Now that we are going to defer any changes to the HK_TYPE_DOMAIN housekeeping cpumasks to either task_work or workqueue where rebuild_sched_domains() call will be issued. The current rebuild_sched_domains_locked() call near the end of the cpuset critical section can be removed in such cases.
Currently, a boolean force_sd_rebuild flag is used to decide if rebuild_sched_domains_locked() call needs to be invoked. To allow deferral that like, we change it to a tri-state sd_rebuild enumaration type. Signed-off-by: Waiman Long <[email protected]> --- kernel/cgroup/cpuset.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index d26c77a726b2..e224df321e34 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -173,7 +173,11 @@ static bool isolcpus_twork_queued; /* T */ * Note that update_relax_domain_level() in cpuset-v1.c can still call * rebuild_sched_domains_locked() directly without using this flag. */ -static bool force_sd_rebuild; /* RWCS */ +static enum { + SD_NO_REBUILD = 0, + SD_REBUILD, + SD_DEFER_REBUILD, +} sd_rebuild; /* RWCS */ /* * Partition root states: @@ -990,7 +994,7 @@ void rebuild_sched_domains_locked(void) lockdep_assert_cpus_held(); lockdep_assert_cpuset_lock_held(); - force_sd_rebuild = false; + sd_rebuild = SD_NO_REBUILD; /* Generate domain masks and attrs */ ndoms = generate_sched_domains(&doms, &attr); @@ -1377,6 +1381,9 @@ static void update_isolation_cpumasks(void) else isolated_cpus_updating = false; + /* Defer rebuild_sched_domains() to task_work or wq */ + sd_rebuild = SD_DEFER_REBUILD; + /* * This function can be reached either directly from regular cpuset * control file write or via CPU hotplug. In the latter case, it is @@ -3011,7 +3018,7 @@ static int update_prstate(struct cpuset *cs, int new_prs) update_partition_sd_lb(cs, old_prs); notify_partition_change(cs, old_prs); - if (force_sd_rebuild) + if (sd_rebuild == SD_REBUILD) rebuild_sched_domains_locked(); free_tmpmasks(&tmpmask); return 0; @@ -3288,7 +3295,7 @@ ssize_t cpuset_write_resmask(struct kernfs_open_file *of, } free_cpuset(trialcs); - if (force_sd_rebuild) + if (sd_rebuild == SD_REBUILD) rebuild_sched_domains_locked(); out_unlock: cpuset_full_unlock(); @@ -3771,7 +3778,8 @@ hotplug_update_tasks(struct cpuset *cs, void cpuset_force_rebuild(void) { - force_sd_rebuild = true; + if (!sd_rebuild) + sd_rebuild = SD_REBUILD; } /** @@ -3981,7 +3989,7 @@ static void cpuset_handle_hotplug(void) } /* rebuild sched domains if necessary */ - if (force_sd_rebuild) + if (sd_rebuild == SD_REBUILD) rebuild_sched_domains_cpuslocked(); free_tmpmasks(ptmp); -- 2.52.0
