Commit f4f9bda4 authored by John Hubbard's avatar John Hubbard Committed by Linus Torvalds
Browse files

selftests/vm: gup_test: introduce the dump_pages() sub-test 

For quite a while, I was doing a quick hack to gup_test.c (previously,
gup_benchmark.c) whenever I wanted to try out my changes to dump_page().
This makes that hack unnecessary, and instead allows anyone to easily get
the same coverage from a user space program.  That saves a lot of time
because you don't have to change the kernel, in order to test different
pages and options.

The new sub-test takes advantage of the existing gup_test infrastructure,
which already provides a simple user space program, some allocated user
space pages, an ioctl call, pinning of those pages (via either
get_user_pages or pin_user_pages) and a corresponding kernel-side test
invocation.  There's not much more required, mainly just a couple of
inputs from the user.

In fact, the new test re-uses the existing command line options in order
to get various helpful combinations (THP or normal, _fast or slow gup, gup
vs.  pup, and more).

New command line options are: which pages to dump, and what type of
"get/pin" to use.

In order to figure out which pages to dump, the logic is:

* If the user doesn't specify anything, the page 0 (the first page in
  the address range that the program sets up for testing) is dumped.

* Or, the user can type up to 8 page indices anywhere on the command
  line.  If you type more than 8, then it uses the first 8 and ignores the
  remaining items.

For example:

    ./gup_test -ct -F 1 0 19 0x1000

Meaning:
    -c:          dump pages sub-test
    -t:          use THP pages
    -F 1:        use pin_user_pages() instead of get_user_pages()
    0 19 0x1000: dump pages 0, 19, and 4096

Link: https://lkml.kernel.org/r/20201026064021.3545418-7-jhubbard@nvidia.com


Signed-off-by: default avatarJohn Hubbard <jhubbard@nvidia.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a9bed1e1

mm/Kconfig

+6 −0
Original line number Diff line number Diff line
@@ -832,6 +832,12 @@ config GUP_TEST 
	  get_user_pages*() and pin_user_pages*(), as well as smoke tests of

	  the non-_fast variants.



	  There is also a sub-test that allows running dump_page() on any

	  of up to eight pages (selected by command line args) within the

	  range of user-space addresses. These pages are either pinned via

	  pin_user_pages*(), or pinned via get_user_pages*(), as specified

	  by other command line arguments.



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



config GUP_GET_PTE_LOW_HIGH

mm/gup_test.c

+54 −2
Original line number Diff line number Diff line
@@ -7,7 +7,7 @@ 
#include "gup_test.h"



static void put_back_pages(unsigned int cmd, struct page **pages,

			   unsigned long nr_pages)

			   unsigned long nr_pages, unsigned int gup_test_flags)

{

	unsigned long i;
@@ -23,6 +23,15 @@ static void put_back_pages(unsigned int cmd, struct page **pages, 
	case PIN_LONGTERM_BENCHMARK:

		unpin_user_pages(pages, nr_pages);

		break;

	case DUMP_USER_PAGES_TEST:

		if (gup_test_flags & GUP_TEST_FLAG_DUMP_PAGES_USE_PIN) {

			unpin_user_pages(pages, nr_pages);

		} else {

			for (i = 0; i < nr_pages; i++)

				put_page(pages[i]);



		}

		break;

	}

}
@@ -49,6 +58,37 @@ static void verify_dma_pinned(unsigned int cmd, struct page **pages, 
	}

}



static void dump_pages_test(struct gup_test *gup, struct page **pages,

			    unsigned long nr_pages)

{

	unsigned int index_to_dump;

	unsigned int i;



	/*

	 * Zero out any user-supplied page index that is out of range. Remember:

	 * .which_pages[] contains a 1-based set of page indices.

	 */

	for (i = 0; i < GUP_TEST_MAX_PAGES_TO_DUMP; i++) {

		if (gup->which_pages[i] > nr_pages) {

			pr_warn("ZEROING due to out of range: .which_pages[%u]: %u\n",

				i, gup->which_pages[i]);

			gup->which_pages[i] = 0;

		}

	}



	for (i = 0; i < GUP_TEST_MAX_PAGES_TO_DUMP; i++) {

		index_to_dump = gup->which_pages[i];



		if (index_to_dump) {

			index_to_dump--; // Decode from 1-based, to 0-based

			pr_info("---- page #%u, starting from user virt addr: 0x%llx\n",

				index_to_dump, gup->addr);

			dump_page(pages[index_to_dump],

				  "gup_test: dump_pages() test");

		}

	}

}



static int __gup_test_ioctl(unsigned int cmd,

		struct gup_test *gup)

{
@@ -111,6 +151,14 @@ static int __gup_test_ioctl(unsigned int cmd, 
					    gup->flags | FOLL_LONGTERM,

					    pages + i, NULL);

			break;

		case DUMP_USER_PAGES_TEST:

			if (gup->flags & GUP_TEST_FLAG_DUMP_PAGES_USE_PIN)

				nr = pin_user_pages(addr, nr, gup->flags,

						    pages + i, NULL);

			else

				nr = get_user_pages(addr, nr, gup->flags,

						    pages + i, NULL);

			break;

		default:

			ret = -EINVAL;

			goto unlock;
@@ -134,9 +182,12 @@ static int __gup_test_ioctl(unsigned int cmd, 
	 */

	verify_dma_pinned(cmd, pages, nr_pages);



	if (cmd == DUMP_USER_PAGES_TEST)

		dump_pages_test(gup, pages, nr_pages);



	start_time = ktime_get();



	put_back_pages(cmd, pages, nr_pages);

	put_back_pages(cmd, pages, nr_pages, gup->flags);



	end_time = ktime_get();

	gup->put_delta_usec = ktime_us_delta(end_time, start_time);
@@ -161,6 +212,7 @@ static long gup_test_ioctl(struct file *filep, unsigned int cmd, 
	case PIN_LONGTERM_BENCHMARK:

	case GUP_BASIC_TEST:

	case PIN_BASIC_TEST:

	case DUMP_USER_PAGES_TEST:

		break;

	default:

		return -EINVAL;

mm/gup_test.h

+10 −0
Original line number Diff line number Diff line
@@ -9,6 +9,11 @@ 
#define PIN_LONGTERM_BENCHMARK	_IOWR('g', 3, struct gup_test)

#define GUP_BASIC_TEST		_IOWR('g', 4, struct gup_test)

#define PIN_BASIC_TEST		_IOWR('g', 5, struct gup_test)

#define DUMP_USER_PAGES_TEST	_IOWR('g', 6, struct gup_test)



#define GUP_TEST_MAX_PAGES_TO_DUMP		8



#define GUP_TEST_FLAG_DUMP_PAGES_USE_PIN	0x1



struct gup_test {

	__u64 get_delta_usec;
@@ -17,6 +22,11 @@ struct gup_test { 
	__u64 size;

	__u32 nr_pages_per_call;

	__u32 flags;

	/*

	 * Each non-zero entry is the number of the page (1-based: first page is

	 * page 1, so that zero entries mean "do nothing") from the .addr base.

	 */

	__u32 which_pages[GUP_TEST_MAX_PAGES_TO_DUMP];

};



#endif	/* __GUP_TEST_H */

tools/testing/selftests/vm/gup_test.c

+43 −2
Original line number Diff line number Diff line
@@ -27,13 +27,15 @@ static char *cmd_to_str(unsigned long cmd) 
		return "GUP_BASIC_TEST";

	case PIN_BASIC_TEST:

		return "PIN_BASIC_TEST";

	case DUMP_USER_PAGES_TEST:

		return "DUMP_USER_PAGES_TEST";

	}

	return "Unknown command";

}



int main(int argc, char **argv)

{

	struct gup_test gup;

	struct gup_test gup = { 0 };

	unsigned long size = 128 * MB;

	int i, fd, filed, opt, nr_pages = 1, thp = -1, repeats = 1, write = 0;

	unsigned long cmd = GUP_FAST_BENCHMARK;
@@ -41,7 +43,7 @@ int main(int argc, char **argv) 
	char *file = "/dev/zero";

	char *p;



	while ((opt = getopt(argc, argv, "m:r:n:f:abtTLUuwSH")) != -1) {

	while ((opt = getopt(argc, argv, "m:r:n:F:f:abctTLUuwSH")) != -1) {

		switch (opt) {

		case 'a':

			cmd = PIN_FAST_BENCHMARK;
@@ -52,6 +54,21 @@ int main(int argc, char **argv) 
		case 'L':

			cmd = PIN_LONGTERM_BENCHMARK;

			break;

		case 'c':

			cmd = DUMP_USER_PAGES_TEST;

			/*

			 * Dump page 0 (index 1). May be overridden later, by

			 * user's non-option arguments.

			 *

			 * .which_pages is zero-based, so that zero can mean "do

			 * nothing".

			 */

			gup.which_pages[0] = 1;

			break;

		case 'F':

			/* strtol, so you can pass flags in hex form */

			gup.flags = strtol(optarg, 0, 0);

			break;

		case 'm':

			size = atoi(optarg) * MB;

			break;
@@ -91,6 +108,30 @@ int main(int argc, char **argv) 
		}

	}



	if (optind < argc) {

		int extra_arg_count = 0;

		/*

		 * For example:

		 *

		 *   ./gup_test -c 0 1 0x1001

		 *

		 * ...to dump pages 0, 1, and 4097

		 */



		while ((optind < argc) &&

		       (extra_arg_count < GUP_TEST_MAX_PAGES_TO_DUMP)) {

			/*

			 * Do the 1-based indexing here, so that the user can

			 * use normal 0-based indexing on the command line.

			 */

			long page_index = strtol(argv[optind], 0, 0) + 1;



			gup.which_pages[extra_arg_count] = page_index;

			extra_arg_count++;

			optind++;

		}

	}



	filed = open(file, O_RDWR|O_CREAT);

	if (filed < 0) {

		perror("open");