mm/dynamic_hugetlb: free huge pages to dhugetlb_pool

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

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

Add function to free huge page to dhugetlb_pool.
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

@@ -102,6 +102,7 @@ bool file_has_mem_in_hpool(struct hugetlbfs_inode_info *p);
 int dhugetlb_acct_memory(struct hstate *h, long delta, struct hugetlbfs_inode_info *p);
 struct page *alloc_huge_page_from_dhugetlb_pool(struct hstate *h, struct dhugetlb_pool *hpool,
 						bool need_unreserved);
+void free_huge_page_to_dhugetlb_pool(struct page *page, bool restore_reserve);
 
 #else
 
@@ -162,6 +163,10 @@ struct page *alloc_huge_page_from_dhugetlb_pool(struct hstate *h, struct dhugetl
 {
 	return NULL;
 }
+static inline
+void free_huge_page_to_dhugetlb_pool(struct page *page, bool restore_reserve)
+{
+}
 #endif
 
 #endif /* CONFIG_DYNAMIC_HUGETLB */

mm/dynamic_hugetlb.c

@@ -649,6 +649,36 @@ struct page *alloc_huge_page_from_dhugetlb_pool(struct hstate *h, struct dhugetl
 	return page;
 }
 
+void free_huge_page_to_dhugetlb_pool(struct page *page, bool restore_reserve)
+{
+	struct hstate *h = page_hstate(page);
+	struct huge_pages_pool *hpages_pool;
+	struct dhugetlb_pool *hpool;
+
+	hpool = find_hpool_by_dhugetlb_pagelist(page);
+
+	if (!get_hpool_unless_zero(hpool)) {
+		pr_err("dhugetlb: free error: get hpool failed\n");
+		return;
+	}
+
+	spin_lock(&hpool->lock);
+	ClearPagePool(page);
+	set_compound_page_dtor(page, NULL_COMPOUND_DTOR);
+	if (hstate_is_gigantic(h))
+		hpages_pool = &hpool->hpages_pool[HUGE_PAGES_POOL_1G];
+	else
+		hpages_pool = &hpool->hpages_pool[HUGE_PAGES_POOL_2M];
+
+	list_add(&page->lru, &hpages_pool->hugepage_freelists);
+	hpages_pool->free_huge_pages++;
+	hpages_pool->used_huge_pages--;
+	if (restore_reserve)
+		hpages_pool->resv_huge_pages++;
+	spin_unlock(&hpool->lock);
+	put_hpool(hpool);
+}
+
 static int alloc_hugepage_from_hugetlb(struct dhugetlb_pool *hpool,
 				       unsigned long nid, unsigned long nr_pages)
 {

mm/hugetlb.c

@@ -1583,6 +1583,19 @@ void free_huge_page(struct page *page)
 	restore_reserve = HPageRestoreReserve(page);
 	ClearHPageRestoreReserve(page);
 
+	if (dhugetlb_enabled && PagePool(page)) {
+		spin_lock(&hugetlb_lock);
+		ClearHPageMigratable(page);
+		list_del(&page->lru);
+		hugetlb_cgroup_uncharge_page(hstate_index(h),
+					     pages_per_huge_page(h), page);
+		hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h),
+						  pages_per_huge_page(h), page);
+		spin_unlock(&hugetlb_lock);
+		free_huge_page_to_dhugetlb_pool(page, restore_reserve);
+		return;
+	}
+
 	/*
 	 * If HPageRestoreReserve was set on page, page allocation consumed a
 	 * reservation.  If the page was associated with a subpool, there