1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (c) 2018 FUJITSU LIMITED. All rights reserved.
4 * Author(s): Xiao Yang <yangx.jy@cn.fujitsu.com>
5 */
6
7#define TST_NO_DEFAULT_MAIN
8
9#include <unistd.h>
10#include "tst_test.h"
11#include "ksm_helper.h"
12
13void wait_ksmd_full_scan(void)
14{
15	unsigned long full_scans, at_least_one_full_scan;
16	int count = 0;
17
18	SAFE_FILE_SCANF(PATH_KSM "full_scans", "%lu", &full_scans);
19	/*
20	 * The current scan is already in progress so we can't guarantee that
21	 * the get_user_pages() is called on every existing rmap_item if we
22	 * only waited for the remaining part of the scan.
23	 *
24	 * The actual merging happens after the unstable tree has been built so
25	 * we need to wait at least two full scans to guarantee merging, hence
26	 * wait full_scans to increment by 3 so that at least two full scans
27	 * will run.
28	 */
29	at_least_one_full_scan = full_scans + 3;
30	while (full_scans < at_least_one_full_scan) {
31		sleep(1);
32		count++;
33		SAFE_FILE_SCANF(PATH_KSM "full_scans", "%lu", &full_scans);
34	}
35
36	tst_res(TINFO, "ksm daemon takes %ds to run two full scans", count);
37}
38