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 <[email protected]>
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
