mm/memory_hotplug.c: prevent memory leak when reusing pgdat (33fce011) · Commits · 戴 / test

When offlining a node in try_offline_node(), pgdat is not released. So that pgdat could be reused in hotadd_new_pgdat(). While we reallocate pgdat->per_cpu_nodestats if this pgdat is reused. This patch prevents the memory leak by just allocating per_cpu_nodestats when it is a new pgdat. Link: http://lkml.kernel.org/r/20190813020608.10194-1-richardw.yang@linux.intel.com Signed-off-by:

Wei Yang <richardw.yang@linux.intel.com> Acked-by:

Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <OSalvador@suse.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/memory_hotplug.c

+9 −1

Original line number	Diff line number	Diff line
		@@ -925,8 +925,11 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
		if (!pgdat)
		return NULL;

		pgdat->per_cpu_nodestats =
		alloc_percpu(struct per_cpu_nodestat);
		arch_refresh_nodedata(nid, pgdat);
		} else {
		int cpu;
		/*
		* Reset the nr_zones, order and classzone_idx before reuse.
		* Note that kswapd will init kswapd_classzone_idx properly
		@@ -935,6 +938,12 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
		pgdat->nr_zones = 0;
		pgdat->kswapd_order = 0;
		pgdat->kswapd_classzone_idx = 0;
		for_each_online_cpu(cpu) {
		struct per_cpu_nodestat *p;

		p = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu);
		memset(p, 0, sizeof(*p));
		}
		}

		/* we can use NODE_DATA(nid) from here */
		@@ -944,7 +953,6 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)

		/* init node's zones as empty zones, we don't have any present pages.*/
		free_area_init_core_hotplug(nid);
		pgdat->per_cpu_nodestats = alloc_percpu(struct per_cpu_nodestat);

		/*
		* The node we allocated has no zone fallback lists. For avoiding

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