1#include <linux/kernel.h>
  2#include <linux/mm.h>
  3#include <linux/slab.h>
  4#include <linux/uaccess.h>
  5#include <linux/ktime.h>
  6#include <linux/debugfs.h>
  7
  8#define GUP_FAST_BENCHMARK	_IOWR('g', 1, struct gup_benchmark)
  9#define GUP_LONGTERM_BENCHMARK	_IOWR('g', 2, struct gup_benchmark)
 10#define GUP_BENCHMARK		_IOWR('g', 3, struct gup_benchmark)
 11
 12struct gup_benchmark {
 13	__u64 get_delta_usec;
 14	__u64 put_delta_usec;
 15	__u64 addr;
 16	__u64 size;
 17	__u32 nr_pages_per_call;
 18	__u32 flags;
 19	__u64 expansion[10];	/* For future use */
 20};
 21
 22static int __gup_benchmark_ioctl(unsigned int cmd,
 23		struct gup_benchmark *gup)
 24{
 25	ktime_t start_time, end_time;
 26	unsigned long i, nr_pages, addr, next;
 27	int nr;
 28	struct page **pages;
 29
 30	if (gup->size > ULONG_MAX)
 31		return -EINVAL;
 32
 33	nr_pages = gup->size / PAGE_SIZE;
 34	pages = kvcalloc(nr_pages, sizeof(void *), GFP_KERNEL);
 35	if (!pages)
 36		return -ENOMEM;
 37
 38	i = 0;
 39	nr = gup->nr_pages_per_call;
 40	start_time = ktime_get();
 41	for (addr = gup->addr; addr < gup->addr + gup->size; addr = next) {
 42		if (nr != gup->nr_pages_per_call)
 43			break;
 44
 45		next = addr + nr * PAGE_SIZE;
 46		if (next > gup->addr + gup->size) {
 47			next = gup->addr + gup->size;
 48			nr = (next - addr) / PAGE_SIZE;
 49		}
 50
 51		switch (cmd) {
 52		case GUP_FAST_BENCHMARK:
 53			nr = get_user_pages_fast(addr, nr, gup->flags & 1,
 54						 pages + i);
 55			break;
 56		case GUP_LONGTERM_BENCHMARK:
 57			nr = get_user_pages(addr, nr,
 58					    (gup->flags & 1) | FOLL_LONGTERM,
 59					    pages + i, NULL);
 60			break;
 61		case GUP_BENCHMARK:
 62			nr = get_user_pages(addr, nr, gup->flags & 1, pages + i,
 63					    NULL);
 64			break;
 65		default:
 66			return -1;
 67		}
 68
 69		if (nr <= 0)
 70			break;
 71		i += nr;
 72	}
 73	end_time = ktime_get();
 74
 75	gup->get_delta_usec = ktime_us_delta(end_time, start_time);
 76	gup->size = addr - gup->addr;
 77
 78	start_time = ktime_get();
 79	for (i = 0; i < nr_pages; i++) {
 80		if (!pages[i])
 81			break;
 82		put_page(pages[i]);
 83	}
 84	end_time = ktime_get();
 85	gup->put_delta_usec = ktime_us_delta(end_time, start_time);
 86
 87	kvfree(pages);
 88	return 0;
 89}
 90
 91static long gup_benchmark_ioctl(struct file *filep, unsigned int cmd,
 92		unsigned long arg)
 93{
 94	struct gup_benchmark gup;
 95	int ret;
 96
 97	switch (cmd) {
 98	case GUP_FAST_BENCHMARK:
 99	case GUP_LONGTERM_BENCHMARK:
100	case GUP_BENCHMARK:
101		break;
102	default:
103		return -EINVAL;
104	}
105
106	if (copy_from_user(&gup, (void __user *)arg, sizeof(gup)))
107		return -EFAULT;
108
109	ret = __gup_benchmark_ioctl(cmd, &gup);
110	if (ret)
111		return ret;
112
113	if (copy_to_user((void __user *)arg, &gup, sizeof(gup)))
114		return -EFAULT;
115
116	return 0;
117}
118
119static const struct file_operations gup_benchmark_fops = {
120	.open = nonseekable_open,
121	.unlocked_ioctl = gup_benchmark_ioctl,
122};
123
124static int gup_benchmark_init(void)
125{
126	debugfs_create_file_unsafe("gup_benchmark", 0600, NULL, NULL,
127				   &gup_benchmark_fops);
128
129	return 0;
130}
131
132late_initcall(gup_benchmark_init);