shmem/ascend: charge pages to the memcg of current task

ascend inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4EUVI


CVE: NA

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In the share pool scenario, when the shared memory is applied
for, the do_mm_populate function is performed at the same time,
that is, the corresponding pages are allocated. In the current
share pool implementation, the memory is charged to the memcg of
the first task added to this share pool group.

This is unreasonable and may cause memcg of first task oom.
So, we should charge the pages to the memcg of current task.

Signed-off-by: Zhou Guanghui <zhouguanghui1@huawei.com>
Reviewed-by: Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>