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From: "David Hildenbrand (Arm)" <david@kernel.org>
To: Kaitao Cheng <kaitao.cheng@linux.dev>,
	Andy Lutomirski <luto@kernel.org>,
	Thomas Gleixner <tglx@kernel.org>, Ingo Molnar <mingo@redhat.com>,
	Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	x86@kernel.org, "H . Peter Anvin" <hpa@zytor.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Lorenzo Stoakes <ljs@kernel.org>,
	"Liam R . Howlett" <liam@infradead.org>,
	Vlastimil Babka <vbabka@kernel.org>,
	Mike Rapoport <rppt@kernel.org>,
	Suren Baghdasaryan <surenb@google.com>,
	Michal Hocko <mhocko@suse.com>, Kairui Song <kasong@tencent.com>,
	Qi Zheng <qi.zheng@linux.dev>,
	Shakeel Butt <shakeel.butt@linux.dev>,
	Barry Song <baohua@kernel.org>,
	Axel Rasmussen <axelrasmussen@google.com>,
	Yuanchu Xie <yuanchu@google.com>, Wei Xu <weixugc@google.com>,
	Muchun Song <muchun.song@linux.dev>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Kaitao Cheng <chengkaitao@kylinos.cn>
Subject: Re: [PATCH] mm: Add CONFIG_SPARSEMEM_CLASSIC
Date: Mon, 21 Sep 2026 12:34:48 +0200	[thread overview]
Message-ID: <0baf8c5f-1327-4cb1-867c-e0b08085b9d3@kernel.org> (raw)
In-Reply-To: <20260920070406.95354-1-kaitao.cheng@linux.dev>

On 9/20/26 09:04, Kaitao Cheng wrote:
> From: Kaitao Cheng <chengkaitao@kylinos.cn>
> 
> 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.

Sorry, but reading CONFIG_SPARSEMEM_CLASSIC I would have no idea how it relates
to VMEMMAP.

CONFIG_SPARSEMEM && !CONFIG_SPARSEMEM_VMEMMAP

is pretty clear in comparison.

-- 
Cheers,

David


  parent reply	other threads:[~2026-09-21 10:35 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-20  7:04 [PATCH] mm: Add CONFIG_SPARSEMEM_CLASSIC Kaitao Cheng
2026-09-20  9:59 ` Muchun Song
2026-09-21 10:34 ` David Hildenbrand (Arm) [this message]
2026-09-23  5:47   ` Anshuman Khandual

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