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a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1788241458; bh=ig7ZTYrfkjo7NzncPTcndZj/uDDh9JipwJASpm9qtRQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TbN/jnTt+Z5QixddOBXum3DzI2tgmG3n2627m9V+ny+gH5A+Z5kyLNEv8Llz7pZcA yYdms0gvFemF812GEqlwPInMFKiYyzF/9LfCQRigWvwhJRupHqMs6BPyu7Z3zkdyI5 XZnGhxgAubUd2LSoxxhUIREqTa3einEik3lSeLjA= 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 v2 1/8] mm/swapfile: add batched version of folio_dup_swap Date: Tue, 1 Sep 2026 05:43:48 +0000 Message-ID: <20260901054358.4049095-2-dev.jain@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260901054358.4049095-1-dev.jain@arm.com> References: <20260901054358.4049095-1-dev.jain@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 02BC8C0008 X-Stat-Signature: 5jajwhsq39ha4zbxniyrrw9iihscixgy X-Rspam-User: X-HE-Tag: 1788241458-277474 X-HE-Meta: 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 MiKIcS3t GOnyqCYuLl0y3m9GEonc3B6+1Hll25NFHNtHzEWQlQv149mZDcBl99UTtkjHXxFxbG8zfu39/yFm1isc0JLVD6nnW8W2il98bhOxLD3NYinVu0xyFgFBOgKtL2UUiyliVIYBFB8oGAYmJ5QSwFHkTFI/3ZWDhNucXQo0Cra0OfQe9lBIotRpCxenUCVGBOh59Yx9qsuNQSnXbufyJxYWWL7ningC3uN7I29oMZDXy/2HyjfRYjepq294rxH/AGKUtKiBTTRhHk6MdUr4rNjGRHeQIbiSo2m32zZOWwfHlwErDvDZFVtvJarum8VV+CnpE5/cS 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 Reviewed-by: Barry Song --- mm/rmap.c | 2 +- mm/shmem.c | 2 +- mm/swap.h | 18 ++++++++++++++++-- mm/swapfile.c | 16 ++++++++-------- 4 files changed, 26 insertions(+), 12 deletions(-) diff --git a/mm/rmap.c b/mm/rmap.c index 606c8ecf31302..0a4aa06b66de6 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 897fa2b61346f..6cea018d69f04 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1712,7 +1712,7 @@ 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 90a551a88df63..f52ecbedae8b8 100644 --- a/mm/swap.h +++ b/mm/swap.h @@ -244,7 +244,8 @@ 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 */ @@ -368,7 +369,8 @@ 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; } @@ -463,6 +465,18 @@ 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 53bf01d5f7f11..25bb6fc562c57 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 +1802,17 @@ 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); + unsigned long idx = folio_page_idx(folio, page); VM_WARN_ON_FOLIO(!folio_test_locked(folio), folio); VM_WARN_ON_FOLIO(!folio_test_swapcache(folio), folio); + VM_WARN_ON_FOLIO(idx + nr_pages > folio_nr_pages(folio), folio); - if (page) { - entry.val += folio_page_idx(folio, page); - nr_pages = 1; - } + entry.val += idx; return swap_dup_entries_cluster(swap_entry_to_info(entry), swp_offset(entry), nr_pages); -- 2.43.0