diff options
Diffstat (limited to 'mm/gup_benchmark.c')
| -rw-r--r-- | mm/gup_benchmark.c | 210 |
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); |