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-rw-r--r--mm/gup_benchmark.c210
1 files changed, 210 insertions, 0 deletions
diff --git a/mm/gup_benchmark.c b/mm/gup_benchmark.c
new file mode 100644
index 000000000..8b3e5b5cd
--- /dev/null
+++ b/mm/gup_benchmark.c
@@ -0,0 +1,210 @@
+#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)
+#define GUP_BENCHMARK _IOWR('g', 2, struct gup_benchmark)
+#define PIN_FAST_BENCHMARK _IOWR('g', 3, struct gup_benchmark)
+#define PIN_BENCHMARK _IOWR('g', 4, struct gup_benchmark)
+#define PIN_LONGTERM_BENCHMARK _IOWR('g', 5, struct gup_benchmark)
+
+struct gup_benchmark {
+ __u64 get_delta_usec;
+ __u64 put_delta_usec;
+ __u64 addr;
+ __u64 size;
+ __u32 nr_pages_per_call;
+ __u32 flags;
+ __u64 expansion[10]; /* For future use */
+};
+
+static void put_back_pages(unsigned int cmd, struct page **pages,
+ unsigned long nr_pages)
+{
+ unsigned long i;
+
+ switch (cmd) {
+ case GUP_FAST_BENCHMARK:
+ case GUP_BENCHMARK:
+ for (i = 0; i < nr_pages; i++)
+ put_page(pages[i]);
+ break;
+
+ case PIN_FAST_BENCHMARK:
+ case PIN_BENCHMARK:
+ case PIN_LONGTERM_BENCHMARK:
+ unpin_user_pages(pages, nr_pages);
+ break;
+ }
+}
+
+static void verify_dma_pinned(unsigned int cmd, struct page **pages,
+ unsigned long nr_pages)
+{
+ unsigned long i;
+ struct page *page;
+
+ switch (cmd) {
+ case PIN_FAST_BENCHMARK:
+ case PIN_BENCHMARK:
+ case PIN_LONGTERM_BENCHMARK:
+ for (i = 0; i < nr_pages; i++) {
+ page = pages[i];
+ if (WARN(!page_maybe_dma_pinned(page),
+ "pages[%lu] is NOT dma-pinned\n", i)) {
+
+ dump_page(page, "gup_benchmark failure");
+ break;
+ }
+ }
+ break;
+ }
+}
+
+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;
+ int ret = 0;
+ bool needs_mmap_lock =
+ cmd != GUP_FAST_BENCHMARK && cmd != PIN_FAST_BENCHMARK;
+
+ 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;
+
+ if (needs_mmap_lock && mmap_read_lock_killable(current->mm)) {
+ ret = -EINTR;
+ goto free_pages;
+ }
+
+ 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;
+ }
+
+ /* Filter out most gup flags: only allow a tiny subset here: */
+ gup->flags &= FOLL_WRITE;
+
+ switch (cmd) {
+ case GUP_FAST_BENCHMARK:
+ nr = get_user_pages_fast(addr, nr, gup->flags,
+ pages + i);
+ break;
+ case GUP_BENCHMARK:
+ nr = get_user_pages(addr, nr, gup->flags, pages + i,
+ NULL);
+ break;
+ case PIN_FAST_BENCHMARK:
+ nr = pin_user_pages_fast(addr, nr, gup->flags,
+ pages + i);
+ break;
+ case PIN_BENCHMARK:
+ nr = pin_user_pages(addr, nr, gup->flags, pages + i,
+ NULL);
+ break;
+ case PIN_LONGTERM_BENCHMARK:
+ nr = pin_user_pages(addr, nr,
+ gup->flags | FOLL_LONGTERM,
+ pages + i, NULL);
+ break;
+ default:
+ ret = -EINVAL;
+ goto unlock;
+ }
+
+ if (nr <= 0)
+ break;
+ i += nr;
+ }
+ end_time = ktime_get();
+
+ /* Shifting the meaning of nr_pages: now it is actual number pinned: */
+ nr_pages = i;
+
+ gup->get_delta_usec = ktime_us_delta(end_time, start_time);
+ gup->size = addr - gup->addr;
+
+ /*
+ * Take an un-benchmark-timed moment to verify DMA pinned
+ * state: print a warning if any non-dma-pinned pages are found:
+ */
+ verify_dma_pinned(cmd, pages, nr_pages);
+
+ start_time = ktime_get();
+
+ put_back_pages(cmd, pages, nr_pages);
+
+ end_time = ktime_get();
+ gup->put_delta_usec = ktime_us_delta(end_time, start_time);
+
+unlock:
+ if (needs_mmap_lock)
+ mmap_read_unlock(current->mm);
+free_pages:
+ kvfree(pages);
+ return ret;
+}
+
+static long gup_benchmark_ioctl(struct file *filep, unsigned int cmd,
+ unsigned long arg)
+{
+ struct gup_benchmark gup;
+ int ret;
+
+ switch (cmd) {
+ case GUP_FAST_BENCHMARK:
+ case GUP_BENCHMARK:
+ case PIN_FAST_BENCHMARK:
+ case PIN_BENCHMARK:
+ case PIN_LONGTERM_BENCHMARK:
+ break;
+ default:
+ 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)
+{
+ debugfs_create_file_unsafe("gup_benchmark", 0600, NULL, NULL,
+ &gup_benchmark_fops);
+
+ return 0;
+}
+
+late_initcall(gup_benchmark_init);