From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8ACFDC982CC for ; Sun, 20 Sep 2026 07:04:44 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 78EEE6B0088; Sun, 20 Sep 2026 03:04:43 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 740396B008A; Sun, 20 Sep 2026 03:04:43 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6555A6B008C; Sun, 20 Sep 2026 03:04:43 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 3E2CE6B0088 for ; Sun, 20 Sep 2026 03:04:43 -0400 (EDT) Received: from smtpin27.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay05.hostedemail.com (Postfix) with ESMTP id B1DEE403BC for ; Sun, 20 Sep 2026 07:04:42 +0000 (UTC) X-FDA: 85233252804.27.87BB16B Received: from mta0.migadu.com (out-94.mta0.migadu.com [91.218.175.94]) by imf16.hostedemail.com (Postfix) with ESMTP id A89BA180007 for ; Sun, 20 Sep 2026 07:04:40 +0000 (UTC) Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=YcGvSh8Q; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf16.hostedemail.com: domain of kaitao.cheng@linux.dev designates 91.218.175.94 as permitted sender) smtp.mailfrom=kaitao.cheng@linux.dev ARC-Authentication-Results: i=1; imf16.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=YcGvSh8Q; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf16.hostedemail.com: domain of kaitao.cheng@linux.dev designates 91.218.175.94 as permitted sender) smtp.mailfrom=kaitao.cheng@linux.dev ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1789887881; b=SV4+wvtl+sJADoAEol6yNvhP3xLoOuI05GsnUWSaNoHxWjWzc6bsynFsoGfakbHoFi4WpQ wLWxxLEq9O/nD4eLSRhv0502tc6psLGeJxrycA05ZnoPdiC2OJE9tQQWC8xszEJFjW9yKQ vQqwf1FYg7LJroz9B52ywESfe85DtW8= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1789887881; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:references:dkim-signature; bh=bM6amltTQhBYPAMN5a79kJyFJcFla3bjsxZnRyljbew=; b=HCTjfNVxhZ1W2YIoTGWktx8IV4STgXlspsL3wVo95HNKt55hpfuXJ833/id+oCqjgeHFXc iXPT/hdeAVN3lbYdFSQjKbWneSZmkskPmF/eWWHlUjKSWN/4LHmFEOh+R1iUrVUIwTCfSz NRqmPS3AbvVb6PUk1/hIUNy2sf3VdLA= X-Envelope-To: linux-mm@kvack.org DKIM-Signature: a=rsa-sha256; bh=jIL5Xm0hBwRJq72+13iYyBKNUWWSaRe7RMggUGRje9U=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1789887878; v=1; x=1790492678; b=YcGvSh8QsWadQB0J+34j8xfNqv5nMkEJSQzAOxQT6GAzk8K1uktWkjhY03kKaFJz7dxoRUCD rQqNQRrnpZVQNk65eQLwAsmc5OlJjgJiMStY9eZRQHOzUS8JblST78ioZGc2cBXaErh3S+Df0LT 9ZHr4fF0IRbyMTNgTsWAe5hE= X-Envelope-To: linux-mm@kvack.org Received: by smtp.migadu.com with ESMTPS id cd1bdbb1ac128f27; Sun, 20 Sep 2026 07:04:38 +0000 X-Mizu-Trace-ID: cd1bdbb1ac128f27 X-Migadu-Flow: FLOW_OUT From: Kaitao Cheng To: Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H . Peter Anvin" , Andrew Morton , David Hildenbrand , Lorenzo Stoakes , "Liam R . Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Kairui Song , Qi Zheng , Shakeel Butt , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Muchun Song Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Kaitao Cheng Subject: [PATCH] mm: Add CONFIG_SPARSEMEM_CLASSIC Date: Sun, 20 Sep 2026 15:04:06 +0800 Message-ID: <20260920070406.95354-1-kaitao.cheng@linux.dev> X-Mailer: git-send-email 2.54.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Queue-Id: A89BA180007 X-Stat-Signature: 4idgnmx6osm17rh8ke8ik3mnbhtwzzr3 X-Rspamd-Server: rspam01 X-HE-Tag: 1789887880-679261 X-HE-Meta: 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 B48s7hGM THObDiNenwk65v+GKq/Kg1I96h+o5p5cU3bOD+baOBBZifkgCKSF/WQCnf/628iO3T7/mVbQxte23WJBsxdYJWsbnjtVYpVzwmJfOZABp2rQHGKDV0ukrLa8F3DxKZFq98V3OKP26tHe2y2yx9r2oq+poTlGBJXEmk4u8KVydg8bGWueGUM5ilsJjsr+Hb/5LMWLjrf/peHvp3lmdS6t19KF+lWqxGgIzOzV+yUU4JhjVNs4C/CWPd2UVZRb7YFT+DQVMTfTtM5H7BXubyS1tC3O9XA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Kaitao Cheng Several MM paths identify classic sparse memory by testing CONFIG_SPARSEMEM while also testing that CONFIG_SPARSEMEM_VMEMMAP is disabled. Repeating the compound condition obscures the memory model being selected and requires the local SECTION_IN_PAGE_FLAGS alias for the same state. Add CONFIG_SPARSEMEM_CLASSIC as a hidden derived option and use it at the conditional sites. Remove SECTION_IN_PAGE_FLAGS and test the new option directly. The x86 32-bit vDSO build starts with the x86_64 configuration and then undefines CONFIG_SPARSEMEM_VMEMMAP to emulate a 32-bit configuration. Kconfig-derived symbols are not recomputed by the C preprocessor, so define CONFIG_SPARSEMEM_CLASSIC there when CONFIG_SPARSEMEM is enabled. This preserves the existing behavior. Signed-off-by: Kaitao Cheng --- arch/x86/entry/vdso/vdso32/fake_32bit_build.h | 3 +++ include/linux/mm.h | 12 ++++-------- include/linux/mmzone.h | 2 +- include/linux/page-flags-layout.h | 2 +- mm/Kconfig | 3 +++ mm/util.c | 2 +- 6 files changed, 13 insertions(+), 11 deletions(-) diff --git a/arch/x86/entry/vdso/vdso32/fake_32bit_build.h b/arch/x86/entry/vdso/vdso32/fake_32bit_build.h index 72a92cb9b53d..3e07389c4d2b 100644 --- a/arch/x86/entry/vdso/vdso32/fake_32bit_build.h +++ b/arch/x86/entry/vdso/vdso32/fake_32bit_build.h @@ -20,6 +20,9 @@ #define CONFIG_PAGE_OFFSET 0 #define CONFIG_ILLEGAL_POINTER_VALUE 0 #define CONFIG_NR_CPUS 1 +#ifdef CONFIG_SPARSEMEM +#define CONFIG_SPARSEMEM_CLASSIC 1 +#endif #define BUILD_VDSO32_64 diff --git a/include/linux/mm.h b/include/linux/mm.h index ae56d6a2c9f9..b786ee73a20f 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -201,7 +201,7 @@ static inline void __mm_zero_struct_page(struct page *page) extern unsigned long sysctl_user_reserve_kbytes; extern unsigned long sysctl_admin_reserve_kbytes; -#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP) +#ifdef CONFIG_SPARSEMEM_CLASSIC bool page_range_contiguous(const struct page *page, unsigned long nr_pages); #else static inline bool page_range_contiguous(const struct page *page, @@ -2531,10 +2531,6 @@ static inline bool is_nommu_shared_vma_flags(const vma_flags_t *flags) } #endif -#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP) -#define SECTION_IN_PAGE_FLAGS -#endif - /* * The identification function is mainly used by the buddy allocator for * determining if two pages could be buddies. We are not really identifying @@ -2805,7 +2801,7 @@ static inline struct zone *folio_zone(const struct folio *folio) return &folio_pgdat(folio)->node_zones[folio_zonenum(folio)]; } -#ifdef SECTION_IN_PAGE_FLAGS +#ifdef CONFIG_SPARSEMEM_CLASSIC static inline void set_page_section(struct page *page, unsigned long section) { page->flags.f &= ~(SECTIONS_MASK << SECTIONS_PGSHIFT); @@ -2823,7 +2819,7 @@ static inline unsigned long memdesc_section(const memdesc_flags_t *mdf) ASSERT_EXCLUSIVE_BITS(mdf->f, SECTIONS_MASK << SECTIONS_PGSHIFT); return (mdf->f >> SECTIONS_PGSHIFT) & SECTIONS_MASK; } -#else /* !SECTION_IN_PAGE_FLAGS */ +#else /* !CONFIG_SPARSEMEM_CLASSIC */ static inline void set_page_section_from_pfn(struct page *page, unsigned long pfn) { @@ -2833,7 +2829,7 @@ static inline unsigned long memdesc_section(const memdesc_flags_t *mdf) { return 0; } -#endif /* SECTION_IN_PAGE_FLAGS */ +#endif /* CONFIG_SPARSEMEM_CLASSIC */ /** * folio_pfn - Return the Page Frame Number of a folio. diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index ebbda6f31139..c83529ad6e35 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -68,7 +68,7 @@ * memory sections). */ #define MAX_FOLIO_ORDER MAX_PAGE_ORDER -#elif defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP) +#elif defined(CONFIG_SPARSEMEM_CLASSIC) /* * Only pages within a single memory section are guaranteed to be * contiguous. By limiting folios to a single memory section, all folio diff --git a/include/linux/page-flags-layout.h b/include/linux/page-flags-layout.h index 760006b1c480..536003b364a7 100644 --- a/include/linux/page-flags-layout.h +++ b/include/linux/page-flags-layout.h @@ -49,7 +49,7 @@ * " plus space for last_cpupid: | SECTION | NODE | ZONE | LAST_CPUPID ... | FLAGS | * classic sparse no space for node: | SECTION | ZONE | ... | FLAGS | */ -#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP) +#ifdef CONFIG_SPARSEMEM_CLASSIC #define SECTIONS_WIDTH SECTIONS_SHIFT #else #define SECTIONS_WIDTH 0 diff --git a/mm/Kconfig b/mm/Kconfig index 30170a936f1f..c7bbcf086f21 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -461,6 +461,9 @@ config SPARSEMEM_VMEMMAP pfn_to_page and page_to_pfn operations. This is the most efficient option when sufficient kernel resources are available. +config SPARSEMEM_CLASSIC + def_bool SPARSEMEM && !SPARSEMEM_VMEMMAP + config VMEMMAP_OPTIMIZATION bool depends on SPARSEMEM_VMEMMAP diff --git a/mm/util.c b/mm/util.c index c5ee52aede1e..6910b47ca415 100644 --- a/mm/util.c +++ b/mm/util.c @@ -1590,7 +1590,7 @@ unsigned int folio_pte_batch(struct folio *folio, pte_t *ptep, pte_t pte, } #endif /* CONFIG_MMU */ -#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP) +#ifdef CONFIG_SPARSEMEM_CLASSIC /** * page_range_contiguous - test whether the page range is contiguous * @page: the start of the page range. -- 2.54.0 (Apple Git-157)