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 8101C38657E for ; Tue, 1 Sep 2026 05:44:26 +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=1788241469; cv=none; b=Rbx9ELyJfae7Bsf0y7hMb0qiCyR7Izpi2OkAgkuKiguJ4gX0jjfWqgrvRdUpfUFRmur1O9HL911UdfiM3RYa+jzk8MKyuYf27YoYvtRJrAtrCm76r2omtaEe16zrlOuo4MZ6x5JwKHQb4F7Zy5X0r9PCEQ11LKWqmynAQ/0XWUs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788241469; c=relaxed/simple; bh=E2ktIYiViPu9MnUaU8AeLIAVoGUmKFh4+m0Y1CBWS4o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=RdXEH/Ncs8AcrV5xRaOTEWXfEzEZUw3Rt6mW4G5IFK8okfxiSBJJsN4ZLA16GiscxO2LjA8Y9h6Sdtc7+wi6IxKMRmXCQfwStue0hdwhHvf/m4fyYkJjuhgIZpdMpVx92PWMEwTbwMyH23lriC3UGDvEITSlSP+He6aAMCxaszY= 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=BK9TIEMF; 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="BK9TIEMF" 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 D70491756; Mon, 31 Aug 2026 22:44:21 -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 BF7153F85F; Mon, 31 Aug 2026 22:44:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1788241465; bh=E2ktIYiViPu9MnUaU8AeLIAVoGUmKFh4+m0Y1CBWS4o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BK9TIEMFCOEDM5tAyRTeOzg/0PPizZCgEpvn0On2eINATQ6RHoSeKLHTLRcmI4NGk VhIdCsAPgy2d2/fwOlTLKYpkwDAU69IXATxDssn/+V06oTCebY6DuU/YpX58ZU42MQ nYHTpOmHVwtSvuD0jemjfqhEb5b0A9nwHPq1z2Dk= 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 2/8] mm/swapfile: add batched version of folio_put_swap Date: Tue, 1 Sep 2026 05:43:49 +0000 Message-ID: <20260901054358.4049095-3-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> 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_put_swap_pages to handle a batch of consecutive pages. Note that folio_put_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_put_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_put_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/memory.c | 6 +++--- mm/rmap.c | 4 ++-- mm/shmem.c | 6 +++--- mm/swap.h | 17 +++++++++++++++-- mm/swapfile.c | 19 ++++++++++--------- 5 files changed, 33 insertions(+), 19 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 8b0c2c735d3de..6cfea4faf0588 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -5202,7 +5202,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) if (unlikely(folio != swapcache)) { folio_add_new_anon_rmap(folio, vma, address, RMAP_EXCLUSIVE); folio_add_lru_vma(folio, vma); - folio_put_swap(swapcache, NULL); + folio_put_swap(swapcache); } else if (!folio_test_anon(folio)) { /* * We currently only expect !anon folios that are fully @@ -5211,12 +5211,12 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) VM_WARN_ON_ONCE_FOLIO(folio_nr_pages(folio) != nr_pages, folio); VM_WARN_ON_ONCE_FOLIO(folio_mapped(folio), folio); folio_add_new_anon_rmap(folio, vma, address, rmap_flags); - folio_put_swap(folio, NULL); + folio_put_swap(folio); } else { VM_WARN_ON_ONCE(nr_pages != 1 && nr_pages != folio_nr_pages(folio)); folio_add_anon_rmap_ptes(folio, page, nr_pages, vma, address, rmap_flags); - folio_put_swap(folio, nr_pages == 1 ? page : NULL); + folio_put_swap_pages(folio, page, nr_pages); } VM_BUG_ON(!folio_test_anon(folio) || diff --git a/mm/rmap.c b/mm/rmap.c index 0a4aa06b66de6..1b9f07d4d1be9 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -2157,13 +2157,13 @@ static bool ttu_anon_swapbacked_folio(struct vm_area_struct *vma, * so we'll not check/care. */ if (arch_unmap_one(mm, vma, address, pteval) < 0) { - folio_put_swap(folio, page); + folio_put_swap_pages(folio, page, 1); return false; } /* See folio_try_share_anon_rmap(): clear PTE first. */ if (anon_exclusive && folio_try_share_anon_rmap_pte(folio, page)) { - folio_put_swap(folio, page); + folio_put_swap_pages(folio, page, 1); return false; } diff --git a/mm/shmem.c b/mm/shmem.c index 6cea018d69f04..316bf14136d63 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1733,7 +1733,7 @@ int shmem_writeout(struct swap_io_ctx *ctx, struct folio *folio, /* Swap entry might be erased by racing shmem_free_swap() */ if (!error) { shmem_recalc_inode(inode, 0, -nr_pages); - folio_put_swap(folio, NULL); + folio_put_swap(folio); } /* @@ -2163,7 +2163,7 @@ static void shmem_set_folio_swapin_error(struct inode *inode, pgoff_t index, nr_pages = folio_nr_pages(folio); folio_wait_writeback(folio); - folio_put_swap(folio, NULL); + folio_put_swap(folio); swap_cache_del_folio(folio); /* * Don't treat swapin error folio as alloced. Otherwise inode->i_blocks @@ -2393,7 +2393,7 @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index, if (sgp == SGP_WRITE) folio_mark_accessed(folio); - folio_put_swap(folio, NULL); + folio_put_swap(folio); swap_cache_del_folio(folio); folio_mark_dirty(folio); put_swap_device(si); diff --git a/mm/swap.h b/mm/swap.h index f52ecbedae8b8..0e0d00bf4daa6 100644 --- a/mm/swap.h +++ b/mm/swap.h @@ -246,7 +246,8 @@ extern int swap_retry_table_alloc(swp_entry_t entry, gfp_t gfp); int folio_alloc_swap(struct folio *folio); 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); +void folio_put_swap_pages(struct folio *folio, struct page *page, + unsigned long nr_pages); /* For internal use */ extern void __swap_cluster_free_entries(struct swap_info_struct *si, @@ -375,7 +376,8 @@ static inline int folio_dup_swap_pages(struct folio *folio, struct page *page, return -EINVAL; } -static inline void folio_put_swap(struct folio *folio, struct page *page) +static inline void folio_put_swap_pages(struct folio *folio, struct page *page, + unsigned long nr_pages) { } @@ -477,6 +479,17 @@ static inline int folio_dup_swap(struct folio *folio) folio_nr_pages(folio)); } +/** + * folio_put_swap() - Decrease swap count of all swap entries of a folio. + * @folio: folio with swap entries bound. + * + * See folio_put_swap_pages() for more information. + */ +static inline void folio_put_swap(struct folio *folio) +{ + folio_put_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 25bb6fc562c57..da5e66bdcef10 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1819,27 +1819,27 @@ int folio_dup_swap_pages(struct folio *folio, struct page *page, } /** - * folio_put_swap() - Decrease swap count of swap entries of a folio. + * folio_put_swap_pages() - Decrease swap count of swap entries of a folio. * @folio: folio with swap entries bounded, must be in swap cache and locked. - * @page: if not NULL, only decrease the swap count of this page. + * @page: the first page in the folio to decrease the swap count for. + * @nr_pages: the number of pages in the folio to decrease the swap count for. * * This won't free the swap slots even if swap count drops to zero, they are * still pinned by the swap cache. User may call folio_free_swap to free them. * Context: Caller must ensure the folio is locked and in the swap cache. */ -void folio_put_swap(struct folio *folio, struct page *page) +void folio_put_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); struct swap_info_struct *si = __swap_entry_to_info(entry); + 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; swap_put_entries_cluster(si, swp_offset(entry), nr_pages, false); } @@ -2518,7 +2518,8 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd, setpte: set_pte_at(vma->vm_mm, addr, pte, new_pte); - folio_put_swap(swapcache, folio_file_page(swapcache, swp_offset(entry))); + folio_put_swap_pages(swapcache, + folio_file_page(swapcache, swp_offset(entry)), 1); out: if (pte) pte_unmap_unlock(pte, ptl); -- 2.43.0