From: "Vlastimil Babka (SUSE)" <vbabka@kernel.org>
To: Brendan Jackman <jackmanb@google.com>,
Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
David Hildenbrand <david@kernel.org>, Wei Xu <weixugc@google.com>,
Johannes Weiner <hannes@cmpxchg.org>, Zi Yan <ziy@nvidia.com>,
Lorenzo Stoakes <ljs@kernel.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, x86@kernel.org,
rppt@kernel.org, Sumit Garg <sumit.garg@oss.qualcomm.com>,
derkling@google.com, reijiw@google.com,
Will Deacon <will@kernel.org>,
rientjes@google.com, patrick.roy@linux.dev, "Itazuri,
Takahiro" <itazur@amazon.co.uk>,
Andy Lutomirski <luto@kernel.org>,
David Kaplan <david.kaplan@amd.com>,
Thomas Gleixner <tglx@kernel.org>, Yosry Ahmed <yosry@kernel.org>
Subject: Re: [PATCH v2 12/22] mm: add definitions for allocating unmapped pages
Date: Mon, 11 May 2026 20:01:53 +0200 [thread overview]
Message-ID: <2efea0a2-0c3a-40b5-9f76-dc0613725b0b@kernel.org> (raw)
In-Reply-To: <20260320-page_alloc-unmapped-v2-12-28bf1bd54f41@google.com>
On 3/20/26 19:23, Brendan Jackman wrote:
> Create __GFP_UNMAPPED, which requests pages that are not present in the
> direct map. Since this feature has a cost (e.g. more freelists), it's
> behind a kconfig. Unlike other conditionally-defined GFP flags, it
> doesn't fall back to being 0. This prevents building code that uses
> __GFP_UNMAPPED but doesn't depend on the necessary kconfig, since that
> would lead to invisible security issues.
>
> Create a freetype flag to record that pages on the freelists with this
> flag are unmapped. This is currently only needed for MIGRATE_UNMOVABLE
> pages, so the freetype encoding remains trivial.
>
> Also create the corresponding pageblock flag to record the same thing.
>
> To keep patches from being too overwhelming, the actual implementation
> is added separately, this is just types, Kconfig boilerplate, etc.
>
> Signed-off-by: Brendan Jackman <jackmanb@google.com>
Aside from the gfp vs internal flag decision, seems fine.
Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
next prev parent reply other threads:[~2026-05-11 18:02 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20260320-page_alloc-unmapped-v2-0-28bf1bd54f41@google.com>
[not found] ` <20260320-page_alloc-unmapped-v2-8-28bf1bd54f41@google.com>
2026-05-11 13:46 ` [PATCH v2 08/22] mm: introduce for_each_free_list() Vlastimil Babka (SUSE)
[not found] ` <20260320-page_alloc-unmapped-v2-9-28bf1bd54f41@google.com>
2026-05-11 13:51 ` [PATCH v2 09/22] mm/page_alloc: don't overload migratetype in find_suitable_fallback() Vlastimil Babka (SUSE)
2026-05-11 16:44 ` Brendan Jackman
2026-05-11 16:53 ` Vlastimil Babka (SUSE)
[not found] ` <20260320-page_alloc-unmapped-v2-11-28bf1bd54f41@google.com>
2026-05-11 15:35 ` [PATCH v2 11/22] mm: move migratetype definitions to freetype.h Vlastimil Babka (SUSE)
[not found] ` <20260320-page_alloc-unmapped-v2-12-28bf1bd54f41@google.com>
2026-05-11 18:01 ` Vlastimil Babka (SUSE) [this message]
[not found] ` <20260320-page_alloc-unmapped-v2-13-28bf1bd54f41@google.com>
2026-05-11 18:07 ` [PATCH v2 13/22] mm: rejig pageblock mask definitions Vlastimil Babka (SUSE)
[not found] ` <20260320-page_alloc-unmapped-v2-10-28bf1bd54f41@google.com>
2026-05-11 15:34 ` [PATCH v2 10/22] mm: introduce freetype_t Vlastimil Babka (SUSE)
2026-05-11 16:49 ` Brendan Jackman
2026-05-11 16:58 ` Vlastimil Babka (SUSE)
2026-05-11 18:17 ` Vlastimil Babka (SUSE)
2026-05-11 18:26 ` Vlastimil Babka (SUSE)
[not found] ` <20260320-page_alloc-unmapped-v2-14-28bf1bd54f41@google.com>
2026-05-11 18:29 ` [PATCH v2 14/22] mm: encode freetype flags in pageblock flags Vlastimil Babka (SUSE)
[not found] ` <20260320-page_alloc-unmapped-v2-15-28bf1bd54f41@google.com>
2026-05-11 18:30 ` [PATCH v2 15/22] mm/page_alloc: remove ifdefs from pindex helpers Vlastimil Babka (SUSE)
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