Re: gcore and nptl threads on linux

["J. Johnston" <jjohnstn@redhat.com>]

Daniel Jacobowitz wrote:
> On Tue, Mar 04, 2003 at 06:40:51PM -0500, J. Johnston wrote:
> 
>>There is a problem with implementing gcore on linux with nptl thread
>>support.  Under the linux nptl model, each thread is mapped to an
>>lwpid which is distinct from the pid of the process that created the
>>thread.
>>
>>The current linux gcore code is merging the pid with the tid into an 
>>unsigned
>>long value.  This works ok in the old model because the tid and pids are 
>>only
>>16-bits in length.  This no longer can work because tids in the nptl model 
>>are actually
>>addresses and are not restricted to 16-bits.
> 
> 
> I think this used to cause problems, too - it really should be just the
> lwpid, I'd think.  For these cases at least.
> 
> 
>>This change would allow linux-proc.c to get the lwp where possible in a 
>>cleaner
>>fashion.
>>
>>If nobody has any major objections to this proposal, I can post a patch 
>>shortly.
> 
> 
> What do you plan to do when there is not a mapping, i.e. in an M:N
> environment?  This interface assumes 1:1.
> 

I would think the null_ptid would serve in such a case.

-- Jeff J.