tree 2ad0b14b84325fe943d7b3b19b9c70011e46f827
parent 7e486eab1fb599fda8d7b67e50ddd726db0bdad7
author Bram Bonné <brambonne@google.com> 1588765795 +0200
committer Bram Bonné <brambonne@google.com> 1589551806 +0200

Speed up seccomp with priority list.

Allow to provide a list of prioritized syscalls (e.g., syscalls that we
know occur often) which are checked before other syscalls in seccomp.

When constructing the bpf seccomp filter, traverse prioritized syscalls
in a linear list before checking all other syscalls in a binary tree.

Bug: 156732794
Test: make, inspect generated *_system_policy.cpp files
Test: simpleperf on futex/ioctl-heavy app seems to show 5-10% less time
spent in seccomp call

Change-Id: I509343bcd32ada90c0591785ab5cb12d2a38c31e