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d=arm.com; s=foss; t=1784790567; bh=tDN5tu+oBractnjHZpB5YigDPChpchVDV6AVieAZKf4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dZYbH0sYmLklBeRi1wZluPY5iB0EU9QWe8P/nYRI8oP0+uaKu4Kw6MsKYc6nR/Amr HCs77DiyIm+NqqZ1/g63b6DiHXyUHWl8L2qLYcX3uwIwb+mLHj0T4tvrBGbg+tMDw6 QavgdV+80EpAxxo2xRSTI8wYVVh4Fi54cBMwvoEE= From: Dev Jain To: akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org, hughd@google.com, chrisl@kernel.org, kasong@tencent.com Cc: Dev Jain , riel@surriel.com, liam@infradead.org, vbabka@kernel.org, harry@kernel.org, jannh@google.com, lance.yang@linux.dev, baolin.wang@linux.alibaba.com, shikemeng@huaweicloud.com, nphamcs@gmail.com, baoquan.he@linux.dev, baohua@kernel.org, youngjun.park@lge.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, pfalcato@suse.de, ryan.roberts@arm.com, anshuman.khandual@arm.com Subject: [PATCH 1/8] mm/swapfile: add batched version of folio_dup_swap Date: Thu, 23 Jul 2026 07:08:57 +0000 Message-ID: <20260723070905.3422276-2-dev.jain@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260723070905.3422276-1-dev.jain@arm.com> References: <20260723070905.3422276-1-dev.jain@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 1B60340009 X-Stat-Signature: y33aed9w1urfpp5o655br49sz9k4ubom X-Rspam-User: X-HE-Tag: 1784790567-53202 X-HE-Meta: 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 Urfz5b0P Lx2vKcjG4j7Qq6Yj5nYvX6zLJvxhMN5rAtQ1ybPMvni8eqnPLp1RkFSFwmpWBD7B3Ls0veYHyYXKarD/Jj+Qk3uiJB25dKec1BXP62BR6cPfrbc9Rthni44FzIrpeHPbJKksAvE0ZtzD6sJhyxeAKjN5a6GAA9m1eeZc08kBrQOiP1S/fSmlwOBt+l/SulxFEzCqoe8U1nmRiJwsPe76YNIZer0dFaoUdgk7vt8HFMMP6zmRjvolPnJosoJSR44Q8eO67LG4Unp/rN19Mj98sOMnXbyOqntVvlqE7MaewmWiiQTBJWh9f+TIJpgjCOz59CZr/ 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 and folio_nr_pages()), and invokes folio_dup_swap() if it wants to operate on the entire folio. Acked-by: David Hildenbrand (Arm) Signed-off-by: Dev Jain --- mm/rmap.c | 2 +- mm/shmem.c | 2 +- mm/swap.h | 18 ++++++++++++++++-- mm/swapfile.c | 14 ++++++-------- 4 files changed, 24 insertions(+), 12 deletions(-) diff --git a/mm/rmap.c b/mm/rmap.c index b7ead3e9f0641..4ca809a596dfe 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -2148,7 +2148,7 @@ static bool ttu_anon_swapbacked_folio(struct vm_area_struct *vma, swp_entry_t entry = page_swap_entry(page); struct mm_struct *mm = vma->vm_mm; - if (folio_dup_swap(folio, page) < 0) + if (folio_dup_swap_pages(folio, page, 1) < 0) return false; /* diff --git a/mm/shmem.c b/mm/shmem.c index 5071177059a96..501365158f8d8 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1698,7 +1698,7 @@ int shmem_writeout(struct swap_io_ctx *ctx, struct folio *folio, 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 abd26588abd22..bbf665a33014b 100644 --- a/mm/swap.h +++ b/mm/swap.h @@ -251,7 +251,8 @@ 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 *page); +int folio_dup_swap_pages(struct folio *folio, struct page *page, + unsigned long nr_pages); void folio_put_swap(struct folio *folio, struct page *page); /* For internal use */ @@ -375,7 +376,8 @@ 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_pages(struct folio *folio, struct page *page, + unsigned long nr_pages) { return -EINVAL; } @@ -470,6 +472,18 @@ static inline void __swap_cache_replace_folio(struct swap_cluster_info *ci, } #endif /* CONFIG_SWAP */ +/** + * folio_dup_swap() - Increase swap count of all swap entries of a folio. + * @folio: folio with swap entries bound. + * + * See folio_dup_swap_pages() for more information. + */ +static inline int folio_dup_swap(struct folio *folio) +{ + return folio_dup_swap_pages(folio, folio_page(folio, 0), + folio_nr_pages(folio)); +} + extern const struct swap_ops swap_bdev_ops; int shmem_writeout(struct swap_io_ctx *ctx, struct folio *folio, diff --git a/mm/swapfile.c b/mm/swapfile.c index 5d15913dcf863..0709a6266cf1f 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1785,9 +1785,10 @@ 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. - * @page: if not NULL, only increase the swap count of this page. + * @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 @@ -1801,18 +1802,15 @@ 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 *page) +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 (page) { - entry.val += folio_page_idx(folio, page); - 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); -- 2.43.0