1config PAGE_EXTENSION 2 bool "Extend memmap on extra space for more information on page" 3 ---help--- 4 Extend memmap on extra space for more information on page. This 5 could be used for debugging features that need to insert extra 6 field for every page. This extension enables us to save memory 7 by not allocating this extra memory according to boottime 8 configuration. 9 10config DEBUG_PAGEALLOC 11 bool "Debug page memory allocations" 12 depends on DEBUG_KERNEL 13 depends on !HIBERNATION || ARCH_SUPPORTS_DEBUG_PAGEALLOC && !PPC && !SPARC 14 depends on !KMEMCHECK 15 select PAGE_EXTENSION 16 select PAGE_POISONING if !ARCH_SUPPORTS_DEBUG_PAGEALLOC 17 ---help--- 18 Unmap pages from the kernel linear mapping after free_pages(). 19 This results in a large slowdown, but helps to find certain types 20 of memory corruption. 21 22 For architectures which don't enable ARCH_SUPPORTS_DEBUG_PAGEALLOC, 23 fill the pages with poison patterns after free_pages() and verify 24 the patterns before alloc_pages(). Additionally, 25 this option cannot be enabled in combination with hibernation as 26 that would result in incorrect warnings of memory corruption after 27 a resume because free pages are not saved to the suspend image. 28 29config PAGE_POISONING 30 bool 31