Separate caches for separate UIDs (05a4d006) · Commits · e / os / android_frameworks_base

core/java/android/app/PropertyInvalidatedCache.java

+236 −48

Original line number	Diff line number	Diff line
		@@ -32,7 +32,10 @@ import android.os.Process;
		import android.os.SystemClock;
		import android.os.SystemProperties;
		import android.util.ArrayMap;
		import android.util.ArraySet;
		import android.util.Log;
		import android.util.SparseArray;
		import android.util.SparseBooleanArray;

		import com.android.internal.annotations.GuardedBy;
		import com.android.internal.annotations.VisibleForTesting;
		@@ -92,9 +95,6 @@ public class PropertyInvalidatedCache<Query, Result> {
		* caching on behalf of other processes.
		*/
		public boolean shouldBypassCache(@NonNull Q query) {
		if(android.multiuser.Flags.propertyInvalidatedCacheBypassMismatchedUids()) {
		return Binder.getCallingUid() != Process.myUid();
		}
		return false;
		}
		};
		@@ -392,8 +392,213 @@ public class PropertyInvalidatedCache<Query, Result> {
		}
		}

		/**
		* An array of hash maps, indexed by calling UID. The class behaves a bit like a hash map
		* except that it uses the calling UID internally.
		*/
		private class CacheMap<Query, Result> {

		// Create a new map for a UID, using the parent's configuration for max size.
		private LinkedHashMap<Query, Result> createMap() {
		return new LinkedHashMap<Query, Result>(
		2 /* start small */,
		0.75f /* default load factor */,
		true /* LRU access order */) {
		@GuardedBy("mLock")
		@Override
		protected boolean removeEldestEntry(Map.Entry eldest) {
		final int size = size();
		if (size > mHighWaterMark) {
		mHighWaterMark = size;
		}
		if (size > mMaxEntries) {
		mMissOverflow++;
		return true;
		}
		return false;
		}
		};
		}

		// An array of maps, indexed by UID.
		private final SparseArray<LinkedHashMap<Query, Result>> mCache = new SparseArray<>();

		// If true, isolate the hash entries by calling UID. If this is false, allow the cache
		// entries to be combined in a single hash map.
		private final boolean mIsolated;

		// Collect statistics.
		private final boolean mStatistics;

		// An array of booleans to indicate if a UID has been involved in a map access. A value
		// exists for every UID that was ever involved during cache access. This is updated only
		// if statistics are being collected.
		private final SparseBooleanArray mUidSeen;

		// A hash map that ignores the UID. This is used in look-aside fashion just for hit/miss
		// statistics. This is updated only if statistics are being collected.
		private final ArraySet<Query> mShadowCache;

		// Shadow statistics. Only hits and misses need to be recorded. These are updated only
		// if statistics are being collected. The "SelfHits" records hits when the UID is the
		// process uid.
		private int mShadowHits;
		private int mShadowMisses;
		private int mShadowSelfHits;

		// The process UID.
		private final int mSelfUid;

		// True in test mode. In test mode, the cache uses Binder.getWorkSource() as the UID.
		private final boolean mTestMode;

		/**
		* Create a CacheMap. UID isolation is enabled if the input parameter is true and if the
		* isolation feature is enabled.
		*/
		CacheMap(boolean isolate, boolean testMode) {
		mIsolated = Flags.picIsolateCacheByUid() && isolate;
		mStatistics = Flags.picIsolatedCacheStatistics() && mIsolated;
		if (mStatistics) {
		mUidSeen = new SparseBooleanArray();
		mShadowCache = new ArraySet<>();
		} else {
		mUidSeen = null;
		mShadowCache = null;
		}
		mSelfUid = Process.myUid();
		mTestMode = testMode;
		}

		// Return the UID for this cache invocation. If uid isolation is disabled, the value of 0
		// is returned, which effectively places all entries in a single hash map.
		private int callerUid() {
		if (!mIsolated) {
		return 0;
		} else if (mTestMode) {
		return Binder.getCallingWorkSourceUid();
		} else {
		return Binder.getCallingUid();
		}
		}

		/**
		* Lookup an entry in the cache.
		*/
		Result get(Query query) {
		final int uid = callerUid();

		// Shadow statistics
		if (mStatistics) {
		if (mShadowCache.contains(query)) {
		mShadowHits++;
		if (uid == mSelfUid) {
		mShadowSelfHits++;
		}
		} else {
		mShadowMisses++;
		}
		}

		var map = mCache.get(uid);
		if (map != null) {
		return map.get(query);
		} else {
		return null;
		}
		}

		/**
		* Remove an entry from the cache.
		*/
		void remove(Query query) {
		final int uid = callerUid();
		if (mStatistics) {
		mShadowCache.remove(query);
		}

		var map = mCache.get(uid);
		if (map != null) {
		map.remove(query);
		}
		}

		/**
		* Record an entry in the cache.
		*/
		void put(Query query, Result result) {
		final int uid = callerUid();
		if (mStatistics) {
		mShadowCache.add(query);
		mUidSeen.put(uid, true);
		}

		var map = mCache.get(uid);
		if (map == null) {
		map = createMap();
		mCache.put(uid, map);
		}
		map.put(query, result);
		}

		/**
		* Return the number of entries in the cache.
		*/
		int size() {
		int total = 0;
		for (int i = 0; i < mCache.size(); i++) {
		var map = mCache.valueAt(i);
		total += map.size();
		}
		return total;
		}

		/**
		* Clear the entries in the cache. Update the shadow statistics.
		*/
		void clear() {
		if (mStatistics) {
		mShadowCache.clear();
		}

		mCache.clear();
		}

		// Dump basic statistics, if any are collected. Do nothing if statistics are not enabled.
		void dump(PrintWriter pw) {
		if (mStatistics) {
		pw.println(formatSimple(" ShadowHits: %d, ShadowMisses: %d, ShadowSize: %d",
		mShadowHits, mShadowMisses, mShadowCache.size()));
		pw.println(formatSimple(" ShadowUids: %d, SelfUid: %d",
		mUidSeen.size(), mShadowSelfHits));
		}
		}

		// Dump detailed statistics
		void dumpDetailed(PrintWriter pw) {
		for (int i = 0; i < mCache.size(); i++) {
		int uid = mCache.keyAt(i);
		var map = mCache.valueAt(i);

		Set<Map.Entry<Query, Result>> cacheEntries = map.entrySet();
		if (cacheEntries.size() == 0) {
		break;
		}

		pw.println(" Contents:");
		pw.println(formatSimple(" Uid: %d\n", uid));
		for (Map.Entry<Query, Result> entry : cacheEntries) {
		String key = Objects.toString(entry.getKey());
		String value = Objects.toString(entry.getValue());

		pw.println(formatSimple(" Key: %s\n Value: %s\n", key, value));
		}
		}
		}
		}

		@GuardedBy("mLock")
		private final LinkedHashMap<Query, Result> mCache;
		private final CacheMap<Query, Result> mCache;

		/**
		* The nonce handler for this cache.
		@@ -895,7 +1100,8 @@ public class PropertyInvalidatedCache<Query, Result> {
		* is allowed to be null in the record constructor to facility reuse of Args instances.
		* @hide
		*/
		public static record Args(@NonNull String mModule, @Nullable String mApi, int mMaxEntries) {
		public static record Args(@NonNull String mModule, @Nullable String mApi,
		int mMaxEntries, boolean mIsolateUids, boolean mTestMode) {

		// Validation: the module must be one of the known module strings and the maxEntries must
		// be positive.
		@@ -909,15 +1115,28 @@ public class PropertyInvalidatedCache<Query, Result> {
		// which is not legal, but there is no reasonable default. Clients must call the api
		// method to set the field properly.
		public Args(@NonNull String module) {
		this(module, /* api / null, / maxEntries */ 32);
		this(module,
		null, // api
		32, // maxEntries
		true, // isolateUids
		false // testMode
		);
		}

		public Args api(@NonNull String api) {
		return new Args(mModule, api, mMaxEntries);
		return new Args(mModule, api, mMaxEntries, mIsolateUids, mTestMode);
		}

		public Args maxEntries(int val) {
		return new Args(mModule, mApi, val);
		return new Args(mModule, mApi, val, mIsolateUids, mTestMode);
		}

		public Args isolateUids(boolean val) {
		return new Args(mModule, mApi, mMaxEntries, val, mTestMode);
		}

		public Args testMode(boolean val) {
		return new Args(mModule, mApi, mMaxEntries, mIsolateUids, val);
		}
		}

		@@ -936,7 +1155,7 @@ public class PropertyInvalidatedCache<Query, Result> {
		mCacheName = cacheName;
		mNonce = getNonceHandler(mPropertyName);
		mMaxEntries = args.mMaxEntries;
		mCache = createMap();
		mCache = new CacheMap<>(args.mIsolateUids, args.mTestMode);
		mComputer = (computer != null) ? computer : new DefaultComputer<>(this);
		registerCache();
		}
		@@ -1006,28 +1225,6 @@ public class PropertyInvalidatedCache<Query, Result> {
		this(new Args(module).maxEntries(maxEntries).api(api), cacheName, computer);
		}

		// Create a map. This should be called only from the constructor.
		private LinkedHashMap<Query, Result> createMap() {
		return new LinkedHashMap<Query, Result>(
		2 /* start small */,
		0.75f /* default load factor */,
		true /* LRU access order */) {
		@GuardedBy("mLock")
		@Override
		protected boolean removeEldestEntry(Map.Entry eldest) {
		final int size = size();
		if (size > mHighWaterMark) {
		mHighWaterMark = size;
		}
		if (size > mMaxEntries) {
		mMissOverflow++;
		return true;
		}
		return false;
		}
		};
		}

		/**
		* Register the map in the global list. If the cache is disabled globally, disable it
		* now. This method is only ever called from the constructor, which means no other thread has
		@@ -1778,8 +1975,8 @@ public class PropertyInvalidatedCache<Query, Result> {
		pw.println(formatSimple(" Cache Name: %s", cacheName()));
		pw.println(formatSimple(" Property: %s", mPropertyName));
		pw.println(formatSimple(
		" Hits: %d, Misses: %d, Skips: %d, Clears: %d",
		mHits, mMisses, getSkipsLocked(), mClears));
		" Hits: %d, Misses: %d, Skips: %d, Clears: %d, Uids: %d",
		mHits, mMisses, getSkipsLocked(), mClears, mCache.size()));

		// Print all the skip reasons.
		pw.format(" Skip-%s: %d", sNonceName[0], mSkips[0]);
		@@ -1794,25 +1991,16 @@ public class PropertyInvalidatedCache<Query, Result> {
		pw.println(formatSimple(
		" Current Size: %d, Max Size: %d, HW Mark: %d, Overflows: %d",
		mCache.size(), mMaxEntries, mHighWaterMark, mMissOverflow));
		mCache.dump(pw);
		pw.println(formatSimple(" Enabled: %s", mDisabled ? "false" : "true"));

		// No specific cache was requested. This is the default, and no details
		// should be dumped.
		if (!detailed) {
		return;
		}
		Set<Map.Entry<Query, Result>> cacheEntries = mCache.entrySet();
		if (cacheEntries.size() == 0) {
		return;
		// Dump the contents of the cache.
		if (detailed) {
		mCache.dumpDetailed(pw);
		}

		pw.println(" Contents:");
		for (Map.Entry<Query, Result> entry : cacheEntries) {
		String key = Objects.toString(entry.getKey());
		String value = Objects.toString(entry.getValue());

		pw.println(formatSimple(" Key: %s\n Value: %s\n", key, value));
		}
		// Separator between caches.
		pw.println("");
		}
		}

core/java/android/app/performance.aconfig

+17 −0

Original line number	Diff line number	Diff line
		@@ -18,3 +18,20 @@ flag {
		description: "Enforce PropertyInvalidatedCache.setTestMode() protocol"
		bug: "360897450"
		}

		flag {
		namespace: "system_performance"
		name: "pic_isolate_cache_by_uid"
		is_fixed_read_only: true
		description: "Ensure that different UIDs use different caches"
		bug: "373752556"
		}

		flag {
		namespace: "system_performance"
		name: "pic_isolated_cache_statistics"
		is_fixed_read_only: true
		description: "Collects statistics for cache UID isolation strategies"
		bug: "373752556"
		}

core/tests/coretests/src/android/app/PropertyInvalidatedCacheTests.java

+76 −3

Original line number	Diff line number	Diff line
		@@ -16,6 +16,7 @@

		package android.app;

		import static android.app.Flags.FLAG_PIC_ISOLATE_CACHE_BY_UID;
		import static android.app.PropertyInvalidatedCache.NONCE_UNSET;
		import static android.app.PropertyInvalidatedCache.MODULE_BLUETOOTH;
		import static android.app.PropertyInvalidatedCache.MODULE_SYSTEM;
		@@ -30,8 +31,9 @@ import static org.junit.Assert.assertSame;
		import static org.junit.Assert.assertTrue;
		import static org.junit.Assert.fail;

		import android.app.PropertyInvalidatedCache.Args;
		import android.annotation.SuppressLint;
		import android.app.PropertyInvalidatedCache.Args;
		import android.os.Binder;
		import com.android.internal.os.ApplicationSharedMemory;

		import android.platform.test.annotations.IgnoreUnderRavenwood;
		@@ -58,6 +60,7 @@ import org.junit.Test;
		*/
		@SmallTest
		public class PropertyInvalidatedCacheTests {
		@Rule
		public final CheckFlagsRule mCheckFlagsRule =
		DeviceFlagsValueProvider.createCheckFlagsRule();

		@@ -455,8 +458,9 @@ public class PropertyInvalidatedCacheTests {
		// Test the Args-style constructor.
		@Test
		public void testArgsConstructor() {
		// Create a cache with a maximum of four entries.
		TestCache cache = new TestCache(new Args(MODULE_TEST).api("init1").maxEntries(4),
		// Create a cache with a maximum of four entries and non-isolated UIDs.
		TestCache cache = new TestCache(new Args(MODULE_TEST)
		.maxEntries(4).isolateUids(false).api("init1"),
		new TestQuery());

		cache.invalidateCache();
		@@ -570,4 +574,73 @@ public class PropertyInvalidatedCacheTests {
		// Expected exception.
		}
		}

		// Verify that a cache created with isolatedUids(true) separates out the results.
		@RequiresFlagsEnabled(FLAG_PIC_ISOLATE_CACHE_BY_UID)
		@Test
		public void testIsolatedUids() {
		TestCache cache = new TestCache(new Args(MODULE_TEST)
		.maxEntries(4).isolateUids(true).api("testIsolatedUids").testMode(true),
		new TestQuery());
		cache.invalidateCache();
		final int uid1 = 1;
		final int uid2 = 2;

		long token = Binder.setCallingWorkSourceUid(uid1);
		try {
		// Populate the cache for user 1
		assertEquals("foo5", cache.query(5));
		assertEquals(1, cache.getRecomputeCount());
		assertEquals("foo5", cache.query(5));
		assertEquals(1, cache.getRecomputeCount());
		assertEquals("foo6", cache.query(6));
		assertEquals(2, cache.getRecomputeCount());

		// Populate the cache for user 2. User 1 values are not reused.
		Binder.setCallingWorkSourceUid(uid2);
		assertEquals("foo5", cache.query(5));
		assertEquals(3, cache.getRecomputeCount());
		assertEquals("foo5", cache.query(5));
		assertEquals(3, cache.getRecomputeCount());

		// Verify that the cache for user 1 is still populated.
		Binder.setCallingWorkSourceUid(uid1);
		assertEquals("foo5", cache.query(5));
		assertEquals(3, cache.getRecomputeCount());

		} finally {
		Binder.restoreCallingWorkSource(token);
		}

		// Repeat the test with a non-isolated cache.
		cache = new TestCache(new Args(MODULE_TEST)
		.maxEntries(4).isolateUids(false).api("testIsolatedUids2").testMode(true),
		new TestQuery());
		cache.invalidateCache();
		token = Binder.setCallingWorkSourceUid(uid1);
		try {
		// Populate the cache for user 1
		assertEquals("foo5", cache.query(5));
		assertEquals(1, cache.getRecomputeCount());
		assertEquals("foo5", cache.query(5));
		assertEquals(1, cache.getRecomputeCount());
		assertEquals("foo6", cache.query(6));
		assertEquals(2, cache.getRecomputeCount());

		// Populate the cache for user 2. User 1 values are reused.
		Binder.setCallingWorkSourceUid(uid2);
		assertEquals("foo5", cache.query(5));
		assertEquals(2, cache.getRecomputeCount());
		assertEquals("foo5", cache.query(5));
		assertEquals(2, cache.getRecomputeCount());

		// Verify that the cache for user 1 is still populated.
		Binder.setCallingWorkSourceUid(uid1);
		assertEquals("foo5", cache.query(5));
		assertEquals(2, cache.getRecomputeCount());

		} finally {
		Binder.restoreCallingWorkSource(token);
		}
		}
		}