mm: thp: Add memory reliable support for hugepaged collapse

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4SK3S
CVE: NA

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

Hugepaged collapse pages into huge page will use the same memory region.
When hugepaged collapse pages into huge page, hugepaged will check if
there is any reliable pages in the area to be collapsed. If this area
contains any reliable pages, hugepaged will alloc memory from mirrored
region. Otherwise it will alloc momory from non-mirrored region.
Signed-off-by: NMa Wupeng <mawupeng1@huawei.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>

mm/khugepaged.c

@@ -1057,7 +1057,8 @@ static bool __collapse_huge_page_swapin(struct mm_struct *mm,
 static void collapse_huge_page(struct mm_struct *mm,
 				   unsigned long address,
 				   struct page **hpage,
-				   int node, int referenced, int unmapped)
+				   int node, int referenced, int unmapped,
+				   bool reliable)
 {
 	LIST_HEAD(compound_pagelist);
 	pmd_t *pmd, _pmd;
@@ -1075,6 +1076,9 @@ static void collapse_huge_page(struct mm_struct *mm,
 	/* Only allocate from the target node */
 	gfp = alloc_hugepage_khugepaged_gfpmask() | __GFP_THISNODE;
 
+	if (reliable)
+		gfp |= GFP_RELIABLE;
+
 	/*
 	 * Before allocating the hugepage, release the mmap_lock read lock.
 	 * The allocation can take potentially a long time if it involves
@@ -1234,6 +1238,7 @@ static int khugepaged_scan_pmd(struct mm_struct *mm,
 	spinlock_t *ptl;
 	int node = NUMA_NO_NODE, unmapped = 0;
 	bool writable = false;
+	bool reliable = false;
 
 	VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 
@@ -1358,6 +1363,9 @@ static int khugepaged_scan_pmd(struct mm_struct *mm,
 		    page_is_young(page) || PageReferenced(page) ||
 		    mmu_notifier_test_young(vma->vm_mm, address))
 			referenced++;
+
+		if (page_reliable(page))
+			reliable = true;
 	}
 	if (!writable) {
 		result = SCAN_PAGE_RO;
@@ -1373,7 +1381,7 @@ static int khugepaged_scan_pmd(struct mm_struct *mm,
 		node = khugepaged_find_target_node();
 		/* collapse_huge_page will return with the mmap_lock released */
 		collapse_huge_page(mm, address, hpage, node,
-				referenced, unmapped);
+				referenced, unmapped, reliable);
 	}
 out:
 	trace_mm_khugepaged_scan_pmd(mm, page, writable, referenced,
@@ -1633,7 +1641,8 @@ static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff)
  */
 static void collapse_file(struct mm_struct *mm,
 		struct file *file, pgoff_t start,
-		struct page **hpage, int node)
+		struct page **hpage, int node,
+		bool reliable)
 {
 	struct address_space *mapping = file->f_mapping;
 	gfp_t gfp;
@@ -1650,6 +1659,9 @@ static void collapse_file(struct mm_struct *mm,
 	/* Only allocate from the target node */
 	gfp = alloc_hugepage_khugepaged_gfpmask() | __GFP_THISNODE;
 
+	if (reliable)
+		gfp |= GFP_RELIABLE;
+
 	new_page = khugepaged_alloc_page(hpage, gfp, node);
 	if (!new_page) {
 		result = SCAN_ALLOC_HUGE_PAGE_FAIL;
@@ -1977,6 +1989,7 @@ static void khugepaged_scan_file(struct mm_struct *mm,
 	int present, swap;
 	int node = NUMA_NO_NODE;
 	int result = SCAN_SUCCEED;
+	bool reliable = false;
 
 	present = 0;
 	swap = 0;
@@ -2029,6 +2042,9 @@ static void khugepaged_scan_file(struct mm_struct *mm,
 			xas_pause(&xas);
 			cond_resched_rcu();
 		}
+
+		if (page_reliable(page))
+			reliable = true;
 	}
 	rcu_read_unlock();
 
@@ -2037,7 +2053,7 @@ static void khugepaged_scan_file(struct mm_struct *mm,
 			result = SCAN_EXCEED_NONE_PTE;
 		} else {
 			node = khugepaged_find_target_node();
-			collapse_file(mm, file, start, hpage, node);
+			collapse_file(mm, file, start, hpage, node, reliable);
 		}
 	}