Some architectures would want different restrictions. Hence add an architecture-specific override.
Both the PMD_SIZE check and pageblock alignment check are moved there. Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com> --- mm/memory_hotplug.c | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 1b19462f4e72..5921c81fcb70 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1247,9 +1247,25 @@ static int online_memory_block(struct memory_block *mem, void *arg) return device_online(&mem->dev); } +#ifndef arch_supports_memmap_on_memory +static inline bool arch_supports_memmap_on_memory(unsigned long size) +{ + unsigned long nr_vmemmap_pages = size >> PAGE_SHIFT; + unsigned long vmemmap_size = nr_vmemmap_pages * sizeof(struct page); + + /* + * As default, we want the vmemmap to span a complete PMD such that we + * can map the vmemmap using a single PMD if supported by the + * architecture. + */ + return IS_ALIGNED(vmemmap_size, PMD_SIZE); +} +#endif + static bool mhp_supports_memmap_on_memory(unsigned long size) { - unsigned long nr_vmemmap_pages = size / PAGE_SIZE; + + unsigned long nr_vmemmap_pages = size >> PAGE_SHIFT; unsigned long vmemmap_size = nr_vmemmap_pages * sizeof(struct page); unsigned long remaining_size = size - vmemmap_size; @@ -1281,8 +1297,8 @@ static bool mhp_supports_memmap_on_memory(unsigned long size) */ return mhp_memmap_on_memory() && size == memory_block_size_bytes() && - IS_ALIGNED(vmemmap_size, PMD_SIZE) && - IS_ALIGNED(remaining_size, (pageblock_nr_pages << PAGE_SHIFT)); + IS_ALIGNED(remaining_size, (pageblock_nr_pages << PAGE_SHIFT)) && + arch_supports_memmap_on_memory(size); } /* -- 2.41.0