mm/gup_benchmark: rename to mm/gup_test

Patch series "selftests/vm: gup_test, hmm-tests, assorted improvements", v3.

Summary: This series provides two main things, and a number of smaller
supporting goodies.  The two main points are:

1) Add a new sub-test to gup_test, which in turn is a renamed version
   of gup_benchmark.  This sub-test allows nicer testing of dump_pages(),
   at least on user-space pages.

   For quite a while, I was doing a quick hack to gup_test.c whenever I
   wanted to try out changes to dump_page().  Then Matthew Wilcox asked me
   what I meant when I said "I used my dump_page() unit test", and I
   realized that it might be nice to check in a polished up version of
   that.

   Details about how it works and how to use it are in the commit
   description for patch #6 ("selftests/vm: gup_test: introduce the
   dump_pages() sub-test").

2) Fixes a limitation of hmm-tests: these tests are incredibly useful,
   but only if people actually build and run them.  And it turns out that
   libhugetlbfs is a little too effective at throwing a wrench in the
   works, there.  So I've added a little configuration check that removes
   just two of the 21 hmm-tests, if libhugetlbfs is not available.

   Further details in the commit description of patch #8
   ("selftests/vm: hmm-tests: remove the libhugetlbfs dependency").

Other smaller things that this series does:

a) Remove code duplication by creating gup_test.h.

b) Clear up the sub-test organization, and their invocation within
   run_vmtests.sh.

c) Other minor assorted improvements.

[1] v2 is here:
https://lore.kernel.org/linux-doc/20200929212747.251804-1-jhubbard@nvidia.com/

[2] https://lore.kernel.org/r/CAHk-=wgh-TMPHLY3jueHX7Y2fWh3D+nMBqVS__AZm6-oorquWA@mail.gmail.com

This patch (of 9):

Rename nearly every "gup_benchmark" reference and file name to "gup_test".
The one exception is for the actual gup benchmark test itself.

The current code already does a *little* bit more than benchmarking, and
definitely covers more than get_user_pages_fast().  More importantly,
however, subsequent patches are about to add some functionality that is
non-benchmark related.

Closely related changes:

* Kconfig: in addition to renaming the options from GUP_BENCHMARK to
  GUP_TEST, update the help text to reflect that it's no longer a
  benchmark-only test.

Link: https://lkml.kernel.org/r/20201026064021.3545418-1-jhubbard@nvidia.com
Link: https://lkml.kernel.org/r/20201026064021.3545418-2-jhubbard@nvidia.comSigned-off-by: NJohn Hubbard <jhubbard@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Documentation/core-api/pin_user_pages.rst

@@ -221,12 +221,12 @@ Unit testing
 ============
 This file::
 
- tools/testing/selftests/vm/gup_benchmark.c
+ tools/testing/selftests/vm/gup_test.c
 
 has the following new calls to exercise the new pin*() wrapper functions:
 
-* PIN_FAST_BENCHMARK (./gup_benchmark -a)
-* PIN_BENCHMARK (./gup_benchmark -b)
+* PIN_FAST_BENCHMARK (./gup_test -a)
+* PIN_BENCHMARK (./gup_test -b)
 
 You can monitor how many total dma-pinned pages have been acquired and released
 since the system was booted, via two new /proc/vmstat entries: ::

arch/s390/configs/debug_defconfig

@@ -102,7 +102,7 @@ CONFIG_ZSMALLOC_STAT=y
 CONFIG_DEFERRED_STRUCT_PAGE_INIT=y
 CONFIG_IDLE_PAGE_TRACKING=y
 CONFIG_PERCPU_STATS=y
-CONFIG_GUP_BENCHMARK=y
+CONFIG_GUP_TEST=y
 CONFIG_NET=y
 CONFIG_PACKET=y
 CONFIG_PACKET_DIAG=m

arch/s390/configs/defconfig

@@ -95,7 +95,7 @@ CONFIG_ZSMALLOC_STAT=y
 CONFIG_DEFERRED_STRUCT_PAGE_INIT=y
 CONFIG_IDLE_PAGE_TRACKING=y
 CONFIG_PERCPU_STATS=y
-CONFIG_GUP_BENCHMARK=y
+CONFIG_GUP_TEST=y
 CONFIG_NET=y
 CONFIG_PACKET=y
 CONFIG_PACKET_DIAG=m

mm/Kconfig

@@ -821,13 +821,18 @@ config PERCPU_STATS
 	  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() and related calls benchmarking"
+config GUP_TEST
+	bool "Enable infrastructure for get_user_pages()-related unit tests"
 	help
-	  Provides /sys/kernel/debug/gup_benchmark that helps with testing
-	  performance of get_user_pages() and related calls.
+	  Provides /sys/kernel/debug/gup_test, which in turn provides a way
+	  to make ioctl calls that can launch kernel-based unit tests for
+	  the get_user_pages*() and pin_user_pages*() family of API calls.
 
-	  See tools/testing/selftests/vm/gup_benchmark.c
+	  These tests include benchmark testing of the _fast variants of
+	  get_user_pages*() and pin_user_pages*(), as well as smoke tests of
+	  the non-_fast variants.
+
+	  See tools/testing/selftests/vm/gup_test.c
 
 config GUP_GET_PTE_LOW_HIGH
 	bool

mm/Makefile

@@ -90,7 +90,7 @@ 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_GUP_TEST) += gup_test.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 → mm/gup_test.c

@@ -5,13 +5,13 @@
 #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)
+#define GUP_FAST_BENCHMARK	_IOWR('g', 1, struct gup_test)
+#define GUP_BENCHMARK		_IOWR('g', 2, struct gup_test)
+#define PIN_FAST_BENCHMARK	_IOWR('g', 3, struct gup_test)
+#define PIN_BENCHMARK		_IOWR('g', 4, struct gup_test)
+#define PIN_LONGTERM_BENCHMARK	_IOWR('g', 5, struct gup_test)
 
-struct gup_benchmark {
+struct gup_test {
 	__u64 get_delta_usec;
 	__u64 put_delta_usec;
 	__u64 addr;
@@ -56,7 +56,7 @@ static void verify_dma_pinned(unsigned int cmd, struct page **pages,
 			if (WARN(!page_maybe_dma_pinned(page),
 				 "pages[%lu] is NOT dma-pinned\n", i)) {
 
-				dump_page(page, "gup_benchmark failure");
+				dump_page(page, "gup_test failure");
 				break;
 			}
 		}
@@ -64,8 +64,8 @@ static void verify_dma_pinned(unsigned int cmd, struct page **pages,
 	}
 }
 
-static int __gup_benchmark_ioctl(unsigned int cmd,
-		struct gup_benchmark *gup)
+static int __gup_test_ioctl(unsigned int cmd,
+		struct gup_test *gup)
 {
 	ktime_t start_time, end_time;
 	unsigned long i, nr_pages, addr, next;
@@ -164,10 +164,10 @@ static int __gup_benchmark_ioctl(unsigned int cmd,
 	return ret;
 }
 
-static long gup_benchmark_ioctl(struct file *filep, unsigned int cmd,
+static long gup_test_ioctl(struct file *filep, unsigned int cmd,
 		unsigned long arg)
 {
-	struct gup_benchmark gup;
+	struct gup_test gup;
 	int ret;
 
 	switch (cmd) {
@@ -184,7 +184,7 @@ static long gup_benchmark_ioctl(struct file *filep, unsigned int cmd,
 	if (copy_from_user(&gup, (void __user *)arg, sizeof(gup)))
 		return -EFAULT;
 
-	ret = __gup_benchmark_ioctl(cmd, &gup);
+	ret = __gup_test_ioctl(cmd, &gup);
 	if (ret)
 		return ret;
 
@@ -194,17 +194,17 @@ static long gup_benchmark_ioctl(struct file *filep, unsigned int cmd,
 	return 0;
 }
 
-static const struct file_operations gup_benchmark_fops = {
+static const struct file_operations gup_test_fops = {
 	.open = nonseekable_open,
-	.unlocked_ioctl = gup_benchmark_ioctl,
+	.unlocked_ioctl = gup_test_ioctl,
 };
 
-static int gup_benchmark_init(void)
+static int gup_test_init(void)
 {
-	debugfs_create_file_unsafe("gup_benchmark", 0600, NULL, NULL,
-				   &gup_benchmark_fops);
+	debugfs_create_file_unsafe("gup_test", 0600, NULL, NULL,
+				   &gup_test_fops);
 
 	return 0;
 }
 
-late_initcall(gup_benchmark_init);
+late_initcall(gup_test_init);

tools/testing/selftests/vm/.gitignore

@@ -15,7 +15,7 @@ userfaultfd
 mlock-intersect-test
 mlock-random-test
 virtual_address_range
-gup_benchmark
+gup_test
 va_128TBswitch
 map_fixed_noreplace
 write_to_hugetlbfs

tools/testing/selftests/vm/Makefile

@@ -23,7 +23,7 @@ MAKEFLAGS += --no-builtin-rules
 CFLAGS = -Wall -I ../../../../usr/include $(EXTRA_CFLAGS)
 LDLIBS = -lrt
 TEST_GEN_FILES = compaction_test
-TEST_GEN_FILES += gup_benchmark
+TEST_GEN_FILES += gup_test
 TEST_GEN_FILES += hmm-tests
 TEST_GEN_FILES += hugepage-mmap
 TEST_GEN_FILES += hugepage-shm

tools/testing/selftests/vm/config

@@ -3,4 +3,4 @@ CONFIG_USERFAULTFD=y
 CONFIG_TEST_VMALLOC=m
 CONFIG_DEVICE_PRIVATE=y
 CONFIG_TEST_HMM=m
-CONFIG_GUP_BENCHMARK=y
+CONFIG_GUP_TEST=y

tools/testing/selftests/vm/gup_benchmark.c → tools/testing/selftests/vm/gup_test.c

@@ -14,18 +14,18 @@
 #define MB (1UL << 20)
 #define PAGE_SIZE sysconf(_SC_PAGESIZE)
 
-#define GUP_FAST_BENCHMARK	_IOWR('g', 1, struct gup_benchmark)
-#define GUP_BENCHMARK		_IOWR('g', 2, struct gup_benchmark)
+#define GUP_FAST_BENCHMARK	_IOWR('g', 1, struct gup_test)
+#define GUP_BENCHMARK		_IOWR('g', 2, struct gup_test)
 
 /* Similar to above, but use FOLL_PIN instead of FOLL_GET. */
-#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)
+#define PIN_FAST_BENCHMARK	_IOWR('g', 3, struct gup_test)
+#define PIN_BENCHMARK		_IOWR('g', 4, struct gup_test)
+#define PIN_LONGTERM_BENCHMARK	_IOWR('g', 5, struct gup_test)
 
 /* Just the flags we need, copied from mm.h: */
 #define FOLL_WRITE	0x01	/* check pte is writable */
 
-struct gup_benchmark {
+struct gup_test {
 	__u64 get_delta_usec;
 	__u64 put_delta_usec;
 	__u64 addr;
@@ -37,7 +37,7 @@ struct gup_benchmark {
 
 int main(int argc, char **argv)
 {
-	struct gup_benchmark gup;
+	struct gup_test gup;
 	unsigned long size = 128 * MB;
 	int i, fd, filed, opt, nr_pages = 1, thp = -1, repeats = 1, write = 0;
 	int cmd = GUP_FAST_BENCHMARK, flags = MAP_PRIVATE;
@@ -104,7 +104,7 @@ int main(int argc, char **argv)
 	if (write)
 		gup.flags |= FOLL_WRITE;
 
-	fd = open("/sys/kernel/debug/gup_benchmark", O_RDWR);
+	fd = open("/sys/kernel/debug/gup_test", O_RDWR);
 	if (fd == -1) {
 		perror("open");
 		exit(1);

tools/testing/selftests/vm/run_vmtests

@@ -124,9 +124,9 @@ else
 fi
 
 echo "--------------------------------------------"
-echo "running 'gup_benchmark -U' (normal/slow gup)"
+echo "running 'gup_test -U' (normal/slow gup)"
 echo "--------------------------------------------"
-./gup_benchmark -U
+./gup_test -U
 if [ $? -ne 0 ]; then
 	echo "[FAIL]"
 	exitcode=1
@@ -135,9 +135,9 @@ else
 fi
 
 echo "------------------------------------------"
-echo "running gup_benchmark -b (pin_user_pages)"
+echo "running gup_test -b (pin_user_pages)"
 echo "------------------------------------------"
-./gup_benchmark -b
+./gup_test -b
 if [ $? -ne 0 ]; then
 	echo "[FAIL]"
 	exitcode=1