Noticable Delays Since Beta 3 (possible cause)
Sam Lawrance
boris at brooknet.com.au
Mon Oct 11 06:05:06 PDT 2004
Folks,
On Mon, 2004-10-11 at 04:55 -0400, Robert Watson wrote:
> On Sat, 9 Oct 2004, Sam Lawrance wrote:
>
> > I'm sorry, that patch was missing paths.. this one:
> >
> > http://sam.stral.net/freebsd/wakeupdelay-patch
> >
> > is much nicer.
>
> Are there plans to get this patch merged for 5.3? I was chatting with
> Brian yesterday about the accept locking issue in sofree() and he was
> indicating that he was seeing symptoms very much like the ones described
> in this thread (long wakeup times for keypresses, etc).
I just noticed that the messages David sent to me and the list have yet
to make it through to the list. One was a patch which puts the wakeup in
the critical_exit where he suggested (but I didn't understand :). Here
it is:
Index: sys/proc.h
===================================================================
RCS file: /home/ncvs/src/sys/sys/proc.h,v
retrieving revision 1.409
diff -u -r1.409 proc.h
--- sys/proc.h 6 Oct 2004 00:40:40 -0000 1.409
+++ sys/proc.h 9 Oct 2004 10:59:50 -0000
@@ -369,7 +369,7 @@
#define TDP_SA 0x00000080 /* A scheduler activation based thread. */
#define TDP_OWEPREEMPT 0x00000100 /* Thread has a pending preemption. */
#define TDP_OWEUPC 0x00000200 /* Call addupc() at next AST. */
-#define TDP_UNUSED10 0x00000400 /* -- available-- */
+#define TDP_WAKEPROC0 0x00000400 /* Wants caller to wakeup(&proc0) */
#define TDP_CAN_UNBIND 0x00000800 /* Only temporarily bound. */
#define TDP_SCHED1 0x00001000 /* Reserved for scheduler private use */
#define TDP_SCHED2 0x00002000 /* Reserved for scheduler private use */
Index: kern/kern_switch.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/kern_switch.c,v
retrieving revision 1.97
diff -u -r1.97 kern_switch.c
--- kern/kern_switch.c 5 Oct 2004 22:03:10 -0000 1.97
+++ kern/kern_switch.c 9 Oct 2004 10:59:50 -0000
@@ -449,6 +449,10 @@
KASSERT(td->td_critnest != 0,
("critical_exit: td_critnest == 0"));
if (td->td_critnest == 1) {
+ if (td->td_pflags & TDP_WAKEPROC0) {
+ td->td_pflags &= ~TDP_WAKEPROC0;
+ wakeup(&proc0);
+ }
#ifdef PREEMPTION
mtx_assert(&sched_lock, MA_NOTOWNED);
if (td->td_pflags & TDP_OWEPREEMPT) {
Index: kern/kern_synch.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/kern_synch.c,v
retrieving revision 1.262
diff -u -r1.262 kern_synch.c
--- kern/kern_synch.c 5 Oct 2004 18:51:11 -0000 1.262
+++ kern/kern_synch.c 9 Oct 2004 10:59:51 -0000
@@ -390,13 +390,13 @@
if ((p->p_sflag & PS_INMEM) == 0) {
if ((p->p_sflag & PS_SWAPPINGIN) == 0) {
p->p_sflag |= PS_SWAPINREQ;
-#ifndef SMP
/*
- * XXX: Disabled on SMP due to a LOR between
- * sched_lock and the sleepqueue chain locks.
+ * due to a LOR between sched_lock and
+ * the sleepqueue chain locks, delay
+ * wakeup proc0 until thread leaves
+ * critical region.
*/
- wakeup(&proc0);
-#endif
+ curthread->td_pflags |= TDP_WAKEPROC0;
}
} else
sched_wakeup(td);
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