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Commit 522d72b7 authored by Riley Andrews's avatar Riley Andrews
Browse files

Make the default cgroup, the foreground cgroup. 

All kernel services will now be in the same cgroup as
foreground applications. This will now make kernel threads
not implicitly higher priority than android foreground
services.

Bug 17681097

Change-Id: I28e81c7aade50428d5395df86f00ce01c1e7af02
parent af162c8b

libcutils/sched_policy.c

+3 −23
Original line number Diff line number Diff line
@@ -45,8 +45,6 @@ static inline SchedPolicy _policy(SchedPolicy p) 


#define POLICY_DEBUG 0



#define CAN_SET_SP_SYSTEM 0 // non-zero means to implement set_sched_policy(tid, SP_SYSTEM)



// This prctl is only available in Android kernels.

#define PR_SET_TIMERSLACK_PID 41
@@ -60,9 +58,6 @@ static int __sys_supports_schedgroups = -1; 
// File descriptors open to /dev/cpuctl/../tasks, setup by initialize, or -1 on error.

static int bg_cgroup_fd = -1;

static int fg_cgroup_fd = -1;

#if CAN_SET_SP_SYSTEM

static int system_cgroup_fd = -1;

#endif



/* Add tid to the scheduling group defined by the policy */

static int add_tid_to_cgroup(int tid, SchedPolicy policy)
@@ -78,11 +73,6 @@ static int add_tid_to_cgroup(int tid, SchedPolicy policy) 
    case SP_AUDIO_SYS:

        fd = fg_cgroup_fd;

        break;

#if CAN_SET_SP_SYSTEM

    case SP_SYSTEM:

        fd = system_cgroup_fd;

        break;

#endif

    default:

        fd = -1;

        break;
@@ -123,21 +113,13 @@ static void __initialize(void) { 
    if (!access("/dev/cpuctl/tasks", F_OK)) {

        __sys_supports_schedgroups = 1;



#if CAN_SET_SP_SYSTEM

        filename = "/dev/cpuctl/tasks";

        system_cgroup_fd = open(filename, O_WRONLY | O_CLOEXEC);

        if (system_cgroup_fd < 0) {

            SLOGV("open of %s failed: %s\n", filename, strerror(errno));

        }

#endif



        filename = "/dev/cpuctl/apps/tasks";

        fg_cgroup_fd = open(filename, O_WRONLY | O_CLOEXEC);

        if (fg_cgroup_fd < 0) {

            SLOGE("open of %s failed: %s\n", filename, strerror(errno));

        }



        filename = "/dev/cpuctl/apps/bg_non_interactive/tasks";

        filename = "/dev/cpuctl/bg_non_interactive/tasks";

        bg_cgroup_fd = open(filename, O_WRONLY | O_CLOEXEC);

        if (bg_cgroup_fd < 0) {

            SLOGE("open of %s failed: %s\n", filename, strerror(errno));
@@ -233,11 +215,9 @@ int get_sched_policy(int tid, SchedPolicy *policy) 
        if (getSchedulerGroup(tid, grpBuf, sizeof(grpBuf)) < 0)

            return -1;

        if (grpBuf[0] == '\0') {

            *policy = SP_SYSTEM;

        } else if (!strcmp(grpBuf, "apps/bg_non_interactive")) {

            *policy = SP_BACKGROUND;

        } else if (!strcmp(grpBuf, "apps")) {

            *policy = SP_FOREGROUND;

        } else if (!strcmp(grpBuf, "bg_non_interactive")) {

            *policy = SP_BACKGROUND;

        } else {

            errno = ERANGE;

            return -1;

rootdir/init.rc

+8 −15
Original line number Diff line number Diff line
@@ -119,25 +119,18 @@ on init 
    mount cgroup none /dev/cpuctl cpu

    chown system system /dev/cpuctl

    chown system system /dev/cpuctl/tasks

    chmod 0660 /dev/cpuctl/tasks

    chmod 0666 /dev/cpuctl/tasks

    write /dev/cpuctl/cpu.shares 1024

    write /dev/cpuctl/cpu.rt_runtime_us 950000

    write /dev/cpuctl/cpu.rt_runtime_us 800000

    write /dev/cpuctl/cpu.rt_period_us 1000000



    mkdir /dev/cpuctl/apps

    chown system system /dev/cpuctl/apps/tasks

    chmod 0666 /dev/cpuctl/apps/tasks

    write /dev/cpuctl/apps/cpu.shares 1024

    write /dev/cpuctl/apps/cpu.rt_runtime_us 800000

    write /dev/cpuctl/apps/cpu.rt_period_us 1000000



    mkdir /dev/cpuctl/apps/bg_non_interactive

    chown system system /dev/cpuctl/apps/bg_non_interactive/tasks

    chmod 0666 /dev/cpuctl/apps/bg_non_interactive/tasks

    mkdir /dev/cpuctl/bg_non_interactive

    chown system system /dev/cpuctl/bg_non_interactive/tasks

    chmod 0666 /dev/cpuctl/bg_non_interactive/tasks

    # 5.0 %

    write /dev/cpuctl/apps/bg_non_interactive/cpu.shares 52

    write /dev/cpuctl/apps/bg_non_interactive/cpu.rt_runtime_us 700000

    write /dev/cpuctl/apps/bg_non_interactive/cpu.rt_period_us 1000000

    write /dev/cpuctl/bg_non_interactive/cpu.shares 52

    write /dev/cpuctl/bg_non_interactive/cpu.rt_runtime_us 700000

    write /dev/cpuctl/bg_non_interactive/cpu.rt_period_us 1000000



    # qtaguid will limit access to specific data based on group memberships.

    #   net_bw_acct grants impersonation of socket owners.