svn commit: r366391 - head/sys/kern

[Edward Tomasz Napierala]

Author: trasz
Date: Sat Oct  3 12:03:08 2020
New Revision: 366391
URL: https://svnweb.freebsd.org/changeset/base/366391

Log:
  Move KTRUSERRET() from userret() to ast().  It's a really long
  detour - it writes ktrace entries to the filesystem - so the overhead
  of ast() won't make any difference.
  
  Reviewed by:	kib
  Sponsored by:	DARPA
  Differential Revision:	https://reviews.freebsd.org/D26404

Modified:
  head/sys/kern/kern_ktrace.c
  head/sys/kern/subr_trap.c

Modified: head/sys/kern/kern_ktrace.c
==============================================================================
--- head/sys/kern/kern_ktrace.c	Sat Oct  3 10:47:17 2020	(r366390)
+++ head/sys/kern/kern_ktrace.c	Sat Oct  3 12:03:08 2020	(r366391)
@@ -347,6 +347,9 @@ ktr_enqueuerequest(struct thread *td, struct ktr_reque
 	mtx_lock(&ktrace_mtx);
 	STAILQ_INSERT_TAIL(&td->td_proc->p_ktr, req, ktr_list);
 	mtx_unlock(&ktrace_mtx);
+	thread_lock(td);
+	td->td_flags |= TDF_ASTPENDING;
+	thread_unlock(td);
 }
 
 /*

Modified: head/sys/kern/subr_trap.c
==============================================================================
--- head/sys/kern/subr_trap.c	Sat Oct  3 10:47:17 2020	(r366390)
+++ head/sys/kern/subr_trap.c	Sat Oct  3 12:03:08 2020	(r366391)
@@ -130,9 +130,6 @@ userret(struct thread *td, struct trapframe *frame)
 		PROC_UNLOCK(p);
 	}
 #endif
-#ifdef KTRACE
-	KTRUSERRET(td);
-#endif
 
 	/*
 	 * Charge system time if profiling.
@@ -340,6 +337,10 @@ ast(struct trapframe *framep)
 	 */
 	if (td->td_pflags & TDP_SIGFASTPENDING)
 		sigfastblock_setpend(td, false);
+
+#ifdef KTRACE
+	KTRUSERRET(td);
+#endif
 
 	/*
 	 * We need to check to see if we have to exit or wait due to a