Hi!

This is against -mm kernel; it is smp swsusp done right, and it
actually works for me. Unlike previous hacks, it uses cpu hotplug
infrastructure. Disable CONFIG_MTRR before you try this...

Test this if you can, and report any problems. If not enough people
scream, this is going to -mm.
                                                                Pavel

--- clean-mm/drivers/pci/pci.c  2005-03-21 11:39:32.000000000 +0100
+++ linux-mm/drivers/pci/pci.c  2005-03-22 01:41:48.000000000 +0100
@@ -376,11 +376,13 @@
        if (!pci_find_capability(dev, PCI_CAP_ID_PM))
                return PCI_D0;
 
+#if 0
        if (platform_pci_choose_state) {
                ret = platform_pci_choose_state(dev, state);
                if (ret >= 0)
                        state = ret;
        }
+#endif
        switch (state) {
        case 0: return PCI_D0;
        case 3: return PCI_D3hot;
--- clean-mm/kernel/power/Kconfig       2005-01-22 21:24:53.000000000 +0100
+++ linux-mm/kernel/power/Kconfig       2005-03-23 11:40:14.000000000 +0100
@@ -28,7 +28,7 @@
 
 config SOFTWARE_SUSPEND
        bool "Software Suspend (EXPERIMENTAL)"
-       depends on EXPERIMENTAL && PM && SWAP
+       depends on EXPERIMENTAL && PM && SWAP && (HOTPLUG_CPU || !SMP)
        ---help---
          Enable the possibility of suspending the machine.
          It doesn't need APM.
--- clean-mm/kernel/power/smp.c 2005-03-19 00:32:32.000000000 +0100
+++ linux-mm/kernel/power/smp.c 2005-03-23 15:38:30.000000000 +0100
@@ -7,79 +7,53 @@
  * 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>
 #include <asm/tlbflush.h>
+#include <asm/cpu.h>
 
-static atomic_t cpu_counter, freeze;
-
-
-static void smp_pause(void * data)
-{
-       struct saved_context ctxt;
-       __save_processor_state(&ctxt);
-       printk("Sleeping in:\n");
-       dump_stack();
-       atomic_inc(&cpu_counter);
-       while (atomic_read(&freeze)) {
-               /* FIXME: restore takes place at random piece inside this.
-                  This should probably be written in assembly, and
-                  preserve general-purpose registers, too
-
-                  What about stack? We may need to move to new stack here.
-
-                  This should better be ran with interrupts disabled.
-                */
-               cpu_relax();
-               barrier();
-       }
-       atomic_dec(&cpu_counter);
-       __restore_processor_state(&ctxt);
-}
-
-static cpumask_t oldmask;
+cpumask_t frozen_cpus;
 
 void disable_nonboot_cpus(void)
 {
-       printk("Freezing CPUs (at %d)", smp_processor_id());
-       oldmask = current->cpus_allowed;
-       set_cpus_allowed(current, cpumask_of_cpu(0));
-       current->state = TASK_INTERRUPTIBLE;
-       schedule_timeout(HZ);
-       printk("...");
-       BUG_ON(smp_processor_id() != 0);
-
-       /* FIXME: for this to work, all the CPUs must be running
-        * "idle" thread (or we deadlock). Is that guaranteed? */
+       int cpu, error;
 
-       atomic_set(&cpu_counter, 0);
-       atomic_set(&freeze, 1);
-       smp_call_function(smp_pause, NULL, 0, 0);
-       while (atomic_read(&cpu_counter) < (num_online_cpus() - 1)) {
-               cpu_relax();
-               barrier();
+       error = 0;
+       cpus_clear(frozen_cpus);
+       printk("Freezing cpus ...\n");
+       for_each_online_cpu(cpu) {
+               if (cpu == 0)
+                       continue;
+               error = cpu_down(cpu);
+               if (!error) {
+                       cpu_set(cpu, frozen_cpus);
+                       printk("CPU%d is down\n", cpu);
+                       continue;
+               }
+               printk("Error taking cpu %d down: %d\n", cpu, error);
        }
-       printk("ok\n");
+       BUG_ON(smp_processor_id() != 0);
+       if (error)
+               panic("cpus not sleeping");
 }
 
 void enable_nonboot_cpus(void)
 {
-       printk("Restarting CPUs");
-       atomic_set(&freeze, 0);
-       while (atomic_read(&cpu_counter)) {
-               cpu_relax();
-               barrier();
-       }
-       printk("...");
-       set_cpus_allowed(current, oldmask);
-       schedule();
-       printk("ok\n");
+       int cpu, error;
 
+       printk("Thawing cpus ...\n");
+       for_each_cpu_mask(cpu, frozen_cpus) {
+               if (cpu == 0)
+                       continue;
+               error = cpu_up(cpu);
+               if (!error) {
+                       printk("CPU%d is up\n", cpu);
+                       continue;
+               }
+               printk("Error taking cpu %d up: %d\n", cpu, error);
+               panic("Not enough cpus");
+       }
 }
-
-
--- clean-mm/kernel/power/swsusp.c      2005-03-21 11:39:33.000000000 +0100
+++ linux-mm/kernel/power/swsusp.c      2005-03-23 15:34:53.000000000 +0100
@@ -1194,8 +1194,11 @@
                return "version";
        if (strcmp(swsusp_info.uts.machine,system_utsname.machine))
                return "machine";
+#if 0
+       /* We can't use number of CPUs when we use hotplug to remove them ;-))) 
*/
        if(swsusp_info.cpus != num_online_cpus())
                return "number of cpus";
+#endif
        return NULL;
 }
 

-- 
People were complaining that M$ turns users into beta-testers...
...jr ghea gurz vagb qrirybcref, naq gurl frrz gb yvxr vg gung jnl!
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