(2014/10/22 1:56), Toshi Kani wrote:
On Mon, 2014-10-20 at 19:05 +0900, Yasuaki Ishimatsu wrote:
  :
When hot removing memory, pgdat is set to 0 in try_offline_node().
But if the pgdat is allocated by bootmem allocator, the clearing
step is skipped. And when hot adding the same memory, the uninitialized
pgdat is reused. But free_area_init_node() chacks wether pgdat is set


s/chacks/checks

I'll update it.



to zero. As a result, free_area_init_node() hits WARN_ON().

This patch clears pgdat which is allocated by bootmem allocator
in try_offline_node().

Signed-off-by: Yasuaki Ishimatsu <isimatu.yasu...@jp.fujitsu.com>
CC: Zhang Zhen <zhenzhang.zh...@huawei.com>
CC: Wang Nan <wangn...@huawei.com>
CC: Tang Chen <tangc...@cn.fujitsu.com>
CC: Toshi Kani <toshi.k...@hp.com>
CC: Dave Hansen <dave.han...@intel.com>
CC: David Rientjes <rient...@google.com>

---
  mm/memory_hotplug.c | 3 ++-
  1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 29d8693..7649f7c 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1943,7 +1943,7 @@ void try_offline_node(int nid)

        if (!PageSlab(pgdat_page) && !PageCompound(pgdat_page))
                /* node data is allocated from boot memory */
-               return;
+               goto out;


Do we still need this if-statement?  That is, do we have to skip the
for-loop below even though it checks with is_vmalloc_addr()?

You are right. The if-statement is not necessary. So the issue can be
fixed by just removing the if-statement.

I'll post updated patch soon.

Thanks,
Yasuaki Ishimatsu


Thanks,
-Toshi


        /* free waittable in each zone */
        for (i = 0; i < MAX_NR_ZONES; i++) {
@@ -1957,6 +1957,7 @@ void try_offline_node(int nid)
                        vfree(zone->wait_table);
        }

+out:
        /*
         * Since there is no way to guarentee the address of pgdat/zone is not
         * on stack of any kernel threads or used by other kernel objects




--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to