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 select PAGE_GUARD if ARCH_SUPPORTS_DEBUG_PAGEALLOC 18 ---help--- 19 Unmap pages from the kernel linear mapping after free_pages(). 20 This results in a large slowdown, but helps to find certain types 21 of memory corruption. 22 23 For architectures which don't enable ARCH_SUPPORTS_DEBUG_PAGEALLOC, 24 fill the pages with poison patterns after free_pages() and verify 25 the patterns before alloc_pages(). Additionally, 26 this option cannot be enabled in combination with hibernation as 27 that would result in incorrect warnings of memory corruption after 28 a resume because free pages are not saved to the suspend image. 29 30config WANT_PAGE_DEBUG_FLAGS 31 bool 32 33config PAGE_POISONING 34 bool 35 select WANT_PAGE_DEBUG_FLAGS 36 37config PAGE_GUARD 38 bool 39 select WANT_PAGE_DEBUG_FLAGS 40