Start/stop cgroup monitoring for cgroups when intel_cmt device is started/stopped.
Signed-off-by: David Carrillo-Cisneros <[email protected]> --- arch/x86/events/intel/cmt.c | 99 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 99 insertions(+) diff --git a/arch/x86/events/intel/cmt.c b/arch/x86/events/intel/cmt.c index f7da8cf..5c64d94 100644 --- a/arch/x86/events/intel/cmt.c +++ b/arch/x86/events/intel/cmt.c @@ -766,6 +766,11 @@ static struct perf_cgroup *perf_cgroup_from_css(struct cgroup_subsys_state *css) return container_of(css, struct perf_cgroup, css); } +static struct monr *monr_from_css(struct cgroup_subsys_state *css) +{ + return ((struct monr *)perf_cgroup_from_css(css)->arch_info); +} + /** * perf_cgroup_mon_started() - Tell if cgroup is monitored by its own monr. * @@ -1445,6 +1450,45 @@ static struct pmu intel_cmt_pmu = { .read = intel_cmt_event_read, }; +#ifdef CONFIG_CGROUP_PERF +static int __css_go_online(struct cgroup_subsys_state *css) +{ + struct perf_cgroup *lma, *cgrp = perf_cgroup_from_css(css); + int err; + + if (!css->parent) { + err = __css_start_monitoring(css); + if (err) + return err; + return monr_apply_uflags(monr_from_css(css), NULL); + } + lma = perf_cgroup_find_lma(cgrp); + perf_cgroup_set_monr(cgrp, monr_from_perf_cgroup(lma)); + + return 0; +} + +static void __css_go_offline(struct cgroup_subsys_state *css) +{ + struct monr *monr; + struct perf_cgroup *cgrp = perf_cgroup_from_css(css); + + monr = monr_from_perf_cgroup(cgrp); + if (!perf_cgroup_mon_started(cgrp)) { + perf_cgroup_set_monr(cgrp, NULL); + return; + } + + monr_apply_uflags(monr, pkg_uflags_zeroes); + /* + * Terminate monr even if there are other users (events), monr will + * stay zombie until those events are terminated. + */ + monr_destroy(monr); +} + +#endif + static void free_pkg_data(struct pkg_data *pkg_data) { kfree(pkg_data); @@ -1666,6 +1710,42 @@ static const struct x86_cpu_id intel_cmt_match[] = { {} }; +#ifdef CONFIG_CGROUP_PERF +/* Start monitoring for all cgroups in cgroup hierarchy. */ +static int __switch_monitoring_all_cgroups(bool online) +{ + int err = 0; + struct cgroup_subsys_state *css_root, *css = NULL; + + lockdep_assert_held(&cmt_mutex); + monr_hrchy_assert_held_mutexes(); + + rcu_read_lock(); + /* Get css for root cgroup */ + css_root = get_root_perf_css(); + + css_for_each_descendant_pre(css, css_root) { + if (!css_tryget_online(css)) + continue; + + rcu_read_unlock(); + + if (online) + err = __css_go_online(css); + else + __css_go_offline(css); + css_put(css); + if (err) + return err; + + rcu_read_lock(); + } + rcu_read_unlock(); + return 0; +} + +#endif + static void cmt_dealloc(void) { kfree(monr_hrchy_root); @@ -1682,6 +1762,13 @@ static void cmt_stop(void) { cpuhp_remove_state(CPUHP_AP_PERF_X86_CMT_ONLINE); cpuhp_remove_state(CPUHP_PERF_X86_CMT_PREP); + + mutex_lock(&cmt_mutex); + monr_hrchy_acquire_mutexes(); + __switch_monitoring_all_cgroups(false); + monr_hrchy_release_mutexes(); + + mutex_unlock(&cmt_mutex); } static int __init cmt_alloc(void) @@ -1743,6 +1830,18 @@ static int __init cmt_start(void) } event_attr_intel_cmt_llc_scale.event_str = str; +#ifdef CONFIG_CGROUP_PERF + mutex_lock(&cmt_mutex); + monr_hrchy_acquire_mutexes(); + err = __switch_monitoring_all_cgroups(true); + if (err) + __switch_monitoring_all_cgroups(false); + monr_hrchy_release_mutexes(); + mutex_unlock(&cmt_mutex); + if (err) + goto rm_online; +#endif + return 0; rm_online: -- 2.8.0.rc3.226.g39d4020
