Exemple #1
0
/*
 * Look for the cgroup in a specific cgroup namespace that owns
 * a particular pid
 *
 * returned values:
 *  - XCGROUP_ERROR
 *  - XCGROUP_SUCCESS
 */
int xcgroup_ns_find_by_pid(xcgroup_ns_t* cgns, xcgroup_t* cg, pid_t pid)
{
	int fstatus = SLURM_ERROR;
	char file_path[PATH_MAX];
	char* buf;
	size_t fsize;
	char* p;
	char* e;
	char* entry;
	char* subsys;

	/* build pid cgroup meta filepath */
	if (snprintf(file_path, PATH_MAX, "/proc/%u/cgroup",
		      pid) >= PATH_MAX) {
		debug2("unable to build cgroup meta filepath for pid=%u : %m",
		       pid);
		return XCGROUP_ERROR;
	}

	/*
	 * read file content
	 * multiple lines of the form :
	 * num_mask:subsystems:relative_path
	 */
	fstatus = _file_read_content(file_path, &buf, &fsize);
	if (fstatus == XCGROUP_SUCCESS) {
		fstatus = XCGROUP_ERROR;
		p = buf;
		while ((e = index(p, '\n')) != NULL) {
			*e='\0';
			/* get subsystems entry */
			subsys = index(p, ':');
			p = e + 1;
			if (subsys == NULL)
				continue;
			subsys++;
			/* get relative path entry */
			entry = index(subsys, ':');
			if (entry == NULL)
				continue;
			*entry='\0';
			/* check subsystem versus ns one */
			if (xstrcmp(cgns->subsystems, subsys) != 0) {
				debug("skipping cgroup subsys %s(%s)",
				      subsys, cgns->subsystems);
				continue;
			}
			entry++;
			fstatus = xcgroup_load(cgns, cg, entry);
			break;
		}
		xfree(buf);
	}

	return fstatus;
}
Exemple #2
0
extern void attach_system_cgroup_pid(pid_t pid)
{
	char* slurm_cgpath;

	if (read_slurm_cgroup_conf(&slurm_cgroup_conf))
		return;

	slurm_cgpath = (char*) xstrdup(slurm_cgroup_conf.cgroup_prepend);
#ifdef MULTIPLE_SLURMD
	if ( conf->node_name != NULL )
		xstrsubstitute(slurm_cgpath,"%n", conf->node_name);
	else {
		xfree(slurm_cgpath);
		slurm_cgpath = (char*) xstrdup("/slurm");
	}
#endif
	xstrcat(slurm_cgpath,"/system");
	if (xcgroup_ns_load(&slurm_cgroup_conf, &cpuset_ns, "cpuset")
	    == XCGROUP_SUCCESS) {
		if (xcgroup_load(&cpuset_ns, &system_cpuset_cg, slurm_cgpath)
		    == XCGROUP_SUCCESS)
			if (attach_system_cpuset_pid(pid) != SLURM_SUCCESS)
				debug2("system cgroup: unable to attach pid to "
				       "system cpuset cgroup");
	}
	if (xcgroup_ns_load(&slurm_cgroup_conf, &memory_ns, "memory")
	    == XCGROUP_SUCCESS) {
		if (xcgroup_load(&memory_ns, &system_memory_cg, slurm_cgpath)
		    == XCGROUP_SUCCESS)
			if (attach_system_memory_pid(pid) != SLURM_SUCCESS)
				debug2("system cgroup: unable to attach pid to "
				       "system memory cgroup");
	}
	xfree(slurm_cgpath);
	free_slurm_cgroup_conf(&slurm_cgroup_conf);
	return;
}
/* when cgroups are configured with cpuset, at least
 * cpuset.cpus and cpuset.mems must be set or the cgroup
 * will not be available at all.
 * we duplicate the ancestor configuration in the init step */
static int _xcgroup_cpuset_init(xcgroup_t* cg)
{
	int fstatus,i;

	char* cpuset_metafiles[] = {
		"cpuset.cpus",
		"cpuset.mems"
	};
	char* cpuset_meta;
	char* cpuset_conf;
	size_t csize;

	xcgroup_t acg;
	char* acg_name;
	char* p;

	fstatus = XCGROUP_ERROR;

	/* load ancestor cg */
	acg_name = (char*) xstrdup(cg->name);
	p = rindex(acg_name,'/');
	if (p == NULL) {
		debug2("task/cgroup: unable to get ancestor path for "
		       "cpuset cg '%s' : %m",cg->path);
		return fstatus;
	} else
		*p = '\0';
	if (xcgroup_load(cg->ns,&acg,acg_name) != XCGROUP_SUCCESS) {
		debug2("task/cgroup: unable to load ancestor for "
		       "cpuset cg '%s' : %m",cg->path);
		return fstatus;
	}

	/* inherits ancestor params */
	for (i = 0 ; i < 2 ; i++) {
		cpuset_meta = cpuset_metafiles[i];
		if (xcgroup_get_param(&acg,cpuset_meta,
				       &cpuset_conf,&csize)
		     != XCGROUP_SUCCESS) {
			debug2("task/cgroup: assuming no cpuset cg "
			       "support for '%s'",acg.path);
			xcgroup_destroy(&acg);
			return fstatus;
		}
		if (csize > 0)
			cpuset_conf[csize-1]='\0';
		if (xcgroup_set_param(cg,cpuset_meta,cpuset_conf)
		     != XCGROUP_SUCCESS) {
			debug2("task/cgroup: unable to write %s configuration "
			       "(%s) for cpuset cg '%s'",cpuset_meta,
			       cpuset_conf,cg->path);
			xcgroup_destroy(&acg);
			xfree(cpuset_conf);
			return fstatus;
		}
		xfree(cpuset_conf);
	}

	xcgroup_destroy(&acg);
	return XCGROUP_SUCCESS;
}
extern int task_cgroup_cpuset_create(slurmd_job_t *job)
{
	int rc;
	int fstatus = SLURM_ERROR;

	xcgroup_t cpuset_cg;

	uint32_t jobid = job->jobid;
	uint32_t stepid = job->stepid;
	uid_t uid = job->uid;
	uid_t gid = job->gid;
	char* user_alloc_cores = NULL;
	char* job_alloc_cores = NULL;
	char* step_alloc_cores = NULL;

	char* cpus = NULL;
	size_t cpus_size;

	char* slurm_cgpath ;
	xcgroup_t slurm_cg;

	/* create slurm root cg in this cg namespace */
	slurm_cgpath = task_cgroup_create_slurm_cg(&cpuset_ns);
	if ( slurm_cgpath == NULL ) {
		return SLURM_ERROR;
	}

	/* check that this cgroup has cpus allowed or initialize them */
	if (xcgroup_load(&cpuset_ns,&slurm_cg,slurm_cgpath)
	    != XCGROUP_SUCCESS) {
		error("task/cgroup: unable to load slurm cpuset xcgroup");
		xfree(slurm_cgpath);
		return SLURM_ERROR;
	}
	rc = xcgroup_get_param(&slurm_cg,"cpuset.cpus",&cpus,&cpus_size);
	if (rc != XCGROUP_SUCCESS || cpus_size == 1) {
		/* initialize the cpusets as it was inexistant */
		if (_xcgroup_cpuset_init(&slurm_cg) !=
		    XCGROUP_SUCCESS) {
			xfree(slurm_cgpath);
			xcgroup_destroy(&slurm_cg);
			return SLURM_ERROR;
		}
	}
	xfree(cpus);

	/* build user cgroup relative path if not set (should not be) */
	if (*user_cgroup_path == '\0') {
		if (snprintf(user_cgroup_path, PATH_MAX,
			     "%s/uid_%u", slurm_cgpath, uid) >= PATH_MAX) {
			error("unable to build uid %u cgroup relative "
			      "path : %m", uid);
			xfree(slurm_cgpath);
			return SLURM_ERROR;
		}
	}
	xfree(slurm_cgpath);

	/* build job cgroup relative path if no set (should not be) */
	if (*job_cgroup_path == '\0') {
		if (snprintf(job_cgroup_path,PATH_MAX,"%s/job_%u",
			      user_cgroup_path,jobid) >= PATH_MAX) {
			error("task/cgroup: unable to build job %u cpuset "
			      "cg relative path : %m",jobid);
			return SLURM_ERROR;
		}
	}

	/* build job step cgroup relative path (should not be) */
	if (*jobstep_cgroup_path == '\0') {
		if (stepid == NO_VAL) {
			if (snprintf(jobstep_cgroup_path, PATH_MAX,
				     "%s/step_batch", job_cgroup_path)
			    >= PATH_MAX) {
				error("task/cgroup: unable to build job step"
				      " %u.batch cpuset cg relative path: %m",
				      jobid);
				return SLURM_ERROR;
			}
		} else {
			if (snprintf(jobstep_cgroup_path, PATH_MAX, "%s/step_%u",
				     job_cgroup_path, stepid) >= PATH_MAX) {
				error("task/cgroup: unable to build job step"
				      " %u.%u cpuset cg relative path: %m",
				      jobid, stepid);
				return SLURM_ERROR;
			}
		}
	}

	/*
	 * create cpuset root cg and lock it
	 *
	 * we will keep the lock until the end to avoid the effect of a release
	 * agent that would remove an existing cgroup hierarchy while we are
	 * setting it up. As soon as the step cgroup is created, we can release
	 * the lock.
	 * Indeed, consecutive slurm steps could result in cg being removed
	 * between the next EEXIST instanciation and the first addition of
	 * a task. The release_agent will have to lock the root cpuset cgroup
	 * to avoid this scenario.
	 */
	if (xcgroup_create(&cpuset_ns,&cpuset_cg,"",0,0) != XCGROUP_SUCCESS) {
		error("task/cgroup: unable to create root cpuset xcgroup");
		return SLURM_ERROR;
	}
	if (xcgroup_lock(&cpuset_cg) != XCGROUP_SUCCESS) {
		xcgroup_destroy(&cpuset_cg);
		error("task/cgroup: unable to lock root cpuset cg");
		return SLURM_ERROR;
	}

	/*
	 * build job and job steps allocated cores lists
	 */
	debug("task/cgroup: job abstract cores are '%s'",
	      job->job_alloc_cores);
	debug("task/cgroup: step abstract cores are '%s'",
	      job->step_alloc_cores);
	if (xcpuinfo_abs_to_mac(job->job_alloc_cores,
				 &job_alloc_cores) != XCPUINFO_SUCCESS) {
		error("task/cgroup: unable to build job physical cores");
		goto error;
	}
	if (xcpuinfo_abs_to_mac(job->step_alloc_cores,
				 &step_alloc_cores) != XCPUINFO_SUCCESS) {
		error("task/cgroup: unable to build step physical cores");
		goto error;
	}
	debug("task/cgroup: job physical cores are '%s'",
	      job->job_alloc_cores);
	debug("task/cgroup: step physical cores are '%s'",
	      job->step_alloc_cores);

	/*
	 * create user cgroup in the cpuset ns (it could already exist)
	 */
	if (xcgroup_create(&cpuset_ns,&user_cpuset_cg,
			    user_cgroup_path,
			    getuid(),getgid()) != XCGROUP_SUCCESS) {
		goto error;
	}
	if (xcgroup_instanciate(&user_cpuset_cg) != XCGROUP_SUCCESS) {
		xcgroup_destroy(&user_cpuset_cg);
		goto error;
	}

	/*
	 * check that user's cpuset cgroup is consistant and add the job cores
	 */
	rc = xcgroup_get_param(&user_cpuset_cg,"cpuset.cpus",&cpus,&cpus_size);
	if (rc != XCGROUP_SUCCESS || cpus_size == 1) {
		/* initialize the cpusets as it was inexistant */
		if (_xcgroup_cpuset_init(&user_cpuset_cg) !=
		     XCGROUP_SUCCESS) {
			xcgroup_delete(&user_cpuset_cg);
			xcgroup_destroy(&user_cpuset_cg);
			goto error;
		}
	}
	user_alloc_cores = xstrdup(job_alloc_cores);
	if (cpus != NULL && cpus_size > 1) {
		cpus[cpus_size-1]='\0';
		xstrcat(user_alloc_cores,",");
		xstrcat(user_alloc_cores,cpus);
	}
	xcgroup_set_param(&user_cpuset_cg,"cpuset.cpus",user_alloc_cores);
	xfree(cpus);

	/*
	 * create job cgroup in the cpuset ns (it could already exist)
	 */
	if (xcgroup_create(&cpuset_ns,&job_cpuset_cg,
			    job_cgroup_path,
			    getuid(),getgid()) != XCGROUP_SUCCESS) {
		xcgroup_destroy(&user_cpuset_cg);
		goto error;
	}
	if (xcgroup_instanciate(&job_cpuset_cg) != XCGROUP_SUCCESS) {
		xcgroup_destroy(&user_cpuset_cg);
		xcgroup_destroy(&job_cpuset_cg);
		goto error;
	}
	if (_xcgroup_cpuset_init(&job_cpuset_cg) != XCGROUP_SUCCESS) {
		xcgroup_destroy(&user_cpuset_cg);
		xcgroup_destroy(&job_cpuset_cg);
		goto error;
	}
	xcgroup_set_param(&job_cpuset_cg,"cpuset.cpus",job_alloc_cores);

	/*
	 * create step cgroup in the cpuset ns (it should not exists)
	 * use job's user uid/gid to enable tasks cgroups creation by
	 * the user inside the step cgroup owned by root
	 */
	if (xcgroup_create(&cpuset_ns,&step_cpuset_cg,
			    jobstep_cgroup_path,
			    uid,gid) != XCGROUP_SUCCESS) {
		/* do not delete user/job cgroup as */
		/* they can exist for other steps */
		xcgroup_destroy(&user_cpuset_cg);
		xcgroup_destroy(&job_cpuset_cg);
		goto error;
	}
	if (xcgroup_instanciate(&step_cpuset_cg) != XCGROUP_SUCCESS) {
		xcgroup_destroy(&user_cpuset_cg);
		xcgroup_destroy(&job_cpuset_cg);
		xcgroup_destroy(&step_cpuset_cg);
		goto error;
	}
	if (_xcgroup_cpuset_init(&step_cpuset_cg) != XCGROUP_SUCCESS) {
		xcgroup_destroy(&user_cpuset_cg);
		xcgroup_destroy(&job_cpuset_cg);
		xcgroup_delete(&step_cpuset_cg);
		xcgroup_destroy(&step_cpuset_cg);
		goto error;
	}
	xcgroup_set_param(&step_cpuset_cg,"cpuset.cpus",step_alloc_cores);

	/* attach the slurmstepd to the step cpuset cgroup */
	pid_t pid = getpid();
	rc = xcgroup_add_pids(&step_cpuset_cg,&pid,1);
	if (rc != XCGROUP_SUCCESS) {
		error("task/cgroup: unable to add slurmstepd to cpuset cg '%s'",
		      step_cpuset_cg.path);
		fstatus = SLURM_ERROR;
	} else
		fstatus = SLURM_SUCCESS;

error:
	xcgroup_unlock(&cpuset_cg);
	xcgroup_destroy(&cpuset_cg);

	xfree(user_alloc_cores);
	xfree(job_alloc_cores);
	xfree(step_alloc_cores);

	return fstatus;
}
Exemple #5
0
extern int init_system_cpuset_cgroup(void)
{
	int rc;
	int fstatus = SLURM_ERROR;
	char* cpus = NULL;
	size_t cpus_size;
	char* slurm_cgpath;
	xcgroup_t slurm_cg;

	/* read cgroup configuration */
	if (read_slurm_cgroup_conf(&slurm_cgroup_conf))
		return SLURM_ERROR;

	/* initialize cpuset cgroup namespace */
	if (xcgroup_ns_create(&slurm_cgroup_conf, &cpuset_ns, "", "cpuset")
	    != XCGROUP_SUCCESS) {
		error("system cgroup: unable to create cpuset namespace");
		free_slurm_cgroup_conf(&slurm_cgroup_conf);
		return SLURM_ERROR;
	}

	/* create slurm root cg in this cg namespace */
	slurm_cgpath = _system_cgroup_create_slurm_cg(&cpuset_ns);
	if ( slurm_cgpath == NULL ) {
		xcgroup_ns_destroy(&cpuset_ns);
		free_slurm_cgroup_conf(&slurm_cgroup_conf);
		return SLURM_ERROR;
	}

	/* check that this cgroup has cpus allowed or initialize them */
	if (xcgroup_load(&cpuset_ns, &slurm_cg, slurm_cgpath)
	    != XCGROUP_SUCCESS) {
		error("system cgroup: unable to load slurm cpuset xcgroup");
		xfree(slurm_cgpath);
		xcgroup_ns_destroy(&cpuset_ns);
		free_slurm_cgroup_conf(&slurm_cgroup_conf);
		return SLURM_ERROR;
	}

again:
	snprintf(cpuset_meta, sizeof(cpuset_meta), "%scpus", cpuset_prefix);
	rc = xcgroup_get_param(&slurm_cg, cpuset_meta, &cpus, &cpus_size);
	if (rc != XCGROUP_SUCCESS || cpus_size == 1) {
		if (!cpuset_prefix_set && (rc != XCGROUP_SUCCESS)) {
			cpuset_prefix_set = 1;
			cpuset_prefix = "cpuset.";
			goto again;
		}

		/* initialize the cpusets as it was nonexistent */
		if (_xcgroup_cpuset_init(&slurm_cg) != XCGROUP_SUCCESS) {
			xfree(slurm_cgpath);
			xcgroup_destroy(&slurm_cg);
			xcgroup_ns_destroy(&cpuset_ns);
			free_slurm_cgroup_conf(&slurm_cgroup_conf);
			xfree(cpus);
			return SLURM_ERROR;
		}
	}
	xcgroup_destroy(&slurm_cg);
	xfree(cpus);

	/* build system cgroup relative path */
	snprintf(system_cgroup_path, PATH_MAX, "%s/system", slurm_cgpath);
	xfree(slurm_cgpath);

	/* create system cgroup in the cpuset ns */
	if (xcgroup_create(&cpuset_ns, &system_cpuset_cg, system_cgroup_path,
			   getuid(),getgid()) != XCGROUP_SUCCESS) {
		goto error;
	}
	if (xcgroup_instantiate(&system_cpuset_cg) != XCGROUP_SUCCESS) {
		goto error;
	}
	if (_xcgroup_cpuset_init(&system_cpuset_cg) != XCGROUP_SUCCESS) {
		goto error;
	}

	free_slurm_cgroup_conf(&slurm_cgroup_conf);
	debug("system cgroup: system cpuset cgroup initialized");
	return SLURM_SUCCESS;

error:
	xcgroup_unlock(&system_cpuset_cg);
	xcgroup_destroy(&system_cpuset_cg);
	xcgroup_ns_destroy(&cpuset_ns);
	free_slurm_cgroup_conf(&slurm_cgroup_conf);
	return fstatus;
}
Exemple #6
0
/* when cgroups are configured with cpuset, at least
 * cpuset.cpus and cpuset.mems must be set or the cgroup
 * will not be available at all.
 * we duplicate the ancestor configuration in the init step */
static int _xcgroup_cpuset_init(xcgroup_t* cg)
{
	int fstatus, i;

	char* cpuset_metafiles[] = {
		"cpus",
		"mems"
	};
	char* cpuset_conf = NULL;
	size_t csize = 0;

	xcgroup_t acg;
	char* acg_name = NULL;
	char* p;

	fstatus = XCGROUP_ERROR;

	/* load ancestor cg */
	acg_name = (char*) xstrdup(cg->name);
	p = xstrrchr(acg_name, '/');
	if (p == NULL) {
		debug2("system cgroup: unable to get ancestor path for "
		       "cpuset cg '%s' : %m", cg->path);
		xfree(acg_name);
		return fstatus;
	} else
		*p = '\0';
	if (xcgroup_load(cg->ns, &acg, acg_name) != XCGROUP_SUCCESS) {
		debug2("system cgroup: unable to load ancestor for "
		       "cpuset cg '%s' : %m", cg->path);
		xfree(acg_name);
		return fstatus;
	}
	xfree(acg_name);

	/* inherits ancestor params */
	for (i = 0 ; i < 2 ; i++) {
	again:
		snprintf(cpuset_meta, sizeof(cpuset_meta), "%s%s",
			 cpuset_prefix, cpuset_metafiles[i]);
		if (xcgroup_get_param(&acg ,cpuset_meta,
				      &cpuset_conf, &csize)
		    != XCGROUP_SUCCESS) {
			if (!cpuset_prefix_set) {
				cpuset_prefix_set = 1;
				cpuset_prefix = "cpuset.";
				goto again;
			}

			debug("system cgroup: assuming no cpuset cg "
			       "support for '%s'",acg.path);
			xcgroup_destroy(&acg);
			return fstatus;
		}
		if (csize > 0)
			cpuset_conf[csize-1] = '\0';
		if (xcgroup_set_param(cg,cpuset_meta, cpuset_conf)
		    != XCGROUP_SUCCESS) {
			debug("system cgroup: unable to write %s configuration "
			       "(%s) for cpuset cg '%s'",cpuset_meta,
			       cpuset_conf, cg->path);
			xcgroup_destroy(&acg);
			xfree(cpuset_conf);
			return fstatus;
		}
		xfree(cpuset_conf);
	}

	xcgroup_destroy(&acg);
	return XCGROUP_SUCCESS;
}
extern int task_cgroup_cpuset_create(stepd_step_rec_t *job)
{
	int rc;
	int fstatus = SLURM_ERROR;

	xcgroup_t cpuset_cg;

	uint32_t jobid = job->jobid;
	uint32_t stepid = job->stepid;
	uid_t uid = job->uid;
	uid_t gid = job->gid;
	char* user_alloc_cores = NULL;
	char* job_alloc_cores = NULL;
	char* step_alloc_cores = NULL;
	char cpuset_meta[PATH_MAX];

	char* cpus = NULL;
	size_t cpus_size;

	char* slurm_cgpath;
	xcgroup_t slurm_cg;

#ifdef HAVE_NATIVE_CRAY
	char expected_usage[32];
#endif

	/* create slurm root cg in this cg namespace */
	slurm_cgpath = task_cgroup_create_slurm_cg(&cpuset_ns);
	if ( slurm_cgpath == NULL ) {
		return SLURM_ERROR;
	}

	/* check that this cgroup has cpus allowed or initialize them */
	if (xcgroup_load(&cpuset_ns,&slurm_cg,slurm_cgpath)
	    != XCGROUP_SUCCESS) {
		error("task/cgroup: unable to load slurm cpuset xcgroup");
		xfree(slurm_cgpath);
		return SLURM_ERROR;
	}
again:
	snprintf(cpuset_meta, sizeof(cpuset_meta), "%scpus", cpuset_prefix);
	rc = xcgroup_get_param(&slurm_cg, cpuset_meta, &cpus,&cpus_size);
	if (rc != XCGROUP_SUCCESS || cpus_size == 1) {
		if (!cpuset_prefix_set && (rc != XCGROUP_SUCCESS)) {
			cpuset_prefix_set = 1;
			cpuset_prefix = "cpuset.";
			goto again;
		}

		/* initialize the cpusets as it was inexistant */
		if (_xcgroup_cpuset_init(&slurm_cg) !=
		    XCGROUP_SUCCESS) {
			xfree(slurm_cgpath);
			xcgroup_destroy(&slurm_cg);
			return SLURM_ERROR;
		}
	}
	xfree(cpus);

	/* build user cgroup relative path if not set (should not be) */
	if (*user_cgroup_path == '\0') {
		if (snprintf(user_cgroup_path, PATH_MAX,
			     "%s/uid_%u", slurm_cgpath, uid) >= PATH_MAX) {
			error("task/cgroup: unable to build uid %u cgroup "
			      "relative path : %m", uid);
			xfree(slurm_cgpath);
			return SLURM_ERROR;
		}
	}
	xfree(slurm_cgpath);

	/* build job cgroup relative path if no set (should not be) */
	if (*job_cgroup_path == '\0') {
		if (snprintf(job_cgroup_path,PATH_MAX,"%s/job_%u",
			     user_cgroup_path,jobid) >= PATH_MAX) {
			error("task/cgroup: unable to build job %u cpuset "
			      "cg relative path : %m",jobid);
			return SLURM_ERROR;
		}
	}

	/* build job step cgroup relative path (should not be) */
	if (*jobstep_cgroup_path == '\0') {
		int cc;
		if (stepid == SLURM_BATCH_SCRIPT) {
			cc = snprintf(jobstep_cgroup_path, PATH_MAX,
				      "%s/step_batch", job_cgroup_path);
		} else if (stepid == SLURM_EXTERN_CONT) {
			cc = snprintf(jobstep_cgroup_path, PATH_MAX,
				      "%s/step_extern", job_cgroup_path);
		} else {
			cc = snprintf(jobstep_cgroup_path, PATH_MAX,
				      "%s/step_%u", job_cgroup_path, stepid);
		}
		if (cc >= PATH_MAX) {
			error("task/cgroup: unable to build job step %u.%u "
			      "cpuset cg relative path: %m",
			      jobid, stepid);
			return SLURM_ERROR;
		}
	}

	/*
	 * create cpuset root cg and lock it
	 *
	 * we will keep the lock until the end to avoid the effect of a release
	 * agent that would remove an existing cgroup hierarchy while we are
	 * setting it up. As soon as the step cgroup is created, we can release
	 * the lock.
	 * Indeed, consecutive slurm steps could result in cg being removed
	 * between the next EEXIST instanciation and the first addition of
	 * a task. The release_agent will have to lock the root cpuset cgroup
	 * to avoid this scenario.
	 */
	if (xcgroup_create(&cpuset_ns,&cpuset_cg,"",0,0) != XCGROUP_SUCCESS) {
		error("task/cgroup: unable to create root cpuset xcgroup");
		return SLURM_ERROR;
	}
	if (xcgroup_lock(&cpuset_cg) != XCGROUP_SUCCESS) {
		xcgroup_destroy(&cpuset_cg);
		error("task/cgroup: unable to lock root cpuset cg");
		return SLURM_ERROR;
	}

	/*
	 * build job and job steps allocated cores lists
	 */
	debug("task/cgroup: job abstract cores are '%s'",
	      job->job_alloc_cores);
	debug("task/cgroup: step abstract cores are '%s'",
	      job->step_alloc_cores);
	if (xcpuinfo_abs_to_mac(job->job_alloc_cores,
				&job_alloc_cores) != SLURM_SUCCESS) {
		error("task/cgroup: unable to build job physical cores");
		goto error;
	}
	if (xcpuinfo_abs_to_mac(job->step_alloc_cores,
				&step_alloc_cores) != SLURM_SUCCESS) {
		error("task/cgroup: unable to build step physical cores");
		goto error;
	}
	debug("task/cgroup: job physical cores are '%s'",
	      job_alloc_cores);
	debug("task/cgroup: step physical cores are '%s'",
	      step_alloc_cores);

	/*
	 * create user cgroup in the cpuset ns (it could already exist)
	 */
	if (xcgroup_create(&cpuset_ns,&user_cpuset_cg,
			   user_cgroup_path,
			   getuid(),getgid()) != XCGROUP_SUCCESS) {
		goto error;
	}
	if (xcgroup_instanciate(&user_cpuset_cg) != XCGROUP_SUCCESS) {
		xcgroup_destroy(&user_cpuset_cg);
		goto error;
	}

	/*
	 * check that user's cpuset cgroup is consistant and add the job cores
	 */
	rc = xcgroup_get_param(&user_cpuset_cg, cpuset_meta, &cpus,&cpus_size);
	if (rc != XCGROUP_SUCCESS || cpus_size == 1) {
		/* initialize the cpusets as it was inexistant */
		if (_xcgroup_cpuset_init(&user_cpuset_cg) !=
		    XCGROUP_SUCCESS) {
			xcgroup_delete(&user_cpuset_cg);
			xcgroup_destroy(&user_cpuset_cg);
			goto error;
		}
	}
	user_alloc_cores = xstrdup(job_alloc_cores);
	if (cpus != NULL && cpus_size > 1) {
		cpus[cpus_size-1]='\0';
		xstrcat(user_alloc_cores,",");
		xstrcat(user_alloc_cores,cpus);
	}
	xcgroup_set_param(&user_cpuset_cg, cpuset_meta, user_alloc_cores);
	xfree(cpus);

	/*
	 * create job cgroup in the cpuset ns (it could already exist)
	 */
	if (xcgroup_create(&cpuset_ns,&job_cpuset_cg,
			   job_cgroup_path,
			   getuid(),getgid()) != XCGROUP_SUCCESS) {
		xcgroup_destroy(&user_cpuset_cg);
		goto error;
	}
	if (xcgroup_instanciate(&job_cpuset_cg) != XCGROUP_SUCCESS) {
		xcgroup_destroy(&user_cpuset_cg);
		xcgroup_destroy(&job_cpuset_cg);
		goto error;
	}
	if (_xcgroup_cpuset_init(&job_cpuset_cg) != XCGROUP_SUCCESS) {
		xcgroup_destroy(&user_cpuset_cg);
		xcgroup_destroy(&job_cpuset_cg);
		goto error;
	}
	xcgroup_set_param(&job_cpuset_cg, cpuset_meta, job_alloc_cores);

	/*
	 * create step cgroup in the cpuset ns (it should not exists)
	 * use job's user uid/gid to enable tasks cgroups creation by
	 * the user inside the step cgroup owned by root
	 */
	if (xcgroup_create(&cpuset_ns,&step_cpuset_cg,
			   jobstep_cgroup_path,
			   uid,gid) != XCGROUP_SUCCESS) {
		/* do not delete user/job cgroup as */
		/* they can exist for other steps */
		xcgroup_destroy(&user_cpuset_cg);
		xcgroup_destroy(&job_cpuset_cg);
		goto error;
	}
	if (xcgroup_instanciate(&step_cpuset_cg) != XCGROUP_SUCCESS) {
		xcgroup_destroy(&user_cpuset_cg);
		xcgroup_destroy(&job_cpuset_cg);
		xcgroup_destroy(&step_cpuset_cg);
		goto error;
	}
	if (_xcgroup_cpuset_init(&step_cpuset_cg) != XCGROUP_SUCCESS) {
		xcgroup_destroy(&user_cpuset_cg);
		xcgroup_destroy(&job_cpuset_cg);
		xcgroup_delete(&step_cpuset_cg);
		xcgroup_destroy(&step_cpuset_cg);
		goto error;
	}
	xcgroup_set_param(&step_cpuset_cg, cpuset_meta, step_alloc_cores);

	/*
	 * on Cray systems, set the expected usage in bytes.
	 * This is used by the Cray OOM killer
	 */
#ifdef HAVE_NATIVE_CRAY
	snprintf(expected_usage, sizeof(expected_usage), "%"PRIu64,
		 (uint64_t)job->step_mem * 1024 * 1024);
	xcgroup_set_param(&step_cpuset_cg, "expected_usage_in_bytes",
			  expected_usage);
#endif

	/* attach the slurmstepd to the step cpuset cgroup */
	pid_t pid = getpid();
	rc = xcgroup_add_pids(&step_cpuset_cg,&pid,1);
	if (rc != XCGROUP_SUCCESS) {
		error("task/cgroup: unable to add slurmstepd to cpuset cg '%s'",
		      step_cpuset_cg.path);
		fstatus = SLURM_ERROR;
	} else
		fstatus = SLURM_SUCCESS;

	/* validate the requested cpu frequency and set it */
	cpu_freq_cgroup_validate(job, step_alloc_cores);

error:
	xcgroup_unlock(&cpuset_cg);
	xcgroup_destroy(&cpuset_cg);

	xfree(user_alloc_cores);
	xfree(job_alloc_cores);
	xfree(step_alloc_cores);

	return fstatus;
}