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authorJohn Hubbard <jhubbard@nvidia.com>2020-12-15 06:05:05 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-12-15 23:13:38 +0300
commit9c84f229268fa229e250b7225611d0eb7094fea0 (patch)
tree065d92c78996894ff34a8edcddcae3051c78b35e /mm/gup_test.c
parent800bca7c56023c2a89fe9a206a56f3788b54f767 (diff)
downloadlinux-9c84f229268fa229e250b7225611d0eb7094fea0.tar.xz
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>
Diffstat (limited to 'mm/gup_test.c')
-rw-r--r--mm/gup_test.c210
1 files changed, 210 insertions, 0 deletions
diff --git a/mm/gup_test.c b/mm/gup_test.c
new file mode 100644
index 000000000000..59472ea6aa39
--- /dev/null
+++ b/mm/gup_test.c
@@ -0,0 +1,210 @@
+#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_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_test {
+ __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_test failure");
+ break;
+ }
+ }
+ break;
+ }
+}
+
+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;
+ 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_test_ioctl(struct file *filep, unsigned int cmd,
+ unsigned long arg)
+{
+ struct gup_test 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_test_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_test_fops = {
+ .open = nonseekable_open,
+ .unlocked_ioctl = gup_test_ioctl,
+};
+
+static int gup_test_init(void)
+{
+ debugfs_create_file_unsafe("gup_test", 0600, NULL, NULL,
+ &gup_test_fops);
+
+ return 0;
+}
+
+late_initcall(gup_test_init);