2 bool "Extend memmap on extra space for more information on page"
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
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
16 select PAGE_POISONING if !ARCH_SUPPORTS_DEBUG_PAGEALLOC
18 Unmap pages from the kernel linear mapping after free_pages().
19 Depending on runtime enablement, this results in a small or large
20 slowdown, but helps to find certain types of memory corruption.
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.
29 By default this option will have a small overhead, e.g. by not
30 allowing the kernel mapping to be backed by large pages on some
31 architectures. Even bigger overhead comes when the debugging is
32 enabled by DEBUG_PAGEALLOC_ENABLE_DEFAULT or the debug_pagealloc
33 command line parameter.
35 config DEBUG_PAGEALLOC_ENABLE_DEFAULT
36 bool "Enable debug page memory allocations by default?"
38 depends on DEBUG_PAGEALLOC
40 Enable debug page memory allocations by default? This value
41 can be overridden by debug_pagealloc=off|on.