/*
 * Stress test for transparent huge pages, memory compaction and migration.
 *
 * Authors: Konstantin Khlebnikov <koct9i@gmail.com>
 *
 * This is free and unencumbered software released into the public domain.
 */

#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <err.h>
#include <time.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <sys/mman.h>
#include "vm_util.h"
#include "kselftest.h"

int backing_fd = -1;
int mmap_flags = MAP_ANONYMOUS | MAP_NORESERVE | MAP_PRIVATE;
#define PROT_RW (PROT_READ | PROT_WRITE)

int main(int argc, char **argv)
{
        size_t ram, len;
        void *ptr, *p;
        struct timespec start, a, b;
        int i = 0;
        char *name = NULL;
        double s;
        uint8_t *map;
        size_t map_len;
        int pagemap_fd;
        int duration = 0;

        ksft_print_header();

        ram = sysconf(_SC_PHYS_PAGES);
        if (ram > SIZE_MAX / psize() / 4)
                ram = SIZE_MAX / 4;
        else
                ram *= psize();
        len = ram;

        while (++i < argc) {
                if (!strcmp(argv[i], "-h"))
                        ksft_exit_fail_msg("usage: %s [-f <filename>] [-d <duration>] [size in MiB]\n",
                                           argv[0]);
                else if (!strcmp(argv[i], "-f"))
                        name = argv[++i];
                else if (!strcmp(argv[i], "-d"))
                        duration = atoi(argv[++i]);
                else
                        len = atoll(argv[i]) << 20;
        }

        ksft_set_plan(1);

        if (name) {
                backing_fd = open(name, O_RDWR);
                if (backing_fd == -1)
                        ksft_exit_fail_msg("open %s\n", name);
                mmap_flags = MAP_SHARED;
        }

        warnx("allocate %zd transhuge pages, using %zd MiB virtual memory"
              " and %zd MiB of ram", len >> HPAGE_SHIFT, len >> 20,
              ram >> (20 + HPAGE_SHIFT - pshift() - 1));

        pagemap_fd = open("/proc/self/pagemap", O_RDONLY);
        if (pagemap_fd < 0)
                ksft_exit_fail_msg("open pagemap\n");

        len -= len % HPAGE_SIZE;
        ptr = mmap(NULL, len + HPAGE_SIZE, PROT_RW, mmap_flags, backing_fd, 0);
        if (ptr == MAP_FAILED)
                ksft_exit_fail_msg("initial mmap");
        ptr += HPAGE_SIZE - (uintptr_t)ptr % HPAGE_SIZE;

        if (madvise(ptr, len, MADV_HUGEPAGE))
                ksft_exit_fail_msg("MADV_HUGEPAGE");

        map_len = ram >> (HPAGE_SHIFT - 1);
        map = malloc(map_len);
        if (!map)
                ksft_exit_fail_msg("map malloc\n");

        clock_gettime(CLOCK_MONOTONIC, &start);

        while (1) {
                int nr_succeed = 0, nr_failed = 0, nr_pages = 0;

                memset(map, 0, map_len);

                clock_gettime(CLOCK_MONOTONIC, &a);
                for (p = ptr; p < ptr + len; p += HPAGE_SIZE) {
                        int64_t pfn;

                        pfn = allocate_transhuge(p, pagemap_fd);

                        if (pfn < 0) {
                                nr_failed++;
                        } else {
                                size_t idx = pfn >> (HPAGE_SHIFT - pshift());

                                nr_succeed++;
                                if (idx >= map_len) {
                                        map = realloc(map, idx + 1);
                                        if (!map)
                                                ksft_exit_fail_msg("map realloc\n");
                                        memset(map + map_len, 0, idx + 1 - map_len);
                                        map_len = idx + 1;
                                }
                                if (!map[idx])
                                        nr_pages++;
                                map[idx] = 1;
                        }

                        /* split transhuge page, keep last page */
                        if (madvise(p, HPAGE_SIZE - psize(), MADV_DONTNEED))
                                ksft_exit_fail_msg("MADV_DONTNEED");
                }
                clock_gettime(CLOCK_MONOTONIC, &b);
                s = b.tv_sec - a.tv_sec + (b.tv_nsec - a.tv_nsec) / 1000000000.;

                ksft_print_msg("%.3f s/loop, %.3f ms/page, %10.3f MiB/s\t"
                               "%4d succeed, %4d failed, %4d different pages\n",
                               s, s * 1000 / (len >> HPAGE_SHIFT), len / s / (1 << 20),
                               nr_succeed, nr_failed, nr_pages);

                if (duration > 0 && b.tv_sec - start.tv_sec >= duration) {
                        ksft_test_result_pass("Completed\n");
                        ksft_finished();
                }
        }
}