Finding whether a process blocked while executing a syscall

Finding whether a process blocked while executing a syscall

[selvakumar nagendran]

Hello,
    I am intercepting system calls in linux kernel
2.4.28 for my project work. 
    A process can be blocked while executing a syscall
in the light of some resources needed. Now, I want to
find out whether a process has been blocked while
executing a particular syscall or it has finished it
successfully? If it was blocked I want to perform some
operation on it. Can anyone help me regarding this?

Thanks,
selva

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Re: Finding whether a process blocked while executing a syscall

[bert hubert]

On Wed, Dec 29, 2004 at 08:52:36PM -0800, selvakumar nagendran wrote:

>     A process can be blocked while executing a syscall
> in the light of some resources needed. Now, I want to
> find out whether a process has been blocked while
> executing a particular syscall or it has finished it
> successfully? If it was blocked I want to perform some
> operation on it. Can anyone help me regarding this?

This question is fraught with difficulty. For one thing, many many system
calls will block for a short time, which you would probably not describe as
'blocked', even though this was true for a few milliseconds.

You did not entirely specify why you want to do this, there may be better
solutions to your problem.

bert

-- 
http://www.PowerDNS.com      Open source, database driven DNS Software 
http://lartc.org           Linux Advanced Routing & Traffic Control HOWTO

Resource unavailabilty on a syscall

[selvakumar nagendran]

Thanks for ur help,
   For a syscall to complete successfully, a process
should acquire the particular resource like
filelock,semaphore key etc. Now, I want to determine
whether a process blocked only due to the
unavailability of a semaphore key or a file lock etc.
I accept a process may block on a syscall for many
reasons. But I want to determine it for resource
starvation alone. How can I do that?
Do u have any suggestions regarding this?

Regards,
selva

--- bert hubert <ahu@ds9a.nl> wrote:

> On Wed, Dec 29, 2004 at 08:52:36PM -0800, selvakumar
> nagendran wrote:
> 
> >     A process can be blocked while executing a
> syscall
> > in the light of some resources needed. Now, I want
> to
> > find out whether a process has been blocked while
> > executing a particular syscall or it has finished
> it
> > successfully? If it was blocked I want to perform
> some
> > operation on it. Can anyone help me regarding
> this?
> 
> This question is fraught with difficulty. For one
> thing, many many system
> calls will block for a short time, which you would
> probably not describe as
> 'blocked', even though this was true for a few
> milliseconds.
> 
> You did not entirely specify why you want to do
> this, there may be better
> solutions to your problem.
> 
> bert
> 
> -- 
> http://www.PowerDNS.com      Open source, database
> driven DNS Software 
> http://lartc.org           Linux Advanced Routing &
> Traffic Control HOWTO
> 



		
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Resource unavailabilty on a syscall

[selvakumar nagendran]

Thanks for ur help,
   For a syscall to complete successfully, a process
should acquire the particular resource like
filelock,semaphore key etc. Now, I want to determine
whether a process blocked only due to the
unavailability of a semaphore key or a file lock etc.
I accept a process may block on a syscall for many
reasons. But I want to determine it for resource
starvation alone. How can I do that?
Do u have any suggestions regarding this?

Regards,
selva

--- bert hubert <ahu@ds9a.nl> wrote:

> On Wed, Dec 29, 2004 at 08:52:36PM -0800, selvakumar
> nagendran wrote:
> 
> >     A process can be blocked while executing a
> syscall
> > in the light of some resources needed. Now, I want
> to
> > find out whether a process has been blocked while
> > executing a particular syscall or it has finished
> it
> > successfully? If it was blocked I want to perform
> some
> > operation on it. Can anyone help me regarding
> this?
> 
> This question is fraught with difficulty. For one
> thing, many many system
> calls will block for a short time, which you would
> probably not describe as
> 'blocked', even though this was true for a few
> milliseconds.
> 
> You did not entirely specify why you want to do
> this, there may be better
> solutions to your problem.
> 
> bert
> 
> -- 
> http://www.PowerDNS.com      Open source, database
> driven DNS Software 
> http://lartc.org           Linux Advanced Routing &
> Traffic Control HOWTO
> 



		
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