tree 7b01eb60edeac13786dae1d01892a94d7949deb6
parent cc03f7956e67da4caafdc0d4948ed644651b39bf
author Igor Murashkin <iam@google.com> 1416006119 -0800
committer Igor Murashkin <iam@google.com> 1416441895 -0800

dex2oat: Pack likely-dirty objects together when generating the boot image

This introduces a new algorithm into image writer which "bins" objects
by how likely they are to be dirtied at runtime. Objects in the same bin
are placed contiguously in memory (i.e. into the same page). We try to
tune the bin selection based on how clean or how dirty the object will
likely be at runtime.

As-is, this saves about 150KB per-process (private-dirty pages) and 700KB in
zygote (shared-dirty).

There is still about 800KB of objects that are clean but located in
dirty pages, so with more analysis we can tune the bin selection and get
even more memory savings.

Bug: 17611661
Change-Id: Ia1455e4c56ffd0a36ae2a723d35b7e06502980f7