Module Name: src
Committed By: ad
Date: Thu Mar 26 19:42:39 UTC 2020
Modified Files:
src/sys/kern: kern_idle.c kern_synch.c
Log Message:
Leave the idle LWPs in state LSIDL even when running, so they don't mess up
output from ps/top/etc. Correctness isn't at stake, LWPs in other states
are temporarily on the CPU at times too (e.g. LSZOMB, LSSLEEP).
To generate a diff of this commit:
cvs rdiff -u -r1.32 -r1.33 src/sys/kern/kern_idle.c
cvs rdiff -u -r1.344 -r1.345 src/sys/kern/kern_synch.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_idle.c
diff -u src/sys/kern/kern_idle.c:1.32 src/sys/kern/kern_idle.c:1.33
--- src/sys/kern/kern_idle.c:1.32 Sat Feb 15 18:12:15 2020
+++ src/sys/kern/kern_idle.c Thu Mar 26 19:42:39 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_idle.c,v 1.32 2020/02/15 18:12:15 ad Exp $ */
+/* $NetBSD: kern_idle.c,v 1.33 2020/03/26 19:42:39 ad Exp $ */
/*-
* Copyright (c)2002, 2006, 2007 YAMAMOTO Takashi,
@@ -28,7 +28,7 @@
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_idle.c,v 1.32 2020/02/15 18:12:15 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_idle.c,v 1.33 2020/03/26 19:42:39 ad Exp $");
#include <sys/param.h>
#include <sys/cpu.h>
@@ -56,8 +56,8 @@ idle_loop(void *dummy)
/* Update start time for this thread. */
binuptime(&l->l_stime);
spc->spc_flags |= SPCF_RUNNING;
- KASSERT(l->l_stat == LSONPROC);
KASSERT((l->l_pflag & LP_RUNNING) != 0);
+ l->l_stat = LSIDL;
lwp_unlock(l);
/*
@@ -91,11 +91,10 @@ idle_loop(void *dummy)
}
KASSERT(l->l_mutex == l->l_cpu->ci_schedstate.spc_lwplock);
lwp_lock(l);
- l->l_stat = LSIDL;
spc_lock(l->l_cpu);
mi_switch(l);
KASSERT(curlwp == l);
- KASSERT(l->l_stat == LSONPROC);
+ KASSERT(l->l_stat == LSIDL);
}
}
@@ -119,7 +118,7 @@ create_idle_lwp(struct cpu_info *ci)
* mi_switch(). Make the picture look good in case the CPU
* takes an interrupt before it calls idle_loop().
*/
- l->l_stat = LSONPROC;
+ l->l_stat = LSIDL;
l->l_pflag |= LP_RUNNING;
ci->ci_onproc = l;
}
Index: src/sys/kern/kern_synch.c
diff -u src/sys/kern/kern_synch.c:1.344 src/sys/kern/kern_synch.c:1.345
--- src/sys/kern/kern_synch.c:1.344 Sat Mar 14 20:23:51 2020
+++ src/sys/kern/kern_synch.c Thu Mar 26 19:42:39 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_synch.c,v 1.344 2020/03/14 20:23:51 ad Exp $ */
+/* $NetBSD: kern_synch.c,v 1.345 2020/03/26 19:42:39 ad Exp $ */
/*-
* Copyright (c) 1999, 2000, 2004, 2006, 2007, 2008, 2009, 2019, 2020
@@ -69,7 +69,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_synch.c,v 1.344 2020/03/14 20:23:51 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_synch.c,v 1.345 2020/03/26 19:42:39 ad Exp $");
#include "opt_kstack.h"
#include "opt_dtrace.h"
@@ -387,11 +387,7 @@ kpreempt(uintptr_t where)
atomic_swap_uint(&l->l_dopreempt, 0);
return true;
}
- if (__predict_false((l->l_flag & LW_IDLE) != 0)) {
- /* Can't preempt idle loop, don't count as failure. */
- atomic_swap_uint(&l->l_dopreempt, 0);
- return true;
- }
+ KASSERT((l->l_flag & LW_IDLE) == 0);
if (__predict_false(l->l_nopreempt != 0)) {
/* LWP holds preemption disabled, explicitly. */
if ((dop & DOPREEMPT_COUNTED) == 0) {
@@ -547,12 +543,10 @@ nextlwp(struct cpu_info *ci, struct sche
lwp_setlock(newl, spc->spc_lwplock);
} else {
/*
- * Updates to newl here are unlocked, but newl is the idle
- * LWP and thus sheltered from outside interference, so no
- * harm is going to come of it.
+ * The idle LWP does not get set to LSONPROC, because
+ * otherwise it screws up the output from top(1) etc.
*/
newl = ci->ci_data.cpu_idlelwp;
- newl->l_stat = LSONPROC;
newl->l_pflag |= LP_RUNNING;
spc->spc_curpriority = PRI_IDLE;
spc->spc_flags = (spc->spc_flags & ~SPCF_SWITCHCLEAR) |
@@ -840,7 +834,7 @@ mi_switch(lwp_t *l)
}
KASSERT(l == curlwp);
- KASSERT(l->l_stat == LSONPROC);
+ KASSERT(l->l_stat == LSONPROC || (l->l_flag & LW_IDLE) != 0);
SYSCALL_TIME_WAKEUP(l);
LOCKDEBUG_BARRIER(NULL, 1);
