sigtd(): prefer non-stopped thread as a target for signal queue

This should improve signal delivery latency and better expose the
process state to the executing threads.

Reviewed by:	markj
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D41128

This commit is contained in:

Konstantin Belousov

2023-07-21 12:41:39 +03:00

parent aaa924138a

commit dfe172484d

1 changed files with 5 additions and 1 deletions

									
										sys/kern/kern_sig.c
									
		+5
		-1
	
												View File
												
				@@ -2157,14 +2157,18 @@ sigtd(struct proc *p, int sig, bool fast_sigblock)

					if (curproc == p && !SIGISMEMBER(curthread->td_sigmask, sig) &&

					    (!fast_sigblock || curthread->td_sigblock_val == 0))

						return (curthread);

					/* Find a non-stopped thread that does not mask the signal. */

					signal_td = NULL;

					FOREACH_THREAD_IN_PROC(p, td) {

						if (!SIGISMEMBER(td->td_sigmask, sig) && (!fast_sigblock ||

						    td != curthread || td->td_sigblock_val == 0)) {

						    td != curthread || td->td_sigblock_val == 0) &&

						    (td->td_flags & TDF_BOUNDARY) == 0) {

							signal_td = td;

							break;

						}

					}

					/* Select random (first) thread if no better match was found. */

					if (signal_td == NULL)

						signal_td = FIRST_THREAD_IN_PROC(p);

					return (signal_td);