(2014/11/11 10:27), Tang Chen wrote:
> When onlining memory on node2, node2 zoneinfo and node3 meminfo corrupted:
>
> # for ((i = 2048; i < 2064; i++)); do echo online_movable > /sys/devices/system/node/node2/memory$i/state; done
> # cat /sys/devices/system/node/node2/meminfo
> Node 2 MemTotal: 33554432 kB
> Node 2 MemFree: 33549092 kB
> Node 2 MemUsed: 5340 kB
> ......
> # cat /sys/devices/system/node/node3/meminfo
> Node 3 MemTotal: 0 kB
> Node 3 MemFree: 248 kB /* corrupted, should be 0 */
> Node 3 MemUsed: 0 kB
> ......
>
> # cat /proc/zoneinfo
> ......
> Node 2, zone Movable
> ......
> spanned 8388608
> present 16777216 /* corrupted, should be 8388608 */
> managed 8388608
>
>
> When memory is hot-added, all the memory is in offline state. So
> clear all zone->present_pages because they will be updated in
> online_pages() and offline_pages().
>
> Signed-off-by: Tang Chen <tangchen@xxxxxxxxxxxxxx>
> Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
I has reviewed your patch. But I have one comment.
Please see below.
> ---
> mm/memory_hotplug.c | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 8aba12b..26eac61 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1067,6 +1067,14 @@ out:
> }
> #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
>
> +static void reset_node_present_pages(pg_data_t *pgdat)
> +{
> + struct zone *z;
> +
> + for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++)
> + z->present_pages = 0;
> +}
You should reset pgdat->node_present_pages.
pgdat->node_present_pages is set to realtotalpages by calculate_node_totalpages().
And it is also incremented/decremented by memroy online/offline.
So pgdat->node_present_pages is broken internally too.
Thanks,
Yasuaki Ishimatsu.
> +
> /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
> static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
> {
> @@ -1105,6 +1113,13 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
> */
> reset_node_managed_pages(pgdat);
>
> + /*
> + * When memory is hot-added, all the memory is in offline state. So
> + * clear all zones' present_pages because they will be updated in
> + * online_pages() and offline_pages().
> + */
> + reset_node_present_pages(pgdat);
> +
> return pgdat;
> }
>
>
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