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
10 struct gup_benchmark {
11 __u64 delta_usec;
12 __u64 addr;
13 __u64 size;
14 __u32 nr_pages_per_call;
15 __u32 flags;
16 };
17
__gup_benchmark_ioctl(unsigned int cmd,struct gup_benchmark * gup)18 static int __gup_benchmark_ioctl(unsigned int cmd,
19 struct gup_benchmark *gup)
20 {
21 ktime_t start_time, end_time;
22 unsigned long i, nr_pages, addr, next;
23 int nr;
24 struct page **pages;
25
26 nr_pages = gup->size / PAGE_SIZE;
27 pages = kvcalloc(nr_pages, sizeof(void *), GFP_KERNEL);
28 if (!pages)
29 return -ENOMEM;
30
31 i = 0;
32 nr = gup->nr_pages_per_call;
33 start_time = ktime_get();
34 for (addr = gup->addr; addr < gup->addr + gup->size; addr = next) {
35 if (nr != gup->nr_pages_per_call)
36 break;
37
38 next = addr + nr * PAGE_SIZE;
39 if (next > gup->addr + gup->size) {
40 next = gup->addr + gup->size;
41 nr = (next - addr) / PAGE_SIZE;
42 }
43
44 nr = get_user_pages_fast(addr, nr, gup->flags & 1, pages + i);
45 if (nr <= 0)
46 break;
47 i += nr;
48 }
49 end_time = ktime_get();
50
51 gup->delta_usec = ktime_us_delta(end_time, start_time);
52 gup->size = addr - gup->addr;
53
54 for (i = 0; i < nr_pages; i++) {
55 if (!pages[i])
56 break;
57 put_page(pages[i]);
58 }
59
60 kvfree(pages);
61 return 0;
62 }
63
gup_benchmark_ioctl(struct file * filep,unsigned int cmd,unsigned long arg)64 static long gup_benchmark_ioctl(struct file *filep, unsigned int cmd,
65 unsigned long arg)
66 {
67 struct gup_benchmark gup;
68 int ret;
69
70 if (cmd != GUP_FAST_BENCHMARK)
71 return -EINVAL;
72
73 if (copy_from_user(&gup, (void __user *)arg, sizeof(gup)))
74 return -EFAULT;
75
76 ret = __gup_benchmark_ioctl(cmd, &gup);
77 if (ret)
78 return ret;
79
80 if (copy_to_user((void __user *)arg, &gup, sizeof(gup)))
81 return -EFAULT;
82
83 return 0;
84 }
85
86 static const struct file_operations gup_benchmark_fops = {
87 .open = nonseekable_open,
88 .unlocked_ioctl = gup_benchmark_ioctl,
89 };
90
gup_benchmark_init(void)91 static int gup_benchmark_init(void)
92 {
93 void *ret;
94
95 ret = debugfs_create_file_unsafe("gup_benchmark", 0600, NULL, NULL,
96 &gup_benchmark_fops);
97 if (!ret)
98 pr_warn("Failed to create gup_benchmark in debugfs");
99
100 return 0;
101 }
102
103 late_initcall(gup_benchmark_init);
104
