Re: preemption

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Fri, Jul 31, 2009 at 10:43 PM, Chetan Nanda<chetannanda@xxxxxxxxx> wrote:
>
>
> On Fri, Jul 31, 2009 at 12:33 PM, er krishna <erkrishna@xxxxxxxxx> wrote:
>>
>>
>> On Fri, Jul 31, 2009 at 11:21 AM, Vivek Subbarao <viveks@xxxxxxxxxxx>
>> wrote:
>>>
>>> >weather the second process has its priority must be higher than the
>>> > running one ?
>>>
>>> Yes. Only a process of higher or same priority can pre-empt a process of
>>> lower priority.
>>>
>>>
>>>
>>> If pre-empt_count is +ve means that i can be pre-empted then you are
>>> right.
>>
>> If a lower process has taken a lock & its preempt_count value is +ve , can
>> it be preempted by higher priority process ?
>
> positive value of preempt_count means that kernel preemption is disabled, in
> that case even high priority process will not be able to preempt low
> priority process, people please CMIIW

This is correct. A positive value disables preemption.

>>
>>
>>
>>>
>>>
>>>
>>> From: kernelnewbies-bounce@xxxxxxxxxxxx
>>> [mailto:kernelnewbies-bounce@xxxxxxxxxxxx] On Behalf Of er krishna
>>> Sent: 30 July 2009 14:32
>>> To: kernelnewbies@xxxxxxxxxxxx
>>> Subject: preemption
>>>
>>>
>>>
>>> Dear All,
>>>
>>> I have some confusion about preemption. Can anybody please clear my query
>>> :
>>>
>>> 1) If there are two process running in kernel space & one of them has a
>>> lock & its preempt_count value is +ve ,  can the other process preempt it ?
>>> If it preempt the first process ( which is in running state with a lock ) ,
>>> then how ( weather the second process has its priority must be higher than
>>> the running one ? )?
>>>
>>> Thanks & Best Regards,
>>> Krishna
>
> Thanks,
> Chetan Nanda
>


Regards,
Sandeep.





 	
“To learn is to change. Education is a process that changes the learner.”

--
To unsubscribe from this list: send an email with
"unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx
Please read the FAQ at http://kernelnewbies.org/FAQ



[Index of Archives]     [Newbies FAQ]     [Linux Kernel Mentors]     [Linux Kernel Development]     [IETF Annouce]     [Git]     [Networking]     [Security]     [Bugtraq]     [Yosemite]     [MIPS Linux]     [ARM Linux]     [Linux RAID]     [Linux SCSI]     [Linux ACPI]
  Powered by Linux