On 2015/1/28 17:07, Wanlong Gao wrote:
> On 01/28/2015 04:49 PM, Lijinyue wrote:
>> On 2015/1/28 16:23, Wanlong Gao wrote:
>>> On 01/19/2015 04:36 PM, Li Jinyue wrote:
>>>> For kernel commit c4c27fbdda4e8ba87806c415b6d15266b07bce4b,
>>>> disallow attaching kthreadd or PF_THREAD_BOUND threads to cgroups.
>>>>
>>>> So, we kindly avoid to attach these threads in cgroup tests.
>>>>
>>>> Signed-off-by: Li Jinyue <lijin...@huawei.com>
>>>> ---
>>>> testcases/kernel/controllers/cgroup_fj/cgroup_fj_function.sh | 10
>>>> ++++++++++
>>>> 1 file changed, 10 insertions(+)
>>>>
>>>> diff --git a/testcases/kernel/controllers/cgroup_fj/cgroup_fj_function.sh
>>>> b/testcases/kernel/controllers/cgroup_fj/cgroup_fj_function.sh
>>>> index 30476bd..30fffb6 100755
>>>> --- a/testcases/kernel/controllers/cgroup_fj/cgroup_fj_function.sh
>>>> +++ b/testcases/kernel/controllers/cgroup_fj/cgroup_fj_function.sh
>>>> @@ -186,6 +186,16 @@ case $attach_operation in
>>>> do
>>>> cur_pid=`sed -n "$i""p" $TMPFILE`
>>>> if [ -e /proc/$cur_pid/ ];then
>>>> + #For kernel 3.4.0 and higher,kernel disallow attaching
>>>> kthreadd or
>>>> + #PF_THREAD_BOUND threads to cgroups.
>>>
>>> I check the current kernel and find that this flag already removed now,
>>> please check the following
>>> commit:
>>>
>>> commit 14a40ffccd6163bbcd1d6f32b28a88ffe6149fc6
>>> Author: Tejun Heo <t...@kernel.org>
>>> Date: Tue Mar 19 13:45:20 2013 -0700
>>>
>>> sched: replace PF_THREAD_BOUND with PF_NO_SETAFFINITY
>>>
>>> PF_THREAD_BOUND was originally used to mark kernel threads which were
>>> bound to a specific CPU using kthread_bind() and a task with the flag
>>> set allows cpus_allowed modifications only to itself. Workqueue is
>>> currently abusing it to prevent userland from meddling with
>>> cpus_allowed of workqueue workers.
>>>
>>>
>> Yes,I had also checked this patch. Actually,the PF_THREAD_BOUND had been
>> replaced with PF_NO_SETAFFINITY.
>> However, Kernel still disallow attaching kthreadd or threads with flag
>> 0x04000000 to cgroups.
>
>
> I know, I mean you should comment this change at least, because future users
> may
> ask, "what's PF_THREAD_BOUND ? I never see this flag".
>
> And as I said, you should also comment that the 0x04000000 is just
> PF_THREAD_BOUND or PF_NO_SETAFFINITY,
> because you used it in the following code but others don't know where this
> magic number come from.
>
> Thanks,
> Wanlong Gao
>
>
Yes, I misunderstand it. Thanks for the advice.^V^
I'll comment this in the code.
Thanks,
Li Jinyue
>> -#define PF_THREAD_BOUND 0x04000000 /* Thread bound to specific cpu
>> */
>> +#define PF_NO_SETAFFINITY 0x04000000 /* Userland is not allowed to
>> meddle with cpus_allowed */
>>
>> diff --git a/kernel/cgroup.c b/kernel/cgroup.c
>> index a32f943..3852d92 100644
>> --- a/kernel/cgroup.c
>> +++ b/kernel/cgroup.c
>> <at> <at> -2224,11 +2224,11 <at> <at> retry_find_task:
>> tsk = tsk->group_leader;
>>
>> /*
>> - * Workqueue threads may acquire PF_THREAD_BOUND and become
>> + * Workqueue threads may acquire PF_NO_SETAFFINITY and become
>> * trapped in a cpuset, or RT worker may be born in a cgroup
>> * with no rt_runtime allocated. Just say no.
>> */
>> - if (tsk == kthreadd_task || (tsk->flags & PF_THREAD_BOUND)) {
>> + if (tsk == kthreadd_task || (tsk->flags & PF_NO_SETAFFINITY)) {
>> ret = -EINVAL;
>> rcu_read_unlock();
>> goto out_unlock_cgroup;
>>>> + #kernel commit: c4c27fbdda4e8ba87806c415b6d15266b07bce4b
>>>> + tst_kvercmp 3 4 0
>>>> + if [ $? -ne 0 ]; then
>>>
>>> And where to go if tst_kvercmp failed and return -1?
>> For kernel <3.4, we just attach all tasks to the cgroup as before.
>> "do_echo 1 1 "$cur_pid" /dev/cgroup/subgroup_1/tasks"
>>
>> I had test passed with the v2 patch on kernel 3.10.
>> cgroup_test_fj 1 TPASS : case98(function 1 1 1 1 1 3 1 1 1)
>> PASS
>> /tmp/ltp/ltp/testcases/bin/cgroup_fj_utility.sh: line 497: 31010 Killed
>> $TESTROOT/cgroup_fj_proc
>> /tmp/ltp/ltp/testcases/bin/cgroup_fj_utility.sh: line 497: 31012 Killed
>> $TESTROOT/cgroup_fj_proc
>> cgroup_test_fj 1 TPASS : case99(function 1 1 1 1 1 3 2 1 1)
>> PASS
>> /tmp/ltp/ltp/testcases/bin/cgroup_fj_function.sh: line 273: 31511 Killed
>> $TESTROOT/cgroup_fj_proc
>> /tmp/ltp/ltp/testcases/bin/cgroup_fj_utility.sh: line 497: 31513 Killed
>> $TESTROOT/cgroup_fj_proc
>> cgroup_test_fj 1 TPASS : case100(function 1 1 1 1 1 3 4 1 1)
>> PASS
>> /tmp/ltp/ltp/testcases/bin/cgroup_fj_utility.sh: line 497: 32010 Killed
>>
>> Regards,
>> Li Jinyue
>>>
>>>> + thread_flag=`cat /proc/$cur_pid/stat | awk
>>>> '{print $9}'`
>>>> + if [ $cur_pid -eq 2 -o
>>>> $((${thread_flag}&0x04000000)) -eq 67108864 ];then
>>>
>>> These magic numbers must at least be commented to be understand easily.
>>>
>>> Thanks,
>>> Wanlong Gao
>>>
>>>> + continue
>>>> + fi
>>>> + fi
>>>> do_echo 1 1 "$cur_pid" /dev/cgroup/subgroup_1/tasks
>>>> fi
>>>> done
>>>>
>>>
>>>
>>> .
>>>
>>
>>
>> .
>>
>
>
> .
>
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