tree 273de364ca29c868a4d3168ac26fa293daffae58
parent 491ac24c0e85eb3c310d397c9f6ae4f75a2282d2
author Luis Chamberlain <mcgrof@kernel.org> 1677719193 -0800
committer Luis Chamberlain <mcgrof@kernel.org> 1677719203 -0800

fs/proc: sysctl: remove register ctl_table end with empty

Sysctls are being moved out of kernel/sysctl.c and out to
their own respective subsystems / users to help with easier
maintance and avoid merge conflicts. But when we move just
one entry and to its own new file the last entry for this
new file must be empty, so we are essentialy bloating the
kernel one extra empty entry per each newly moved sysctl.

To help with this, I have added support for registering just
one ctl_table, therefore not bloating the kernel when we
move a single ctl_table to its own file.

The optimization has been implemented in the previous patch,
here use register_sysctl_single() to register single one
ctl_table.

In this modification, I counted the size changes of each
object file during the compilation process.

When there is no strip, size changes are as follows:
                            before    now    save space
fs/dcache.o                  904936  904760   176bytes
fs/exec.o                    883584  883440   144bytes
fs/namespace.o              1614776 1614616   160bytes
fs/notify/dnotify/dnotify.o  255992  255872   120bytes
init/do_mounts_initrd.o      296552  296392   160bytes
kernel/acct.o                459184  459032   152bytes
kernel/delayacct.o           208680  208536   144bytes
kernel/kprobes.o             794968  794936    32bytes
kernel/panic.o               367696  367560   136bytes

When there is exec with 'strip -d', size changes are as follows:
                            before    now    save space
fs/dcache.o                  79040   78952     88bytes
fs/exec.o                    57960   57864     96bytes
fs/namespace.o              111904  111824     80bytes
fs/notify/dnotify/dnotify.o   8816    8736     80bytes
init/do_mounts_initrd.o       4872    4760    112bytes
kernel/acct.o                18104   18000    104bytes
kernel/delayacct.o            8768    8664    104bytes
kernel/kprobes.o             63192   63104     88bytes
kernel/panic.o               26760   26672     88bytes

Suggested-by: Matthew Wilcox <willy@infradead.org>
Suggested-by: Xiaoming Ni <nixiaoming@huawei.com>
Originally-by: Meng Tang <tangmeng@uniontech.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>