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(s: buf, res: &_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(s: buf, base: 10, res: &res) < 0 || res > MAX_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 | int migratetype) |
37 | { |
38 | if (order >= debug_guardpage_minorder()) |
39 | return false; |
40 | |
41 | __SetPageGuard(page); |
42 | INIT_LIST_HEAD(list: &page->buddy_list); |
43 | set_page_private(page, private: order); |
44 | /* Guard pages are not available for any usage */ |
45 | if (!is_migrate_isolate(migratetype)) |
46 | __mod_zone_freepage_state(zone, nr_pages: -(1 << order), migratetype); |
47 | |
48 | return true; |
49 | } |
50 | |
51 | void __clear_page_guard(struct zone *zone, struct page *page, unsigned int order, |
52 | int migratetype) |
53 | { |
54 | __ClearPageGuard(page); |
55 | |
56 | set_page_private(page, private: 0); |
57 | if (!is_migrate_isolate(migratetype)) |
58 | __mod_zone_freepage_state(zone, nr_pages: (1 << order), migratetype); |
59 | } |
60 | |