mm: add infrastructure for get_user_pages_fast() benchmarking (64c349f4) · Commits · 戴 / test

mm/Kconfig

+9 −0

Original line number	Diff line number	Diff line
		@@ -756,3 +756,12 @@ config PERCPU_STATS
		This feature collects and exposes statistics via debugfs. The
		information includes global and per chunk statistics, which can
		be used to help understand percpu memory usage.

		config GUP_BENCHMARK
		bool "Enable infrastructure for get_user_pages_fast() benchmarking"
		default n
		help
		Provides /sys/kernel/debug/gup_benchmark that helps with testing
		performance of get_user_pages_fast().

		See tools/testing/selftests/vm/gup_benchmark.c

mm/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -80,6 +80,7 @@ obj-$(CONFIG_PAGE_COUNTER) += page_counter.o
		obj-$(CONFIG_MEMCG) += memcontrol.o vmpressure.o
		obj-$(CONFIG_MEMCG_SWAP) += swap_cgroup.o
		obj-$(CONFIG_CGROUP_HUGETLB) += hugetlb_cgroup.o
		obj-$(CONFIG_GUP_BENCHMARK) += gup_benchmark.o
		obj-$(CONFIG_MEMORY_FAILURE) += memory-failure.o
		obj-$(CONFIG_HWPOISON_INJECT) += hwpoison-inject.o
		obj-$(CONFIG_DEBUG_KMEMLEAK) += kmemleak.o

mm/gup_benchmark.c

0 → 100644

+100 −0

Original line number	Diff line number	Diff line
		#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, nr_pages, addr, next;
		struct page **pages;

		nr_pages = gup->size / PAGE_SIZE;
		pages = kvmalloc(sizeof(void ) nr_pages, 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);
		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);

tools/testing/selftests/vm/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -18,6 +18,7 @@ TEST_GEN_FILES += transhuge-stress
		TEST_GEN_FILES += userfaultfd
		TEST_GEN_FILES += mlock-random-test
		TEST_GEN_FILES += virtual_address_range
		TEST_GEN_FILES += gup_benchmark

		TEST_PROGS := run_vmtests

tools/testing/selftests/vm/gup_benchmark.c

0 → 100644

+91 −0

Original line number	Diff line number	Diff line
		#include <fcntl.h>
		#include <stdio.h>
		#include <stdlib.h>
		#include <unistd.h>

		#include <sys/ioctl.h>
		#include <sys/mman.h>
		#include <sys/prctl.h>
		#include <sys/stat.h>
		#include <sys/types.h>

		#include <linux/types.h>

		#define MB (1UL << 20)
		#define PAGE_SIZE sysconf(_SC_PAGESIZE)

		#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;
		};

		int main(int argc, char **argv)
		{
		struct gup_benchmark gup;
		unsigned long size = 128 * MB;
		int i, fd, opt, nr_pages = 1, thp = -1, repeats = 1, write = 0;
		char *p;

		while ((opt = getopt(argc, argv, "m:r:n:tT")) != -1) {
		switch (opt) {
		case 'm':
		size = atoi(optarg) * MB;
		break;
		case 'r':
		repeats = atoi(optarg);
		break;
		case 'n':
		nr_pages = atoi(optarg);
		break;
		case 't':
		thp = 1;
		break;
		case 'T':
		thp = 0;
		break;
		case 'w':
		write = 1;
		default:
		return -1;
		}
		}

		gup.nr_pages_per_call = nr_pages;
		gup.flags = write;

		fd = open("/sys/kernel/debug/gup_benchmark", O_RDWR);
		if (fd == -1)
		perror("open"), exit(1);

		p = mmap(NULL, size, PROT_READ \| PROT_WRITE,
		MAP_ANONYMOUS \| MAP_PRIVATE, -1, 0);
		if (p == MAP_FAILED)
		perror("mmap"), exit(1);
		gup.addr = (unsigned long)p;

		if (thp == 1)
		madvise(p, size, MADV_HUGEPAGE);
		else if (thp == 0)
		madvise(p, size, MADV_NOHUGEPAGE);

		for (; (unsigned long)p < gup.addr + size; p += PAGE_SIZE)
		p[0] = 0;

		for (i = 0; i < repeats; i++) {
		gup.size = size;
		if (ioctl(fd, GUP_FAST_BENCHMARK, &gup))
		perror("ioctl"), exit(1);

		printf("Time: %lld us", gup.delta_usec);
		if (gup.size != size)
		printf(", truncated (size: %lld)", gup.size);
		printf("\n");
		}

		return 0;
		}

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