From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 7F83F3C81AD for ; Wed, 30 Sep 2026 19:01:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790794906; cv=none; b=p34yNaX4boZio7lOhR44ZkCPc/gQVtPRjxISQCNFAUjpnoDBfGhXxLJFfBi7LYcSt6+ZpWhLs2uoEUSvYPuz7w5I/g92MFG/zmG/ZXGS97OUjFtsl/jxezXv+7oYBOTXxIH9lddA9znYV0HVAplNoWmTt3ytLh/uPy1ULPrdHSg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790794906; c=relaxed/simple; bh=GJl9cJIuMQMSoMBl9TTrhCu9svM2dFpeEa3szQ930OQ=; h=Date:To:From:Subject:Message-Id; b=Sz30PN9tqXTSg5HlsRpEv0sVQwGqhvfj5CwDflC6Cum4K468qOstXLKaGptIUDD977FF89ilxGkfNk5rEY9g1S3MBDe9lQuA7A6+LIz10+DZXRC5+gg3Bbtra8ocWa39TUL0vHq/wf4IRk9F2ACH7jd6Y7xpJ7KPnEHsaIuOaDY= 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=d8YlBTSj; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="d8YlBTSj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 092831F00898; Wed, 30 Sep 2026 19:01:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1790794905; bh=8q3CUeXuRQTT6L+uwSVgG/xdEp6CccuFiO259ysFhrA=; h=Date:To:From:Subject; b=d8YlBTSj1NWJD2mJJMREDuuGIYaIG83womHxcsoyCJJ+HJoZcUaYHprRTtxnIJ6jB lbbLJ5oSC5LvQyrpDWTlqL3yK5DZYGckDZXP2i9WRObM9yLtdNL7CNqMYKFzDTEl6e zgSkhr47uZVqFE6a4FXUf6oBonUNbCXWAupZbS2s= Date: Wed, 30 Sep 2026 12:01:44 -0700 To: mm-commits@vger.kernel.org,muchun.song@linux.dev,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-sparse-vmemmap-open-code-init_compound_tail.patch added to mm-unstable branch Message-Id: <20260930190145.092831F00898@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm/sparse-vmemmap: open-code init_compound_tail() has been added to the -mm mm-unstable branch. Its filename is mm-sparse-vmemmap-open-code-init_compound_tail.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-sparse-vmemmap-open-code-init_compound_tail.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 various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: Muchun Song Subject: mm/sparse-vmemmap: open-code init_compound_tail() Date: Wed, 30 Sep 2026 22:06:19 +0800 init_compound_tail() is only used by vmemmap_shared_tail_page(), where the shared tail page setup intentionally passes NULL as the compound head. Keeping this helper in mm/internal.h exposes that special case to the rest of the MM code and can make the NULL head argument look generally valid. Open-code the initialization at the only call site so the special-case use stays local to sparse vmemmap optimization. No functional change intended. Link: https://lore.kernel.org/20260930140627.57431-5-songmuchun@bytedance.com Signed-off-by: Muchun Song Signed-off-by: Andrew Morton Acked-by: Qi Zheng Acked-by: David Hildenbrand (Arm) Acked-by: Mike Rapoport (Microsoft) Cc: Oscar Salvador Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Jonathan Corbet Cc: Lorenzo Stoakes Cc: Nicholas Piggin Cc: Christophe Leroy Cc: Ritesh Harjani (IBM) Cc: Shrikanth Hegde Cc: Randy Dunlap Cc: Lance Yang --- mm/internal.h | 9 --------- mm/sparse-vmemmap.c | 5 ++++- 2 files changed, 4 insertions(+), 10 deletions(-) --- a/mm/internal.h~mm-sparse-vmemmap-open-code-init_compound_tail +++ a/mm/internal.h @@ -786,15 +786,6 @@ static inline void prep_compound_tail(st VM_WARN_ON_ONCE(tail->private); } -static inline void init_compound_tail(struct page *tail, - const struct page *head, unsigned int order, struct zone *zone) -{ - atomic_set(&tail->_mapcount, -1); - set_page_node(tail, zone_to_nid(zone)); - set_page_zone(tail, zone_idx(zone)); - prep_compound_tail(tail, head, order); -} - #if defined CONFIG_COMPACTION || defined CONFIG_CMA /* --- a/mm/sparse-vmemmap.c~mm-sparse-vmemmap-open-code-init_compound_tail +++ a/mm/sparse-vmemmap.c @@ -221,7 +221,10 @@ struct page __ref *vmemmap_shared_tail_p for (int i = 0; i < PAGE_SIZE / sizeof(struct page); i++) { page = (struct page *)addr + i; mm_zero_struct_page(page); - init_compound_tail(page, NULL, order, zone); + atomic_set(&page->_mapcount, -1); + set_page_node(page, zone_to_nid(zone)); + set_page_zone(page, zone_idx(zone)); + prep_compound_tail(page, NULL, order); } page = virt_to_page(addr); _ Patches currently in -mm which might be from muchun.song@linux.dev are mm-sparse-vmemmap-factor-out-shared-vmemmap-tail-page-allocation.patch mm-sparse-vmemmap-allocate-shared-tail-page-array-dynamically.patch mm-sparse-vmemmap-introduce-config_vmemmap_optimization.patch mm-sparse-vmemmap-open-code-init_compound_tail.patch mm-sparse-vmemmap-prepare-dax-vmemmap-population-for-compound-page-orders.patch mm-sparse-vmemmap-set-compound-page-order-for-device-dax.patch mm-sparse-vmemmap-switch-device-dax-to-shared-tail-vmemmap-pages.patch mm-sparse-vmemmap-switch-device-dax-to-shared-tail-vmemmap-pages-fix.patch mm-sparse-vmemmap-move-vmemmap-optimization-helpers-to-a-public-header.patch powerpc-mm-switch-device-dax-to-shared-tail-vmemmap-pages.patch powerpc-mm-switch-device-dax-to-shared-tail-vmemmap-pages-fix.patch mm-sparse-vmemmap-drop-the-extra-tail-page-from-device-dax-reservation.patch mm-sparse-vmemmap-drop-unused-section_nr_vmemmap_pages-arguments.patch documentation-mm-update-dax-vmemmap-deduplication-docs.patch mm-sparse-vmemmap-drop-vmemmap_populate_dax.patch mm-sparse-vmemmap-support-device-dax-in-common-vmemmap-path.patch mm-sparse-vmemmap-drop-device-dax-specific-population-path.patch mm-sparse-vmemmap-remove-the-unused-ptpfn-argument.patch mm-sparse-vmemmap-open-code-vmemmap_populate_address.patch mm-mm_init-add-zone-mismatch-warning-during-page-init.patch