From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id A1F813DB31E for ; Thu, 23 Jul 2026 07:09:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784790570; cv=none; b=SMTXTLDgh4titloZZfVss0zI+L2s8tL3sYh2W0Kv99B1vmXfcv65+ijWd9jeyLIdM2QlD1vjFHRrf3mK+VN5NglOZGMvTZCNKN3uYpPH89fOlVLGcR1EJgVl+ihR7uHr2zt280KcHZRElF/kenocnqya3nM1y048i5WZh3nbqIk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784790570; c=relaxed/simple; bh=tDN5tu+oBractnjHZpB5YigDPChpchVDV6AVieAZKf4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=p8+TJnE/X+G2+4BHJeSL5fr0me1QJvnQAoldSLsSclspTO7Lvnqj0WPmHUml8/zaWawDjuya5c2Y4AWsROdTDG4Kbf+WLRmXOXdgF7RMzWLdOA3zUZb8z03yIl79EJwQUGcy7hpZwQZGNtTRdoKgdszmDZTWKmWYG9oBAoPPbWY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=dZYbH0sY; arc=none smtp.client-ip=217.140.110.172 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.b="dZYbH0sY" 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 C91251477; Thu, 23 Jul 2026 00:09:22 -0700 (PDT) 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 1A6A03F66F; Thu, 23 Jul 2026 00:09:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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) 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