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Commit c583305e authored by Tom Cherry's avatar Tom Cherry
Browse files

ueventd: parallelize uevent handling 

fork() subprocesses to handle uevents in parallel.

This reduces coldboot time on bullhead from ~446ms to ~230ms.
This reduces coldboot time on sailfish from ~690ms to ~360ms.
This reduces coldboot time on ryu from ~187ms to ~122ms.

Bug: 33785894

Test: boot bullhead x40, observe no major differences in /dev and /sys
Test: boot sailfish x40, observe no major differences in /dev and /sys
Test: boot ryu x40, observe no major differences in /dev and /sys
Test: boottime tests on bullhead and sailfish
Test: init unit tests

Change-Id: Ie2f63e000b8af78d187477d31fe109f20304d749
parent 28c11dcf

init/devices.cpp

+5 −4
Original line number Diff line number Diff line
@@ -175,7 +175,7 @@ void DeviceHandler::FixupSysPermissions(const std::string& upath, 
        if (s.MatchWithSubsystem(path, subsystem)) s.SetPermissions(path);

    }



    if (access(path.c_str(), F_OK) == 0) {

    if (!skip_restorecon_ && access(path.c_str(), F_OK) == 0) {

        LOG(VERBOSE) << "restorecon_recursive: " << path;

        if (selinux_android_restorecon(path.c_str(), SELINUX_ANDROID_RESTORECON_RECURSE) != 0) {

            PLOG(ERROR) << "selinux_android_restorecon(" << path << ") failed";
@@ -467,12 +467,13 @@ void DeviceHandler::HandleDeviceEvent(const Uevent& uevent) { 


DeviceHandler::DeviceHandler(std::vector<Permissions> dev_permissions,

                             std::vector<SysfsPermissions> sysfs_permissions,

                             std::vector<Subsystem> subsystems)

                             std::vector<Subsystem> subsystems, bool skip_restorecon)

    : dev_permissions_(std::move(dev_permissions)),

      sysfs_permissions_(std::move(sysfs_permissions)),

      subsystems_(std::move(subsystems)),

      sehandle_(selinux_android_file_context_handle()) {}

      sehandle_(selinux_android_file_context_handle()),

      skip_restorecon_(skip_restorecon) {}



DeviceHandler::DeviceHandler()

    : DeviceHandler(std::vector<Permissions>{}, std::vector<SysfsPermissions>{},

                    std::vector<Subsystem>{}) {}
 
                    std::vector<Subsystem>{}, false) {}

init/devices.h

+10 −5
Original line number Diff line number Diff line
@@ -114,14 +114,21 @@ class DeviceHandler { 
    DeviceHandler();

    DeviceHandler(std::vector<Permissions> dev_permissions,

                  std::vector<SysfsPermissions> sysfs_permissions,

                  std::vector<Subsystem> subsystems);

                  std::vector<Subsystem> subsystems, bool skip_restorecon);

    ~DeviceHandler(){};



    void HandleDeviceEvent(const Uevent& uevent);



    void FixupSysPermissions(const std::string& upath, const std::string& subsystem) const;



    void HandlePlatformDeviceEvent(const Uevent& uevent);

    void HandleBlockDeviceEvent(const Uevent& uevent) const;

    void HandleGenericDeviceEvent(const Uevent& uevent) const;



    std::vector<std::string> GetBlockDeviceSymlinks(const Uevent& uevent) const;

    void set_skip_restorecon(bool value) { skip_restorecon_ = value; }



  private:

    void FixupSysPermissions(const std::string& upath, const std::string& subsystem) const;

    std::tuple<mode_t, uid_t, gid_t> GetDevicePermissions(

        const std::string& path, const std::vector<std::string>& links) const;

    void MakeDevice(const std::string& path, int block, int major, int minor,
@@ -129,15 +136,13 @@ class DeviceHandler { 
    std::vector<std::string> GetCharacterDeviceSymlinks(const Uevent& uevent) const;

    void HandleDevice(const std::string& action, const std::string& devpath, int block, int major,

                      int minor, const std::vector<std::string>& links) const;

    void HandlePlatformDeviceEvent(const Uevent& uevent);

    void HandleBlockDeviceEvent(const Uevent& uevent) const;

    void HandleGenericDeviceEvent(const Uevent& uevent) const;



    std::vector<Permissions> dev_permissions_;

    std::vector<SysfsPermissions> sysfs_permissions_;

    std::vector<Subsystem> subsystems_;

    PlatformDeviceList platform_devices_;

    selabel_handle* sehandle_;

    bool skip_restorecon_;

};



// Exposed for testing

init/firmware_handler.cpp

+22 −6
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 


#include <fcntl.h>

#include <sys/sendfile.h>

#include <sys/wait.h>

#include <unistd.h>



#include <string>
@@ -103,14 +104,29 @@ void HandleFirmwareEvent(const Uevent& uevent) { 
    if (uevent.subsystem != "firmware" || uevent.action != "add") return;



    // Loading the firmware in a child means we can do that in parallel...

    // (We ignore SIGCHLD rather than wait for our children.)

    // We double fork instead of waiting for these processes.

    pid_t pid = fork();

    if (pid == -1) {

        PLOG(ERROR) << "could not fork to process firmware event for " << uevent.firmware;

        return;

    }



    if (pid == 0) {

        pid = fork();

        if (pid == -1) {

            PLOG(ERROR) << "could not fork a sceond time to process firmware event for "

                        << uevent.firmware;

            _exit(EXIT_FAILURE);

        }

        if (pid == 0) {

            Timer t;

            ProcessFirmwareEvent(uevent);

            LOG(INFO) << "loading " << uevent.path << " took " << t;

            _exit(EXIT_SUCCESS);

    } else if (pid == -1) {

        PLOG(ERROR) << "could not fork to process firmware event for " << uevent.firmware;

        }



        _exit(EXIT_SUCCESS);

    }



    waitpid(pid, nullptr, 0);

}

init/uevent_listener.cpp

+1 −1
Original line number Diff line number Diff line
@@ -165,7 +165,7 @@ RegenerationAction UeventListener::RegenerateUeventsForPath(const std::string& p 
    return RegenerateUeventsForDir(d.get(), callback);

}



static const char* kRegenerationPaths[] = {"/sys/class", "/sys/block", "/sys/devices"};

const char* kRegenerationPaths[] = {"/sys/class", "/sys/block", "/sys/devices"};



void UeventListener::RegenerateUevents(RegenerateCallback callback) const {

    for (const auto path : kRegenerationPaths) {

init/uevent_listener.h

+2 −0
Original line number Diff line number Diff line
@@ -35,6 +35,8 @@ enum class RegenerationAction { 
using RegenerateCallback = std::function<RegenerationAction(const Uevent&)>;

using PollCallback = std::function<void(const Uevent&)>;



extern const char* kRegenerationPaths[3];



class UeventListener {

  public:

    UeventListener();