From: Pavel Tatashin <pasha.tatashin@soleen.com>
To: pasha.tatashin@soleen.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, akpm@linux-foundation.org, vbabka@suse.cz,
mhocko@suse.com, david@redhat.com, osalvador@suse.de,
dan.j.williams@intel.com, sashal@kernel.org,
tyhicks@linux.microsoft.com, iamjoonsoo.kim@lge.com,
mike.kravetz@oracle.com, rostedt@goodmis.org, mingo@redhat.com,
jgg@ziepe.ca, peterz@infradead.org, mgorman@suse.de,
willy@infradead.org, rientjes@google.com, jhubbard@nvidia.com,
linux-doc@vger.kernel.org, ira.weiny@intel.com,
linux-kselftest@vger.kernel.org, jmorris@namei.org
Subject: [PATCH v9 14/14] selftests/vm: gup_test: test faulting in kernel, and verify pinnable pages
Date: Mon, 1 Feb 2021 10:38:27 -0500 [thread overview]
Message-ID: <20210201153827.444374-15-pasha.tatashin@soleen.com> (raw)
In-Reply-To: <20210201153827.444374-1-pasha.tatashin@soleen.com>
When pages are pinned they can be faulted in userland and migrated, and
they can be faulted right in kernel without migration.
In either case, the pinned pages must end-up being pinnable (not movable).
Add a new test to gup_test, to help verify that the gup/pup
(get_user_pages() / pin_user_pages()) behavior with respect to pinnable
and movable pages is reasonable and correct. Specifically, provide a
way to:
1) Verify that only "pinnable" pages are pinned. This is checked
automatically for you.
2) Verify that gup/pup performance is reasonable. This requires
comparing benchmarks between doing gup/pup on pages that have been
pre-faulted in from user space, vs. doing gup/pup on pages that are not
faulted in until gup/pup time (via FOLL_TOUCH). This decision is
controlled with the new -z command line option.
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
---
mm/gup_test.c | 6 ++++++
tools/testing/selftests/vm/gup_test.c | 23 +++++++++++++++++++----
2 files changed, 25 insertions(+), 4 deletions(-)
diff --git a/mm/gup_test.c b/mm/gup_test.c
index a6ed1c877679..d974dec19e1c 100644
--- a/mm/gup_test.c
+++ b/mm/gup_test.c
@@ -52,6 +52,12 @@ static void verify_dma_pinned(unsigned int cmd, struct page **pages,
dump_page(page, "gup_test failure");
break;
+ } else if (cmd == PIN_LONGTERM_BENCHMARK &&
+ WARN(!is_pinnable_page(page),
+ "pages[%lu] is NOT pinnable but pinned\n",
+ i)) {
+ dump_page(page, "gup_test failure");
+ break;
}
}
break;
diff --git a/tools/testing/selftests/vm/gup_test.c b/tools/testing/selftests/vm/gup_test.c
index 943cc2608dc2..1e662d59c502 100644
--- a/tools/testing/selftests/vm/gup_test.c
+++ b/tools/testing/selftests/vm/gup_test.c
@@ -13,6 +13,7 @@
/* Just the flags we need, copied from mm.h: */
#define FOLL_WRITE 0x01 /* check pte is writable */
+#define FOLL_TOUCH 0x02 /* mark page accessed */
static char *cmd_to_str(unsigned long cmd)
{
@@ -39,11 +40,11 @@ int main(int argc, char **argv)
unsigned long size = 128 * MB;
int i, fd, filed, opt, nr_pages = 1, thp = -1, repeats = 1, write = 1;
unsigned long cmd = GUP_FAST_BENCHMARK;
- int flags = MAP_PRIVATE;
+ int flags = MAP_PRIVATE, touch = 0;
char *file = "/dev/zero";
char *p;
- while ((opt = getopt(argc, argv, "m:r:n:F:f:abctTLUuwWSHp")) != -1) {
+ while ((opt = getopt(argc, argv, "m:r:n:F:f:abctTLUuwWSHpz")) != -1) {
switch (opt) {
case 'a':
cmd = PIN_FAST_BENCHMARK;
@@ -110,6 +111,10 @@ int main(int argc, char **argv)
case 'H':
flags |= (MAP_HUGETLB | MAP_ANONYMOUS);
break;
+ case 'z':
+ /* fault pages in gup, do not fault in userland */
+ touch = 1;
+ break;
default:
return -1;
}
@@ -167,8 +172,18 @@ int main(int argc, char **argv)
else if (thp == 0)
madvise(p, size, MADV_NOHUGEPAGE);
- for (; (unsigned long)p < gup.addr + size; p += PAGE_SIZE)
- p[0] = 0;
+ /*
+ * FOLL_TOUCH, in gup_test, is used as an either/or case: either
+ * fault pages in from the kernel via FOLL_TOUCH, or fault them
+ * in here, from user space. This allows comparison of performance
+ * between those two cases.
+ */
+ if (touch) {
+ gup.gup_flags |= FOLL_TOUCH;
+ } else {
+ for (; (unsigned long)p < gup.addr + size; p += PAGE_SIZE)
+ p[0] = 0;
+ }
/* Only report timing information on the *_BENCHMARK commands: */
if ((cmd == PIN_FAST_BENCHMARK) || (cmd == GUP_FAST_BENCHMARK) ||
--
2.25.1
prev parent reply other threads:[~2021-02-01 15:43 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-01 15:38 [PATCH v9 00/14] prohibit pinning pages in ZONE_MOVABLE Pavel Tatashin
2021-02-01 15:38 ` [PATCH v9 01/14] mm/gup: don't pin migrated cma pages in movable zone Pavel Tatashin
2021-02-01 15:38 ` [PATCH v9 02/14] mm/gup: check every subpage of a compound page during isolation Pavel Tatashin
2021-02-01 15:38 ` [PATCH v9 03/14] mm/gup: return an error on migration failure Pavel Tatashin
2021-02-01 15:38 ` [PATCH v9 04/14] mm/gup: check for isolation errors Pavel Tatashin
2021-02-01 15:38 ` [PATCH v9 05/14] mm cma: rename PF_MEMALLOC_NOCMA to PF_MEMALLOC_PIN Pavel Tatashin
2021-02-01 15:38 ` [PATCH v9 06/14] mm: apply per-task gfp constraints in fast path Pavel Tatashin
2021-02-01 15:38 ` [PATCH v9 07/14] mm: honor PF_MEMALLOC_PIN for all movable pages Pavel Tatashin
2021-02-01 15:38 ` [PATCH v9 08/14] mm/gup: do not migrate zero page Pavel Tatashin
2021-02-02 2:41 ` kernel test robot
2021-02-02 4:05 ` Pavel Tatashin
2021-02-01 15:38 ` [PATCH v9 09/14] mm/gup: migrate pinned pages out of movable zone Pavel Tatashin
2021-02-01 15:38 ` [PATCH v9 10/14] memory-hotplug.rst: add a note about ZONE_MOVABLE and page pinning Pavel Tatashin
2021-02-01 15:38 ` [PATCH v9 11/14] mm/gup: change index type to long as it counts pages Pavel Tatashin
2021-02-01 15:38 ` [PATCH v9 12/14] mm/gup: longterm pin migration cleanup Pavel Tatashin
2021-02-01 15:38 ` [PATCH v9 13/14] selftests/vm: gup_test: fix test flag Pavel Tatashin
2021-02-01 15:38 ` Pavel Tatashin [this message]
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