Commit d9c9a0b9 authored Sep 06, 2017 by Michal Hocko Committed by Linus Torvalds Sep 06, 2017

mm, page_alloc: do not set_cpu_numa_mem on empty nodes initialization

__build_all_zonelists reinitializes each online cpu local node for
CONFIG_HAVE_MEMORYLESS_NODES.  This makes sense because previously
memory less nodes could gain some memory during memory hotplug and so
the local node should be changed for CPUs close to such a node.  It
makes less sense to do that unconditionally for a newly creaded NUMA
node which is still offline and without any memory.

Let's also simplify the cpu loop and use for_each_online_cpu instead of
an explicit cpu_online check for all possible cpus.

Link: http://lkml.kernel.org/r/20170721143915.14161-4-mhocko@kernel.org


Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Shaohua Li <shaohua.li@intel.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent afb6ebb3

mm/page_alloc.c

+2 −4

Original line number	Diff line number	Diff line
		@@ -5160,10 +5160,8 @@ static int __build_all_zonelists(void *data)

		build_zonelists(pgdat);
		}
		}

		#ifdef CONFIG_HAVE_MEMORYLESS_NODES
		for_each_possible_cpu(cpu) {
		/*
		* We now know the "local memory node" for each node--
		* i.e., the node of the first zone in the generic zonelist.
		@@ -5172,10 +5170,10 @@ static int __build_all_zonelists(void *data)
		* secondary cpus' numa_mem as they come on-line. During
		* node/memory hotplug, we'll fixup all on-line cpus.
		*/
		if (cpu_online(cpu))
		for_each_online_cpu(cpu)
		set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu)));
		}
		#endif
		}

		return 0;
		}

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