From e30825f1869a75b29a69dc8e0aaaaccc492092cf Mon Sep 17 00:00:00 2001 From: Joonsoo Kim Date: Fri, 12 Dec 2014 16:55:49 -0800 Subject: mm/debug-pagealloc: prepare boottime configurable on/off Until now, debug-pagealloc needs extra flags in struct page, so we need to recompile whole source code when we decide to use it. This is really painful, because it takes some time to recompile and sometimes rebuild is not possible due to third party module depending on struct page. So, we can't use this good feature in many cases. Now, we have the page extension feature that allows us to insert extra flags to outside of struct page. This gets rid of third party module issue mentioned above. And, this allows us to determine if we need extra memory for this page extension in boottime. With these property, we can avoid using debug-pagealloc in boottime with low computational overhead in the kernel built with CONFIG_DEBUG_PAGEALLOC. This will help our development process greatly. This patch is the preparation step to achive above goal. debug-pagealloc originally uses extra field of struct page, but, after this patch, it will use field of struct page_ext. Because memory for page_ext is allocated later than initialization of page allocator in CONFIG_SPARSEMEM, we should disable debug-pagealloc feature temporarily until initialization of page_ext. This patch implements this. Signed-off-by: Joonsoo Kim Cc: Mel Gorman Cc: Johannes Weiner Cc: Minchan Kim Cc: Dave Hansen Cc: Michal Nazarewicz Cc: Jungsoo Son Cc: Ingo Molnar Cc: Joonsoo Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/Kconfig.debug | 1 + 1 file changed, 1 insertion(+) (limited to 'mm/Kconfig.debug') diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug index 1ba81c7769f7..56badfc4810a 100644 --- a/mm/Kconfig.debug +++ b/mm/Kconfig.debug @@ -12,6 +12,7 @@ config DEBUG_PAGEALLOC depends on DEBUG_KERNEL depends on !HIBERNATION || ARCH_SUPPORTS_DEBUG_PAGEALLOC && !PPC && !SPARC depends on !KMEMCHECK + select PAGE_EXTENSION select PAGE_POISONING if !ARCH_SUPPORTS_DEBUG_PAGEALLOC select PAGE_GUARD if ARCH_SUPPORTS_DEBUG_PAGEALLOC ---help--- -- cgit v1.2.3