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t=1783918884; bh=2tuAypSOUoMtv+0uqE76bfgNGfGZZgqedDGetxR7zmk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DFdwqHfF5ity3M0SjHqgtJRiKIgc8ppCAzieiQcwDH1vlKJFI7TYBN37Q8C/38lrY 4M2teU53an0hvPU3Ryp894f9pUvVV9Ej3PSEHzi51qTq+7uGPKr1MIi0I2dUoeDkzw +F6qXHZiJm7hnBmysf8Zsq4rTxUWEnk5vOHQEVOQ= From: Dev Jain To: akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org, muchun.song@linux.dev, osalvador@suse.de Cc: Dev Jain , riel@surriel.com, liam@infradead.org, vbabka@kernel.org, harry@kernel.org, jannh@google.com, lance.yang@linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, ryan.roberts@arm.com, anshuman.khandual@arm.com Subject: [PATCH v3 4/5] mm/rmap: refactor anon folio unmap in try_to_unmap_one Date: Mon, 13 Jul 2026 05:00:47 +0000 Message-ID: <20260713050050.1017741-5-dev.jain@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260713050050.1017741-1-dev.jain@arm.com> References: <20260713050050.1017741-1-dev.jain@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: C2CBA1C0004 X-Stat-Signature: cbkt9semgzo37fnrf9i3imxrqk8ephdr X-HE-Tag: 1783918885-387202 X-HE-Meta: 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 eb+KVXN7 I9nePrdmVBxJ/193bOEBDC9pkfwzPSpw1eLEdWk5Fy9FZEXJHy61SrEkwkGO6bPj8USW9FG6gDXDGFcU3XvPApcomGRkIc+IyVOvODSCwEYkZ2H9YWOASTuukSEG2VBc8zEBasvsY/A3U6WouNUjHQZTmw/RptgHsUy0O/9eX243oEOckvScwX+aoXV8Ssu4SDQoQ4V4fob/tnpvPzD63Kf+hceoeIGGJ3kvyjaipIYZlt0bHZuZxw3LsB3ngc8mO5tpSFZ80GW85nZVR9MYwpQJhd7/KNZw5YeJ2Mikw/ENMpkw= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Refactor anonymous swapbacked folio unmap to ttu_anon_swapbacked_folio(). While at it, rename the remaining subpage variables to page; folios have pages, not subpages. No functional change intended. Signed-off-by: Dev Jain --- mm/rmap.c | 115 ++++++++++++++++++++++++++++++++---------------------- 1 file changed, 68 insertions(+), 47 deletions(-) diff --git a/mm/rmap.c b/mm/rmap.c index 4465c88ddb77b..2c910d4575981 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -2112,6 +2112,66 @@ static bool ttu_anon_lazyfree_folio(struct vm_area_struct *vma, return true; } +static pte_t swp_pte_prepare(swp_entry_t entry, pte_t old_pte, + bool anon_exclusive) +{ + pte_t swp_pte = swp_entry_to_pte(entry); + + if (anon_exclusive) + swp_pte = pte_swp_mkexclusive(swp_pte); + + if (likely(pte_present(old_pte))) { + if (pte_soft_dirty(old_pte)) + swp_pte = pte_swp_mksoft_dirty(swp_pte); + if (pte_uffd(old_pte)) + swp_pte = pte_swp_mkuffd(swp_pte); + } else { + /* Device-exclusive entry */ + if (pte_swp_soft_dirty(old_pte)) + swp_pte = pte_swp_mksoft_dirty(swp_pte); + if (pte_swp_uffd(old_pte)) + swp_pte = pte_swp_mkuffd(swp_pte); + } + + return swp_pte; +} + +static bool ttu_anon_swapbacked_folio(struct vm_area_struct *vma, + struct folio *folio, struct page *page, unsigned long address, + pte_t *ptep, pte_t pteval) +{ + const bool anon_exclusive = folio_test_anon(folio) && + PageAnonExclusive(page); + swp_entry_t entry = page_swap_entry(page); + struct mm_struct *mm = vma->vm_mm; + + if (folio_dup_swap(folio, page) < 0) + return false; + + /* + * arch_unmap_one() is expected to be a NOP on + * architectures where we could have PFN swap PTEs, + * so we'll not check/care. + */ + if (arch_unmap_one(mm, vma, address, pteval) < 0) { + folio_put_swap(folio, page); + return false; + } + + /* See folio_try_share_anon_rmap(): clear PTE first. */ + if (anon_exclusive && folio_try_share_anon_rmap_pte(folio, page)) { + folio_put_swap(folio, page); + return false; + } + + mm_prepare_for_swap_entries(mm); + dec_mm_counter(mm, MM_ANONPAGES); + inc_mm_counter(mm, MM_SWAPENTS); + set_pte_at(mm, address, ptep, + swp_pte_prepare(entry, pteval, anon_exclusive)); + return true; +} + /* * @arg: enum ttu_flags will be passed to this argument */ @@ -2120,9 +2180,9 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, { struct mm_struct *mm = vma->vm_mm; DEFINE_FOLIO_VMA_WALK(pvmw, folio, vma, address, 0); - bool anon_exclusive, ret = true; + bool ret = true; pte_t pteval; - struct page *subpage; + struct page *page; struct mmu_notifier_range range; enum ttu_flags flags = (enum ttu_flags)(long)arg; unsigned long nr_pages = 1, end_addr; @@ -2233,9 +2293,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, pfn = softleaf_to_pfn(entry); } - subpage = folio_page(folio, pfn - folio_pfn(folio)); - anon_exclusive = folio_test_anon(folio) && - PageAnonExclusive(subpage); + page = folio_page(folio, pfn - folio_pfn(folio)); if (likely(pte_present(pteval))) { nr_pages = folio_unmap_pte_batch(folio, &pvmw, flags, pteval); @@ -2274,7 +2332,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, /* With TTU_HWPOISON, we only expect small folios here. */ if (folio_test_hwpoison(folio) && (flags & TTU_HWPOISON)) { - pteval = swp_entry_to_pte(make_hwpoison_entry(subpage)); + pteval = swp_entry_to_pte(make_hwpoison_entry(page)); dec_mm_counter(mm, mm_counter(folio)); set_pte_at(mm, address, pvmw.pte, pteval); } else if (likely(pte_present(pteval)) && pte_unused(pteval) && @@ -2291,8 +2349,6 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, */ dec_mm_counter(mm, mm_counter(folio)); } else if (folio_test_anon(folio)) { - swp_entry_t entry = page_swap_entry(subpage); - pte_t swp_pte; /* * Store the swap location in the pte. * See handle_pte_fault() ... @@ -2313,47 +2369,12 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, goto finish_unmap; } - if (folio_dup_swap(folio, subpage) < 0) { - set_pte_at(mm, address, pvmw.pte, pteval); - goto walk_abort; - } - - /* - * arch_unmap_one() is expected to be a NOP on - * architectures where we could have PFN swap PTEs, - * so we'll not check/care. - */ - if (arch_unmap_one(mm, vma, address, pteval) < 0) { - folio_put_swap(folio, subpage); - set_pte_at(mm, address, pvmw.pte, pteval); - goto walk_abort; - } - - /* See folio_try_share_anon_rmap(): clear PTE first. */ - if (anon_exclusive && - folio_try_share_anon_rmap_pte(folio, subpage)) { - folio_put_swap(folio, subpage); + if (!ttu_anon_swapbacked_folio(vma, folio, page, address, + pvmw.pte, pteval)) { set_pte_at(mm, address, pvmw.pte, pteval); goto walk_abort; } - mm_prepare_for_swap_entries(mm); - dec_mm_counter(mm, MM_ANONPAGES); - inc_mm_counter(mm, MM_SWAPENTS); - swp_pte = swp_entry_to_pte(entry); - if (anon_exclusive) - swp_pte = pte_swp_mkexclusive(swp_pte); - if (likely(pte_present(pteval))) { - if (pte_soft_dirty(pteval)) - swp_pte = pte_swp_mksoft_dirty(swp_pte); - if (pte_uffd(pteval)) - swp_pte = pte_swp_mkuffd(swp_pte); - } else { - if (pte_swp_soft_dirty(pteval)) - swp_pte = pte_swp_mksoft_dirty(swp_pte); - if (pte_swp_uffd(pteval)) - swp_pte = pte_swp_mkuffd(swp_pte); - } - set_pte_at(mm, address, pvmw.pte, swp_pte); + goto finish_unmap; } else { /* * This is a locked file-backed folio, @@ -2369,7 +2390,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, add_mm_counter(mm, mm_counter_file(folio), -nr_pages); } finish_unmap: - folio_remove_rmap_ptes(folio, subpage, nr_pages, vma); + folio_remove_rmap_ptes(folio, page, nr_pages, vma); if (vma->vm_flags & VM_LOCKED) mlock_drain_local(); folio_put_refs(folio, nr_pages); -- 2.43.0