* Re: Smp swsusp testing wanted
2004-05-23 17:34 ` Pavel Machek
@ 2004-05-23 17:35 ` Pavel Machek
0 siblings, 0 replies; 3+ messages in thread
From: Pavel Machek @ 2004-05-23 17:35 UTC (permalink / raw)
To: samg, kernel list
Hi!
> > >Hi! If you have smp machine where swsusp works with only one procesor and
> > >can test patches, please let me know. --p
>
> > I have (1) smp machine (dual proc), running 2.4.18/2.6.5/2.6.6, If you
> > have a patch I can test it for you.
>
> Please verify that swsusp works in "UP" mode, first. Then apply this
> and go to "SMP" mode, and see if it still works.
>
> I have SMP machine here but swsusp will not work there even in "UP"
> mode; I'll need to debug it.
Sorry, here it is.
Pavel
--- clean/include/linux/suspend.h 2004-05-20 23:11:46.000000000 +0200
+++ linux/include/linux/suspend.h 2004-05-21 15:02:33.000000000 +0200
@@ -81,6 +81,14 @@
}
#endif /* CONFIG_PM */
+#ifdef CONFIG_SMP
+extern void smp_freeze(void);
+extern void smp_restart(void);
+#else
+static inline void smp_freeze(void) {}
+static inline void smp_restart(void) {}
+#endif
+
asmlinkage void do_magic(int is_resume);
asmlinkage void do_magic_resume_1(void);
asmlinkage void do_magic_resume_2(void);
--- clean/kernel/power/Makefile 2003-09-28 22:06:44.000000000 +0200
+++ linux/kernel/power/Makefile 2004-05-21 14:22:50.000000000 +0200
@@ -1,4 +1,5 @@
obj-y := main.o process.o console.o pm.o
+obj-$(CONFIG_SMP) += smp.o
obj-$(CONFIG_SOFTWARE_SUSPEND) += swsusp.o
obj-$(CONFIG_PM_DISK) += disk.o pmdisk.o
--- clean/kernel/power/smp.c 2004-05-21 14:08:45.000000000 +0200
+++ linux/kernel/power/smp.c 2004-05-21 14:46:40.000000000 +0200
@@ -0,0 +1,62 @@
+/*
+ * drivers/power/smp.c - Functions for stopping other CPUs.
+ *
+ * Copyright 2004 Pavel Machek <pavel@suse.cz>
+ * Copyright (C) 2002-2003 Nigel Cunningham <ncunningham@clear.net.nz>
+ *
+ * This file is released under the GPLv2.
+ */
+
+#undef DEBUG
+
+#include <linux/smp_lock.h>
+#include <linux/interrupt.h>
+#include <linux/suspend.h>
+#include <linux/module.h>
+#include <asm/atomic.h>
+
+static atomic_t cpu_counter, freeze;
+
+static void smp_pause(void * data)
+{
+ atomic_inc(&cpu_counter);
+ while (atomic_read(&freeze)) {
+ cpu_relax();
+ barrier();
+ {
+ int i;
+ for (i=0; i<10000; i++)
+ barrier();
+ }
+ }
+ atomic_dec(&cpu_counter);
+}
+
+void smp_freeze(void)
+{
+ /* FIXME: for this to work, all the CPUs must be running
+ * "idle" thread (or we deadlock). Is that guaranteed? */
+ printk("Freezing CPUs...");
+ atomic_set(&cpu_counter, 0);
+ atomic_set(&freeze, 1);
+ smp_call_function(smp_pause, NULL, 0, 0);
+ if (num_online_cpus() != 2)
+ printk("not HT machine?");
+ while (atomic_read(&cpu_counter) < (num_online_cpus() - 1)) {
+ cpu_relax();
+ barrier();
+ }
+ printk("ok\n");
+}
+
+void smp_restart(void)
+{
+ printk("Restarting CPUs...");
+ atomic_set(&freeze, 0);
+ while (atomic_read(&cpu_counter)) {
+ cpu_relax();
+ barrier();
+ }
+ printk("ok\n");
+}
+
--- clean/kernel/power/swsusp.c 2004-05-21 09:49:11.000000000 +0200
+++ linux/kernel/power/swsusp.c 2004-05-21 14:39:38.000000000 +0200
@@ -859,6 +859,8 @@
free_some_memory();
+ mdelay(1000);
+ smp_freeze();
/* Save state of all device drivers, and stop them. */
if ((res = device_suspend(4))==0)
/* If stopping device drivers worked, we proceed basically into
@@ -872,6 +874,7 @@
*/
do_magic(0);
thaw_processes();
+ smp_restart();
} else
res = -EBUSY;
software_suspend_enabled = 1;
@@ -1195,8 +1198,7 @@
static int __init software_resume(void)
{
if (num_online_cpus() > 1) {
- printk(KERN_WARNING "Software Suspend has malfunctioning SMP support. Disabled :(\n");
- return -EINVAL;
+ printk(KERN_WARNING "SMP support is very experimental.\n");
}
/* We enable the possibility of machine suspend */
software_suspend_enabled = 1;
@@ -1223,6 +1225,8 @@
printk( "resuming from %s\n", resume_file);
if (read_suspend_image(resume_file, 0))
goto read_failure;
+ mdelay(1000);
+ smp_freeze();
device_suspend(4);
do_magic(1);
panic("This never returns");
--
934a471f20d6580d5aad759bf0d97ddc
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