From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=217.140.110.172 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794753569; b=TPxwfTUlsclckA6KSgMZiQYfbXJepsiqbjaNXdp5jTZTTUGipn3k8SijTQ1JdO3399lW oEF36BtOD1H4oj5S8QZrx5TMikjB/1u85Z9TnNENNXVuMbLuYn8I/JtS/W4k8wjmJ12ok cZ6u/3BHl/kb1N5UbB9OBFnWthGw0IZ6U9ut2FGv7wXDUQSapN4olVLmWwcMEx+h4v4fW D9zDkx3pWDRL1biQ1KpkGRGk8YSoimfYPb1UKvaAnIEUxdIGCtmp52+Kh7NtPZ8JU9tNw qGCqdqr/3zoc35z6kRxl6ZFVr5qdyPRerc+5wP7kACY0XHcY2uaupqRK7WvRFI/UU4Q== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794753569; h=DMARC-Filter:Received:Received:DKIM-Signature:From:To:Cc:Subject: Date:Message-ID:X-Mailer:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=TskDAOAWXEo8flmJwWvmjXmj7YUn6WxOmJxYrefk24E=; b=cSuQyUN0t6tVbYomeDMmA3vah9KPhsVLbS9nOnu8ImWF4XYuZ+1cuEXed4u213HvdPtT 14ERU0Hu5KpclvdgZlORFxveIaTLVztYp61LIOOeKLF8pz2TjbAQRtZTcvV5589NtYI/t q8Vqmdzrhmu8O31jtnjperAZ+UB4NMXPdabgOORe8k/+3yeNLiZIMYK34pKe0pBGL1lrr PcGfVW7aRfOhhgkssZ7WzJ7LZ6saBxpBPw4gYTYQz7+AHBeUPk/px8dXq5S+1UndX76q2 rwYMMf5OAfDxwFt3NyZE6tGuBqjI8vnTI1y2daogXhSXIHXZ5Ilj/eTp1whyFtuy8dg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=dGY+3TkQ; arc=none smtp.remote-ip=217.140.110.172 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 83B05606A31D; Sun, 15 Nov 2026 14:39:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 83B05606A31D Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=dGY+3TkQ Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D88F71476; Sun, 15 Nov 2026 06:39:24 -0800 (PST) Received: from cesw-amp-gbt-1s-m12830-01.blr.arm.com (cesw-amp-gbt-1s-m12830-01.blr.arm.com [10.164.195.33]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 1063F3F85F; Sun, 15 Nov 2026 06:39:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1794753567; bh=IRV0Se7ac+aPU1wxdxXwDgPgVOJdcgTy6K/y0/wG5B4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dGY+3TkQ+VgGngptslyasnoZpm9Yj8NS4w09ek+LZL0mTIqzRaBpDUc5jGG1Ed2DJ sK0OjKBZDEwa/YRcNoZGJYHYfM12KtRPersett9Qx4i6pCmZCotZU5wPk66mu+m+no xl6d9kcEV3X3vFYAMzmNuk6f62viZZPOPADhEKpY= From: Dev Jain To: david@kernel.org, ljs@kernel.org, akpm@linux-foundation.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, anshuman.khandual@arm.com, geert@linux-m68k.org, sparclinux@vger.kernel.org, ryan.roberts@arm.com Subject: [PATCH v4 1/9] mm/swapfile: add batched version of folio_dup_swap Date: Sun, 15 Nov 2026 14:38:56 +0000 Message-ID: <20261115143905.3045084-2-dev.jain@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20261115143905.3045084-1-dev.jain@arm.com> References: <20261115143905.3045084-1-dev.jain@arm.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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: Kairui Song 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 0faef46806e5c..512a3a1c63c73 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -2165,7 +2165,7 @@ 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 4686875a3adde..e3db6e45cae0c 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1958,7 +1958,7 @@ int shmem_writeout(struct swap_io_ctx *ctx, struct folio *folio, */ shmem_disallow_eviction(info); - 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 d488a69c28091..cbcfd587aac1a 100644 --- a/mm/swap.h +++ b/mm/swap.h @@ -245,7 +245,8 @@ 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 */ @@ -387,7 +388,8 @@ 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; } @@ -489,6 +491,18 @@ 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)); +} + static inline bool swap_cache_folio_mappable(struct folio *folio, unsigned int nr_pages) { diff --git a/mm/swapfile.c b/mm/swapfile.c index fcda5eba17140..d46cb1cf6469d 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1860,9 +1860,10 @@ 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 @@ -1876,18 +1877,15 @@ 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