mm: vmalloc: Let user to control huge vmalloc default behavior

maillist inclusion
category: Feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4NDAW
CVE: NA

Reference: https://lore.kernel.org/lkml/20211226083912.166512-4-wangkefeng.wang@huawei.com/t/



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Add HUGE_VMALLOC_DEFAULT_ENABLED to let user to choose whether or
not enable huge vmalloc mappings by default, and this could make
more architectures to enable huge vmalloc mappings feature but
don't want to enable it by default.

Add hugevmalloc=on/off parameter to enable or disable this feature
at boot time, nohugevmalloc is still supported and equivalent to
hugevmalloc=off.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Wang Wensheng <wangwensheng4@huawei.com>
Reviewed-by: Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>