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 03D8C3B6C09 for ; Sun, 27 Sep 2026 05:51:30 +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=1790488292; cv=none; b=HlA4k5o8Z/8BL08DIftNNqhXeBhsJ8GofR4ZrT+ck0//MsJYqLRg6E9VO5z3IdU2Y8EvAOgiAOdmkWlRLLNDq8p86n+/YDr8rchvaCZgEK68lIJJKufWFRk04ZSRrbU+eG7G5mF2+iAw+got+RLfbAN8LB/EhVan/+mayhkECIk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790488292; c=relaxed/simple; bh=q9TwriU9B681MlCpOjGxiZCeQxnsQVeU4GXBU3sYLc4=; h=Date:To:From:Subject:Message-Id; b=Qc00+4AMs8QOqFURBbjdx7as5sd1QllMiGlIB3+mzea4TX/EGeGl7c7loucJbajDGKeJBG7/WJogT3ynjhYUUQvylwQ7UaG6YNG1k8JIUhYLE/Y9eW2tyi48ASqHdZ8a/MRYCTOMykpSHlrVyBnEB/0N16FjqsN95J5hv7h7bik= 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=tzBUkBh6; 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="tzBUkBh6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 868171F000FF; Sun, 27 Sep 2026 05:51:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1790488290; bh=udUY4qIo44eiFQVRuKbWJroGMBQ6E8Yj8/UEaK0SkFA=; h=Date:To:From:Subject; b=tzBUkBh60YiC5a8oLMbk0eoz9dNm9niFXdOpGmJ+oHu5PtOGX/8gP0WTVVKk5eTRv vfjyCUSjxhxCRChBN73m1t/wYLhBXpEUCBe5DsWs5f+W77uTZT6fN1lL12MVBkUZ5t kfr5dP4PSwq1OWhEiwM8rXxhJmkSI/kXf3ucsYJI= Date: Sat, 26 Sep 2026 22:51:30 -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: <20260927055130.868171F000FF@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: Sun, 27 Sep 2026 10:54:33 +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/20260927025441.741633-5-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: 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 @@ -217,7 +217,10 @@ 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-move-vmemmap-optimization-helpers-to-a-public-header.patch powerpc-mm-switch-device-dax-to-shared-tail-vmemmap-pages.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