// SPDX-License-Identifier: GPL-2.0#include <linux/mm.h>#include <linux/page-isolation.h> unsigned int _debug_guardpage_minorder; bool _debug_pagealloc_enabled_early __read_mostly			= IS_ENABLED(CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT);EXPORT_SYMBOL(_debug_pagealloc_enabled_early);DEFINE_STATIC_KEY_FALSE(_debug_pagealloc_enabled);EXPORT_SYMBOL(_debug_pagealloc_enabled); DEFINE_STATIC_KEY_FALSE(_debug_guardpage_enabled); static int __init early_debug_pagealloc(char *buf){	return kstrtobool(buf, &_debug_pagealloc_enabled_early);}early_param("debug_pagealloc", early_debug_pagealloc); static int __init debug_guardpage_minorder_setup(char *buf){	unsigned long res; 	if (kstrtoul(buf, 10, &res) < 0 ||  res > MAX_PAGE_ORDER / 2) {		pr_err("Bad debug_guardpage_minorder value: %s\n", buf);		return 0;	}	_debug_guardpage_minorder = res;	pr_info("Setting debug_guardpage_minorder to %lu\n", res);	return 0;}early_param("debug_guardpage_minorder", debug_guardpage_minorder_setup); bool __set_page_guard(struct zone *zone, struct page *page, unsigned int order){	if (order >= debug_guardpage_minorder())		return false; 	__SetPageGuard(page);	INIT_LIST_HEAD(&page->buddy_list);	set_page_private(page, order); 	return true;} void __clear_page_guard(struct zone *zone, struct page *page, unsigned int order){	__ClearPageGuard(page);	set_page_private(page, 0);}