tree 63b64546b7de078632172b12e99616e3deaf5a2e
parent eaf2d0bfe37415ba1e42a97608823e8dbef53220
author Mathias Agopian <mathias@google.com> 1309215952 -0700
committer Mathias Agopian <mathias@google.com> 1340842075 -0700

PermissionCache caches permission checks

This is intended to absorb the cost of the IPC
to the permission controller.
Cached permission checks cost about 3us, while
full blown ones are two orders of magnitude slower.

CAVEAT: PermissionCache can only handle system
permissions safely for now, because the cache is
not purged upon global permission changes.

Change-Id: I8b8a5e71e191e3c01e8f792f253c379190eee62e