The patch titled
Subject: mm/memory_hotplug.c: prevent memory leak when reusing pgdat
has been added to the -mm tree. Its filename is
mm-hotplug-prevent-memory-leak-when-reuse-pgdat.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-hotplug-prevent-memory-leak-when-reuse-pgdat.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-hotplug-prevent-memory-leak-when-reuse-pgdat.patch
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------------------------------------------------------
From: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
Subject: mm/memory_hotplug.c: prevent memory leak when reusing pgdat
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@xxxxxxxxxxxxxxx
Signed-off-by: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Oscar Salvador <OSalvador@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory_hotplug.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
--- a/mm/memory_hotplug.c~mm-hotplug-prevent-memory-leak-when-reuse-pgdat
+++ a/mm/memory_hotplug.c
@@ -919,8 +919,11 @@ static pg_data_t __ref *hotadd_new_pgdat
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
@@ -929,6 +932,12 @@ static pg_data_t __ref *hotadd_new_pgdat
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 */
@@ -938,7 +947,6 @@ static pg_data_t __ref *hotadd_new_pgdat
/* 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
_
Patches currently in -mm which might be from richardw.yang@xxxxxxxxxxxxxxx are
mm-remove-redundant-assignment-of-entry.patch
mm-hotplug-prevent-memory-leak-when-reuse-pgdat.patch
mm-sparse-use-__nr_to_sectionsection_nr-to-get-mem_section.patch
mm-mmapc-refine-find_vma_prev-with-rb_last.patch
