there was a modification. This folio cannot be + * reclaimed right now either way, so act just like nothing + * happened. + * We'll come back here later and detect if the folio was + * dirtied when the additional reference is gone. + */ + set_ptes(mm, address, ptep, pteval, nr_pages); + return 1; + } + + add_mm_counter(mm, MM_ANONPAGES, -nr_pages); + return 0; +} + /* * @arg: enum ttu_flags will be passed to this argument */ @@ -2227,46 +2278,10 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, /* MADV_FREE page check */ if (!folio_test_swapbacked(folio)) { - int ref_count, map_count; - - /* - * Synchronize with gup_pte_range(): - * - clear PTE; barrier; read refcount - * - inc refcount; barrier; read PTE - */ - smp_mb(); - - ref_count = folio_ref_count(folio); - map_count = folio_mapcount(folio); - - /* - * Order reads for page refcount and dirty flag - * (see comments in __remove_mapping()). - */ - smp_rmb(); - - if (folio_test_dirty(folio) && !(vma->vm_flags & VM_DROPPABLE)) { - /* - * redirtied either using the page table or a previously - * obtained GUP reference. - */ - set_ptes(mm, address, pvmw.pte, pteval, nr_pages); - folio_set_swapbacked(folio); + if (commit_ttu_lazyfree_folio(vma, folio, address, + pvmw.pte, pteval, + nr_pages)) goto walk_abort; - } else if (ref_count != 1 + map_count) { - /* - * Additional reference. Could be a GUP reference or any - * speculative reference. GUP users must mark the folio - * dirty if there was a modification. This folio cannot be - * reclaimed right now either way, so act just like nothing - * happened. - * We'll come back here later and detect if the folio was - * dirtied when the additional reference is gone. - */ - set_ptes(mm, address, pvmw.pte, pteval, nr_pages); - goto walk_abort; - } - add_mm_counter(mm, MM_ANONPAGES, -nr_pages); goto discard; } -- 2.34.1