[LTP] [PATCH v2] syscalls/madvise09.c: Use custom mount point instead of /sys/fs/cgroup/memory

[Xiao Yang <yangx.jy@cn.fujitsu.com>]

On 2018/01/15 16:06, Jan Stancek wrote:
>
> ----- Original Message -----
>> Hi Jan,
>>
>> Could you help me review this patch.
> Hi,
>
> I think it would be better to use existing mount, if it's already mounted.
> umount may fail with -EBUSY if the subsystem is already part of existing
> hierarchy.
Hi Jan,

1) I want to run madvise09 on as many distros supporting memcg as possible.

2) The custom mount point is just created and mounted for running 
madvise09, and will be
     released after finishing madvise09, so i think it doesn't affect 
existing hierarchy.  Additionally,
     i use custom mount point according to some tests(oom03, oom05, 
cpuset01, etc.) on LTP.

Thanks,
Xiao Yang
> Regards,
> Jan
>
>> Thanks,
>> Xiao Yang
>> On 2018/01/04 10:43, xiao yang wrote:
>>> 1) on some distros(e.g. RHEL6), memory cgroup was supported and
>>>     mounted on /cgroup/memory by default, but the test was skipped
>>>     if /sys/fs/cgroup/memory did not exist.
>>>
>>> 2) We got the following error if memory cgroup wasn't mounted
>>>     on /sys/fs/cgroup/memory:
>>>     ------------------------------------------------------------
>>>     safe_macros.c:169: BROK: madvise09.c:175:
>>>     mkdir(/sys/fs/cgroup/memory/ltp_madvise09_16386/,0777) failed: EROFS
>>>     ------------------------------------------------------------
>>>
>>> We use custom mount point and mount memory cgroup on it manually
>>> to fix these issues.
>>>
>>> Signed-off-by: xiao yang<yangx.jy@cn.fujitsu.com>
>>> ---
>>>   testcases/kernel/syscalls/madvise/madvise09.c | 26
>>>   ++++++++++++++++++++++----
>>>   1 file changed, 22 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/testcases/kernel/syscalls/madvise/madvise09.c
>>> b/testcases/kernel/syscalls/madvise/madvise09.c
>>> index f744405..25cf81f 100644
>>> --- a/testcases/kernel/syscalls/madvise/madvise09.c
>>> +++ b/testcases/kernel/syscalls/madvise/madvise09.c
>>> @@ -53,12 +53,14 @@
>>>   #include<errno.h>
>>>   #include<stdio.h>
>>>   #include<ctype.h>
>>> +#include<sys/mount.h>
>>>
>>>   #include "tst_test.h"
>>>   #include "lapi/mmap.h"
>>>
>>> -#define MEMCG_PATH "/sys/fs/cgroup/memory/"
>>> +#define MEMCG_PATH "/dev/memcg_madvise09/"
>>>
>>> +static int memcg_mounted;
>>>   static char cgroup_path[PATH_MAX];
>>>   static char tasks_path[PATH_MAX];
>>>   static char limit_in_bytes_path[PATH_MAX];
>>> @@ -277,6 +279,15 @@ static void cleanup(void)
>>>   {
>>>   	if (cgroup_path[0]&&  !access(cgroup_path, F_OK))
>>>   		rmdir(cgroup_path);
>>> +
>>> +	if (memcg_mounted) {
>>> +		tst_res(TINFO, "Umount memory cgroup after testing");
>>> +		SAFE_UMOUNT(MEMCG_PATH);
>>> +		memcg_mounted = 0;
>>> +	}
>>> +
>>> +	if (!access(MEMCG_PATH, F_OK)&&  rmdir(MEMCG_PATH))
>>> +		tst_res(TWARN | TERRNO, "Rmdir %s failed", MEMCG_PATH);
>>>   }
>>>
>>>   static void run(void)
>>> @@ -316,10 +327,17 @@ static void setup(void)
>>>   {
>>>   	long int swap_total;
>>>
>>> -	if (access(MEMCG_PATH, F_OK)) {
>>> -		tst_brk(TCONF, "'" MEMCG_PATH
>>> -			"' not present, CONFIG_MEMCG missing?");
>>> +	SAFE_MKDIR(MEMCG_PATH, 0777);
>>> +
>>> +	tst_res(TINFO, "Mount memory cgroup on %s", MEMCG_PATH);
>>> +	if (mount("memcg", MEMCG_PATH, "cgroup", 0, "memory") == -1) {
>>> +		if (errno == ENODEV) {
>>> +			tst_brk(TCONF,
>>> +				 "Memory cgroup was not configured in kernel");
>>> +		}
>>> +		tst_brk(TBROK | TERRNO, "Failed to mount memory cgroup");
>>>   	}
>>> +	memcg_mounted = 1;
>>>
>>>   	if (!access(MEMCG_PATH "memory.memsw.limit_in_bytes", F_OK))
>>>   		swap_accounting_enabled = 1;
>>
>>
>>
>
> .
>