| 1 | config 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 | |
| 10 | config 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 | |
| 29 | config PAGE_POISONING |
| 30 | bool |