Re: [PATCH 1/2] KVM: s390: use switch vs jump table in priv.c

[Cornelia Huck <cohuck@redhat.com>]

On Tue,  6 Feb 2018 11:21:26 +0000
Christian Borntraeger <borntraeger@de.ibm.com> wrote:

> instead of having huge jump tables for function selection,

s/instead/Instead/

> lets use normal switch/case statements for the instruction

s/lets/let's/

> handlers in priv.c
> 
> bloat-o-meter shows that the saving are even bigger than
> just the removed jump tables.
> 
> add/remove: 0/11 grow/shrink: 8/0 up/down: 1934/-10246 (-8312)
> Function                                     old     new   delta
> kvm_s390_handle_b2                            42     958    +916
> handle_iske                                  178     558    +380
> handle_rrbe                                  178     546    +368
> kvm_s390_handle_b9                            42     222    +180
> kvm_s390_handle_01                            42      74     +32
> kvm_s390_handle_eb                            42      70     +28
> handle_sckpf                                 176     204     +28
> handle_lctlg                                 628     630      +2
> handle_ptff                                   36       -     -36
> handle_sckpf.part                             78       -     -78
> handle_epsw                                  154       -    -154
> handle_stfl                                  316       -    -316
> handle_rrbe.part                             470       -    -470
> handle_iske.part                             482       -    -482
> handle_io_inst                               518       -    -518
> x01_handlers                                2048       -   -2048
> eb_handlers                                 2048       -   -2048
> b9_handlers                                 2048       -   -2048
> b2_handlers                                 2048       -   -2048

Neat.

> 
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
> ---
>  arch/s390/kvm/priv.c | 183 +++++++++++++++++++++++++--------------------------
>  1 file changed, 91 insertions(+), 92 deletions(-)

Reviewed-by: Cornelia Huck <cohuck@redhat.com>