On Tue, Aug 08, 2017 at 12:54:02PM +0000, Kirill A. Shutemov wrote: > Size of mem_section array depends on size of physical address space. > > In preparation for boot-time switching between paging modes on x86-64 > we need to make allocation of mem_section dynamic. > > The patch allocates the array on the first call to > sparse_memory_present_with_active_regions(). > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Fixup for the patch: diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index c8eb668eab79..9799c2c58ce6 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -1144,6 +1144,10 @@ extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT]; static inline struct mem_section *__nr_to_section(unsigned long nr) { +#ifdef CONFIG_SPARSEMEM_EXTREME + if (!mem_section) + return NULL; +#endif if (!mem_section[SECTION_NR_TO_ROOT(nr)]) return NULL; return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK]; -- Kirill A. Shutemov -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>