mm/dynamic_hugetlb: alloc huge pages from dhugetlb_pool

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

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

Add function to alloc huge page from dhugetlb_pool.
When process is bound to a mem_cgroup configured with dhugetlb_pool,
only allowed to alloc huge page from dhugetlb_pool. If there is no huge
pages in dhugetlb_pool, the mmap() will failed due to the reserve count
introduced in previous patch.
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

@@ -100,6 +100,8 @@ void link_hpool(struct hugetlbfs_inode_info *p);
 void unlink_hpool(struct hugetlbfs_inode_info *p);
 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);
 
 #else
 
@@ -154,6 +156,12 @@ static inline int dhugetlb_acct_memory(struct hstate *h, long delta, struct huge
 {
 	return 0;
 }
+static inline
+struct page *alloc_huge_page_from_dhugetlb_pool(struct hstate *h, struct dhugetlb_pool *hpool,
+						bool need_unreserved)
+{
+	return NULL;
+}
 #endif
 
 #endif /* CONFIG_DYNAMIC_HUGETLB */

mm/dynamic_hugetlb.c

@@ -103,7 +103,7 @@ static int hpool_split_page(struct dhugetlb_pool *hpool, int hpages_pool_idx)
 	if (!split_page)
 		return -ENOMEM;
 
-	page = list_entry(hpages_pool->hugepage_freelists.next, struct page, lru);
+	page = list_entry(hpages_pool->hugepage_freelists.prev, struct page, lru);
 	list_del(&page->lru);
 	hpages_pool->free_normal_pages--;
 
@@ -612,6 +612,43 @@ int dhugetlb_acct_memory(struct hstate *h, long delta, struct hugetlbfs_inode_in
 	return ret;
 }
 
+struct page *alloc_huge_page_from_dhugetlb_pool(struct hstate *h, struct dhugetlb_pool *hpool,
+						bool need_unreserved)
+{
+	struct huge_pages_pool *hpages_pool;
+	struct page *page = NULL;
+	unsigned long flags;
+
+	if (!dhugetlb_enabled)
+		return NULL;
+
+	spin_lock_irqsave(&hpool->lock, flags);
+	if (hstate_is_gigantic(h))
+		hpages_pool = &hpool->hpages_pool[HUGE_PAGES_POOL_1G];
+	else
+		hpages_pool = &hpool->hpages_pool[HUGE_PAGES_POOL_2M];
+
+	if (hpages_pool->free_huge_pages) {
+		page = list_entry(hpages_pool->hugepage_freelists.next, struct page, lru);
+		list_del(&page->lru);
+		hpages_pool->free_huge_pages--;
+		hpages_pool->used_huge_pages++;
+		if (need_unreserved) {
+			SetHPageRestoreReserve(page);
+			hpages_pool->resv_huge_pages--;
+		}
+	}
+	if (page) {
+		INIT_LIST_HEAD(&page->lru);
+		set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
+		set_page_refcounted(page);
+		SetPagePool(page);
+	}
+	spin_unlock_irqrestore(&hpool->lock, flags);
+
+	return page;
+}
+
 static int alloc_hugepage_from_hugetlb(struct dhugetlb_pool *hpool,
 				       unsigned long nid, unsigned long nr_pages)
 {

mm/hugetlb.c

@@ -2534,6 +2534,19 @@ struct page *alloc_huge_page(struct vm_area_struct *vma,
 	if (ret)
 		goto out_uncharge_cgroup_reservation;
 
+	if (file_has_mem_in_hpool(info)) {
+		bool need_unreserved = false;
+
+		if (!avoid_reserve && vma_has_reserves(vma, gbl_chg))
+			need_unreserved = true;
+		page = alloc_huge_page_from_dhugetlb_pool(h, info->hpool, need_unreserved);
+		if (!page)
+			goto out_uncharge_cgroup;
+		spin_lock_irq(&hugetlb_lock);
+		list_add(&page->lru, &h->hugepage_activelist);
+		goto out;
+	}
+
 	spin_lock_irq(&hugetlb_lock);
 	/*
 	 * glb_chg is passed to indicate whether or not a page must be taken
@@ -2554,6 +2567,7 @@ struct page *alloc_huge_page(struct vm_area_struct *vma,
 		list_add(&page->lru, &h->hugepage_activelist);
 		/* Fall through */
 	}
+out:
 	hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
 	/* If allocation is not consuming a reservation, also store the
 	 * hugetlb_cgroup pointer on the page.