On 9/18/21 1:41 AM, David Hildenbrand wrote:
On 18.09.21 00:45, Shuah Khan wrote:
Hi David,
I am running into the following warning when try to build this test:
madv_populate.c:334:2: warning: #warning "missing MADV_POPULATE_READ or MADV_POPULATE_WRITE definition" [-Wcpp]
334 | #warning "missing MADV_POPULATE_READ or MADV_POPULATE_WRITE definition"
| ^~~~~~~
I see that the following handling is in place. However there is no
other information to explain why the check is necessary.
#if defined(MADV_POPULATE_READ) && defined(MADV_POPULATE_WRITE)
#else /* defined(MADV_POPULATE_READ) && defined(MADV_POPULATE_WRITE) */
#warning "missing MADV_POPULATE_READ or MADV_POPULATE_WRITE definition"
I do see these defined in:
include/uapi/asm-generic/mman-common.h:#define MADV_POPULATE_READ 22
include/uapi/asm-generic/mman-common.h:#define MADV_POPULATE_WRITE 23
Is this the case of missing include from madv_populate.c?
Hi Shuan,
note that we're including "#include <sys/mman.h>", which in my
understanding maps to the version installed on your system instead
of the one in our build environment.ing.
So as soon as you have a proper kernel + the proper headers installed
and try to build, it would pick up MADV_POPULATE_READ and
MADV_POPULATE_WRITE from the updated headers. That makes sense: you
annot run any MADV_POPULATE_READ/MADV_POPULATE_WRITE tests on a kernel
that doesn't support it.
See vm/userfaultfd.c where we do something similar.
Kselftest is for testing the kernel with kernel headers. That is the
reason why there is the dependency on header install.
As soon as we have a proper environment, it seems to work just fine:
Linux vm-0 5.15.0-0.rc1.20210915git3ca706c189db.13.fc36.x86_64 #1 SMP Thu Sep 16 11:32:54 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
[root@vm-0 linux]# cat /etc/redhat-release
Fedora release 36 (Rawhide)
This is a distro release. We don't want to have dependency on headers
from the distro to run selftests. Hope this makes sense.
I still see this on my test system running Linux 5.15-rc5.
Can we make this work with kernel headers?
thanks,
-- Shuah
