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Commit a10db39e authored by Piyush Mehrotra's avatar Piyush Mehrotra
Browse files

Set buffer size to match Linux pipe internal buffer when reading/writing... 

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
parent c835e984

core/java/android/app/backup/FullBackup.java

+1 −1
Original line number Diff line number Diff line
@@ -239,7 +239,7 @@ public class FullBackup { 
                Log.e(TAG, "Unable to create/open file " + outFile.getPath(), e);

            }



            byte[] buffer = new byte[32 * 1024];

            byte[] buffer = new byte[64 * 1024];

            final long origSize = size;

            FileInputStream in = new FileInputStream(data.getFileDescriptor());

            while (size > 0) {

libs/androidfw/Android.bp

+10 −1
Original line number Diff line number Diff line
@@ -31,6 +31,12 @@ license { 
    ],

}



cc_aconfig_library {

    name: "backup_flags_cc_lib",

    host_supported: true,

    aconfig_declarations: "backup_flags",

}



cc_defaults {

    name: "libandroidfw_defaults",

    cpp_std: "gnu++2b",
@@ -115,7 +121,10 @@ cc_library { 
                "libutils",

                "libz",

            ],

            static_libs: ["libziparchive_for_incfs"],

            static_libs: [

                "libziparchive_for_incfs",

                "backup_flags_cc_lib",

            ],

            static: {

                enabled: false,

            },

libs/androidfw/BackupHelpers.cpp

+7 −3
Original line number Diff line number Diff line
@@ -36,6 +36,9 @@ 
#include <utils/KeyedVector.h>

#include <utils/String8.h>



#include <com_android_server_backup.h>

namespace backup_flags = com::android::server::backup;



namespace android {



#define MAGIC0 0x70616e53 // Snap
@@ -214,7 +217,7 @@ write_update_file(BackupDataWriter* dataStream, int fd, int mode, const String8& 
{

    LOGP("write_update_file %s (%s) : mode 0%o\n", realFilename, key.c_str(), mode);



    const int bufsize = 4*1024;

    const int bufsize = backup_flags::enable_max_size_writes_to_pipes() ? (64*1024) : (4*1024);

    int err;

    int amt;

    int fileSize;
@@ -550,7 +553,8 @@ int write_tarfile(const String8& packageName, const String8& domain, 
    }



    // read/write up to this much at a time.

    const size_t BUFSIZE = 32 * 1024;

    const size_t BUFSIZE = backup_flags::enable_max_size_writes_to_pipes() ? (64*1024) : (32*1024);



    char* buf = (char *)calloc(1,BUFSIZE);

    const size_t PAXHEADER_OFFSET = 512;

    const size_t PAXHEADER_SIZE = 512;
@@ -726,7 +730,7 @@ done: 






#define RESTORE_BUF_SIZE (8*1024)

const size_t RESTORE_BUF_SIZE = backup_flags::enable_max_size_writes_to_pipes() ? 64*1024 : 8*1024;



RestoreHelperBase::RestoreHelperBase()

{

services/backup/flags.aconfig

+8 −0
Original line number Diff line number Diff line
@@ -8,3 +8,11 @@ flag { 
    bug: "308401499"

    is_fixed_read_only: true

}



flag {

    name: "enable_max_size_writes_to_pipes"

    namespace: "onboarding"

    description: "Enables the write buffer to pipes to be of maximum size."

    bug: "265976737"

    is_fixed_read_only: true

}
 
 No newline at end of file

services/backup/java/com/android/server/backup/fullbackup/PerformFullTransportBackupTask.java

+6 −3
Original line number Diff line number Diff line
@@ -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;