debug_guardpage_minorder=
[KNL] When CONFIG_DEBUG_PAGEALLOC is set, this
- parameter allows control order of pages that will be
- intentionally kept free (and hence protected) by buddy
- allocator. Bigger value increase probability of
- catching random memory corruption, but reduce amount
- of memory for normal system use. Maximum possible
- value is MAX_ORDER/2. Setting this parameter to 1 or 2,
- should be enough to identify most random memory
- corruption problems caused by bugs in kernel/drivers
- code when CPU write to (or read from) random memory
- location. Note that there exist class of memory
- corruptions problems caused by buggy H/W or F/W or by
- drivers badly programing DMA (basically when memory is
- written at bus level and CPU MMU is bypassed), which
- are not detectable by CONFIG_DEBUG_PAGEALLOC, hence this
- option would not help tracking down these problems too.
+ parameter allows control of the order of pages that will
+ be intentionally kept free (and hence protected) by the
+ buddy allocator. Bigger value increase the probability
+ of catching random memory corruption, but reduce the
+ amount of memory for normal system use. The maximum
+ possible value is MAX_ORDER/2. Setting this parameter
+ to 1 or 2 should be enough to identify most random
+ memory corruption problems caused by bugs in kernel or
+ driver code when a CPU writes to (or reads from) a
+ random memory location. Note that there exists a class
+ of memory corruptions problems caused by buggy H/W or
+ F/W or by drivers badly programing DMA (basically when
+ memory is written at bus level and the CPU MMU is
+ bypassed) which are not detectable by
+ CONFIG_DEBUG_PAGEALLOC, hence this option will not help
+ tracking down these problems.
debugpat [X86] Enable PAT debugging
}
__setup("debug_guardpage_minorder=", debug_guardpage_minorder_setup);
-static inline void set_page_guard_flg(struct page *page)
+static inline void set_page_guard_flag(struct page *page)
{
__set_bit(PAGE_DEBUG_FLAG_GUARD, &page->debug_flags);
}
-static inline void clear_page_guard_flg(struct page *page)
+static inline void clear_page_guard_flag(struct page *page)
{
__clear_bit(PAGE_DEBUG_FLAG_GUARD, &page->debug_flags);
}
#else
-static inline void set_page_guard_flg(struct page *page) { }
-static inline void clear_page_guard_flg(struct page *page) { }
+static inline void set_page_guard_flag(struct page *page) { }
+static inline void clear_page_guard_flag(struct page *page) { }
#endif
static inline void set_page_order(struct page *page, int order)
* merge with it and move up one order.
*/
if (page_is_guard(buddy)) {
- clear_page_guard_flg(buddy);
+ clear_page_guard_flag(buddy);
set_page_private(page, 0);
__mod_zone_page_state(zone, NR_FREE_PAGES, 1 << order);
} else {
* pages will stay not present in virtual address space
*/
INIT_LIST_HEAD(&page[size].lru);
- set_page_guard_flg(&page[size]);
+ set_page_guard_flag(&page[size]);
set_page_private(&page[size], high);
/* Guard pages are not available for any usage */
__mod_zone_page_state(zone, NR_FREE_PAGES, -(1 << high));