Use hugetlb.xMB.rsvd.limit_in_bytes for a better hugepages behaviors

[qiuyuhang]

hugetlb.xMB.limit_in_bytes does not provide a good behaviors when using hugepages[1]. In short, application might request hugepages successfully but SIGBUS will raise when application try to access the hugepages memory. Linux kernel solve this problem from 5.7[2].

Maybe we should use hugetlb.xMB.rsvd.limit_in_bytes to provide a better hugepages behaviors.

Any thoughts?

Regards.
Yuhang.

[1] https://www.postgresql.org/message-id/flat/HE1PR0701MB256920EEAA3B2A9C06249F339E110%40HE1PR0701MB2569.eurprd07.prod.outlook.com
[2] https://lkml.org/lkml/2020/2/3/1153