Re: [PATCH 3.5] arm: make initialization of zero page independent of the memory map (was Re: [PATCH v2 22/28] arch, mm: consolidate initialization of nodes, zones and memory map)

Andrew Morton <[email protected]> Thu, 8 Jan 2026 11:19:19 -0800
Newsgroups org.kernel.vger.linux-hexagon,dev.linux.lists.loongarch,org.infradead.lists.linux-riscv,org.infradead.lists.linux-snps-arc,org.infradead.lists.linux-um,org.kernel.vger.linux-alpha,org.kernel.vger.linux-csky,org.kernel.vger.linux-cxl,org.kernel.vger.linux-doc,org.kernel.vger.linux-kernel,org.kernel.vger.linux-m68k,org.kernel.vger.linux-mips,org.kernel.vger.linux-openrisc,org.kernel.vger.linux-parisc,org.kernel.vger.linux-s390,org.kernel.vger.linux-sh,org.kernel.vger.sparclinux,org.kvack.linux-mm,org.ozlabs.lists.linuxppc-dev
Message-ID <[email protected]> 
On Sun, 4 Jan 2026 14:01:40 +0200 Mike Rapoport <[email protected]> wrote:

> Can you please stick this between patch 3 (arm: introduce
> arch_zone_limits_init()) and patch 4 (arm64: introduce
> arch_zone_limits_init())?

Did, thanks.  I made this a standalone patch rather than  a
squashable -fix.

> >From 35d016bbf5da7c08cc5c5547c85558fc50cb63aa Mon Sep 17 00:00:00 2001
> From: Klara Modin <[email protected]>
> Date: Sat, 3 Jan 2026 20:40:09 +0200
> Subject: [PATCH] arm: make initialization of zero page independent of the
>  memory map
> 
> Unlike most architectures, arm keeps a struct page pointer to the
> empty_zero_page and to initialize it requires conversion of a virtual
> address to page which makes it necessary to have memory map initialized
> before creating the empty_zero_page.
> 
> Make empty_zero_page a stataic array in BSS to decouple it's
> initialization from the initialization of the memory map.
> 
> This also aligns arm with vast majorty of architectures.

Russell, can you please update us on your concerns with this change?