Nathan Fontenot 1d9a090783 powerpc/numa: Invalidate numa_cpu_lookup_table on cpu remove
When DLPAR removing a CPU, the unmapping of the cpu from a node in
unmap_cpu_from_node() should also invalidate the CPUs entry in the
numa_cpu_lookup_table. There is not a guarantee that on a subsequent
DLPAR add of the CPU the associativity will be the same and thus
could be in a different node. Invalidating the entry in the
numa_cpu_lookup_table causes the associativity to be read from the
device tree at the time of the add.

The current behavior of not invalidating the CPUs entry in the
numa_cpu_lookup_table can result in scenarios where the the topology
layout of CPUs in the partition does not match the device tree
or the topology reported by the HMC.

This bug looks like it was introduced in 2004 in the commit titled
"ppc64: cpu hotplug notifier for numa", which is 6b15e4e87e32 in the
linux-fullhist tree. Hence tag it for all stable releases.

Cc: stable@vger.kernel.org
Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Reviewed-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-02-08 23:56:10 +11:00

130 lines
3.0 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_POWERPC_TOPOLOGY_H
#define _ASM_POWERPC_TOPOLOGY_H
#ifdef __KERNEL__
struct device;
struct device_node;
#ifdef CONFIG_NUMA
/*
* If zone_reclaim_mode is enabled, a RECLAIM_DISTANCE of 10 will mean that
* all zones on all nodes will be eligible for zone_reclaim().
*/
#define RECLAIM_DISTANCE 10
#include <asm/mmzone.h>
#define cpumask_of_node(node) ((node) == -1 ? \
cpu_all_mask : \
node_to_cpumask_map[node])
struct pci_bus;
#ifdef CONFIG_PCI
extern int pcibus_to_node(struct pci_bus *bus);
#else
static inline int pcibus_to_node(struct pci_bus *bus)
{
return -1;
}
#endif
#define cpumask_of_pcibus(bus) (pcibus_to_node(bus) == -1 ? \
cpu_all_mask : \
cpumask_of_node(pcibus_to_node(bus)))
extern int __node_distance(int, int);
#define node_distance(a, b) __node_distance(a, b)
extern void __init dump_numa_cpu_topology(void);
extern int sysfs_add_device_to_node(struct device *dev, int nid);
extern void sysfs_remove_device_from_node(struct device *dev, int nid);
extern int numa_update_cpu_topology(bool cpus_locked);
static inline void update_numa_cpu_lookup_table(unsigned int cpu, int node)
{
numa_cpu_lookup_table[cpu] = node;
}
static inline int early_cpu_to_node(int cpu)
{
int nid;
nid = numa_cpu_lookup_table[cpu];
/*
* Fall back to node 0 if nid is unset (it should be, except bugs).
* This allows callers to safely do NODE_DATA(early_cpu_to_node(cpu)).
*/
return (nid < 0) ? 0 : nid;
}
#else
static inline int early_cpu_to_node(int cpu) { return 0; }
static inline void dump_numa_cpu_topology(void) {}
static inline int sysfs_add_device_to_node(struct device *dev, int nid)
{
return 0;
}
static inline void sysfs_remove_device_from_node(struct device *dev,
int nid)
{
}
static inline int numa_update_cpu_topology(bool cpus_locked)
{
return 0;
}
#endif /* CONFIG_NUMA */
#if defined(CONFIG_NUMA) && defined(CONFIG_PPC_SPLPAR)
extern int start_topology_update(void);
extern int stop_topology_update(void);
extern int prrn_is_enabled(void);
#else
static inline int start_topology_update(void)
{
return 0;
}
static inline int stop_topology_update(void)
{
return 0;
}
static inline int prrn_is_enabled(void)
{
return 0;
}
#endif /* CONFIG_NUMA && CONFIG_PPC_SPLPAR */
#if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_NEED_MULTIPLE_NODES)
#if defined(CONFIG_PPC_SPLPAR)
extern int timed_topology_update(int nsecs);
#else
#define timed_topology_update(nsecs)
#endif /* CONFIG_PPC_SPLPAR */
#endif /* CONFIG_HOTPLUG_CPU || CONFIG_NEED_MULTIPLE_NODES */
#include <asm-generic/topology.h>
#ifdef CONFIG_SMP
#include <asm/cputable.h>
#ifdef CONFIG_PPC64
#include <asm/smp.h>
#define topology_physical_package_id(cpu) (cpu_to_chip_id(cpu))
#define topology_sibling_cpumask(cpu) (per_cpu(cpu_sibling_map, cpu))
#define topology_core_cpumask(cpu) (per_cpu(cpu_core_map, cpu))
#define topology_core_id(cpu) (cpu_to_core_id(cpu))
#endif
#endif
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_TOPOLOGY_H */