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

[Greg Ungerer]

Hi Mike,

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.

Regards
Greg



> Using memblock_add_node() with nid = 0 to register memory banks solves the
> problem.
>
> Fixes: 3f08a302f533 ("mm: remove CONFIG_HAVE_MEMBLOCK_NODE_MAP option")
> Fixes: fa3354e4ea39 ("mm: free_area_init: use maximal zone PFNs rather than zone sizes")
> Signed-off-by: Angelo Dureghello <angelo.dureghello@xxxxxxxxxxx>
> Co-developed-by: Mike Rapoport <rppt@xxxxxxxxxxxxx>
> Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxx>
> ---
>   arch/m68k/kernel/setup_no.c | 2 +-
>   arch/m68k/mm/mcfmmu.c       | 2 +-
>   2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/m68k/kernel/setup_no.c b/arch/m68k/kernel/setup_no.c
> index e779b19e0193..0c4589a39ba9 100644
> --- a/arch/m68k/kernel/setup_no.c
> +++ b/arch/m68k/kernel/setup_no.c
> @@ -138,7 +138,7 @@ 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_node(memory_start, memory_end - memory_start, 0);
>   
>   	/* Keep a copy of command line */
>   	*cmdline_p = &command_line[0];
> diff --git a/arch/m68k/mm/mcfmmu.c b/arch/m68k/mm/mcfmmu.c
> index 29f47923aa46..7d04210d34f0 100644
> --- a/arch/m68k/mm/mcfmmu.c
> +++ b/arch/m68k/mm/mcfmmu.c
> @@ -174,7 +174,7 @@ void __init cf_bootmem_alloc(void)
>   	m68k_memory[0].addr = _rambase;
>   	m68k_memory[0].size = _ramend - _rambase;
>   
> -	memblock_add(m68k_memory[0].addr, m68k_memory[0].size);
> +	memblock_add_node(m68k_memory[0].addr, m68k_memory[0].size, 0);
>   
>   	/* compute total pages in system */
>   	num_pages = PFN_DOWN(_ramend - _rambase);