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

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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: John 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
John Hubbard 2020-12-14 19:05:21 -08:00 committed by Linus Torvalds
parent a9bed1e1c2
commit f4f9bda418
4 changed files with 113 additions and 4 deletions
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6
mm/Kconfig
View File

@ -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

56
mm/gup_test.c
View File

@ -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;

10
mm/gup_test.h
View File

@ -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 */

45
tools/testing/selftests/vm/gup_test.c
View File

@ -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");