1 files changed, 106 insertions, 0 deletions
diff --git a/mm/gup_benchmark.c b/mm/gup_benchmark.c
new file mode 100644
index 000000000..7e6f2d2da
--- /dev/null
+++ b/mm/gup_benchmark.c
@@ -0,0 +1,106 @@
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/ktime.h>
+#include <linux/debugfs.h>
+
+#define GUP_FAST_BENCHMARK	_IOWR('g', 1, struct gup_benchmark)
+
+struct gup_benchmark {
+	__u64 delta_usec;
+	__u64 addr;
+	__u64 size;
+	__u32 nr_pages_per_call;
+	__u32 flags;
+};
+
+static int __gup_benchmark_ioctl(unsigned int cmd,
+		struct gup_benchmark *gup)
+{
+	ktime_t start_time, end_time;
+	unsigned long i, nr_pages, addr, next;
+	int nr;
+	struct page **pages;
+
+	if (gup->size > ULONG_MAX)
+		return -EINVAL;
+
+	nr_pages = gup->size / PAGE_SIZE;
+	pages = kvcalloc(nr_pages, sizeof(void *), GFP_KERNEL);
+	if (!pages)
+		return -ENOMEM;
+
+	i = 0;
+	nr = gup->nr_pages_per_call;
+	start_time = ktime_get();
+	for (addr = gup->addr; addr < gup->addr + gup->size; addr = next) {
+		if (nr != gup->nr_pages_per_call)
+			break;
+
+		next = addr + nr * PAGE_SIZE;
+		if (next > gup->addr + gup->size) {
+			next = gup->addr + gup->size;
+			nr = (next - addr) / PAGE_SIZE;
+		}
+
+		nr = get_user_pages_fast(addr, nr, gup->flags & 1, pages + i);
+		if (nr <= 0)
+			break;
+		i += nr;
+	}
+	end_time = ktime_get();
+
+	gup->delta_usec = ktime_us_delta(end_time, start_time);
+	gup->size = addr - gup->addr;
+
+	for (i = 0; i < nr_pages; i++) {
+		if (!pages[i])
+			break;
+		put_page(pages[i]);
+	}
+
+	kvfree(pages);
+	return 0;
+}
+
+static long gup_benchmark_ioctl(struct file *filep, unsigned int cmd,
+		unsigned long arg)
+{
+	struct gup_benchmark gup;
+	int ret;
+
+	if (cmd != GUP_FAST_BENCHMARK)
+		return -EINVAL;
+
+	if (copy_from_user(&gup, (void __user *)arg, sizeof(gup)))
+		return -EFAULT;
+
+	ret = __gup_benchmark_ioctl(cmd, &gup);
+	if (ret)
+		return ret;
+
+	if (copy_to_user((void __user *)arg, &gup, sizeof(gup)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static const struct file_operations gup_benchmark_fops = {
+	.open = nonseekable_open,
+	.unlocked_ioctl = gup_benchmark_ioctl,
+};
+
+static int gup_benchmark_init(void)
+{
+	void *ret;
+
+	ret = debugfs_create_file_unsafe("gup_benchmark", 0600, NULL, NULL,
+			&gup_benchmark_fops);
+	if (!ret)
+		pr_warn("Failed to create gup_benchmark in debugfs");
+
+	return 0;
+}
+
+late_initcall(gup_benchmark_init);