uslurp change

uslurp change

[Mike Cvet]

Code in frysk-sys/proc/cni/slurp.cxx : uslurp which previously was:

  int fd = ::open (file, O_RDONLY);
  if (errno != 0) {
     ::free(buf);
     return NULL;

Has been changed to replicate behaviour seen in FileDescriptor.cxx 
where, if the maximum number of file descriptors has been reached, the 
garbage collector will be continually prodded until some descriptors get 
freed up.

- Mike

Re: uslurp change

[Phil Muldoon]

Mike Cvet wrote:
> Code in frysk-sys/proc/cni/slurp.cxx : uslurp which previously was:
>
>  int fd = ::open (file, O_RDONLY);
>  if (errno != 0) {
>     ::free(buf);
>     return NULL;
>
> Has been changed to replicate behaviour seen in FileDescriptor.cxx 
> where, if the maximum number of file descriptors has been reached, the 
> garbage collector will be continually prodded until some descriptors 
> get freed up.
>
Mike

uslurp is a "special case" function for /proc/$$/maps which can be 
large. It does the realloc dance on multiple 4k page reads while slurp 
just reads one page from /proc. The older slurp still does the vast 
majority of reads from /proc, so this optimization will be needed there 
to. I cannot think of a reason why I just did not replace uslurp with 
slurp many moons ago, but thinking about it, it probably should.

Regards

Phil

Re: uslurp change

[Mike Cvet]

Phil Muldoon wrote:
> uslurp is a "special case" function for /proc/$$/maps which can be 
> large. It does the realloc dance on multiple 4k page reads while slurp 
> just reads one page from /proc. The older slurp still does the vast 
> majority of reads from /proc, so this optimization will be needed 
> there to. I cannot think of a reason why I just did not replace uslurp 
> with slurp many moons ago, but thinking about it, it probably should.
>

The update has been added to slurp() and slurp_thread() as well, through 
a new method in Errno.cxx called tryOpen().

- Mike