svn commit: r340786 - head/sys/kern

[Mateusz Guzik]

Author: mjg
Date: Thu Nov 22 21:38:24 2018
New Revision: 340786
URL: https://svnweb.freebsd.org/changeset/base/340786

Log:
  Annotate TDP_RFPPWAIT as unlikely.
  
  The flag is only set on vfork, but is tested for *all* syscalls.
  On amd64 this shortens common-case (not vfork) code.

Modified:
  head/sys/kern/subr_syscall.c

Modified: head/sys/kern/subr_syscall.c
==============================================================================
--- head/sys/kern/subr_syscall.c	Thu Nov 22 21:29:36 2018	(r340785)
+++ head/sys/kern/subr_syscall.c	Thu Nov 22 21:38:24 2018	(r340786)
@@ -230,7 +230,7 @@ syscallret(struct thread *td, int error)
 		PROC_UNLOCK(p);
 	}
 
-	if (td->td_pflags & TDP_RFPPWAIT) {
+	if (__predict_false(td->td_pflags & TDP_RFPPWAIT)) {
 		/*
 		 * Preserve synchronization semantics of vfork.  If
 		 * waiting for child to exec or exit, fork set