From dfe172484d0e1de0bb32bcab8775eb83e15031c0 Mon Sep 17 00:00:00 2001 From: Konstantin Belousov Date: Fri, 21 Jul 2023 12:41:39 +0300 Subject: [PATCH] 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 --- sys/kern/kern_sig.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c index de42255017d..5876e2e9392 100644 --- a/sys/kern/kern_sig.c +++ b/sys/kern/kern_sig.c @@ -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);