[PATCH 4/5] cpu-hotplug,memory-hotplug: clear cpu_to_node() when offlining the node
From: Wen Congyang <hidden>
Date: 2012-11-26 10:51:40
Also in:
linux-acpi, linux-mm, lkml
Subsystem:
memory hot(un)plug, memory management, the rest · Maintainers:
David Hildenbrand, Oscar Salvador, Andrew Morton, Linus Torvalds
When the node is offlined, there is no memory/cpu on the node. If a sleep task runs on a cpu of this node, it will be migrated to the cpu on the other node. So we can clear cpu-to-node mapping. Cc: Yasuaki Ishimatsu <redacted> Cc: David Rientjes <rientjes@google.com> Cc: Jiang Liu <redacted> Cc: Minchan Kim <redacted> Cc: KOSAKI Motohiro <redacted> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Mel Gorman <redacted> Cc: Thomas Gleixner <redacted> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tang Chen <redacted> Signed-off-by: Wen Congyang <redacted> --- mm/memory_hotplug.c | 30 +++++++++++++++++++++++++++++- 1 file changed, 29 insertions(+), 1 deletion(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index b7c30bb..5ae86d7 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c@@ -1669,6 +1669,34 @@ static int check_cpu_on_node(void *data) return 0; } +static void unmap_cpu_on_node(void *data) +{ +#ifdef CONFIG_ACPI_NUMA + struct pglist_data *pgdat = data; + int cpu; + + for_each_possible_cpu(cpu) + if (cpu_to_node(cpu) == pgdat->node_id) + numa_clear_node(cpu); +#endif +} + +static int check_and_unmap_cpu_on_node(void *data) +{ + int ret = check_cpu_on_node(data); + + if (ret) + return ret; + + /* + * the node will be offlined when we come here, so we can clear + * the cpu_to_node() now. + */ + + unmap_cpu_on_node(data); + return 0; +} + /* offline the node if all memory sections of this node are removed */ void try_offline_node(int nid) {
@@ -1695,7 +1723,7 @@ void try_offline_node(int nid) return; } - if (stop_machine(check_cpu_on_node, NODE_DATA(nid), NULL)) + if (stop_machine(check_and_unmap_cpu_on_node, NODE_DATA(nid), NULL)) return; /*
--
1.8.0
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