[RFC][PATCH] selftests/vm/transhuge-stress: fix ram size thinko

From: George G. Davis
Date: Wed Aug 25 2021 - 09:59:03 EST


From: "George G. Davis" <davis.george@xxxxxxxxxxx>

When executing transhuge-stress with an argument to specify the virtual
memory size for testing, the ram size is reported as 0, e.g.

transhuge-stress 384
thp-mmap: allocate 192 transhuge pages, using 384 MiB virtual memory and 0 MiB of ram
thp-mmap: 0.184 s/loop, 0.957 ms/page, 2090.265 MiB/s 192 succeed, 0 failed

This appears to be due to a thinko in commit 0085d61fe05e
("selftests/vm/transhuge-stress: stress test for memory compaction"),
where, at a guess, the intent was to base "xyz MiB of ram" on `ram`
size. Here are results after using `ram` size:

thp-mmap: allocate 192 transhuge pages, using 384 MiB virtual memory and 14 MiB of ram

Fixes: 0085d61fe05e ("selftests/vm/transhuge-stress: stress test for memory compaction")
Signed-off-by: George G. Davis <davis.george@xxxxxxxxxxx>
---
tools/testing/selftests/vm/transhuge-stress.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/vm/transhuge-stress.c b/tools/testing/selftests/vm/transhuge-stress.c
index fd7f1b4a96f9..5e4c036f6ad3 100644
--- a/tools/testing/selftests/vm/transhuge-stress.c
+++ b/tools/testing/selftests/vm/transhuge-stress.c
@@ -79,7 +79,7 @@ int main(int argc, char **argv)

warnx("allocate %zd transhuge pages, using %zd MiB virtual memory"
" and %zd MiB of ram", len >> HPAGE_SHIFT, len >> 20,
- len >> (20 + HPAGE_SHIFT - PAGE_SHIFT - 1));
+ ram >> (20 + HPAGE_SHIFT - PAGE_SHIFT - 1));

pagemap_fd = open("/proc/self/pagemap", O_RDONLY);
if (pagemap_fd < 0)
--
2.17.1