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.com
Signed-off-by: John 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 0 insertions, 210 deletions

diff --git a/mm/gup_benchmark.c b/mm/gup_benchmark.c
deleted file mode 100644
index 8b3e5b5cd8fa..000000000000
--- a/mm/gup_benchmark.c
+++ /dev/null
@@ -1,210 +0,0 @@
-#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)
-#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)
-
-struct gup_benchmark {
-	__u64 get_delta_usec;
-	__u64 put_delta_usec;
-	__u64 addr;
-	__u64 size;
-	__u32 nr_pages_per_call;
-	__u32 flags;
-	__u64 expansion[10];	/* For future use */
-};
-
-static void put_back_pages(unsigned int cmd, struct page **pages,
-			   unsigned long nr_pages)
-{
-	unsigned long i;
-
-	switch (cmd) {
-	case GUP_FAST_BENCHMARK:
-	case GUP_BENCHMARK:
-		for (i = 0; i < nr_pages; i++)
-			put_page(pages[i]);
-		break;
-
-	case PIN_FAST_BENCHMARK:
-	case PIN_BENCHMARK:
-	case PIN_LONGTERM_BENCHMARK:
-		unpin_user_pages(pages, nr_pages);
-		break;
-	}
-}
-
-static void verify_dma_pinned(unsigned int cmd, struct page **pages,
-			      unsigned long nr_pages)
-{
-	unsigned long i;
-	struct page *page;
-
-	switch (cmd) {
-	case PIN_FAST_BENCHMARK:
-	case PIN_BENCHMARK:
-	case PIN_LONGTERM_BENCHMARK:
-		for (i = 0; i < nr_pages; i++) {
-			page = pages[i];
-			if (WARN(!page_maybe_dma_pinned(page),
-				 "pages[%lu] is NOT dma-pinned\n", i)) {
-
-				dump_page(page, "gup_benchmark failure");
-				break;
-			}
-		}
-		break;
-	}
-}
-
-static int __gup_benchmark_ioctl(unsigned int cmd,
-		struct gup_benchmark *gup)
-{
-	ktime_t start_time, end_time;
-	unsigned long i, nr_pages, addr, next;
-	int nr;
-	struct page **pages;
-	int ret = 0;
-	bool needs_mmap_lock =
-		cmd != GUP_FAST_BENCHMARK && cmd != PIN_FAST_BENCHMARK;
-
-	if (gup->size > ULONG_MAX)
-		return -EINVAL;
-
-	nr_pages = gup->size / PAGE_SIZE;
-	pages = kvcalloc(nr_pages, sizeof(void *), GFP_KERNEL);
-	if (!pages)
-		return -ENOMEM;
-
-	if (needs_mmap_lock && mmap_read_lock_killable(current->mm)) {
-		ret = -EINTR;
-		goto free_pages;
-	}
-
-	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;
-		}
-
-		/* Filter out most gup flags: only allow a tiny subset here: */
-		gup->flags &= FOLL_WRITE;
-
-		switch (cmd) {
-		case GUP_FAST_BENCHMARK:
-			nr = get_user_pages_fast(addr, nr, gup->flags,
-						 pages + i);
-			break;
-		case GUP_BENCHMARK:
-			nr = get_user_pages(addr, nr, gup->flags, pages + i,
-					    NULL);
-			break;
-		case PIN_FAST_BENCHMARK:
-			nr = pin_user_pages_fast(addr, nr, gup->flags,
-						 pages + i);
-			break;
-		case PIN_BENCHMARK:
-			nr = pin_user_pages(addr, nr, gup->flags, pages + i,
-					    NULL);
-			break;
-		case PIN_LONGTERM_BENCHMARK:
-			nr = pin_user_pages(addr, nr,
-					    gup->flags | FOLL_LONGTERM,
-					    pages + i, NULL);
-			break;
-		default:
-			ret = -EINVAL;
-			goto unlock;
-		}
-
-		if (nr <= 0)
-			break;
-		i += nr;
-	}
-	end_time = ktime_get();
-
-	/* Shifting the meaning of nr_pages: now it is actual number pinned: */
-	nr_pages = i;
-
-	gup->get_delta_usec = ktime_us_delta(end_time, start_time);
-	gup->size = addr - gup->addr;
-
-	/*
-	 * Take an un-benchmark-timed moment to verify DMA pinned
-	 * state: print a warning if any non-dma-pinned pages are found:
-	 */
-	verify_dma_pinned(cmd, pages, nr_pages);
-
-	start_time = ktime_get();
-
-	put_back_pages(cmd, pages, nr_pages);
-
-	end_time = ktime_get();
-	gup->put_delta_usec = ktime_us_delta(end_time, start_time);
-
-unlock:
-	if (needs_mmap_lock)
-		mmap_read_unlock(current->mm);
-free_pages:
-	kvfree(pages);
-	return ret;
-}
-
-static long gup_benchmark_ioctl(struct file *filep, unsigned int cmd,
-		unsigned long arg)
-{
-	struct gup_benchmark gup;
-	int ret;
-
-	switch (cmd) {
-	case GUP_FAST_BENCHMARK:
-	case GUP_BENCHMARK:
-	case PIN_FAST_BENCHMARK:
-	case PIN_BENCHMARK:
-	case PIN_LONGTERM_BENCHMARK:
-		break;
-	default:
-		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)
-{
-	debugfs_create_file_unsafe("gup_benchmark", 0600, NULL, NULL,
-				   &gup_benchmark_fops);
-
-	return 0;
-}
-
-late_initcall(gup_benchmark_init);