On Thu Dec 5 18:01:07 EST 2013, cinap_len...@felloff.net wrote:
> i just tried something out. it appears that _schedexecwait()'s
> purpose is to serve thredwaitchan():
>
> Threadwaitchan returns a channel of pointers to Waitmsg
> structures (see wait(2)). When an exec'ed process exits, a
> pointer to a Waitmsg is sent to this channel. These Waitmsg
> structures have been allocated with malloc(2) and should be
> freed after use.
>
> when threadwaitchan isnt used, we can rfork the execing child
> with RFNOWAIT which will make the process doing the original
> procexecl() not wait for the child.
>
> i just tried this out with rio (and abaco) and it seems to work fine.
>
> diff -r 42807d2e3f4b sys/src/libthread/main.c
> --- a/sys/src/libthread/main.cThu Dec 05 22:43:44 2013 +0100
> +++ b/sys/src/libthread/main.cFri Dec 06 23:50:34 2013 +0100
> @@ -121,9 +121,10 @@
> int
> _schedexec(Execargs *e)
> {
> - int pid;
> + int pid, flag;
>
> - switch(pid = rfork(RFREND|RFNOTEG|RFFDG|RFMEM|RFPROC)){
> + flag = (_threadwaitchan == nil) ? RFNOWAIT : 0;
> + switch(pid = rfork(RFREND|RFNOTEG|RFFDG|RFMEM|RFPROC|flag)){
> case 0:
> efork(e);
> default:
>
> this is saving a couple of few processes. is it worth it?
hey, that's pretty cool. i'll bet that with this change the leaked memory
actually shows up as leaked.
- erik
