Re: [PATCH 04/21] mm: free_area_init: use maximal zone PFNs rather than zone sizes

[Greg Ungerer]

Hi Mike,

On 15/6/20 6:29 pm, Mike Rapoport wrote:
> (reduced the spam list)
>
> On Mon, Jun 15, 2020 at 05:17:28PM +1000, Greg Ungerer wrote:
> > On 15/6/20 4:22 pm, Mike Rapoport wrote:
> > > On Mon, Jun 15, 2020 at 01:53:42PM +1000, Greg Ungerer wrote:
> > > > From: Mike Rapoport <rppt@xxxxxxxxxxxxx>
> > > > > Currently, architectures that use free_area_init() to initialize memory map
> > > > > and node and zone structures need to calculate zone and hole sizes. We can
> > > > > use free_area_init_nodes() instead and let it detect the zone boundaries
> > > > > while the architectures will only have to supply the possible limits for
> > > > > the zones.
> > > > >
> > > > > Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxx>
> > > >
> > > > This is causing some new warnings for me on boot on at least one non-MMU m68k target:
> > >
> > > There were a couple of changes that cause this. The free_area_init()
> > > now relies on memblock data and architectural limits for zone sizes
> > > rather than on explisit pfns calculated by the arch code. I've update
> > > motorola variant and missed coldfire. Angelo sent a fix for mcfmmu.c
> > > [1] and I've updated it to include nommu as well
> > >
> > > [1] https://lore.kernel.org/linux-m68k/20200614225119.777702-1-angelo.dureghello@xxxxxxxxxxx
> > >
> > > >  From 55b8523df2a5c4565b132c0691990f0821040fec Mon Sep 17 00:00:00 2001
> > > From: Angelo Dureghello <angelo.dureghello@xxxxxxxxxxx>
> > > Date: Mon, 15 Jun 2020 00:51:19 +0200
> > > Subject: [PATCH] m68k: fix registration of memory regions with memblock
> > >
> > > Commit 3f08a302f533 ("mm: remove CONFIG_HAVE_MEMBLOCK_NODE_MAP option")
> > > introduced assumption that UMA systems have their memory at node 0 and
> > > updated most of them, but it forgot nommu and coldfire variants of m68k.
> > >
> > > The later change in free area initialization in commit fa3354e4ea39 ("mm:
> > > free_area_init: use maximal zone PFNs rather than zone sizes") exposed that
> > > and caused a lot of "BUG: Bad page state in process swapper" reports.
> >
> > Even with this patch applied I am still seeing the same messages.
>
> Argh, it was to early in the morning...
> Can you please try the one below?
>
> It seems that coldfire didn't register all its physical memory with
> memblock and the pfn list was damaged because of that.
>
>
> diff --git a/arch/m68k/kernel/setup_no.c b/arch/m68k/kernel/setup_no.c
> index e779b19e0193..f66f4b1d062e 100644
> --- a/arch/m68k/kernel/setup_no.c
> +++ b/arch/m68k/kernel/setup_no.c
> @@ -138,7 +138,8 @@ void __init setup_arch(char **cmdline_p)
>   	pr_debug("MEMORY -> ROMFS=0x%p-0x%06lx MEM=0x%06lx-0x%06lx\n ",
>   		 __bss_stop, memory_start, memory_start, memory_end);
>   
> -	memblock_add(memory_start, memory_end - memory_start);
> +	memblock_add(_rambase, memory_end - _rambase);
> +	memblock_reserve(_rambase, memory_start - _rambase);
>   
>   	/* Keep a copy of command line */
>   	*cmdline_p = &command_line[0];

Yep, thats got it. Boots clean again with this one.

Regards
Greg