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SubjectRe: [PATCH v2 4/7] mm,memory_hotplug: Enforce struct page size to be multiple of PMD
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On 09.02.21 14:38, Oscar Salvador wrote:
> When struct page's size is not multiple of PMD, these do not get
> fully populated when adding sections, hence two sections will
> intersect the same the PMD. This goes against the vmemmap-per-device
> premise, so reject it if that is the case.
>
> Signed-off-by: Oscar Salvador <osalvador@suse.de>
> ---
> mm/memory_hotplug.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 95695483a622..d3fb036d33fd 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -57,10 +57,11 @@ static __meminit int memmap_on_memory_store(const char *val,
> const struct kernel_param *kp)
> {
> /*
> - * Fail silently in case we cannot enable it due to platform constraints.
> + * Fail silently in case we cannot enable it due to system constraints.
> * User can always check whether it is enabled or not via /sys/module.
> */
> - if (!IS_ENABLED(CONFIG_ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE))
> + if (!IS_ENABLED(CONFIG_ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE) ||
> + (PMD_SIZE % sizeof(struct page)))
> return 0;
>
> return param_set_bool(val, kp);
>

Squash that into #1 - it's part of basic operation.

--
Thanks,

David / dhildenb

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