From cf23422b9d76215316855253da491d4c9f294372 Mon Sep 17 00:00:00 2001 From: minskey guo Date: Mon, 24 May 2010 14:32:41 -0700 Subject: [PATCH] cpu/mem hotplug: enable CPUs online before local memory online Enable users to online CPUs even if the CPUs belongs to a numa node which doesn't have onlined local memory. The zonlists(pg_data_t.node_zonelists[]) of a numa node are created either in system boot/init period, or at the time of local memory online. For a numa node without onlined local memory, its zonelists are not initialized at present. As a result, any memory allocation operations executed by CPUs within this node will fail. In fact, an out-of-memory error is triggered when attempt to online CPUs before memory comes to online. This patch tries to create zonelists for such numa nodes, so that the memory allocation for this node can be fallback'ed to other nodes. [akpm@linux-foundation.org: remove unneeded export] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: minskey guo Cc: Minchan Kim Cc: Yasunori Goto Cc: Andi Kleen Cc: Christoph Lameter Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memory_hotplug.h | 1 + kernel/cpu.c | 25 +++++++++++++++++++++++++ mm/memory_hotplug.c | 23 +++++++++++++++++++++++ 3 files changed, 49 insertions(+) diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h index 35b07b7..864035f 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -202,6 +202,7 @@ static inline int is_mem_section_removable(unsigned long pfn, } #endif /* CONFIG_MEMORY_HOTREMOVE */ +extern int mem_online_node(int nid); extern int add_memory(int nid, u64 start, u64 size); extern int arch_add_memory(int nid, u64 start, u64 size); extern int remove_memory(u64 start, u64 size); diff --git a/kernel/cpu.c b/kernel/cpu.c index 5457775..a3fbcc0 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -326,6 +326,12 @@ out_notify: int __cpuinit cpu_up(unsigned int cpu) { int err = 0; + +#ifdef CONFIG_MEMORY_HOTPLUG + int nid; + pg_data_t *pgdat; +#endif + if (!cpu_possible(cpu)) { printk(KERN_ERR "can't online cpu %d because it is not " "configured as may-hotadd at boot time\n", cpu); @@ -336,6 +342,25 @@ int __cpuinit cpu_up(unsigned int cpu) return -EINVAL; } +#ifdef CONFIG_MEMORY_HOTPLUG + nid = cpu_to_node(cpu); + if (!node_online(nid)) { + err = mem_online_node(nid); + if (err) + return err; + } + + pgdat = NODE_DATA(nid); + if (!pgdat) { + printk(KERN_ERR + "Can't online cpu %d due to NULL pgdat\n", cpu); + return -ENOMEM; + } + + if (pgdat->node_zonelists->_zonerefs->zone == NULL) + build_all_zonelists(); +#endif + cpu_maps_update_begin(); if (cpu_hotplug_disabled) { diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index be211a5..85eb4d3 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -482,6 +482,29 @@ static void rollback_node_hotadd(int nid, pg_data_t *pgdat) } +/* + * called by cpu_up() to online a node without onlined memory. + */ +int mem_online_node(int nid) +{ + pg_data_t *pgdat; + int ret; + + lock_system_sleep(); + pgdat = hotadd_new_pgdat(nid, 0); + if (pgdat) { + ret = -ENOMEM; + goto out; + } + node_set_online(nid); + ret = register_one_node(nid); + BUG_ON(ret); + +out: + unlock_system_sleep(); + return ret; +} + /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */ int __ref add_memory(int nid, u64 start, u64 size) { -- 2.7.4