hugepage: add sysctl for hugepage alloc and mig

euleros inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I7RO5Q
CVE: NA
Reference: https://gitee.com/openeuler/kernel/commit/80ed6b3203c960b286e1fd5d8db1b39a19cdc40c



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Add /proc/sys/kernel/hugepage_pmem_allocall switch. Set 1 to allowed all
memory in pmem could alloc for hugepage. Set 0(default) hugepage alloc is
limited by zone watermark as usual.
Add /proc/sys/kernel/hugepage_mig_noalloc switch. Set 1 to forbid new
hugepage alloc in hugepage migration when hugepage in dest node runs
out. Set 0(default) to allow hugepage alloc in hugepage migration as
usual.

Signed-off-by: Kemeng Shi <shikemeng@huawei.com>
Reviewed-by: louhongxiang <louhongxiang@huawei.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>