First pass at updated cache clearing logic.
The old clearing algorithm is very naive and it sorts all cached files
globally by modified time. This sadly lets apps gamify the system by
setting their modified times far in the future, and it's very
expensive because it requires a global filesystem traversal to free
up even the smallest amount of data.
Instead, this CL introduces a much more fair cache clearing algorithm
that deletes files from specific UIDs based on how much cache space
that UID is using proportional to the space allocated to them. This
new design has several nice properties:
-- It uses the recently added quotactl() feature to rapidly target
the apps that are using the most space.
-- We only need to traverse the filesystem for UIDs that actively
enter the crosshairs of the clearing algorithm.
-- Disciplined apps who stay under their allocated quota will be
the last to have their cached data cleared.
-- This design can be easily adapted to support additional features
such as atomic purging and tombstones.
In summary, the new algorithm is extremely efficient when freeing up
the typical small-to-medium amounts of disk space, and is only
moderately less efficient than the old algorithm when forced to clear
all cached data.
Test: builds, boots, clearing strategy looks sane
Bug: 33965858
Change-Id: I66f95089cb33f1add3f31fcf1082ab2469870fda
diff --git a/cmds/installd/binder/android/os/IInstalld.aidl b/cmds/installd/binder/android/os/IInstalld.aidl
index 2f12ea9..aa5e4f2 100644
--- a/cmds/installd/binder/android/os/IInstalld.aidl
+++ b/cmds/installd/binder/android/os/IInstalld.aidl
@@ -38,6 +38,8 @@
long[] getUserSize(@nullable @utf8InCpp String uuid, int userId, int flags, in int[] appIds);
long[] getExternalSize(@nullable @utf8InCpp String uuid, int userId, int flags);
+ void setAppQuota(@nullable @utf8InCpp String uuid, int userId, int appId, long cacheQuota);
+
void moveCompleteApp(@nullable @utf8InCpp String fromUuid, @nullable @utf8InCpp String toUuid,
@utf8InCpp String packageName, @utf8InCpp String dataAppName, int appId,
@utf8InCpp String seInfo, int targetSdkVersion);
@@ -58,7 +60,7 @@
void idmap(@utf8InCpp String targetApkPath, @utf8InCpp String overlayApkPath, int uid);
void rmPackageDir(@utf8InCpp String packageDir);
void markBootComplete(@utf8InCpp String instructionSet);
- void freeCache(@nullable @utf8InCpp String uuid, long freeStorageSize);
+ void freeCache(@nullable @utf8InCpp String uuid, long freeStorageSize, int flags);
void linkNativeLibraryDirectory(@nullable @utf8InCpp String uuid,
@utf8InCpp String packageName, @utf8InCpp String nativeLibPath32, int userId);
void createOatDir(@utf8InCpp String oatDir, @utf8InCpp String instructionSet);