[PATCH] Allow system call restarts upon signal interruption

[Michel Dänzer]

On 13.05.2015 07:39, Daniel Drake wrote:
> The X server frequently deals with SIGIO and SIGALRM interruptions.
> If process execution is inside certain blocking system calls
> when these signals arrive, e.g. with the kernel blocked on
> a contended semaphore, the system calls will be interrupted.
> 
> Some system calls are automatically restartable (the kernel re-executes
> them with the same parameters once the signal handler returns) but
> only if the signal handler allows it.
> 
> Set SA_RESTART on the signal handlers to enable this convenient
> behaviour.

The discussion about this on IRC sounded to me like we don't want to do
this for both signals, because at least one of them should interrupt
select(). My guess would be that SIGIO should interrupt select() and
thus shouldn't use SA_RESTART.


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer