#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <errno.h>

#include "inc/testsuite.h"

struct swap_struct {
	int		page_size;

	int		fd;
	int		flags;
	void		*buf;
	unsigned long 	len;

	int		key_break;
};

#define SWAP_DEFAULT_SIZE	0x200000	/* 2MB */
#define SWAP_PAGE_TO_SPLIT	511
#define SWAP_PAGE_TO_SWAP	1
#define SWAP_PAGE_TO_SWAP_NUM	256

#ifndef MADV_PAGEOUT
#define MADV_PAGEOUT		21
#endif


static void usage(void)
{
	fprintf(stdout, "testsuite mm swap -l <size> -k\n");
	fprintf(stdout, "\n");
	fprintf(stdout, "-l: Length of memory to be mapped\n");
	fprintf(stdout, "-w: Length of memory to be copied-on-write\n");
	fprintf(stdout, "-k: Stop at various stages\n");
	fprintf(stdout, "\n");
}

static int swap_init_data(struct swap_struct *m)
{
	m->page_size	= getpagesize();

	m->fd		= -1;
	m->flags	= (MAP_PRIVATE | MAP_ANONYMOUS);
	m->len		= SWAP_DEFAULT_SIZE;
	m->key_break	= 0;

	return 0;
}

static int swap_handler(int argc, char **argv)
{
	struct swap_struct m;
	unsigned long *pval;
	int i, opt, ret;

	ret = swap_init_data(&m);
	if (ret)
		return ret;

	while ((opt = getopt(argc, argv, "l:w:kh")) != -1) {
		switch (opt) {
		case 'l':
			m.len = util_memory_parse_size(optarg);
			if (m.len <= SWAP_DEFAULT_SIZE) {
				fprintf(stderr, "%s: length 0x%lx less than 0x%x\n",
					__func__, m.len, SWAP_DEFAULT_SIZE);
				return -1;
			}

			break;
		case 'k':
			m.key_break = 1;
			break;
		case 'h':
			usage();
			return 0;
		}
	}

	/*
	 * Setup the area. The area should be backed up with huge pages
	 * if it suits. Write to the area to ensure the area is populted
	 * completely.
	 */
	m.buf = mmap(NULL, m.len, PROT_READ | PROT_WRITE, m.flags, m.fd, 0);
	if (m.buf == (void *)-1) {
		fprintf(stderr, "Unable do mmap()\n");
		goto out;
	}

        memset(m.buf, 0xff, m.len);

	/* Force to split the huge page */
	util_misc_key_press(m.key_break, "  ", "Any key to split THP");
	ret = madvise(m.buf + SWAP_PAGE_TO_SPLIT * m.page_size,
		      m.page_size, MADV_FREE);
	if (ret) {
		fprintf(stderr, "Error %d to split THP\n", ret); 
		goto out;
	}

	/* Swap one sub-page */
	util_misc_key_press(m.key_break, "  ", "Any key to swap sub-pages");
	ret = madvise(m.buf + SWAP_PAGE_TO_SWAP * m.page_size,
		      SWAP_PAGE_TO_SWAP_NUM * m.page_size,
		      MADV_PAGEOUT);
	if (ret) {
		fprintf(stderr, "Error %d to swap one sub-page\n", ret);
		goto out;
	}

	/* Read the swapped sub-page */
	util_misc_key_press(m.key_break, "  ", "Any key to read the swapped sub-pages");
	for (i = 0; i < SWAP_PAGE_TO_SWAP_NUM; i++) {
		pval = (unsigned long *)(m.buf + (SWAP_PAGE_TO_SWAP + i) * m.page_size);
		fprintf(stdout, "  Page[%03d]: 0x%016lx\n", i, *pval);
	}

	/* Exit */
	util_misc_key_press(m.key_break, "  ", "Any key to exit");

out:
	if (m.buf != (void *)-1)
		munmap(m.buf, m.len);
	if (m.fd > 0)
		close(m.fd);

	return 0;
}

static struct command swap_command = {
	.name		= "swap",
	.handler	= swap_handler,
	.children	= LIST_HEAD_INIT(swap_command.children),
	.link		= LIST_HEAD_INIT(swap_command.link),
};

int mm_swap_init(void)
{
	return command_add(&mm_command, &swap_command);
}