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 EDFA944C63 for ; Wed, 15 Oct 2025 00:03:11 +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=1760486592; cv=none; b=o9ENj/vphdTWHzTcZlZn1QKG9f0iVe3Z5L/5PWRFlRmQ/mr40L5xhv6ru7UTCynwYMj+uyVfPL5dd1UgqXZsCE9HWwoPmVY8qKOJ7wpdzpqPtNqzCc5xhtw1Ip1iYH88i+yWFAt0iBRw+P6jrZe0uA51xP8scl9atL6fFwWIVUQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760486592; c=relaxed/simple; bh=UvXFDlzLZSmH4lX3Ut0nkdf4h37QR4bjUp0r6cE496M=; h=Date:To:From:Subject:Message-Id; b=aH14ctMZ+KzagHuemGYtc9Xmp7qvjUZbznECct3kqizFVCGf/KQe8YFWgpfpw6/0EksKlcV3IdaEQz9lnPzNSaCqD0GMK5RETaeHlLnKKKhKATesjRFynAfF8iWYg/+DERWkb+3KnC5sEia9mKFwo5CnI3/iZUt4rvgibUJ23Z8= 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=Si9oBDhL; 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="Si9oBDhL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 69387C4CEE7; Wed, 15 Oct 2025 00:03:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1760486591; bh=UvXFDlzLZSmH4lX3Ut0nkdf4h37QR4bjUp0r6cE496M=; h=Date:To:From:Subject:From; b=Si9oBDhLnnl9CtJNl9IIJFp//+lEtWZ5CS8B458G2XALubSPOAoOGZXBuRjulLN+G Gm2JZvF2i2SNEsOyYO2NYetBlafV0VuPAkLiYcHITQkmXoxeo4rXmJ9eO3RqEJzWsx bs6gqYnQtO5+iHBaX8egUKBGCkxaHjPsHkbjFGTw= Date: Tue, 14 Oct 2025 17:03:10 -0700 To: mm-commits@vger.kernel.org,ziy@nvidia.com,ryan.roberts@arm.com,npache@redhat.com,lorenzo.stoakes@oracle.com,liam.howlett@oracle.com,lance.yang@linux.dev,dev.jain@arm.com,david@redhat.com,baolin.wang@linux.alibaba.com,baohua@kernel.org,richard.weiyang@gmail.com,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-huge_memory-update-folio-stat-after-successful-split.patch added to mm-new branch Message-Id: <20251015000311.69387C4CEE7@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: update folio stat after successful split has been added to the -mm mm-new branch. Its filename is mm-huge_memory-update-folio-stat-after-successful-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-update-folio-stat-after-successful-split.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. 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: Wei Yang Subject: mm/huge_memory: update folio stat after successful split Date: Tue, 14 Oct 2025 13:46:03 +0000 When a folio is successfully split, its statistics must be updated. The current implementation complicates this process: * It iterates over the resulting new folios. * It uses a flag (@stop_split) to conditionally skip updating the stat for the folio at @split_at during the loop. * It then attempts to update the skipped stat on a subsequent failure path. This logic is unnecessarily hard to follow. This commit refactors the code to update the folio statistics only after a successful split. This makes the logic much cleaner and sets the stage for further simplification of the stat-handling code. Link: https://lkml.kernel.org/r/20251014134606.22543-3-richard.weiyang@gmail.com Signed-off-by: Wei Yang Cc: Zi Yan Cc: Baolin Wang Cc: Barry Song Cc: David Hildenbrand Cc: Dev Jain Cc: Lance Yang Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Mariano Pache Cc: Ryan Roberts Signed-off-by: Andrew Morton --- mm/huge_memory.c | 44 +++++++++++--------------------------------- 1 file changed, 11 insertions(+), 33 deletions(-) --- a/mm/huge_memory.c~mm-huge_memory-update-folio-stat-after-successful-split +++ a/mm/huge_memory.c @@ -3530,13 +3530,8 @@ static int __split_unmapped_folio(struct bool is_anon = folio_test_anon(folio); int order = folio_order(folio); int start_order = uniform_split ? new_order : order - 1; - bool stop_split = false; struct folio *next; int split_order; - int ret = 0; - - if (is_anon) - mod_mthp_stat(order, MTHP_STAT_NR_ANON, -1); folio_clear_has_hwpoisoned(folio); @@ -3545,7 +3540,7 @@ static int __split_unmapped_folio(struct * folio is split to new_order directly. */ for (split_order = start_order; - split_order >= new_order && !stop_split; + split_order >= new_order; split_order--) { struct folio *end_folio = folio_next(folio); int old_order = folio_order(folio); @@ -3568,49 +3563,32 @@ static int __split_unmapped_folio(struct else { xas_set_order(xas, folio->index, split_order); xas_try_split(xas, folio, old_order); - if (xas_error(xas)) { - ret = xas_error(xas); - stop_split = true; - } + if (xas_error(xas)) + return xas_error(xas); } } - if (!stop_split) { - folio_split_memcg_refs(folio, old_order, split_order); - split_page_owner(&folio->page, old_order, split_order); - pgalloc_tag_split(folio, old_order, split_order); - - __split_folio_to_order(folio, old_order, split_order); - } + folio_split_memcg_refs(folio, old_order, split_order); + split_page_owner(&folio->page, old_order, split_order); + pgalloc_tag_split(folio, old_order, split_order); + __split_folio_to_order(folio, old_order, split_order); + if (is_anon) + mod_mthp_stat(old_order, MTHP_STAT_NR_ANON, -1); /* * Iterate through after-split folios and update folio stats. - * But in buddy allocator like split, the folio - * containing the specified page is skipped until its order - * is new_order, since the folio will be worked on in next - * iteration. */ for (new_folio = folio; new_folio != end_folio; new_folio = next) { next = folio_next(new_folio); - /* - * for buddy allocator like split, new_folio containing - * @split_at page could be split again, thus do not - * change stats yet. Wait until new_folio's order is - * @new_order or stop_split is set to true by the above - * xas_split() failure. - */ - if (new_folio == page_folio(split_at)) { + if (new_folio == page_folio(split_at)) folio = new_folio; - if (split_order != new_order && !stop_split) - continue; - } if (is_anon) mod_mthp_stat(folio_order(new_folio), MTHP_STAT_NR_ANON, 1); } } - return ret; + return 0; } bool non_uniform_split_supported(struct folio *folio, unsigned int new_order, _ Patches currently in -mm which might be from richard.weiyang@gmail.com are mm-compaction-check-the-range-to-pageblock_pfn_to_page-is-within-the-zone-first.patch mm-compaction-fix-the-range-to-pageblock_pfn_to_page.patch mm-huge_memory-add-pmd-folio-to-ds_queue-in-do_huge_zero_wp_pmd.patch mm-khugepaged-unify-pmd-folio-installation-with-map_anon_folio_pmd.patch mm-huge_memory-only-get-folio_order-once-during-__folio_split.patch mm-huge_memory-cache-folio-attribute-in-__split_unmapped_folio.patch mm-huge_memory-update-folio-stat-after-successful-split.patch mm-huge_memory-optimize-and-simplify-folio-stat-update-after-split.patch mm-huge_memory-optimize-old_order-derivation-during-folio-splitting.patch mm-huge_memory-remove-redundant-split_order-=-new_order-check-in-uniform_split.patch