mm/huge_memory: disable THP when dynamic hugetlb is enabled

hulk inclusion
category: feature
bugzilla: 46904, https://gitee.com/openeuler/kernel/issues/I4QSHG
CVE: NA

--------------------------------

When THP is enabled, the allocation of a page(order=0) may be converted to
an allocation of pages(order>0). In this case, the allocation will skip the
dhugetlb_pool. When we want to use dynamic hugetlb feature, we have to
disable THP for now.
Signed-off-by: NLiu Shixin <liushixin2@huawei.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

include/linux/dynamic_hugetlb.h

@@ -9,6 +9,7 @@
 
 #ifdef CONFIG_DYNAMIC_HUGETLB
 
+extern bool enable_dhugetlb;
 extern struct static_key_false dhugetlb_enabled_key;
 #define dhugetlb_enabled (static_branch_unlikely(&dhugetlb_enabled_key))
 
@@ -106,6 +107,7 @@ void free_huge_page_to_dhugetlb_pool(struct page *page, bool restore_reserve);
 
 #else
 
+#define enable_dhugetlb		0
 #define dhugetlb_enabled	0
 
 struct dhugetlb_pool {};

mm/dynamic_hugetlb.c

@@ -15,7 +15,7 @@
 #include <trace/events/dynamic_hugetlb.h>
 #endif
 
-static bool enable_dhugetlb = false;
+bool enable_dhugetlb = false;
 DEFINE_STATIC_KEY_FALSE(dhugetlb_enabled_key);
 
 #define hugepage_index(pfn)	((pfn) >> (PUD_SHIFT - PAGE_SHIFT))

mm/huge_memory.c

@@ -33,6 +33,7 @@
 #include <linux/oom.h>
 #include <linux/numa.h>
 #include <linux/page_owner.h>
+#include <linux/dynamic_hugetlb.h>
 
 #include <asm/tlb.h>
 #include <asm/pgalloc.h>
@@ -392,6 +393,18 @@ static int __init hugepage_init(void)
 		return -EINVAL;
 	}
 
+	/*
+	 * When we alloc some pages(order = 0), system may help us to alloc a page(order > 0)
+	 * due to transparent hugepage. This result dynamic hugetlb to be skipped.
+	 * Actually, using dynamic hugetlb means we have already optimized the program, so we
+	 * should not use transparent hugepage in addition. (May result negative optimization)
+	 */
+	if (enable_dhugetlb) {
+		transparent_hugepage_flags = 0;
+		pr_info("transparent hugepage is disabled due to confilct with dynamic hugetlb\n");
+		return -EINVAL;
+	}
+
 	/*
 	 * hugepages can't be allocated by the buddy allocator
 	 */