hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4SK3S
CVE: NA

--------------------------------

Introduce fallback mechanism for memory reliable. The following process
will fallback to non-mirrored region if their allocation from mirrored
region failed

- User tasks with reliable flag
- thp collapse pages
- init tasks
- pagecache
- tmpfs

In order to achieve this goals. Buddy system will fallback to non-mirrored
in the following situations.

- if __GFP_THISNODE is set in gfp_mask and dest nodes do not have any zones
  available

- high_zoneidx will be set to ZONE_MOVABLE to alloc memory before oom

This mechanism is enabled by defalut and can be disabled by adding
"reliable_debug=F" to the kernel parameters. This mechanism rely on
CONFIG_MEMORY_RELIABLE and need "kernelcore=reliable" in the kernel
parameters.
Signed-off-by: NMa Wupeng <mawupeng1@huawei.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>