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b=OGl6sOykpiKuUGpPHYNW3WsssRjASb58n/v+6w4wigNQnm45sUm2cXaKSfDidrUzc 3TMlGcU+6HxYy/Jz0JrMmF0OXfYgOwsVli/Au+F95g7+6yZqMB1dzhm/kT1e7TAhaF wiWO6tTmG+eE7AMFB2xAgFpPM69bTpivyA2TtibNIODXgjpLPDpwJfFTxpW5YU1+hX QheZ8hXHu3X3v9IkQYbhwGTa8myw0VrgXcri6E12B5sXkN8KaS5NMP91RUY/lr/U7w +AUgO3bx8yrsyWyqinrp/OtkE9SGuDz8msiUUTfvnvXCfpj7tF+M8ZJA1+Z12a0d28 5r6D8VDXA1OhA== Message-ID: <1221180d-6217-401f-a479-3a5d9684659e@kernel.org> Date: Tue, 7 Jul 2026 16:26:03 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 4/5] mm/rmap: refactor anon swapbacked folio unmap in try_to_unmap_one To: Dev Jain , akpm@linux-foundation.org, ljs@kernel.org, muchun.song@linux.dev, osalvador@suse.de Cc: 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 References: <20260707121128.373192-1-dev.jain@arm.com> <20260707121128.373192-5-dev.jain@arm.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 5E97840006 X-Stat-Signature: b4kadbnq6dyj85u1otyzh7ibgikkqtb7 X-HE-Tag: 1783434369-553877 X-HE-Meta: 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 kLW5YZs1 0tb0nxKFxUmPHI9g43a7FPUIpWfy93pp7HelyI7EyJrvqyK2MPAlHzn4HQIAC2faJY2wlbK10hHtuySsVJ6ckCLpojmuXaYtAl6skOxCVWUx5X7aEOg3W7zPmuGlhyMrFMIcaHOdFz3GBvANhz5BvQBcu9RHNW6zuBEZRk8fresAakzdC9qzuVGL5f3R4dKqT4/iIF27A0YjiNfbgFLDkShdzjkudo2xAorI4GOowR+Elro2y24JBIz/3erSQyG5MsZxg2An5JwnxoJtqHrMwi4fk95E42I+P9HAHuBHKkOc3o4CfNdEUgV6OY2MGjXf89PpoQuyiCHEgiYmbh77YaGHZlKFP8mWeBJlxaUsyF4qTsJY= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 7/7/26 14:11, Dev Jain wrote: > Refactor anonymous swapbacked folio unmap to ttu_anon_swapbacked_folio(). > > No functional change intended. > > Signed-off-by: Dev Jain > --- > mm/rmap.c | 105 ++++++++++++++++++++++++++++++++---------------------- > 1 file changed, 62 insertions(+), 43 deletions(-) > > diff --git a/mm/rmap.c b/mm/rmap.c > index 00b571c2a1bab..ade78df5be2bd 100644 > --- a/mm/rmap.c > +++ b/mm/rmap.c > @@ -2113,6 +2113,64 @@ static inline bool ttu_anon_lazyfree_folio(struct vm_area_struct *vma, > return true; > } > BTW, no need for the "inline" for most of these functions (applies to other patches as well). > +static inline void set_swp_pte_at(struct mm_struct *mm, unsigned long address, > + pte_t *ptep, swp_entry_t entry, pte_t pteval, bool anon_exclusive) It's confusing that we say "set_swp_pte_at", but the pte_t we was is actually the old pte. Can we instead have a function that creates us a swap_pte from the other data, and then do the set_pte_at() in the caller? static pte_t swp_pte_prepare(...) { ... return swp_pte; } > +{ > + pte_t 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_wp(pteval)) > + swp_pte = pte_swp_mkuffd_wp(swp_pte); > + } else { > + /* Device-exclusive entry */ > + if (pte_swp_soft_dirty(pteval)) > + swp_pte = pte_swp_mksoft_dirty(swp_pte); > + if (pte_swp_uffd_wp(pteval)) > + swp_pte = pte_swp_mkuffd_wp(swp_pte); > + } > + > + set_pte_at(mm, address, ptep, swp_pte); > +} > + > +static inline bool ttu_anon_swapbacked_folio(struct vm_area_struct *vma, struct folio *folio, > + struct page *subpage, unsigned long address, pte_t *ptep, Subpages do not exist :) > + pte_t pteval) > +{ > + bool anon_exclusive = folio_test_anon(folio) && PageAnonExclusive(subpage); const? > + swp_entry_t entry = page_swap_entry(subpage); > + struct mm_struct *mm = vma->vm_mm; > + > + if (folio_dup_swap(folio, subpage) < 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, subpage); > + return false; > + } > + > + /* 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); I recall I stumbled over this before, but there is no way to undo the arch_unmap_one(), right? > + return false; > + } > + > + mm_prepare_for_swap_entries(mm); > + dec_mm_counter(mm, MM_ANONPAGES); > + inc_mm_counter(mm, MM_SWAPENTS); > + set_swp_pte_at(mm, address, ptep, entry, pteval, anon_exclusive); > + return true; > +} > + -- Cheers, David