From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0EEFA25A2C8 for ; Wed, 26 Feb 2025 21:14:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740604476; cv=none; b=tmlq5A1sTN98EyjE2X1mx2XFMrO781zXH0PAqzC2lXJERvBfElGPbbJrtM9142Pi83XgBXVd7wvlXm0S8bkQ4tqgYma92QqvwH/u8MiORX0N35vgLvn14BQp36gcxx21l4t5w71yTTuogZHP5hh/p7vNVscQ8eBX9RNHYRF8+6A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740604476; c=relaxed/simple; bh=3vjd7AnlI6lBCNJFumPRX7ZtyXgQsofAFalK4ry2vPQ=; h=Date:To:From:Subject:Message-Id; b=fGRgdPOFfyZZ0TULBG+dOM/1XZJUd9gpwKu2Uvna/pilbyBurFn6do03nL0ty9rlQwSPJcXZEeioIX9gtiUgbj9En6lrL9FAg0ggrTxRLxYA9puvyAGqd3oltXPT/BcGIBG5i2h7DQetOMQZ75UkbQHZewOTJg7AG4IJq1bahJU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=Clc8XgUf; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="Clc8XgUf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 748E2C4CED6; Wed, 26 Feb 2025 21:14:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1740604474; bh=3vjd7AnlI6lBCNJFumPRX7ZtyXgQsofAFalK4ry2vPQ=; h=Date:To:From:Subject:From; b=Clc8XgUf87z0y3pOZ/EARibLM7qYmUeWfMWdJNOz/7+cELSa8akMjO5s8G6JT35cY TDAn0A24tv9mS4zaKKLE5ylaI15pBDyGQKrcaiOBEX9/L5j0GP1iVCMyavGiIlzIK0 fI2yzEOnGucKhOka8zKzIl9zRv48A0Z614ngvRr4= Date: Wed, 26 Feb 2025 13:14:33 -0800 To: mm-commits@vger.kernel.org,yuzhao@google.com,yang@os.amperecomputing.com,willy@infradead.org,wangkefeng.wang@huawei.com,ryan.roberts@arm.com,linmiaohe@huawei.com,kirill.shutemov@linux.intel.com,kasong@tencent.com,jhubbard@nvidia.com,hughd@google.com,david@redhat.com,baolin.wang@linux.alibaba.com,ziy@nvidia.com,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-huge_memory-move-folio-split-common-code-to-__folio_split.patch added to mm-unstable branch Message-Id: <20250226211434.748E2C4CED6@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm/huge_memory: move folio split common code to __folio_split() has been added to the -mm mm-unstable branch. Its filename is mm-huge_memory-move-folio-split-common-code-to-__folio_split.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-huge_memory-move-folio-split-common-code-to-__folio_split.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Zi Yan Subject: mm/huge_memory: move folio split common code to __folio_split() Date: Wed, 26 Feb 2025 16:00:26 -0500 This is a preparation patch for folio_split(). In the upcoming patch folio_split() will share folio unmapping and remapping code with split_huge_page_to_list_to_order(), so move the code to a common function __folio_split() first. Link: https://lkml.kernel.org/r/20250226210032.2044041-4-ziy@nvidia.com Signed-off-by: Zi Yan Cc: Baolin Wang Cc: David Hildenbrand Cc: Hugh Dickins Cc: John Hubbard Cc: Kefeng Wang Cc: Kirill A. Shuemov Cc: Matthew Wilcox Cc: Miaohe Lin Cc: Ryan Roberts Cc: Yang Shi Cc: Yu Zhao Cc: Kairui Song Signed-off-by: Andrew Morton --- mm/huge_memory.c | 107 +++++++++++++++++++++++---------------------- 1 file changed, 57 insertions(+), 50 deletions(-) --- a/mm/huge_memory.c~mm-huge_memory-move-folio-split-common-code-to-__folio_split +++ a/mm/huge_memory.c @@ -3847,57 +3847,9 @@ after_split: return ret; } -/* - * This function splits a large folio into smaller folios of order @new_order. - * @page can point to any page of the large folio to split. The split operation - * does not change the position of @page. - * - * Prerequisites: - * - * 1) The caller must hold a reference on the @page's owning folio, also known - * as the large folio. - * - * 2) The large folio must be locked. - * - * 3) The folio must not be pinned. Any unexpected folio references, including - * GUP pins, will result in the folio not getting split; instead, the caller - * will receive an -EAGAIN. - * - * 4) @new_order > 1, usually. Splitting to order-1 anonymous folios is not - * supported for non-file-backed folios, because folio->_deferred_list, which - * is used by partially mapped folios, is stored in subpage 2, but an order-1 - * folio only has subpages 0 and 1. File-backed order-1 folios are supported, - * since they do not use _deferred_list. - * - * After splitting, the caller's folio reference will be transferred to @page, - * resulting in a raised refcount of @page after this call. The other pages may - * be freed if they are not mapped. - * - * If @list is null, tail pages will be added to LRU list, otherwise, to @list. - * - * Pages in @new_order will inherit the mapping, flags, and so on from the - * huge page. - * - * Returns 0 if the huge page was split successfully. - * - * Returns -EAGAIN if the folio has unexpected reference (e.g., GUP) or if - * the folio was concurrently removed from the page cache. - * - * Returns -EBUSY when trying to split the huge zeropage, if the folio is - * under writeback, if fs-specific folio metadata cannot currently be - * released, or if some unexpected race happened (e.g., anon VMA disappeared, - * truncation). - * - * Callers should ensure that the order respects the address space mapping - * min-order if one is set for non-anonymous folios. - * - * Returns -EINVAL when trying to split to an order that is incompatible - * with the folio. Splitting to order 0 is compatible with all folios. - */ -int split_huge_page_to_list_to_order(struct page *page, struct list_head *list, - unsigned int new_order) +static int __folio_split(struct folio *folio, unsigned int new_order, + struct page *page, struct list_head *list) { - struct folio *folio = page_folio(page); struct deferred_split *ds_queue = get_deferred_split_queue(folio); /* reset xarray order to new order after split */ XA_STATE_ORDER(xas, &folio->mapping->i_pages, folio->index, new_order); @@ -4107,6 +4059,61 @@ out: return ret; } +/* + * This function splits a large folio into smaller folios of order @new_order. + * @page can point to any page of the large folio to split. The split operation + * does not change the position of @page. + * + * Prerequisites: + * + * 1) The caller must hold a reference on the @page's owning folio, also known + * as the large folio. + * + * 2) The large folio must be locked. + * + * 3) The folio must not be pinned. Any unexpected folio references, including + * GUP pins, will result in the folio not getting split; instead, the caller + * will receive an -EAGAIN. + * + * 4) @new_order > 1, usually. Splitting to order-1 anonymous folios is not + * supported for non-file-backed folios, because folio->_deferred_list, which + * is used by partially mapped folios, is stored in subpage 2, but an order-1 + * folio only has subpages 0 and 1. File-backed order-1 folios are supported, + * since they do not use _deferred_list. + * + * After splitting, the caller's folio reference will be transferred to @page, + * resulting in a raised refcount of @page after this call. The other pages may + * be freed if they are not mapped. + * + * If @list is null, tail pages will be added to LRU list, otherwise, to @list. + * + * Pages in @new_order will inherit the mapping, flags, and so on from the + * huge page. + * + * Returns 0 if the huge page was split successfully. + * + * Returns -EAGAIN if the folio has unexpected reference (e.g., GUP) or if + * the folio was concurrently removed from the page cache. + * + * Returns -EBUSY when trying to split the huge zeropage, if the folio is + * under writeback, if fs-specific folio metadata cannot currently be + * released, or if some unexpected race happened (e.g., anon VMA disappeared, + * truncation). + * + * Callers should ensure that the order respects the address space mapping + * min-order if one is set for non-anonymous folios. + * + * Returns -EINVAL when trying to split to an order that is incompatible + * with the folio. Splitting to order 0 is compatible with all folios. + */ +int split_huge_page_to_list_to_order(struct page *page, struct list_head *list, + unsigned int new_order) +{ + struct folio *folio = page_folio(page); + + return __folio_split(folio, new_order, page, list); +} + int min_order_for_split(struct folio *folio) { if (folio_test_anon(folio)) _ Patches currently in -mm which might be from ziy@nvidia.com are selftests-mm-make-file-backed-thp-split-work-by-writing-pmd-size-data.patch mm-huge_memory-allow-split-shmem-large-folio-to-any-lower-order.patch selftests-mm-test-splitting-file-backed-thp-to-any-lower-order.patch xarray-add-xas_try_split-to-split-a-multi-index-entry.patch mm-huge_memory-add-two-new-not-yet-used-functions-for-folio_split.patch mm-huge_memory-move-folio-split-common-code-to-__folio_split.patch mm-huge_memory-add-buddy-allocator-like-non-uniform-folio_split.patch mm-huge_memory-remove-the-old-unused-__split_huge_page.patch mm-huge_memory-add-folio_split-to-debugfs-testing-interface.patch mm-truncate-use-buddy-allocator-like-folio-split-for-truncate-operation.patch selftests-mm-add-tests-for-folio_split-buddy-allocator-like-split.patch mm-filemap-use-xas_try_split-in-__filemap_add_folio.patch mm-shmem-use-xas_try_split-in-shmem_split_large_entry.patch mm-shmem-use-xas_try_split-in-shmem_split_large_entry-fix.patch