Module Name: src Committed By: bouyer Date: Sat Jan 16 17:39:07 UTC 2010
Modified Files: src/sys/kern [netbsd-5-0]: kern_runq.c Log Message: Pull up following revision(s) (requested by rmind in ticket #1240): sys/kern/kern_runq.c: revision 1.28 sched_catchlwp: fix the case when other CPU might see curlwp->l_cpu != curcpu() while LWP is finishing context switch. Should fix PR/42539, tested by mar...@. To generate a diff of this commit: cvs rdiff -u -r1.22.4.3 -r1.22.4.3.2.1 src/sys/kern/kern_runq.c Please note that diffs are not public domain; they are subject to the copyright notices on the relevant files.
Modified files: Index: src/sys/kern/kern_runq.c diff -u src/sys/kern/kern_runq.c:1.22.4.3 src/sys/kern/kern_runq.c:1.22.4.3.2.1 --- src/sys/kern/kern_runq.c:1.22.4.3 Mon Mar 2 19:51:01 2009 +++ src/sys/kern/kern_runq.c Sat Jan 16 17:39:07 2010 @@ -1,4 +1,4 @@ -/* $NetBSD: kern_runq.c,v 1.22.4.3 2009/03/02 19:51:01 snj Exp $ */ +/* $NetBSD: kern_runq.c,v 1.22.4.3.2.1 2010/01/16 17:39:07 bouyer Exp $ */ /* * Copyright (c) 2007, 2008 Mindaugas Rasiukevicius <rmind at NetBSD org> @@ -27,7 +27,7 @@ */ #include <sys/cdefs.h> -__KERNEL_RCSID(0, "$NetBSD: kern_runq.c,v 1.22.4.3 2009/03/02 19:51:01 snj Exp $"); +__KERNEL_RCSID(0, "$NetBSD: kern_runq.c,v 1.22.4.3.2.1 2010/01/16 17:39:07 bouyer Exp $"); #include <sys/param.h> #include <sys/kernel.h> @@ -482,6 +482,17 @@ /* Grab the thread, and move to the local run queue */ sched_dequeue(l); + + /* + * If LWP is still context switching, we may need to + * spin-wait before changing its CPU. + */ + if (__predict_false(l->l_ctxswtch != 0)) { + u_int count; + count = SPINLOCK_BACKOFF_MIN; + while (l->l_ctxswtch) + SPINLOCK_BACKOFF(count); + } l->l_cpu = curci; ci_rq->r_ev_pull.ev_count++; lwp_unlock_to(l, curspc->spc_mutex);