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 31E7344C63 for ; Wed, 15 Oct 2025 00:03:14 +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=1760486594; cv=none; b=C5UQp4CnQIvrZC1kPkuABTpdC8+BZ/GyGjj1cd4l2ckbMg6KJtlVDi86ybfkiMsFMH5g07hSPSwm+04ArcRWW6hWV0eQteuApEIZrWENQzpkuj+p8iO4JHiLNn6W3p5DAjf81sQSmE2oMjiDx4Avd0n+A75y8VFmFPFPA2/tHU4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760486594; c=relaxed/simple; bh=CTg1aR4OIwf3N/DaxLdiMRQokmOFIk43VC+WhWs6kzc=; h=Date:To:From:Subject:Message-Id; b=PfcaVRJsd6nrdt70P97r8DSPRY5zCrxnpWe/qQ4tNzjGReYr2yP5mk/UyaKFl5/3OcfSJk1VVJCVJd86EQ7k8jzjhMwfugxOIgspzqa4sBB+OyCNRGkD2JzGvK/vQK+wLZ7GQODNy1vkFgaFDa8t4eOLTxxw3h3N3nbHJOSW42Y= 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=tyeamxoV; 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="tyeamxoV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CC59EC4CEE7; Wed, 15 Oct 2025 00:03:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1760486593; bh=CTg1aR4OIwf3N/DaxLdiMRQokmOFIk43VC+WhWs6kzc=; h=Date:To:From:Subject:From; b=tyeamxoVB4f2CDxi30DWCKSDgZq+/Xt/zfYUPbzTUmq4gHWbTFy/JNAdl1mTnOsrC WhOpl8Sq70HWm9APMyT/g4ozTQSrely7BNno4Qh+GXe3ibNBp3UF5x2A3dqW42s4DZ vig7zx/dnBO9QACvZvpd8hXVcL/AMyRiEWfe9RBE= Date: Tue, 14 Oct 2025 17:03:12 -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-optimize-and-simplify-folio-stat-update-after-split.patch added to mm-new branch Message-Id: <20251015000313.CC59EC4CEE7@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: Optimize and simplify folio stat update after split has been added to the -mm mm-new branch. Its filename is mm-huge_memory-optimize-and-simplify-folio-stat-update-after-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-optimize-and-simplify-folio-stat-update-after-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: Optimize and simplify folio stat update after split Date: Tue, 14 Oct 2025 13:46:04 +0000 The loop executed after a successful folio split currently has two combined responsibilities: * updating statistics for the new folios * determining the folio for the next split iteration. This commit refactors the logic to directly calculate and update folio statistics, eliminating the need for the iteration step. We can do this because all necessary information is already available: * All resulting new folios have the same order, which is @split_order. * The exact number of new folios can be calculated directly using @old_order and @split_order. * The folio for the subsequent split is simply the one containing @split_at. By leveraging this knowledge, we can achieve the stat update more cleanly and efficiently without the looping logic. Link: https://lkml.kernel.org/r/20251014134606.22543-4-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 | 18 ++++-------------- 1 file changed, 4 insertions(+), 14 deletions(-) --- a/mm/huge_memory.c~mm-huge_memory-optimize-and-simplify-folio-stat-update-after-split +++ a/mm/huge_memory.c @@ -3530,7 +3530,6 @@ 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; - struct folio *next; int split_order; folio_clear_has_hwpoisoned(folio); @@ -3542,9 +3541,8 @@ static int __split_unmapped_folio(struct for (split_order = start_order; split_order >= new_order; split_order--) { - struct folio *end_folio = folio_next(folio); int old_order = folio_order(folio); - struct folio *new_folio; + int new_folios = 1UL << (old_order - split_order); /* order-1 anonymous folio is not supported */ if (is_anon && split_order == 1) @@ -3573,19 +3571,11 @@ static int __split_unmapped_folio(struct pgalloc_tag_split(folio, old_order, split_order); __split_folio_to_order(folio, old_order, split_order); - if (is_anon) + if (is_anon) { mod_mthp_stat(old_order, MTHP_STAT_NR_ANON, -1); - /* - * Iterate through after-split folios and update folio stats. - */ - for (new_folio = folio; new_folio != end_folio; new_folio = next) { - next = folio_next(new_folio); - if (new_folio == page_folio(split_at)) - folio = new_folio; - if (is_anon) - mod_mthp_stat(folio_order(new_folio), - MTHP_STAT_NR_ANON, 1); + mod_mthp_stat(split_order, MTHP_STAT_NR_ANON, new_folios); } + folio = page_folio(split_at); } return 0; _ 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