Set buffer size to match Linux pipe internal buffer when reading/writing from/to pipes in Backup/Restore flow.

ag/21072118 used of feature flags to control buffer sizes, which are now deprecated. Those flags were also never used.
This change makes use of trunk-stable frozen flags to set the buffer size to match Linux pipe internal buffer when reading/writing from/to pipes in Backup/Restore flow.
See 'Pipe capacity' section in https://man7.org/linux/man-pages/man7/pipe.7.html

Bug: 265976737
Test: Ensure that the change builds (m -j frameworks/base)
	Ensure CTS and GTS B&R tests pass
Change-Id: I8bb96e2e273b0c7eb4809af985fe322e49bb0268

5 files changed, 38 insertions, 11 deletions

diff --git a/services/backup/java/com/android/server/backup/fullbackup/PerformFullTransportBackupTask.java b/services/backup/java/com/android/server/backup/fullbackup/PerformFullTransportBackupTask.java
index 6aed9aa15860..cca166b0939c 100644
--- a/services/backup/java/com/android/server/backup/fullbackup/PerformFullTransportBackupTask.java
+++ b/services/backup/java/com/android/server/backup/fullbackup/PerformFullTransportBackupTask.java
@@ -40,8 +40,8 @@ import android.util.Slog;
 
 import com.android.server.EventLogTags;
 import com.android.server.backup.BackupAgentTimeoutParameters;
-import com.android.server.backup.BackupAndRestoreFeatureFlags;
 import com.android.server.backup.BackupRestoreTask;
+import com.android.server.backup.Flags;
 import com.android.server.backup.FullBackupJob;
 import com.android.server.backup.OperationStorage;
 import com.android.server.backup.OperationStorage.OpState;
@@ -390,8 +390,11 @@ public class PerformFullTransportBackupTask extends FullBackupTask implements Ba
 
             // Set up to send data to the transport
             final int N = mPackages.size();
-            final int chunkSizeInBytes =
-                    BackupAndRestoreFeatureFlags.getFullBackupWriteToTransportBufferSizeBytes();
+            int chunkSizeInBytes = 8 * 1024; // 8KB
+            if (Flags.enableMaxSizeWritesToPipes()) {
+                // Linux pipe capacity (buffer size) is 16 pages where each page is 4KB
+                chunkSizeInBytes = 64 * 1024; // 64KB
+            }
             final byte[] buffer = new byte[chunkSizeInBytes];
             for (int i = 0; i < N; i++) {
                 mBackupRunner = null;
diff --git a/services/backup/java/com/android/server/backup/restore/FullRestoreEngine.java b/services/backup/java/com/android/server/backup/restore/FullRestoreEngine.java
index ff72476d4bf1..2c9eb51972af 100644
--- a/services/backup/java/com/android/server/backup/restore/FullRestoreEngine.java
+++ b/services/backup/java/com/android/server/backup/restore/FullRestoreEngine.java
@@ -29,7 +29,6 @@ import android.app.ApplicationThreadConstants;
 import android.app.IBackupAgent;
 import android.app.backup.BackupAgent;
 import android.app.backup.BackupAnnotations;
-import android.app.backup.BackupManager;
 import android.app.backup.FullBackup;
 import android.app.backup.IBackupManagerMonitor;
 import android.app.backup.IFullBackupRestoreObserver;
@@ -51,6 +50,7 @@ import com.android.server.LocalServices;
 import com.android.server.backup.BackupAgentTimeoutParameters;
 import com.android.server.backup.BackupRestoreTask;
 import com.android.server.backup.FileMetadata;
+import com.android.server.backup.Flags;
 import com.android.server.backup.KeyValueAdbRestoreEngine;
 import com.android.server.backup.OperationStorage;
 import com.android.server.backup.OperationStorage.OpType;
@@ -157,13 +157,19 @@ public class FullRestoreEngine extends RestoreEngine {
         mMonitor = monitor;
         mOnlyPackage = onlyPackage;
         mAllowApks = allowApks;
-        mBuffer = new byte[32 * 1024];
         mAgentTimeoutParameters = Objects.requireNonNull(
                 backupManagerService.getAgentTimeoutParameters(),
                 "Timeout parameters cannot be null");
         mIsAdbRestore = isAdbRestore;
         mUserId = backupManagerService.getUserId();
         mBackupEligibilityRules = backupEligibilityRules;
+
+        if (Flags.enableMaxSizeWritesToPipes()) {
+            // Linux pipe capacity (buffer size) is 16 pages where each page is 4KB
+            mBuffer = new byte[64 * 1024]; // 64KB
+        } else {
+            mBuffer = new byte[32 * 1024];
+        }
     }
 
     @VisibleForTesting
diff --git a/services/backup/java/com/android/server/backup/restore/PerformUnifiedRestoreTask.java b/services/backup/java/com/android/server/backup/restore/PerformUnifiedRestoreTask.java
index 316a16d9934c..2fbc3cd24d65 100644
--- a/services/backup/java/com/android/server/backup/restore/PerformUnifiedRestoreTask.java
+++ b/services/backup/java/com/android/server/backup/restore/PerformUnifiedRestoreTask.java
@@ -968,7 +968,12 @@ public class PerformUnifiedRestoreTask implements BackupRestoreTask {
             throws Exception {
         Set<String> excludedKeysForPackage = getExcludedKeysForPackage(packageName);
 
-        byte[] buffer = new byte[8192]; // will grow when needed
+        int bufferSize = 8192; // 8KB
+        if (Flags.enableMaxSizeWritesToPipes()) {
+            // Linux pipe capacity (buffer size) is 16 pages where each page is 4KB
+            bufferSize = 64 * 1024; // 64KB
+        }
+        byte[] buffer = new byte[bufferSize]; // will grow when needed
         while (in.readNextHeader()) {
             final String key = in.getKey();
             final int size = in.getDataSize();
@@ -1116,7 +1121,11 @@ public class PerformUnifiedRestoreTask implements BackupRestoreTask {
             ParcelFileDescriptor tReadEnd = mTransportPipes[0];
             ParcelFileDescriptor tWriteEnd = mTransportPipes[1];
 
-            int bufferSize = 32 * 1024;
+            int bufferSize = 32 * 1024; // 32KB
+            if (Flags.enableMaxSizeWritesToPipes()) {
+                // Linux pipe capacity (buffer size) is 16 pages where each page is 4KB
+                bufferSize = 64 * 1024; // 64KB
+            }
             byte[] buffer = new byte[bufferSize];
             FileOutputStream engineOut = new FileOutputStream(eWriteEnd.getFileDescriptor());
             FileInputStream transportIn = new FileInputStream(tReadEnd.getFileDescriptor());
diff --git a/services/backup/java/com/android/server/backup/utils/FullBackupUtils.java b/services/backup/java/com/android/server/backup/utils/FullBackupUtils.java
index 1c0cd87cec6f..843354e719bb 100644
--- a/services/backup/java/com/android/server/backup/utils/FullBackupUtils.java
+++ b/services/backup/java/com/android/server/backup/utils/FullBackupUtils.java
@@ -21,7 +21,7 @@ import static com.android.server.backup.BackupManagerService.TAG;
 import android.os.ParcelFileDescriptor;
 import android.util.Slog;
 
-import com.android.server.backup.BackupAndRestoreFeatureFlags;
+import com.android.server.backup.Flags;
 
 import java.io.DataInputStream;
 import java.io.EOFException;
@@ -46,8 +46,11 @@ public class FullBackupUtils {
         // We do not take close() responsibility for the pipe FD
         FileInputStream raw = new FileInputStream(inPipe.getFileDescriptor());
         DataInputStream in = new DataInputStream(raw);
-        final int chunkSizeInBytes =
-                BackupAndRestoreFeatureFlags.getFullBackupUtilsRouteBufferSizeBytes();
+        int chunkSizeInBytes = 32 * 1024; // 32KB
+        if (Flags.enableMaxSizeWritesToPipes()) {
+            // Linux pipe capacity (buffer size) is 16 pages where each page is 4KB
+            chunkSizeInBytes = 64 * 1024; // 64KB
+        }
         byte[] buffer = new byte[chunkSizeInBytes];
         int chunkTotal;
         while ((chunkTotal = in.readInt()) > 0) {
diff --git a/services/backup/java/com/android/server/backup/utils/RestoreUtils.java b/services/backup/java/com/android/server/backup/utils/RestoreUtils.java
index 0accb9fadd04..5a8533a2daee 100644
--- a/services/backup/java/com/android/server/backup/utils/RestoreUtils.java
+++ b/services/backup/java/com/android/server/backup/utils/RestoreUtils.java
@@ -40,6 +40,7 @@ import android.util.Slog;
 import com.android.internal.annotations.GuardedBy;
 import com.android.server.LocalServices;
 import com.android.server.backup.FileMetadata;
+import com.android.server.backup.Flags;
 import com.android.server.backup.restore.RestoreDeleteObserver;
 import com.android.server.backup.restore.RestorePolicy;
 
@@ -93,7 +94,12 @@ public class RestoreUtils {
                 try (Session session = installer.openSession(sessionId)) {
                     try (OutputStream apkStream = session.openWrite(info.packageName, 0,
                             info.size)) {
-                        byte[] buffer = new byte[32 * 1024];
+                        int bufferSize = 32 * 1024; // 32KB
+                        if (Flags.enableMaxSizeWritesToPipes()) {
+                            // Linux pipe capacity (buffer size) is 16 pages where each page is 4KB
+                            bufferSize = 64 * 1024; // 64KB
+                        }
+                        byte[] buffer = new byte[bufferSize];
                         long size = info.size;
                         while (size > 0) {
                             long toRead = (buffer.length < size) ? buffer.length : size;