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Commit 961c01ce authored by Suren Baghdasaryan's avatar Suren Baghdasaryan
Browse files

libprocessgroup: optimize SetAttributeAction::ExecuteForProcess performance 



Current implementation of SetAttributeAction::ExecuteForProcess reuses
SetAttributeAction::ExecuteForTask while not utilizing available uid/pid
information. This results in a call to GetPathForTask() which is an
expensive function due to it reading and parsing /proc/$pid/cgroups.
This can be avoided if we utilize available uid/pid info and the fact
that cgroup v2 attributes share the cgroup v2 hierarchy as process
groups, which use a known path template.

Bug: 292636609
Change-Id: I02e3046bd85d0dfebc68ab444f1796bb54cc69c7
Merged-In: I02e3046bd85d0dfebc68ab444f1796bb54cc69c7
Signed-off-by: default avatarSuren Baghdasaryan <surenb@google.com>
parent 2ffbeaef

libprocessgroup/task_profiles.cpp

+33 −12
Original line number Diff line number Diff line
@@ -126,6 +126,16 @@ void ProfileAttribute::Reset(const CgroupController& controller, const std::stri 
    file_v2_name_ = file_v2_name;

}



bool ProfileAttribute::GetPathForProcess(uid_t uid, pid_t pid, std::string* path) const {

    if (controller()->version() == 2) {

        // all cgroup v2 attributes use the same process group hierarchy

        *path = StringPrintf("%s/uid_%u/pid_%d/%s", controller()->path(), uid, pid,

                             file_name().c_str());

        return true;

    }

    return GetPathForTask(pid, path);

}



bool ProfileAttribute::GetPathForTask(int tid, std::string* path) const {

    std::string subgroup;

    if (!controller()->GetTaskGroup(tid, &subgroup)) {
@@ -209,18 +219,7 @@ bool SetTimerSlackAction::ExecuteForTask(int) const { 


#endif



bool SetAttributeAction::ExecuteForProcess(uid_t, pid_t pid) const {

    return ExecuteForTask(pid);

}



bool SetAttributeAction::ExecuteForTask(int tid) const {

    std::string path;



    if (!attribute_->GetPathForTask(tid, &path)) {

        LOG(ERROR) << "Failed to find cgroup for tid " << tid;

        return false;

    }



bool SetAttributeAction::WriteValueToFile(const std::string& path) const {

    if (!WriteStringToFile(value_, path)) {

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

            if (optional_) {
@@ -240,6 +239,28 @@ bool SetAttributeAction::ExecuteForTask(int tid) const { 
    return true;

}



bool SetAttributeAction::ExecuteForProcess(uid_t uid, pid_t pid) const {

    std::string path;



    if (!attribute_->GetPathForProcess(uid, pid, &path)) {

        LOG(ERROR) << "Failed to find cgroup for uid " << uid << " pid " << pid;

        return false;

    }



    return WriteValueToFile(path);

}



bool SetAttributeAction::ExecuteForTask(int tid) const {

    std::string path;



    if (!attribute_->GetPathForTask(tid, &path)) {

        LOG(ERROR) << "Failed to find cgroup for tid " << tid;

        return false;

    }



    return WriteValueToFile(path);

}



bool SetAttributeAction::ExecuteForUID(uid_t uid) const {

    std::string path;

libprocessgroup/task_profiles.h

+4 −0
Original line number Diff line number Diff line
@@ -36,6 +36,7 @@ class IProfileAttribute { 
                       const std::string& file_v2_name) = 0;

    virtual const CgroupController* controller() const = 0;

    virtual const std::string& file_name() const = 0;

    virtual bool GetPathForProcess(uid_t uid, pid_t pid, std::string* path) const = 0;

    virtual bool GetPathForTask(int tid, std::string* path) const = 0;

    virtual bool GetPathForUID(uid_t uid, std::string* path) const = 0;

};
@@ -55,6 +56,7 @@ class ProfileAttribute : public IProfileAttribute { 
    void Reset(const CgroupController& controller, const std::string& file_name,

               const std::string& file_v2_name) override;



    bool GetPathForProcess(uid_t uid, pid_t pid, std::string* path) const override;

    bool GetPathForTask(int tid, std::string* path) const override;

    bool GetPathForUID(uid_t uid, std::string* path) const override;
@@ -133,6 +135,8 @@ class SetAttributeAction : public ProfileAction { 
    const IProfileAttribute* attribute_;

    std::string value_;

    bool optional_;



    bool WriteValueToFile(const std::string& path) const;

};



// Set cgroup profile element

libprocessgroup/task_profiles_test.cpp

+3 −0
Original line number Diff line number Diff line
@@ -111,6 +111,9 @@ class ProfileAttributeMock : public IProfileAttribute { 
        return {};

    }

    const std::string& file_name() const override { return file_name_; }

    bool GetPathForProcess(uid_t uid, pid_t pid, std::string* path) const override {

        return GetPathForTask(pid, path);

    }

    bool GetPathForTask(int tid, std::string* path) const override {

#ifdef __ANDROID__

        CHECK(CgroupGetControllerPath(CGROUPV2_CONTROLLER_NAME, path));