mm/debug_page_alloc.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/mm.h>
   3 #include <linux/page-isolation.h>
   4
   5 unsigned int _debug_guardpage_minorder;
   6
   7 bool _debug_pagealloc_enabled_early __read_mostly
   8                         = IS_ENABLED(CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT);
   9 EXPORT_SYMBOL(_debug_pagealloc_enabled_early);
  10 DEFINE_STATIC_KEY_FALSE(_debug_pagealloc_enabled);
  11 EXPORT_SYMBOL(_debug_pagealloc_enabled);
  12
  13 DEFINE_STATIC_KEY_FALSE(_debug_guardpage_enabled);
  14
  15 static int __init early_debug_pagealloc(char *buf)
  16 {
  17         return kstrtobool(buf, &_debug_pagealloc_enabled_early);
  18 }
  19 early_param("debug_pagealloc", early_debug_pagealloc);
  20
  21 static int __init debug_guardpage_minorder_setup(char *buf)
  22 {
  23         unsigned long res;
  24
  25         if (kstrtoul(buf, 10, &res) < 0 ||  res > MAX_PAGE_ORDER / 2) {
  26                 pr_err("Bad debug_guardpage_minorder value\n");
  27                 return 0;
  28         }
  29         _debug_guardpage_minorder = res;
  30         pr_info("Setting debug_guardpage_minorder to %lu\n", res);
  31         return 0;
  32 }
  33 early_param("debug_guardpage_minorder", debug_guardpage_minorder_setup);
  34
  35 bool __set_page_guard(struct zone *zone, struct page *page, unsigned int order)
  36 {
  37         if (order >= debug_guardpage_minorder())
  38                 return false;
  39
  40         __SetPageGuard(page);
  41         INIT_LIST_HEAD(&page->buddy_list);
  42         set_page_private(page, order);
  43
  44         return true;
  45 }
  46
  47 void __clear_page_guard(struct zone *zone, struct page *page, unsigned int order)
  48 {
  49         __ClearPageGuard(page);
  50         set_page_private(page, 0);
  51 }