+ selftests-vm-transhuge-stress-fix-ram-size-thinko.patch added to -mm tree

+ selftests-vm-transhuge-stress-fix-ram-size-thinko.patch added to -mm tree

[akpm]

The patch titled
     Subject: selftests/vm/transhuge-stress: fix ram size thinko
has been added to the -mm tree.  Its filename is
     selftests-vm-transhuge-stress-fix-ram-size-thinko.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/selftests-vm-transhuge-stress-fix-ram-size-thinko.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/selftests-vm-transhuge-stress-fix-ram-size-thinko.patch

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------------------------------------------------------
From: "George G. Davis" <davis.george@siemens.com>
Subject: selftests/vm/transhuge-stress: fix ram size thinko

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

Link: https://lkml.kernel.org/r/20210825135843.29052-1-george_davis@mentor.com
Fixes: 0085d61fe05e ("selftests/vm/transhuge-stress: stress test for memory compaction")
Signed-off-by: George G. Davis <davis.george@siemens.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Eugeniu Rosca <erosca@de.adit-jv.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 tools/testing/selftests/vm/transhuge-stress.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/tools/testing/selftests/vm/transhuge-stress.c~selftests-vm-transhuge-stress-fix-ram-size-thinko
+++ a/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)
_

Patches currently in -mm which might be from davis.george@siemens.com are

selftests-vm-transhuge-stress-fix-ram-size-thinko.patch