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>

close #I3W2M9
Signed-off-by: Nchenjing <chenjing139@huawei.com>
Change-Id: If8ba7047e2914a3104182bf017f437c2ae962625

1.remove redundant headfile in kernel, such as:
  compiler.h;debug.h;automount.h;inode.h;syslog.h;net.h;
2.split fs.h to file.h and driver.h
3.move vnode.h and path_cache.h to vfs/include
4.remove redundant interface and defines

close: #I3RTNR
Signed-off-by: Nmucor <mucorwang@gmail.com>

close: #I3T6MZ
Signed-off-by: Nli_zan <371442490@qq.com>

close: #I3I768

Change-Id: I4f801df4abe1a9afdf43391c28276e96a5e81513

Change-Id: I052d930d54e63179b17b77f02c107a015f3cfc3f

Description:Delete VM to support only kernel mode.
Sig:liteos_a
Feature or Bugfix:Feature
Binary Source:No

Change-Id: Ie1029c8fbc0c1b85c138663933118d2d148b7769

Change-Id: Ic443742e125915f0e5332a338dedea5c40348928

Feature or Bugfix:Feature
Binary Source:Huawei
PrivateCode(Yes/No):Yes

Change-Id: I175d2648bc6f9078c34de2c0a5c93fda10b86c47
ChangeID:13306388