Commit 78774718 authored by Liu Shixin's avatar Liu Shixin Committed by Zheng Zengkai
Browse files

mm/dynamic_hugetlb: initialize subpages before merging 

hulk inclusion
category: bugfix
bugzilla: 46904 https://gitee.com/openeuler/kernel/issues/I4Y0XO



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

Patch ("hugetlb: address ref count racing in prep_compound_gigantic_page") add
a check of ref count in prep_compound_gigantic_page. We will call this function
in dynamic hugetlb feature too, so we should initialize subpages before calling
prep_compound_gigantic_page to satisfy the change.
Further, the input of prep_compound_gigantic_page should be a group of pages
rather than compound page, so clear the properties related to compound page.

Signed-off-by: default avatarLiu Shixin <liushixin2@huawei.com>
Reviewed-by: default avatarKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parent fec7b436

mm/dynamic_hugetlb.c

+22 −2
Original line number Diff line number Diff line
@@ -210,7 +210,7 @@ static int hpool_merge_page(struct dhugetlb_pool *hpool, int hpages_pool_idx, bo 
	struct split_hugepage *split_page, *split_next;

	unsigned long nr_pages, block_size;

	struct page *page, *next, *p;

	bool need_migrate = false;

	bool need_migrate = false, need_initial = false;

	int i, try;

	LIST_HEAD(wait_page_list);
@@ -221,8 +221,9 @@ static int hpool_merge_page(struct dhugetlb_pool *hpool, int hpages_pool_idx, bo 


	switch (hpages_pool_idx) {

		case HUGE_PAGES_POOL_1G:

			nr_pages = 1 << (PUD_SHIFT - PMD_SHIFT);

			nr_pages = 1 << (PUD_SHIFT - PAGE_SHIFT);

			block_size = 1 << (PMD_SHIFT - PAGE_SHIFT);

			need_initial = true;

			break;

		case HUGE_PAGES_POOL_2M:

			nr_pages = 1 << (PMD_SHIFT - PAGE_SHIFT);
@@ -258,6 +259,25 @@ static int hpool_merge_page(struct dhugetlb_pool *hpool, int hpages_pool_idx, bo 
			p = pfn_to_page(split_page->start_pfn + i);

			list_del(&p->lru);

			src_hpages_pool->free_normal_pages--;

			/*

			 * The input of prep_compound_gigantic_page should be a

			 * group of pages whose ref count is 1 rather than

			 * compound_page.

			 * Initialize the pages before merge them to 1G.

			 */

			if (need_initial) {

				int j;



				set_compound_page_dtor(p, NULL_COMPOUND_DTOR);

				atomic_set(compound_mapcount_ptr(p), 0);

				set_compound_order(p, 0);

				__ClearPageHead(p);

				set_page_count(p, 1);

				for (j = 1; j < block_size; j++) {

					clear_compound_head(&p[j]);

					set_page_count(&p[j], 1);

				}

			}

		}

		kfree(split_page);

		add_new_page_to_pool(hpool, page, hpages_pool_idx);