mm/debug_pagealloc: ask users for default setting of debug_pagealloc

	select PAGE_POISONING if !ARCH_SUPPORTS_DEBUG_PAGEALLOC

	---help---

	  Unmap pages from the kernel linear mapping after free_pages().

	  This results in a large slowdown, but helps to find certain types

	  of memory corruption.

	  Depending on runtime enablement, this results in a small or large

	  slowdown, but helps to find certain types of memory corruption.

	  For architectures which don't enable ARCH_SUPPORTS_DEBUG_PAGEALLOC,

	  fill the pages with poison patterns after free_pages() and verify

	  that would result in incorrect warnings of memory corruption after

	  a resume because free pages are not saved to the suspend image.

	  By default this option will have a small overhead, e.g. by not

	  allowing the kernel mapping to be backed by large pages on some

	  architectures. Even bigger overhead comes when the debugging is

	  enabled by DEBUG_PAGEALLOC_ENABLE_DEFAULT or the debug_pagealloc

	  command line parameter.

config DEBUG_PAGEALLOC_ENABLE_DEFAULT

	bool "Enable debug page memory allocations by default?"

	default n

	depends on DEBUG_PAGEALLOC

	---help---

	  Enable debug page memory allocations by default? This value

	  can be overridden by debug_pagealloc=off|on.

config PAGE_POISONING

	bool

#ifdef CONFIG_DEBUG_PAGEALLOC

unsigned int _debug_guardpage_minorder;

bool _debug_pagealloc_enabled __read_mostly;

bool _debug_pagealloc_enabled __read_mostly

			= IS_ENABLED(CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT);

bool _debug_guardpage_enabled __read_mostly;

static int __init early_debug_pagealloc(char *buf)

	if (strcmp(buf, "on") == 0)

		_debug_pagealloc_enabled = true;

	if (strcmp(buf, "off") == 0)

		_debug_pagealloc_enabled = false;

	return 0;

}

early_param("debug_pagealloc", early_debug_pagealloc);