s390 updates for 5.18-rc6
- Disable -Warray-bounds warning for gcc12, since there known way to
workaround false positive warnings on lowcore accesses would result
in worse code on fast paths.
- Avoid lockdep_assert_held() warning in kvm vm memop code.
- Reduce overhead within gmap_rmap code to get rid of long latencies
when e.g. shutting down 2nd level guests.
KVM: s390: vsie/gmap: reduce gmap_rmap overhead
there are cases that trigger a 2nd shadow event for the same
vmaddr/raddr combination. (prefix changes, reboots, some known races)
This will increase memory usages and it will result in long latencies
when cleaning up, e.g. on shutdown. To avoid cases with a list that has
hundreds of identical raddrs we check existing entries at insert time.
As this measurably reduces the list length this will be faster than
traversing the list at shutdown time.
In the long run several places will be optimized to create less entries
and a shrinker might be necessary.
Fixes: 4be130a08420 ("s390/mm: add shadow gmap support")
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20220429151526.1560-1-borntraeger@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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