etmem: add etmem scan feature

euleros inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8T1MB?from=project-issue


CVE: NA

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This patch implements the etmem feature.

etmem scan module communicates with the user space program through
registered proc file system. It periodically scans the vma segments
of the target process, by walking its page table and check access
bit of each page, before reporting the scan results to user space,
so that we can better classify hotness of pages and further migrate
hot ones to fast memory tier and cold ones to slow memory tier.

Signed-off-by: yanxiaodan <yanxiaodan@huawei.com>
Signed-off-by: Feilong Lin <linfeilong@huawei.com>
Signed-off-by: geruijun <geruijun@huawei.com>
Signed-off-by: liubo <liubo254@huawei.com>
Signed-off-by: Yuchen Tang <tangyuchen5@huawei.com>