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1// SPDX-License-Identifier: GPL-2.0
2#include <linux/mm.h>
3#include <linux/page-isolation.h>
4
5unsigned int _debug_guardpage_minorder;
6
7bool _debug_pagealloc_enabled_early __read_mostly
8 = IS_ENABLED(CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT);
9EXPORT_SYMBOL(_debug_pagealloc_enabled_early);
10DEFINE_STATIC_KEY_FALSE(_debug_pagealloc_enabled);
11EXPORT_SYMBOL(_debug_pagealloc_enabled);
12
13DEFINE_STATIC_KEY_FALSE(_debug_guardpage_enabled);
14
15static int __init early_debug_pagealloc(char *buf)
16{
17 return kstrtobool(s: buf, res: &_debug_pagealloc_enabled_early);
18}
19early_param("debug_pagealloc", early_debug_pagealloc);
20
21static int __init debug_guardpage_minorder_setup(char *buf)
22{
23 unsigned long res;
24
25 if (kstrtoul(s: buf, base: 10, res: &res) < 0 || res > MAX_PAGE_ORDER / 2) {
26 pr_err("Bad debug_guardpage_minorder value: %s\n", buf);
27 return 0;
28 }
29 _debug_guardpage_minorder = res;
30 pr_info("Setting debug_guardpage_minorder to %lu\n", res);
31 return 0;
32}
33early_param("debug_guardpage_minorder", debug_guardpage_minorder_setup);
34
35bool __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(list: &page->buddy_list);
42 set_page_private(page, private: order);
43
44 return true;
45}
46
47void __clear_page_guard(struct zone *zone, struct page *page, unsigned int order)
48{
49 __ClearPageGuard(page);
50 set_page_private(page, private: 0);
51}
52

source code of linux/mm/debug_page_alloc.c