linux_old1/arch/powerpc/platforms/pseries/hotplug-cpu.c

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/*
* pseries CPU Hotplug infrastructure.
*
* Split out from arch/powerpc/platforms/pseries/setup.c
* arch/powerpc/kernel/rtas.c, and arch/powerpc/platforms/pseries/smp.c
*
* Peter Bergner, IBM March 2001.
* Copyright (C) 2001 IBM.
* Dave Engebretsen, Peter Bergner, and
* Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
* Plus various changes from other IBM teams...
*
* Copyright (C) 2006 Michael Ellerman, IBM Corporation
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/cpu.h>
#include <asm/system.h>
#include <asm/prom.h>
#include <asm/rtas.h>
#include <asm/firmware.h>
#include <asm/machdep.h>
#include <asm/vdso_datapage.h>
#include <asm/pSeries_reconfig.h>
#include "xics.h"
#include "plpar_wrappers.h"
powerpc/pseries: Add hooks to put the CPU into an appropriate offline state When a CPU is offlined on POWER currently, we call rtas_stop_self() and hand the CPU back to the resource pool. This path is used for DLPAR which will cause a change in the LPAR configuration which will be visible outside. This patch changes the default state a CPU is put into when it is offlined. On platforms which support ceding the processor to the hypervisor with latency hint specifier value, during a cpu offline operation, instead of calling rtas_stop_self(), we cede the vCPU to the hypervisor while passing a latency hint specifier value. The Hypervisor can use this hint to provide better energy savings. Also, during the offline operation, the control of the vCPU remains with the LPAR as oppposed to returning it to the resource pool. The patch achieves this by creating an infrastructure to set the preferred_offline_state() which can be either - CPU_STATE_OFFLINE: which is the current behaviour of calling rtas_stop_self() - CPU_STATE_INACTIVE: which cedes the vCPU to the hypervisor with the latency hint specifier. The codepath which wants to perform a DLPAR operation can set the preferred_offline_state() of a CPU to CPU_STATE_OFFLINE before invoking cpu_down(). The patch also provides a boot-time command line argument to disable/enable CPU_STATE_INACTIVE. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-30 03:22:53 +08:00
#include "offline_states.h"
/* This version can't take the spinlock, because it never returns */
static struct rtas_args rtas_stop_self_args = {
.token = RTAS_UNKNOWN_SERVICE,
.nargs = 0,
.nret = 1,
.rets = &rtas_stop_self_args.args[0],
};
powerpc/pseries: Add hooks to put the CPU into an appropriate offline state When a CPU is offlined on POWER currently, we call rtas_stop_self() and hand the CPU back to the resource pool. This path is used for DLPAR which will cause a change in the LPAR configuration which will be visible outside. This patch changes the default state a CPU is put into when it is offlined. On platforms which support ceding the processor to the hypervisor with latency hint specifier value, during a cpu offline operation, instead of calling rtas_stop_self(), we cede the vCPU to the hypervisor while passing a latency hint specifier value. The Hypervisor can use this hint to provide better energy savings. Also, during the offline operation, the control of the vCPU remains with the LPAR as oppposed to returning it to the resource pool. The patch achieves this by creating an infrastructure to set the preferred_offline_state() which can be either - CPU_STATE_OFFLINE: which is the current behaviour of calling rtas_stop_self() - CPU_STATE_INACTIVE: which cedes the vCPU to the hypervisor with the latency hint specifier. The codepath which wants to perform a DLPAR operation can set the preferred_offline_state() of a CPU to CPU_STATE_OFFLINE before invoking cpu_down(). The patch also provides a boot-time command line argument to disable/enable CPU_STATE_INACTIVE. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-30 03:22:53 +08:00
static DEFINE_PER_CPU(enum cpu_state_vals, preferred_offline_state) =
CPU_STATE_OFFLINE;
static DEFINE_PER_CPU(enum cpu_state_vals, current_state) = CPU_STATE_OFFLINE;
static enum cpu_state_vals default_offline_state = CPU_STATE_OFFLINE;
static int cede_offline_enabled __read_mostly = 1;
/*
* Enable/disable cede_offline when available.
*/
static int __init setup_cede_offline(char *str)
{
if (!strcmp(str, "off"))
cede_offline_enabled = 0;
else if (!strcmp(str, "on"))
cede_offline_enabled = 1;
else
return 0;
return 1;
}
__setup("cede_offline=", setup_cede_offline);
enum cpu_state_vals get_cpu_current_state(int cpu)
{
return per_cpu(current_state, cpu);
}
void set_cpu_current_state(int cpu, enum cpu_state_vals state)
{
per_cpu(current_state, cpu) = state;
}
enum cpu_state_vals get_preferred_offline_state(int cpu)
{
return per_cpu(preferred_offline_state, cpu);
}
void set_preferred_offline_state(int cpu, enum cpu_state_vals state)
{
per_cpu(preferred_offline_state, cpu) = state;
}
void set_default_offline_state(int cpu)
{
per_cpu(preferred_offline_state, cpu) = default_offline_state;
}
static void rtas_stop_self(void)
{
struct rtas_args *args = &rtas_stop_self_args;
local_irq_disable();
BUG_ON(args->token == RTAS_UNKNOWN_SERVICE);
printk("cpu %u (hwid %u) Ready to die...\n",
smp_processor_id(), hard_smp_processor_id());
enter_rtas(__pa(args));
panic("Alas, I survived.\n");
}
static void pseries_mach_cpu_die(void)
{
powerpc/pseries: Add hooks to put the CPU into an appropriate offline state When a CPU is offlined on POWER currently, we call rtas_stop_self() and hand the CPU back to the resource pool. This path is used for DLPAR which will cause a change in the LPAR configuration which will be visible outside. This patch changes the default state a CPU is put into when it is offlined. On platforms which support ceding the processor to the hypervisor with latency hint specifier value, during a cpu offline operation, instead of calling rtas_stop_self(), we cede the vCPU to the hypervisor while passing a latency hint specifier value. The Hypervisor can use this hint to provide better energy savings. Also, during the offline operation, the control of the vCPU remains with the LPAR as oppposed to returning it to the resource pool. The patch achieves this by creating an infrastructure to set the preferred_offline_state() which can be either - CPU_STATE_OFFLINE: which is the current behaviour of calling rtas_stop_self() - CPU_STATE_INACTIVE: which cedes the vCPU to the hypervisor with the latency hint specifier. The codepath which wants to perform a DLPAR operation can set the preferred_offline_state() of a CPU to CPU_STATE_OFFLINE before invoking cpu_down(). The patch also provides a boot-time command line argument to disable/enable CPU_STATE_INACTIVE. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-30 03:22:53 +08:00
unsigned int cpu = smp_processor_id();
unsigned int hwcpu = hard_smp_processor_id();
u8 cede_latency_hint = 0;
local_irq_disable();
idle_task_exit();
xics_teardown_cpu();
powerpc/pseries: Add hooks to put the CPU into an appropriate offline state When a CPU is offlined on POWER currently, we call rtas_stop_self() and hand the CPU back to the resource pool. This path is used for DLPAR which will cause a change in the LPAR configuration which will be visible outside. This patch changes the default state a CPU is put into when it is offlined. On platforms which support ceding the processor to the hypervisor with latency hint specifier value, during a cpu offline operation, instead of calling rtas_stop_self(), we cede the vCPU to the hypervisor while passing a latency hint specifier value. The Hypervisor can use this hint to provide better energy savings. Also, during the offline operation, the control of the vCPU remains with the LPAR as oppposed to returning it to the resource pool. The patch achieves this by creating an infrastructure to set the preferred_offline_state() which can be either - CPU_STATE_OFFLINE: which is the current behaviour of calling rtas_stop_self() - CPU_STATE_INACTIVE: which cedes the vCPU to the hypervisor with the latency hint specifier. The codepath which wants to perform a DLPAR operation can set the preferred_offline_state() of a CPU to CPU_STATE_OFFLINE before invoking cpu_down(). The patch also provides a boot-time command line argument to disable/enable CPU_STATE_INACTIVE. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-30 03:22:53 +08:00
if (get_preferred_offline_state(cpu) == CPU_STATE_INACTIVE) {
set_cpu_current_state(cpu, CPU_STATE_INACTIVE);
if (ppc_md.suspend_disable_cpu)
ppc_md.suspend_disable_cpu();
powerpc/pseries: Add hooks to put the CPU into an appropriate offline state When a CPU is offlined on POWER currently, we call rtas_stop_self() and hand the CPU back to the resource pool. This path is used for DLPAR which will cause a change in the LPAR configuration which will be visible outside. This patch changes the default state a CPU is put into when it is offlined. On platforms which support ceding the processor to the hypervisor with latency hint specifier value, during a cpu offline operation, instead of calling rtas_stop_self(), we cede the vCPU to the hypervisor while passing a latency hint specifier value. The Hypervisor can use this hint to provide better energy savings. Also, during the offline operation, the control of the vCPU remains with the LPAR as oppposed to returning it to the resource pool. The patch achieves this by creating an infrastructure to set the preferred_offline_state() which can be either - CPU_STATE_OFFLINE: which is the current behaviour of calling rtas_stop_self() - CPU_STATE_INACTIVE: which cedes the vCPU to the hypervisor with the latency hint specifier. The codepath which wants to perform a DLPAR operation can set the preferred_offline_state() of a CPU to CPU_STATE_OFFLINE before invoking cpu_down(). The patch also provides a boot-time command line argument to disable/enable CPU_STATE_INACTIVE. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-30 03:22:53 +08:00
cede_latency_hint = 2;
get_lppaca()->idle = 1;
if (!get_lppaca()->shared_proc)
get_lppaca()->donate_dedicated_cpu = 1;
while (get_preferred_offline_state(cpu) == CPU_STATE_INACTIVE) {
extended_cede_processor(cede_latency_hint);
}
if (!get_lppaca()->shared_proc)
get_lppaca()->donate_dedicated_cpu = 0;
get_lppaca()->idle = 0;
if (get_preferred_offline_state(cpu) == CPU_STATE_ONLINE) {
unregister_slb_shadow(hwcpu, __pa(get_slb_shadow()));
powerpc/pseries: Add hooks to put the CPU into an appropriate offline state When a CPU is offlined on POWER currently, we call rtas_stop_self() and hand the CPU back to the resource pool. This path is used for DLPAR which will cause a change in the LPAR configuration which will be visible outside. This patch changes the default state a CPU is put into when it is offlined. On platforms which support ceding the processor to the hypervisor with latency hint specifier value, during a cpu offline operation, instead of calling rtas_stop_self(), we cede the vCPU to the hypervisor while passing a latency hint specifier value. The Hypervisor can use this hint to provide better energy savings. Also, during the offline operation, the control of the vCPU remains with the LPAR as oppposed to returning it to the resource pool. The patch achieves this by creating an infrastructure to set the preferred_offline_state() which can be either - CPU_STATE_OFFLINE: which is the current behaviour of calling rtas_stop_self() - CPU_STATE_INACTIVE: which cedes the vCPU to the hypervisor with the latency hint specifier. The codepath which wants to perform a DLPAR operation can set the preferred_offline_state() of a CPU to CPU_STATE_OFFLINE before invoking cpu_down(). The patch also provides a boot-time command line argument to disable/enable CPU_STATE_INACTIVE. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-30 03:22:53 +08:00
/*
* Call to start_secondary_resume() will not return.
* Kernel stack will be reset and start_secondary()
* will be called to continue the online operation.
*/
start_secondary_resume();
}
}
powerpc/pseries: Add hooks to put the CPU into an appropriate offline state When a CPU is offlined on POWER currently, we call rtas_stop_self() and hand the CPU back to the resource pool. This path is used for DLPAR which will cause a change in the LPAR configuration which will be visible outside. This patch changes the default state a CPU is put into when it is offlined. On platforms which support ceding the processor to the hypervisor with latency hint specifier value, during a cpu offline operation, instead of calling rtas_stop_self(), we cede the vCPU to the hypervisor while passing a latency hint specifier value. The Hypervisor can use this hint to provide better energy savings. Also, during the offline operation, the control of the vCPU remains with the LPAR as oppposed to returning it to the resource pool. The patch achieves this by creating an infrastructure to set the preferred_offline_state() which can be either - CPU_STATE_OFFLINE: which is the current behaviour of calling rtas_stop_self() - CPU_STATE_INACTIVE: which cedes the vCPU to the hypervisor with the latency hint specifier. The codepath which wants to perform a DLPAR operation can set the preferred_offline_state() of a CPU to CPU_STATE_OFFLINE before invoking cpu_down(). The patch also provides a boot-time command line argument to disable/enable CPU_STATE_INACTIVE. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-30 03:22:53 +08:00
/* Requested state is CPU_STATE_OFFLINE at this point */
WARN_ON(get_preferred_offline_state(cpu) != CPU_STATE_OFFLINE);
powerpc/pseries: Add hooks to put the CPU into an appropriate offline state When a CPU is offlined on POWER currently, we call rtas_stop_self() and hand the CPU back to the resource pool. This path is used for DLPAR which will cause a change in the LPAR configuration which will be visible outside. This patch changes the default state a CPU is put into when it is offlined. On platforms which support ceding the processor to the hypervisor with latency hint specifier value, during a cpu offline operation, instead of calling rtas_stop_self(), we cede the vCPU to the hypervisor while passing a latency hint specifier value. The Hypervisor can use this hint to provide better energy savings. Also, during the offline operation, the control of the vCPU remains with the LPAR as oppposed to returning it to the resource pool. The patch achieves this by creating an infrastructure to set the preferred_offline_state() which can be either - CPU_STATE_OFFLINE: which is the current behaviour of calling rtas_stop_self() - CPU_STATE_INACTIVE: which cedes the vCPU to the hypervisor with the latency hint specifier. The codepath which wants to perform a DLPAR operation can set the preferred_offline_state() of a CPU to CPU_STATE_OFFLINE before invoking cpu_down(). The patch also provides a boot-time command line argument to disable/enable CPU_STATE_INACTIVE. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-30 03:22:53 +08:00
set_cpu_current_state(cpu, CPU_STATE_OFFLINE);
unregister_slb_shadow(hwcpu, __pa(get_slb_shadow()));
rtas_stop_self();
powerpc/pseries: Add hooks to put the CPU into an appropriate offline state When a CPU is offlined on POWER currently, we call rtas_stop_self() and hand the CPU back to the resource pool. This path is used for DLPAR which will cause a change in the LPAR configuration which will be visible outside. This patch changes the default state a CPU is put into when it is offlined. On platforms which support ceding the processor to the hypervisor with latency hint specifier value, during a cpu offline operation, instead of calling rtas_stop_self(), we cede the vCPU to the hypervisor while passing a latency hint specifier value. The Hypervisor can use this hint to provide better energy savings. Also, during the offline operation, the control of the vCPU remains with the LPAR as oppposed to returning it to the resource pool. The patch achieves this by creating an infrastructure to set the preferred_offline_state() which can be either - CPU_STATE_OFFLINE: which is the current behaviour of calling rtas_stop_self() - CPU_STATE_INACTIVE: which cedes the vCPU to the hypervisor with the latency hint specifier. The codepath which wants to perform a DLPAR operation can set the preferred_offline_state() of a CPU to CPU_STATE_OFFLINE before invoking cpu_down(). The patch also provides a boot-time command line argument to disable/enable CPU_STATE_INACTIVE. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-30 03:22:53 +08:00
/* Should never get here... */
BUG();
for(;;);
}
static int pseries_cpu_disable(void)
{
int cpu = smp_processor_id();
set_cpu_online(cpu, false);
vdso_data->processorCount--;
/*fix boot_cpuid here*/
if (cpu == boot_cpuid)
boot_cpuid = cpumask_any(cpu_online_mask);
/* FIXME: abstract this to not be platform specific later on */
xics_migrate_irqs_away();
return 0;
}
powerpc/pseries: Add hooks to put the CPU into an appropriate offline state When a CPU is offlined on POWER currently, we call rtas_stop_self() and hand the CPU back to the resource pool. This path is used for DLPAR which will cause a change in the LPAR configuration which will be visible outside. This patch changes the default state a CPU is put into when it is offlined. On platforms which support ceding the processor to the hypervisor with latency hint specifier value, during a cpu offline operation, instead of calling rtas_stop_self(), we cede the vCPU to the hypervisor while passing a latency hint specifier value. The Hypervisor can use this hint to provide better energy savings. Also, during the offline operation, the control of the vCPU remains with the LPAR as oppposed to returning it to the resource pool. The patch achieves this by creating an infrastructure to set the preferred_offline_state() which can be either - CPU_STATE_OFFLINE: which is the current behaviour of calling rtas_stop_self() - CPU_STATE_INACTIVE: which cedes the vCPU to the hypervisor with the latency hint specifier. The codepath which wants to perform a DLPAR operation can set the preferred_offline_state() of a CPU to CPU_STATE_OFFLINE before invoking cpu_down(). The patch also provides a boot-time command line argument to disable/enable CPU_STATE_INACTIVE. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-30 03:22:53 +08:00
/*
* pseries_cpu_die: Wait for the cpu to die.
* @cpu: logical processor id of the CPU whose death we're awaiting.
*
* This function is called from the context of the thread which is performing
* the cpu-offline. Here we wait for long enough to allow the cpu in question
* to self-destroy so that the cpu-offline thread can send the CPU_DEAD
* notifications.
*
* OTOH, pseries_mach_cpu_die() is called by the @cpu when it wants to
* self-destruct.
*/
static void pseries_cpu_die(unsigned int cpu)
{
int tries;
powerpc/pseries: Add hooks to put the CPU into an appropriate offline state When a CPU is offlined on POWER currently, we call rtas_stop_self() and hand the CPU back to the resource pool. This path is used for DLPAR which will cause a change in the LPAR configuration which will be visible outside. This patch changes the default state a CPU is put into when it is offlined. On platforms which support ceding the processor to the hypervisor with latency hint specifier value, during a cpu offline operation, instead of calling rtas_stop_self(), we cede the vCPU to the hypervisor while passing a latency hint specifier value. The Hypervisor can use this hint to provide better energy savings. Also, during the offline operation, the control of the vCPU remains with the LPAR as oppposed to returning it to the resource pool. The patch achieves this by creating an infrastructure to set the preferred_offline_state() which can be either - CPU_STATE_OFFLINE: which is the current behaviour of calling rtas_stop_self() - CPU_STATE_INACTIVE: which cedes the vCPU to the hypervisor with the latency hint specifier. The codepath which wants to perform a DLPAR operation can set the preferred_offline_state() of a CPU to CPU_STATE_OFFLINE before invoking cpu_down(). The patch also provides a boot-time command line argument to disable/enable CPU_STATE_INACTIVE. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-30 03:22:53 +08:00
int cpu_status = 1;
unsigned int pcpu = get_hard_smp_processor_id(cpu);
powerpc/pseries: Add hooks to put the CPU into an appropriate offline state When a CPU is offlined on POWER currently, we call rtas_stop_self() and hand the CPU back to the resource pool. This path is used for DLPAR which will cause a change in the LPAR configuration which will be visible outside. This patch changes the default state a CPU is put into when it is offlined. On platforms which support ceding the processor to the hypervisor with latency hint specifier value, during a cpu offline operation, instead of calling rtas_stop_self(), we cede the vCPU to the hypervisor while passing a latency hint specifier value. The Hypervisor can use this hint to provide better energy savings. Also, during the offline operation, the control of the vCPU remains with the LPAR as oppposed to returning it to the resource pool. The patch achieves this by creating an infrastructure to set the preferred_offline_state() which can be either - CPU_STATE_OFFLINE: which is the current behaviour of calling rtas_stop_self() - CPU_STATE_INACTIVE: which cedes the vCPU to the hypervisor with the latency hint specifier. The codepath which wants to perform a DLPAR operation can set the preferred_offline_state() of a CPU to CPU_STATE_OFFLINE before invoking cpu_down(). The patch also provides a boot-time command line argument to disable/enable CPU_STATE_INACTIVE. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-30 03:22:53 +08:00
if (get_preferred_offline_state(cpu) == CPU_STATE_INACTIVE) {
cpu_status = 1;
for (tries = 0; tries < 5000; tries++) {
powerpc/pseries: Add hooks to put the CPU into an appropriate offline state When a CPU is offlined on POWER currently, we call rtas_stop_self() and hand the CPU back to the resource pool. This path is used for DLPAR which will cause a change in the LPAR configuration which will be visible outside. This patch changes the default state a CPU is put into when it is offlined. On platforms which support ceding the processor to the hypervisor with latency hint specifier value, during a cpu offline operation, instead of calling rtas_stop_self(), we cede the vCPU to the hypervisor while passing a latency hint specifier value. The Hypervisor can use this hint to provide better energy savings. Also, during the offline operation, the control of the vCPU remains with the LPAR as oppposed to returning it to the resource pool. The patch achieves this by creating an infrastructure to set the preferred_offline_state() which can be either - CPU_STATE_OFFLINE: which is the current behaviour of calling rtas_stop_self() - CPU_STATE_INACTIVE: which cedes the vCPU to the hypervisor with the latency hint specifier. The codepath which wants to perform a DLPAR operation can set the preferred_offline_state() of a CPU to CPU_STATE_OFFLINE before invoking cpu_down(). The patch also provides a boot-time command line argument to disable/enable CPU_STATE_INACTIVE. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-30 03:22:53 +08:00
if (get_cpu_current_state(cpu) == CPU_STATE_INACTIVE) {
cpu_status = 0;
break;
}
msleep(1);
powerpc/pseries: Add hooks to put the CPU into an appropriate offline state When a CPU is offlined on POWER currently, we call rtas_stop_self() and hand the CPU back to the resource pool. This path is used for DLPAR which will cause a change in the LPAR configuration which will be visible outside. This patch changes the default state a CPU is put into when it is offlined. On platforms which support ceding the processor to the hypervisor with latency hint specifier value, during a cpu offline operation, instead of calling rtas_stop_self(), we cede the vCPU to the hypervisor while passing a latency hint specifier value. The Hypervisor can use this hint to provide better energy savings. Also, during the offline operation, the control of the vCPU remains with the LPAR as oppposed to returning it to the resource pool. The patch achieves this by creating an infrastructure to set the preferred_offline_state() which can be either - CPU_STATE_OFFLINE: which is the current behaviour of calling rtas_stop_self() - CPU_STATE_INACTIVE: which cedes the vCPU to the hypervisor with the latency hint specifier. The codepath which wants to perform a DLPAR operation can set the preferred_offline_state() of a CPU to CPU_STATE_OFFLINE before invoking cpu_down(). The patch also provides a boot-time command line argument to disable/enable CPU_STATE_INACTIVE. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-30 03:22:53 +08:00
}
} else if (get_preferred_offline_state(cpu) == CPU_STATE_OFFLINE) {
for (tries = 0; tries < 25; tries++) {
cpu_status = smp_query_cpu_stopped(pcpu);
if (cpu_status == QCSS_STOPPED ||
cpu_status == QCSS_HARDWARE_ERROR)
powerpc/pseries: Add hooks to put the CPU into an appropriate offline state When a CPU is offlined on POWER currently, we call rtas_stop_self() and hand the CPU back to the resource pool. This path is used for DLPAR which will cause a change in the LPAR configuration which will be visible outside. This patch changes the default state a CPU is put into when it is offlined. On platforms which support ceding the processor to the hypervisor with latency hint specifier value, during a cpu offline operation, instead of calling rtas_stop_self(), we cede the vCPU to the hypervisor while passing a latency hint specifier value. The Hypervisor can use this hint to provide better energy savings. Also, during the offline operation, the control of the vCPU remains with the LPAR as oppposed to returning it to the resource pool. The patch achieves this by creating an infrastructure to set the preferred_offline_state() which can be either - CPU_STATE_OFFLINE: which is the current behaviour of calling rtas_stop_self() - CPU_STATE_INACTIVE: which cedes the vCPU to the hypervisor with the latency hint specifier. The codepath which wants to perform a DLPAR operation can set the preferred_offline_state() of a CPU to CPU_STATE_OFFLINE before invoking cpu_down(). The patch also provides a boot-time command line argument to disable/enable CPU_STATE_INACTIVE. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-30 03:22:53 +08:00
break;
cpu_relax();
}
}
powerpc/pseries: Add hooks to put the CPU into an appropriate offline state When a CPU is offlined on POWER currently, we call rtas_stop_self() and hand the CPU back to the resource pool. This path is used for DLPAR which will cause a change in the LPAR configuration which will be visible outside. This patch changes the default state a CPU is put into when it is offlined. On platforms which support ceding the processor to the hypervisor with latency hint specifier value, during a cpu offline operation, instead of calling rtas_stop_self(), we cede the vCPU to the hypervisor while passing a latency hint specifier value. The Hypervisor can use this hint to provide better energy savings. Also, during the offline operation, the control of the vCPU remains with the LPAR as oppposed to returning it to the resource pool. The patch achieves this by creating an infrastructure to set the preferred_offline_state() which can be either - CPU_STATE_OFFLINE: which is the current behaviour of calling rtas_stop_self() - CPU_STATE_INACTIVE: which cedes the vCPU to the hypervisor with the latency hint specifier. The codepath which wants to perform a DLPAR operation can set the preferred_offline_state() of a CPU to CPU_STATE_OFFLINE before invoking cpu_down(). The patch also provides a boot-time command line argument to disable/enable CPU_STATE_INACTIVE. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-30 03:22:53 +08:00
if (cpu_status != 0) {
printk("Querying DEAD? cpu %i (%i) shows %i\n",
cpu, pcpu, cpu_status);
}
/* Isolation and deallocation are definatly done by
* drslot_chrp_cpu. If they were not they would be
* done here. Change isolate state to Isolate and
* change allocation-state to Unusable.
*/
paca[cpu].cpu_start = 0;
}
/*
* Update cpu_present_mask and paca(s) for a new cpu node. The wrinkle
* here is that a cpu device node may represent up to two logical cpus
* in the SMT case. We must honor the assumption in other code that
* the logical ids for sibling SMT threads x and y are adjacent, such
* that x^1 == y and y^1 == x.
*/
static int pseries_add_processor(struct device_node *np)
{
unsigned int cpu;
cpumask_var_t candidate_mask, tmp;
int err = -ENOSPC, len, nthreads, i;
const u32 *intserv;
intserv = of_get_property(np, "ibm,ppc-interrupt-server#s", &len);
if (!intserv)
return 0;
zalloc_cpumask_var(&candidate_mask, GFP_KERNEL);
zalloc_cpumask_var(&tmp, GFP_KERNEL);
nthreads = len / sizeof(u32);
for (i = 0; i < nthreads; i++)
cpumask_set_cpu(i, tmp);
cpu_maps_update_begin();
BUG_ON(!cpumask_subset(cpu_present_mask, cpu_possible_mask));
/* Get a bitmap of unoccupied slots. */
cpumask_xor(candidate_mask, cpu_possible_mask, cpu_present_mask);
if (cpumask_empty(candidate_mask)) {
/* If we get here, it most likely means that NR_CPUS is
* less than the partition's max processors setting.
*/
printk(KERN_ERR "Cannot add cpu %s; this system configuration"
" supports %d logical cpus.\n", np->full_name,
cpumask_weight(cpu_possible_mask));
goto out_unlock;
}
while (!cpumask_empty(tmp))
if (cpumask_subset(tmp, candidate_mask))
/* Found a range where we can insert the new cpu(s) */
break;
else
cpumask_shift_left(tmp, tmp, nthreads);
if (cpumask_empty(tmp)) {
printk(KERN_ERR "Unable to find space in cpu_present_mask for"
" processor %s with %d thread(s)\n", np->name,
nthreads);
goto out_unlock;
}
for_each_cpu(cpu, tmp) {
BUG_ON(cpumask_test_cpu(cpu, cpu_present_mask));
set_cpu_present(cpu, true);
set_hard_smp_processor_id(cpu, *intserv++);
}
err = 0;
out_unlock:
cpu_maps_update_done();
free_cpumask_var(candidate_mask);
free_cpumask_var(tmp);
return err;
}
/*
* Update the present map for a cpu node which is going away, and set
* the hard id in the paca(s) to -1 to be consistent with boot time
* convention for non-present cpus.
*/
static void pseries_remove_processor(struct device_node *np)
{
unsigned int cpu;
int len, nthreads, i;
const u32 *intserv;
intserv = of_get_property(np, "ibm,ppc-interrupt-server#s", &len);
if (!intserv)
return;
nthreads = len / sizeof(u32);
cpu_maps_update_begin();
for (i = 0; i < nthreads; i++) {
for_each_present_cpu(cpu) {
if (get_hard_smp_processor_id(cpu) != intserv[i])
continue;
BUG_ON(cpu_online(cpu));
set_cpu_present(cpu, false);
set_hard_smp_processor_id(cpu, -1);
break;
}
if (cpu >= nr_cpu_ids)
printk(KERN_WARNING "Could not find cpu to remove "
"with physical id 0x%x\n", intserv[i]);
}
cpu_maps_update_done();
}
static int pseries_smp_notifier(struct notifier_block *nb,
unsigned long action, void *node)
{
int err = NOTIFY_OK;
switch (action) {
case PSERIES_RECONFIG_ADD:
if (pseries_add_processor(node))
err = NOTIFY_BAD;
break;
case PSERIES_RECONFIG_REMOVE:
pseries_remove_processor(node);
break;
default:
err = NOTIFY_DONE;
break;
}
return err;
}
static struct notifier_block pseries_smp_nb = {
.notifier_call = pseries_smp_notifier,
};
powerpc/pseries: Add hooks to put the CPU into an appropriate offline state When a CPU is offlined on POWER currently, we call rtas_stop_self() and hand the CPU back to the resource pool. This path is used for DLPAR which will cause a change in the LPAR configuration which will be visible outside. This patch changes the default state a CPU is put into when it is offlined. On platforms which support ceding the processor to the hypervisor with latency hint specifier value, during a cpu offline operation, instead of calling rtas_stop_self(), we cede the vCPU to the hypervisor while passing a latency hint specifier value. The Hypervisor can use this hint to provide better energy savings. Also, during the offline operation, the control of the vCPU remains with the LPAR as oppposed to returning it to the resource pool. The patch achieves this by creating an infrastructure to set the preferred_offline_state() which can be either - CPU_STATE_OFFLINE: which is the current behaviour of calling rtas_stop_self() - CPU_STATE_INACTIVE: which cedes the vCPU to the hypervisor with the latency hint specifier. The codepath which wants to perform a DLPAR operation can set the preferred_offline_state() of a CPU to CPU_STATE_OFFLINE before invoking cpu_down(). The patch also provides a boot-time command line argument to disable/enable CPU_STATE_INACTIVE. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-30 03:22:53 +08:00
#define MAX_CEDE_LATENCY_LEVELS 4
#define CEDE_LATENCY_PARAM_LENGTH 10
#define CEDE_LATENCY_PARAM_MAX_LENGTH \
(MAX_CEDE_LATENCY_LEVELS * CEDE_LATENCY_PARAM_LENGTH * sizeof(char))
#define CEDE_LATENCY_TOKEN 45
static char cede_parameters[CEDE_LATENCY_PARAM_MAX_LENGTH];
static int parse_cede_parameters(void)
{
memset(cede_parameters, 0, CEDE_LATENCY_PARAM_MAX_LENGTH);
return rtas_call(rtas_token("ibm,get-system-parameter"), 3, 1,
NULL,
CEDE_LATENCY_TOKEN,
__pa(cede_parameters),
CEDE_LATENCY_PARAM_MAX_LENGTH);
powerpc/pseries: Add hooks to put the CPU into an appropriate offline state When a CPU is offlined on POWER currently, we call rtas_stop_self() and hand the CPU back to the resource pool. This path is used for DLPAR which will cause a change in the LPAR configuration which will be visible outside. This patch changes the default state a CPU is put into when it is offlined. On platforms which support ceding the processor to the hypervisor with latency hint specifier value, during a cpu offline operation, instead of calling rtas_stop_self(), we cede the vCPU to the hypervisor while passing a latency hint specifier value. The Hypervisor can use this hint to provide better energy savings. Also, during the offline operation, the control of the vCPU remains with the LPAR as oppposed to returning it to the resource pool. The patch achieves this by creating an infrastructure to set the preferred_offline_state() which can be either - CPU_STATE_OFFLINE: which is the current behaviour of calling rtas_stop_self() - CPU_STATE_INACTIVE: which cedes the vCPU to the hypervisor with the latency hint specifier. The codepath which wants to perform a DLPAR operation can set the preferred_offline_state() of a CPU to CPU_STATE_OFFLINE before invoking cpu_down(). The patch also provides a boot-time command line argument to disable/enable CPU_STATE_INACTIVE. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-30 03:22:53 +08:00
}
static int __init pseries_cpu_hotplug_init(void)
{
struct device_node *np;
const char *typep;
powerpc/pseries: Add hooks to put the CPU into an appropriate offline state When a CPU is offlined on POWER currently, we call rtas_stop_self() and hand the CPU back to the resource pool. This path is used for DLPAR which will cause a change in the LPAR configuration which will be visible outside. This patch changes the default state a CPU is put into when it is offlined. On platforms which support ceding the processor to the hypervisor with latency hint specifier value, during a cpu offline operation, instead of calling rtas_stop_self(), we cede the vCPU to the hypervisor while passing a latency hint specifier value. The Hypervisor can use this hint to provide better energy savings. Also, during the offline operation, the control of the vCPU remains with the LPAR as oppposed to returning it to the resource pool. The patch achieves this by creating an infrastructure to set the preferred_offline_state() which can be either - CPU_STATE_OFFLINE: which is the current behaviour of calling rtas_stop_self() - CPU_STATE_INACTIVE: which cedes the vCPU to the hypervisor with the latency hint specifier. The codepath which wants to perform a DLPAR operation can set the preferred_offline_state() of a CPU to CPU_STATE_OFFLINE before invoking cpu_down(). The patch also provides a boot-time command line argument to disable/enable CPU_STATE_INACTIVE. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-30 03:22:53 +08:00
int cpu;
int qcss_tok;
for_each_node_by_name(np, "interrupt-controller") {
typep = of_get_property(np, "compatible", NULL);
if (strstr(typep, "open-pic")) {
of_node_put(np);
printk(KERN_INFO "CPU Hotplug not supported on "
"systems using MPIC\n");
return 0;
}
}
rtas_stop_self_args.token = rtas_token("stop-self");
qcss_tok = rtas_token("query-cpu-stopped-state");
if (rtas_stop_self_args.token == RTAS_UNKNOWN_SERVICE ||
qcss_tok == RTAS_UNKNOWN_SERVICE) {
printk(KERN_INFO "CPU Hotplug not supported by firmware "
"- disabling.\n");
return 0;
}
ppc_md.cpu_die = pseries_mach_cpu_die;
smp_ops->cpu_disable = pseries_cpu_disable;
smp_ops->cpu_die = pseries_cpu_die;
/* Processors can be added/removed only on LPAR */
powerpc/pseries: Add hooks to put the CPU into an appropriate offline state When a CPU is offlined on POWER currently, we call rtas_stop_self() and hand the CPU back to the resource pool. This path is used for DLPAR which will cause a change in the LPAR configuration which will be visible outside. This patch changes the default state a CPU is put into when it is offlined. On platforms which support ceding the processor to the hypervisor with latency hint specifier value, during a cpu offline operation, instead of calling rtas_stop_self(), we cede the vCPU to the hypervisor while passing a latency hint specifier value. The Hypervisor can use this hint to provide better energy savings. Also, during the offline operation, the control of the vCPU remains with the LPAR as oppposed to returning it to the resource pool. The patch achieves this by creating an infrastructure to set the preferred_offline_state() which can be either - CPU_STATE_OFFLINE: which is the current behaviour of calling rtas_stop_self() - CPU_STATE_INACTIVE: which cedes the vCPU to the hypervisor with the latency hint specifier. The codepath which wants to perform a DLPAR operation can set the preferred_offline_state() of a CPU to CPU_STATE_OFFLINE before invoking cpu_down(). The patch also provides a boot-time command line argument to disable/enable CPU_STATE_INACTIVE. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-30 03:22:53 +08:00
if (firmware_has_feature(FW_FEATURE_LPAR)) {
pSeries_reconfig_notifier_register(&pseries_smp_nb);
powerpc/pseries: Add hooks to put the CPU into an appropriate offline state When a CPU is offlined on POWER currently, we call rtas_stop_self() and hand the CPU back to the resource pool. This path is used for DLPAR which will cause a change in the LPAR configuration which will be visible outside. This patch changes the default state a CPU is put into when it is offlined. On platforms which support ceding the processor to the hypervisor with latency hint specifier value, during a cpu offline operation, instead of calling rtas_stop_self(), we cede the vCPU to the hypervisor while passing a latency hint specifier value. The Hypervisor can use this hint to provide better energy savings. Also, during the offline operation, the control of the vCPU remains with the LPAR as oppposed to returning it to the resource pool. The patch achieves this by creating an infrastructure to set the preferred_offline_state() which can be either - CPU_STATE_OFFLINE: which is the current behaviour of calling rtas_stop_self() - CPU_STATE_INACTIVE: which cedes the vCPU to the hypervisor with the latency hint specifier. The codepath which wants to perform a DLPAR operation can set the preferred_offline_state() of a CPU to CPU_STATE_OFFLINE before invoking cpu_down(). The patch also provides a boot-time command line argument to disable/enable CPU_STATE_INACTIVE. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-30 03:22:53 +08:00
cpu_maps_update_begin();
if (cede_offline_enabled && parse_cede_parameters() == 0) {
default_offline_state = CPU_STATE_INACTIVE;
for_each_online_cpu(cpu)
set_default_offline_state(cpu);
}
cpu_maps_update_done();
}
return 0;
}
arch_initcall(pseries_cpu_hotplug_init);