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h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PNexbu38UIpmS8ZurlXAd4ooPHyE+rz9wcSHywjpLXQ11yC1pGXoJoxDKsLldKMPV +zQiwWNDDMKDh/wdoVY1SIGQqe9pwaIOh9+AtTbNIYcDGDb7jywOncX7VWXlg2lV81 oRFQlx2HzlW0TrxUet4ELXPGTXdzPGfypmTHRvKo= From: Dev Jain To: akpm@linux-foundation.org, david@kernel.org, hughd@google.com, chrisl@kernel.org Cc: ljs@kernel.org, Liam.Howlett@oracle.com, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, kasong@tencent.com, qi.zheng@linux.dev, shakeel.butt@linux.dev, baohua@kernel.org, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, riel@surriel.com, harry@kernel.org, jannh@google.com, pfalcato@suse.de, baolin.wang@linux.alibaba.com, shikemeng@huaweicloud.com, nphamcs@gmail.com, bhe@redhat.com, youngjun.park@lge.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, ryan.roberts@arm.com, anshuman.khandual@arm.com, Dev Jain Subject: [PATCH v2 6/9] mm/swapfile: Add batched version of folio_dup_swap Date: Fri, 10 Apr 2026 16:02:01 +0530 Message-Id: <20260410103204.120409-7-dev.jain@arm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260410103204.120409-1-dev.jain@arm.com> References: <20260410103204.120409-1-dev.jain@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 12E3740005 X-Stat-Signature: m8c6a6ichjtb1pox6cet8bx6jpcpd11j X-HE-Tag: 1775817193-776104 X-HE-Meta: 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 RCAYrWt1 hB+s27ob0AYI5RZnXOxoEF/UZHz72BJlymQ+dPgBNEFad2+BHRAR3prXZOfO9ASj4H+Gr7LGDdrNGU8Y/Pu3NnWac9OE0jUNTYwLgr5e7eQKOSOc9VOH16wPQHfVZXS54f+sImE+guX0hfM5DMj9J2k13PgjbVBrk8s0IvzIvsN6esdjhO7Fr4cRjWu0aaGzj4RfszXuhO93VxRuGk4TX4sl7y128AqpQVSHTuXIWk37MaTl1uf1w4gHFj9qxtp6O5E26SDTlwVXMBJYyVSxGgCn3ZoeMGaPSZdio Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Add folio_dup_swap_pages to handle a batch of consecutive pages. Note that folio_dup_swap already can handle a subset of this: nr_pages == 1 and nr_pages == folio_nr_pages(folio). Generalize this to any nr_pages. Currently we have a not-so-nice logic of passing in subpage == NULL if we mean to exercise the logic on the entire folio, and subpage != NULL if we want to exercise the logic on only that subpage. Remove this indirection: the caller invokes folio_dup_swap_pages() if it wants to operate on a range of pages in the folio (i.e nr_pages may be anything between 1 till folio_nr_pages()), and invokes folio_dup_swap() if it wants to operate on the entire folio. Signed-off-by: Dev Jain --- mm/rmap.c | 2 +- mm/shmem.c | 2 +- mm/swap.h | 12 ++++++++++-- mm/swapfile.c | 20 ++++++++++++-------- 4 files changed, 24 insertions(+), 12 deletions(-) diff --git a/mm/rmap.c b/mm/rmap.c index 7a150edd96819..6412103fcd6cb 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -2311,7 +2311,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, goto finish_unmap; } - if (folio_dup_swap(folio, subpage) < 0) { + if (folio_dup_swap_pages(folio, subpage, 1) < 0) { set_pte_at(mm, address, pvmw.pte, pteval); goto walk_abort; } diff --git a/mm/shmem.c b/mm/shmem.c index 5aa43657886c3..3f9523c97b9ed 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1695,7 +1695,7 @@ int shmem_writeout(struct folio *folio, struct swap_iocb **plug, spin_unlock(&shmem_swaplist_lock); } - folio_dup_swap(folio, NULL); + folio_dup_swap(folio); shmem_delete_from_page_cache(folio, swp_to_radix_entry(folio->swap)); BUG_ON(folio_mapped(folio)); diff --git a/mm/swap.h b/mm/swap.h index a77016f2423b9..3c25f914e908b 100644 --- a/mm/swap.h +++ b/mm/swap.h @@ -206,7 +206,9 @@ extern int swap_retry_table_alloc(swp_entry_t entry, gfp_t gfp); * folio_put_swap(): does the opposite thing of folio_dup_swap(). */ int folio_alloc_swap(struct folio *folio); -int folio_dup_swap(struct folio *folio, struct page *subpage); +int folio_dup_swap(struct folio *folio); +int folio_dup_swap_pages(struct folio *folio, struct page *page, + unsigned long nr_pages); void folio_put_swap(struct folio *folio, struct page *subpage); /* For internal use */ @@ -390,7 +392,13 @@ static inline int folio_alloc_swap(struct folio *folio) return -EINVAL; } -static inline int folio_dup_swap(struct folio *folio, struct page *page) +static inline int folio_dup_swap(struct folio *folio) +{ + return -EINVAL; +} + +static inline int folio_dup_swap_pages(struct folio *folio, struct page *page, + unsigned long nr_pages) { return -EINVAL; } diff --git a/mm/swapfile.c b/mm/swapfile.c index ff315b752afd3..22be05a0bb200 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1740,9 +1740,10 @@ int folio_alloc_swap(struct folio *folio) } /** - * folio_dup_swap() - Increase swap count of swap entries of a folio. + * folio_dup_swap_pages() - Increase swap count of swap entries of a folio. * @folio: folio with swap entries bounded. - * @subpage: if not NULL, only increase the swap count of this subpage. + * @page: the first page in the folio to increase the swap count for. + * @nr_pages: the number of pages in the folio to increase the swap count for. * * Typically called when the folio is unmapped and have its swap entry to * take its place: Swap entries allocated to a folio has count == 0 and pinned @@ -1756,23 +1757,26 @@ int folio_alloc_swap(struct folio *folio) * swap_put_entries_direct on its swap entry before this helper returns, or * the swap count may underflow. */ -int folio_dup_swap(struct folio *folio, struct page *subpage) +int folio_dup_swap_pages(struct folio *folio, struct page *page, + unsigned long nr_pages) { swp_entry_t entry = folio->swap; - unsigned long nr_pages = folio_nr_pages(folio); VM_WARN_ON_FOLIO(!folio_test_locked(folio), folio); VM_WARN_ON_FOLIO(!folio_test_swapcache(folio), folio); - if (subpage) { - entry.val += folio_page_idx(folio, subpage); - nr_pages = 1; - } + entry.val += folio_page_idx(folio, page); return swap_dup_entries_cluster(swap_entry_to_info(entry), swp_offset(entry), nr_pages); } +int folio_dup_swap(struct folio *folio) +{ + return folio_dup_swap_pages(folio, folio_page(folio, 0), + folio_nr_pages(folio)); +} + /** * folio_put_swap() - Decrease swap count of swap entries of a folio. * @folio: folio with swap entries bounded, must be in swap cache and locked. -- 2.34.1