write "clear pathcahe" to clear pathcaches and vnodes
write "clear pagecache" to clear pagecaches
write "clear all" to clear both pathcaches and pagechaches
the cache in use will not be cleared

close: #I3XLPH
Signed-off-by: Nmucor <mucorwang@gmail.com>

add /proc/fs_cache to display vnode, path cache, page cache.
also change some bad virable name

close: #I3WWBD
Signed-off-by: Nmucor <mucorwang@gmail.com>

add /proc/fs_cache to display vnode, path cache, page cache.
also change some bad virable name

close: #I3WESD
Signed-off-by: Nmucor <mucorwang@gmail.com>

support turn off as many features as possible.
current only libc and posix and bsd can not be turned off.
Signed-off-by: NCaoruihong <crh.cao@huawei.com>
Change-Id: I1e97570c67593207a56dc11f357eca4b4a018bfd

Change-Id: I052d930d54e63179b17b77f02c107a015f3cfc3f

Change-Id: Ia6c1f6302407a707b3ec9b805f4c92d8a7970b86