On 6/13/2022 4:21 PM, Wupeng Ma wrote:
> From: Ma Wupeng <mawupeng1@xxxxxxxxxx>
>
> If system have some mirrored memory and mirrored feature is not specified
> in boot parameter, the basic mirrored feature will be enabled and this will
> lead to the following situations:
>
> - memblock memory allocation prefers mirrored region. This may have some
> unexpected influence on numa affinity.
>
> - contiguous memory will be split into several parts if parts of them
> is mirrored memory via memblock_mark_mirror().
>
> To fix this, variable mirrored_kernelcore will be checked in
> memblock_mark_mirror(). Mark mirrored memory with flag MEMBLOCK_MIRROR iff
> kernelcore=mirror is added in the kernel parameters.
>
> Signed-off-by: Ma Wupeng <mawupeng1@xxxxxxxxxx>
> ---
> mm/internal.h | 2 ++
> mm/memblock.c | 3 +++
> mm/page_alloc.c | 2 +-
> 3 files changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/mm/internal.h b/mm/internal.h
> index c0f8fbe0445b..ddd2d6a46f1b 100644
> --- a/mm/internal.h
> +++ b/mm/internal.h
> @@ -861,4 +861,6 @@ struct folio *try_grab_folio(struct page *page, int refs, unsigned int flags);
>
> DECLARE_PER_CPU(struct per_cpu_nodestat, boot_nodestats);
>
> +extern bool mirrored_kernelcore;
> +
> #endif /* __MM_INTERNAL_H */
> diff --git a/mm/memblock.c b/mm/memblock.c
> index b1d2a0009733..a9f18b988b7f 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -924,6 +924,9 @@ int __init_memblock memblock_clear_hotplug(phys_addr_t base, phys_addr_t size)
> */
> int __init_memblock memblock_mark_mirror(phys_addr_t base, phys_addr_t size)
> {
> + if (!mirrored_kernelcore)
> + return 0;
> +
> system_has_some_mirror = true;
>
> return memblock_setclr_flag(base, size, 1, MEMBLOCK_MIRROR);
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index e008a3df0485..9b030aeb4983 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -356,7 +356,7 @@ static unsigned long required_kernelcore_percent __initdata;
> static unsigned long required_movablecore __initdata;
> static unsigned long required_movablecore_percent __initdata;
> static unsigned long zone_movable_pfn[MAX_NUMNODES] __initdata;
> -static bool mirrored_kernelcore __meminitdata;
> +bool mirrored_kernelcore __initdata;
__initdata here is not suitable and will lead to compile warnings.
In my test, __initdata_memblock and ro_after_init are both fine, but I am not
sure which one to choose? Do you have any idea on this?
>
> /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
> int movable_zone;
