diff options
| -rw-r--r-- | Documentation/cpusets.txt | 10 | ||||
| -rw-r--r-- | include/linux/cpuset.h | 4 | ||||
| -rw-r--r-- | kernel/cpuset.c | 28 | ||||
| -rw-r--r-- | mm/memory_hotplug.c | 3 |
4 files changed, 37 insertions, 8 deletions
diff --git a/Documentation/cpusets.txt b/Documentation/cpusets.txt index 76b44290c15..842f0d1ab21 100644 --- a/Documentation/cpusets.txt +++ b/Documentation/cpusets.txt @@ -217,11 +217,11 @@ exclusive cpuset. Also, the use of a Linux virtual file system (vfs) to represent the cpuset hierarchy provides for a familiar permission and name space for cpusets, with a minimum of additional kernel code. -The cpus file in the root (top_cpuset) cpuset is read-only. -It automatically tracks the value of cpu_online_map, using a CPU -hotplug notifier. If and when memory nodes can be hotplugged, -we expect to make the mems file in the root cpuset read-only -as well, and have it track the value of node_online_map. +The cpus and mems files in the root (top_cpuset) cpuset are +read-only. The cpus file automatically tracks the value of +cpu_online_map using a CPU hotplug notifier, and the mems file +automatically tracks the value of node_online_map using the +cpuset_track_online_nodes() hook. 1.4 What are exclusive cpusets ? diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h index 9354722a921..4d8adf66368 100644 --- a/include/linux/cpuset.h +++ b/include/linux/cpuset.h @@ -63,6 +63,8 @@ static inline int cpuset_do_slab_mem_spread(void) return current->flags & PF_SPREAD_SLAB; } +extern void cpuset_track_online_nodes(void); + #else /* !CONFIG_CPUSETS */ static inline int cpuset_init_early(void) { return 0; } @@ -126,6 +128,8 @@ static inline int cpuset_do_slab_mem_spread(void) return 0; } +static inline void cpuset_track_online_nodes(void) {} + #endif /* !CONFIG_CPUSETS */ #endif /* _LINUX_CPUSET_H */ diff --git a/kernel/cpuset.c b/kernel/cpuset.c index 584bb4e6c04..794af5024c2 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -912,6 +912,10 @@ static int update_nodemask(struct cpuset *cs, char *buf) int fudge; int retval; + /* top_cpuset.mems_allowed tracks node_online_map; it's read-only */ + if (cs == &top_cpuset) + return -EACCES; + trialcs = *cs; retval = nodelist_parse(buf, trialcs.mems_allowed); if (retval < 0) @@ -2042,9 +2046,8 @@ out: * (of no affect) on systems that are actively using CPU hotplug * but making no active use of cpusets. * - * This handles CPU hotplug (cpuhp) events. If someday Memory - * Nodes can be hotplugged (dynamically changing node_online_map) - * then we should handle that too, perhaps in a similar way. + * This routine ensures that top_cpuset.cpus_allowed tracks + * cpu_online_map on each CPU hotplug (cpuhp) event. */ #ifdef CONFIG_HOTPLUG_CPU @@ -2063,6 +2066,25 @@ static int cpuset_handle_cpuhp(struct notifier_block *nb, } #endif +/* + * Keep top_cpuset.mems_allowed tracking node_online_map. + * Call this routine anytime after you change node_online_map. + * See also the previous routine cpuset_handle_cpuhp(). + */ + +#ifdef CONFIG_MEMORY_HOTPLUG +void cpuset_track_online_nodes() +{ + mutex_lock(&manage_mutex); + mutex_lock(&callback_mutex); + + top_cpuset.mems_allowed = node_online_map; + + mutex_unlock(&callback_mutex); + mutex_unlock(&manage_mutex); +} +#endif + /** * cpuset_init_smp - initialize cpus_allowed * diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index c37319542b7..9576ed920c0 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -21,6 +21,7 @@ #include <linux/highmem.h> #include <linux/vmalloc.h> #include <linux/ioport.h> +#include <linux/cpuset.h> #include <asm/tlbflush.h> @@ -283,6 +284,8 @@ int add_memory(int nid, u64 start, u64 size) /* we online node here. we can't roll back from here. */ node_set_online(nid); + cpuset_track_online_nodes(); + if (new_pgdat) { ret = register_one_node(nid); /* |