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t=1790255490; bh=GBTBAttj6YqnCR/uq6LNIwfyQljyiydrN9JFyuIuVt8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rKLdvoPcWH10UQwc6ZxfGlsPCWitBVRMqBo/pDpRBjg7890TBpz/IEflern/JSchq scRdr+IQOwuoDOtEZqFEUZ9GnAjXanwvxbjOPI0RB+K9XXhHdGFqrI4ustGAy6toDR hYJKQANAFQgq2qEgHl6lsXUoC0oztWYTDxsY/FhM= From: Dev Jain To: akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org, hughd@google.com, chrisl@kernel.org, kasong@tencent.com, davem@davemloft.net, andreas@gaisler.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, jgg@ziepe.ca, thuth@redhat.com, sparclinux@vger.kernel.org, ryan.roberts@arm.com, anshuman.khandual@arm.com Subject: [PATCH v3 1/9] mm/swapfile: add batched version of folio_dup_swap Date: Thu, 24 Sep 2026 13:09:29 +0000 Message-ID: <20260924131106.1730494-2-dev.jain@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260924131106.1730494-1-dev.jain@arm.com> References: <20260924131106.1730494-1-dev.jain@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 5D50C180015 X-Stat-Signature: e8xdrxjpimhk4j1h31r6mwzm4w9bow8j X-HE-Tag: 1790255491-967434 X-HE-Meta: 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 Aixanxuj WnO21KXP08Datj1LlPoksqMt977JPPwB4KTEeDTUG19uWcfWZJ2586yk5hEoK4VvoBAOXw+Xi12z7ahlS7LU1QVz1Lt72kmgeomvbMmNNVecXdz8uLz05MFCo+hkOzWxOU96xm6oNdlJowF6giabha4/+DvRCvvq3WbPIxiqTawCWib0h+ODDRozaGMphnKdoLKvmp6hfhgEWlxDWGOsdcymTzz2OdnkZUZ1AureC8aNgIv4zRbELc1BVcVnjSrTgD2wL57dSaCPHPV/Yg979AtCBkkkGWSKMmw4/XYLRL/h4bWXD4nUWY68waFAyHWi+XUju 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) Reviewed-by: Barry Song Signed-off-by: Dev Jain --- mm/rmap.c | 2 +- mm/shmem.c | 2 +- mm/swap.h | 18 ++++++++++++++++-- mm/swapfile.c | 18 ++++++++---------- 4 files changed, 26 insertions(+), 14 deletions(-) diff --git a/mm/rmap.c b/mm/rmap.c index 6661bc11ce658..a70dbc8d544e1 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -2150,7 +2150,7 @@ static bool ttu_anon_swapbacked_folio(struct vm_area_struct *vma, swp_entry_t entry = folio_page_swap_entry(folio, 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 b572c60f2af85..d5bd9506ce500 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1914,7 +1914,7 @@ 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 b3b54c28929a1..47290510de264 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; } @@ -464,6 +466,18 @@ 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 c1c5fbb3c909d..75167b8580cc0 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1799,9 +1799,10 @@ 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 @@ -1815,18 +1816,15 @@ 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); + swp_entry_t entry = folio_page_swap_entry(folio, page); + 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); - - if (page) { - entry = folio_page_swap_entry(folio, page); - nr_pages = 1; - } + VM_WARN_ON_FOLIO(idx + nr_pages > folio_nr_pages(folio), folio); return swap_dup_entries_cluster(swap_entry_to_info(entry), swp_offset(entry), nr_pages); -- 2.43.0