[PATCH 12/12] selftests/vm/transhuge-stress: Support file-backed PMD folios

From: Matthew Wilcox (Oracle)
Date: Sun Jan 16 2022 - 07:18:40 EST


Add a -f <filename> option to test PMD folios on files

Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
tools/testing/selftests/vm/transhuge-stress.c | 35 +++++++++++++------
1 file changed, 24 insertions(+), 11 deletions(-)

diff --git a/tools/testing/selftests/vm/transhuge-stress.c b/tools/testing/selftests/vm/transhuge-stress.c
index 5e4c036f6ad3..a03cb3fce1f6 100644
--- a/tools/testing/selftests/vm/transhuge-stress.c
+++ b/tools/testing/selftests/vm/transhuge-stress.c
@@ -26,15 +26,17 @@
#define PAGEMAP_PFN(ent) ((ent) & ((1ull << 55) - 1))

int pagemap_fd;
+int backing_fd = -1;
+int mmap_flags = MAP_ANONYMOUS | MAP_NORESERVE | MAP_PRIVATE;
+#define PROT_RW (PROT_READ | PROT_WRITE)

int64_t allocate_transhuge(void *ptr)
{
uint64_t ent[2];

/* drop pmd */
- if (mmap(ptr, HPAGE_SIZE, PROT_READ | PROT_WRITE,
- MAP_FIXED | MAP_ANONYMOUS |
- MAP_NORESERVE | MAP_PRIVATE, -1, 0) != ptr)
+ if (mmap(ptr, HPAGE_SIZE, PROT_RW, MAP_FIXED | mmap_flags,
+ backing_fd, 0) != ptr)
errx(2, "mmap transhuge");

if (madvise(ptr, HPAGE_SIZE, MADV_HUGEPAGE))
@@ -60,6 +62,8 @@ int main(int argc, char **argv)
size_t ram, len;
void *ptr, *p;
struct timespec a, b;
+ int i = 0;
+ char *name = NULL;
double s;
uint8_t *map;
size_t map_len;
@@ -69,13 +73,23 @@ int main(int argc, char **argv)
ram = SIZE_MAX / 4;
else
ram *= sysconf(_SC_PAGESIZE);
+ len = ram;
+
+ while (++i < argc) {
+ if (!strcmp(argv[i], "-h"))
+ errx(1, "usage: %s [size in MiB]", argv[0]);
+ else if (!strcmp(argv[i], "-f"))
+ name = argv[++i];
+ else
+ len = atoll(argv[i]) << 20;
+ }

- if (argc == 1)
- len = ram;
- else if (!strcmp(argv[1], "-h"))
- errx(1, "usage: %s [size in MiB]", argv[0]);
- else
- len = atoll(argv[1]) << 20;
+ if (name) {
+ backing_fd = open(name, O_RDWR);
+ if (backing_fd == -1)
+ errx(2, "open %s", name);
+ mmap_flags = MAP_SHARED;
+ }

warnx("allocate %zd transhuge pages, using %zd MiB virtual memory"
" and %zd MiB of ram", len >> HPAGE_SHIFT, len >> 20,
@@ -86,8 +100,7 @@ int main(int argc, char **argv)
err(2, "open pagemap");

len -= len % HPAGE_SIZE;
- ptr = mmap(NULL, len + HPAGE_SIZE, PROT_READ | PROT_WRITE,
- MAP_ANONYMOUS | MAP_NORESERVE | MAP_PRIVATE, -1, 0);
+ ptr = mmap(NULL, len + HPAGE_SIZE, PROT_RW, mmap_flags, backing_fd, 0);
if (ptr == MAP_FAILED)
err(2, "initial mmap");
ptr += HPAGE_SIZE - (uintptr_t)ptr % HPAGE_SIZE;
--
2.34.1