s390/sthyi: add cache to store hypervisor info
authorQingFeng Hao <haoqf@linux.vnet.ibm.com>
Fri, 29 Sep 2017 10:41:51 +0000 (12:41 +0200)
committerMartin Schwidefsky <schwidefsky@de.ibm.com>
Mon, 9 Oct 2017 09:15:35 +0000 (11:15 +0200)
commit9fb6c9b3fea1b1d1c6f14178373e8f7235f3b681
tree9b530f5034bad26c87adf9b17919d01438e20e18
parentb7c92f1a4e131e459bcf53a570e7265e5ce64455
s390/sthyi: add cache to store hypervisor info

STHYI requires extensive locking in the higher hypervisors and is
very computational/memory expensive. Therefore we cache the retrieved
hypervisor info whose valid period is 1s with mutex to allow concurrent
access. rw semaphore can't benefit here due to cache line bounce.

Signed-off-by: QingFeng Hao <haoqf@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
arch/s390/include/asm/kvm_host.h
arch/s390/kernel/sthyi.c
arch/s390/kvm/intercept.c
arch/s390/kvm/kvm-s390.c