On 5/6/2014 1:33 AM, Johannes Weiner wrote:
Hi Oliver,
On Mon, May 05, 2014 at 11:00:13PM +0200, Oliver Winker wrote:
Hello,
1) Attached a full function-trace log + other SysRq outputs, see [1]
attached.
I saw bdi_...() calls in the s2disk paths, but didn't check in detail
Probably more efficient when one of you guys looks directly.
Thanks, this looks interesting. balance_dirty_pages() wakes up the
bdi_wq workqueue as it should:
[ 249.148009] s2disk-3327 2.... 48550413us : global_dirty_limits <-balance_dirty_pages_ratelimited
[ 249.148009] s2disk-3327 2.... 48550414us : global_dirtyable_memory <-global_dirty_limits
[ 249.148009] s2disk-3327 2.... 48550414us : writeback_in_progress <-balance_dirty_pages_ratelimited
[ 249.148009] s2disk-3327 2.... 48550414us : bdi_start_background_writeback <-balance_dirty_pages_ratelimited
[ 249.148009] s2disk-3327 2.... 48550414us : mod_delayed_work_on <-balance_dirty_pages_ratelimited
[ 249.148009] s2disk-3327 2.... 48550414us : try_to_grab_pending <-mod_delayed_work_on
[ 249.148009] s2disk-3327 2d... 48550414us : del_timer <-try_to_grab_pending
[ 249.148009] s2disk-3327 2d... 48550415us : get_work_pool <-try_to_grab_pending
[ 249.148009] s2disk-3327 2d... 48550415us : _raw_spin_lock <-try_to_grab_pending
[ 249.148009] s2disk-3327 2d... 48550415us : get_work_pwq <-try_to_grab_pending
[ 249.148009] s2disk-3327 2d... 48550415us : pwq_activate_delayed_work <-try_to_grab_pending
[ 249.148009] s2disk-3327 2d... 48550415us : get_work_pwq <-pwq_activate_delayed_work
[ 249.148009] s2disk-3327 2d... 48550415us : move_linked_works <-pwq_activate_delayed_work
[ 249.148009] s2disk-3327 2d... 48550415us : get_work_pwq <-try_to_grab_pending
[ 249.148009] s2disk-3327 2d... 48550416us : pwq_dec_nr_in_flight <-try_to_grab_pending
[ 249.148009] s2disk-3327 2d... 48550416us : __queue_delayed_work <-mod_delayed_work_on
[ 249.148009] s2disk-3327 2d... 48550416us : __queue_work <-mod_delayed_work_on
[ 249.148009] s2disk-3327 2d... 48550416us : get_work_pool <-__queue_work
[ 249.148009] s2disk-3327 2d... 48550416us : _raw_spin_lock <-__queue_work
[ 249.148009] s2disk-3327 2d... 48550416us : insert_work <-__queue_work
[ 249.148009] s2disk-3327 2d... 48550417us : get_pwq.isra.20 <-insert_work
[ 249.148009] s2disk-3327 2d... 48550417us : wake_up_worker <-__queue_work
[ 249.148009] s2disk-3327 2d... 48550417us : wake_up_process <-__queue_work
[ 249.148009] s2disk-3327 2d... 48550417us : try_to_wake_up <-__queue_work
[ 249.148009] s2disk-3327 2d... 48550417us : _raw_spin_lock_irqsave <-try_to_wake_up
[ 249.148009] s2disk-3327 2d... 48550417us : task_waking_fair <-try_to_wake_up
[ 249.148009] s2disk-3327 2d... 48550418us : select_task_rq_fair <-select_task_rq
[ 249.148009] s2disk-3327 2d... 48550418us : idle_cpu <-select_task_rq_fair
[ 249.148009] s2disk-3327 2d... 48550418us : idle_cpu <-select_task_rq_fair
[ 249.148009] s2disk-3327 2d... 48550418us : cpus_share_cache <-try_to_wake_up
[ 249.148009] s2disk-3327 2d... 48550418us : _raw_spin_lock <-try_to_wake_up
[ 249.148009] s2disk-3327 2d... 48550419us : ttwu_do_activate.constprop.100 <-try_to_wake_up
[ 249.148009] s2disk-3327 2d... 48550419us : activate_task <-ttwu_do_activate.constprop.100
[ 249.148009] s2disk-3327 2d... 48550419us : enqueue_task <-ttwu_do_activate.constprop.100
[ 249.148009] s2disk-3327 2d... 48550419us : update_rq_clock <-enqueue_task
[ 249.148009] s2disk-3327 2d... 48550419us : enqueue_task_fair <-ttwu_do_activate.constprop.100
[ 249.148009] s2disk-3327 2d... 48550419us : update_curr <-enqueue_task_fair
[ 249.148009] s2disk-3327 2d... 48550420us : update_min_vruntime <-update_curr
[ 249.148009] s2disk-3327 2d... 48550420us : __compute_runnable_contrib.part.55 <-update_entity_load_avg
[ 249.148009] s2disk-3327 2d... 48550420us : update_cfs_rq_blocked_load <-enqueue_task_fair
[ 249.148009] s2disk-3327 2d... 48550420us : account_entity_enqueue <-enqueue_task_fair
[ 249.148009] s2disk-3327 2d... 48550420us : update_cfs_shares <-enqueue_task_fair
[ 249.148009] s2disk-3327 2d... 48550420us : __enqueue_entity <-enqueue_task_fair
[ 249.148009] s2disk-3327 2d... 48550421us : hrtick_update <-ttwu_do_activate.constprop.100
[ 249.148009] s2disk-3327 2d... 48550421us : wq_worker_waking_up <-ttwu_do_activate.constprop.100
[ 249.148009] s2disk-3327 2d... 48550421us : kthread_data <-wq_worker_waking_up
[ 249.148009] s2disk-3327 2d... 48550421us : ttwu_do_wakeup <-try_to_wake_up
[ 249.148009] s2disk-3327 2d... 48550421us : check_preempt_curr <-ttwu_do_wakeup
[ 249.148009] s2disk-3327 2d... 48550421us : check_preempt_wakeup <-check_preempt_curr
[ 249.148009] s2disk-3327 2d... 48550422us : update_curr <-check_preempt_wakeup
[ 249.148009] s2disk-3327 2d... 48550422us : wakeup_preempt_entity.isra.53 <-check_preempt_wakeup
[ 249.148009] s2disk-3327 2d... 48550422us : _raw_spin_unlock_irqrestore <-try_to_wake_up
[ 249.148009] s2disk-3327 2.... 48550423us : bdi_dirty_limit <-bdi_dirty_limits
[ 249.148009] s2disk-3327 2d... 48550423us : _raw_spin_lock_irqsave <-__percpu_counter_sum
[ 249.148009] s2disk-3327 2d... 48550423us : _raw_spin_unlock_irqrestore <-__percpu_counter_sum
[ 249.148009] s2disk-3327 2d... 48550423us : _raw_spin_lock_irqsave <-__percpu_counter_sum
[ 249.148009] s2disk-3327 2d... 48550424us : _raw_spin_unlock_irqrestore <-__percpu_counter_sum
[ 249.148009] s2disk-3327 2.... 48550424us : bdi_position_ratio <-balance_dirty_pages_ratelimited
[ 249.148009] s2disk-3327 2.... 48550424us : io_schedule_timeout <-balance_dirty_pages_ratelimited
[ 249.148009] s2disk-3327 2.... 48550424us : __delayacct_blkio_start <-io_schedule_timeout
[ 249.148009] s2disk-3327 2.... 48550424us : ktime_get_ts <-io_schedule_timeout
[ 249.148009] s2disk-3327 2.... 48550424us : blk_flush_plug_list <-io_schedule_timeout
[ 249.148009] s2disk-3327 2.... 48550425us : schedule_timeout <-io_schedule_timeout
[ 249.148009] s2disk-3327 2.... 48550425us : lock_timer_base.isra.35 <-__mod_timer
[ 249.148009] s2disk-3327 2.... 48550425us : _raw_spin_lock_irqsave <-lock_timer_base.isra.35
[ 249.148009] s2disk-3327 2d... 48550425us : detach_if_pending <-__mod_timer
[ 249.148009] s2disk-3327 2d... 48550425us : idle_cpu <-__mod_timer
[ 249.148009] s2disk-3327 2d... 48550425us : internal_add_timer <-__mod_timer
[ 249.148009] s2disk-3327 2d... 48550425us : __internal_add_timer <-internal_add_timer
[ 249.148009] s2disk-3327 2d... 48550426us : _raw_spin_unlock_irqrestore <-__mod_timer
[ 249.148009] s2disk-3327 2.... 48550426us : schedule <-schedule_timeout
[ 249.148009] s2disk-3327 2.... 48550426us : __schedule <-schedule_timeout
[ 249.148009] s2disk-3327 2.... 48550426us : rcu_note_context_switch <-__schedule
[ 249.148009] s2disk-3327 2.... 48550426us : rcu_sched_qs <-rcu_note_context_switch
[ 249.148009] s2disk-3327 2.... 48550426us : _raw_spin_lock_irq <-__schedule
[ 249.148009] s2disk-3327 2d... 48550427us : deactivate_task <-__schedule
[ 249.148009] s2disk-3327 2d... 48550427us : dequeue_task <-__schedule
[ 249.148009] s2disk-3327 2d... 48550427us : update_rq_clock <-dequeue_task
[ 249.148009] s2disk-3327 2d... 48550427us : dequeue_task_fair <-__schedule
[ 249.148009] s2disk-3327 2d... 48550427us : update_curr <-dequeue_task_fair
[ 249.148009] s2disk-3327 2d... 48550427us : update_min_vruntime <-update_curr
[ 249.148009] s2disk-3327 2d... 48550427us : cpuacct_charge <-update_curr
[ 249.148009] s2disk-3327 2d... 48550428us : update_cfs_rq_blocked_load <-dequeue_task_fair
[ 249.148009] s2disk-3327 2d... 48550428us : clear_buddies <-dequeue_task_fair
[ 249.148009] s2disk-3327 2d... 48550428us : account_entity_dequeue <-dequeue_task_fair
[ 249.148009] s2disk-3327 2d... 48550428us : update_min_vruntime <-dequeue_task_fair
[ 249.148009] s2disk-3327 2d... 48550428us : update_cfs_shares <-dequeue_task_fair
[ 249.148009] s2disk-3327 2d... 48550428us : update_curr <-update_cfs_shares
[ 249.148009] s2disk-3327 2d... 48550429us : update_min_vruntime <-update_curr
[ 249.148009] s2disk-3327 2d... 48550429us : account_entity_dequeue <-update_cfs_shares
[ 249.148009] s2disk-3327 2d... 48550429us : account_entity_enqueue <-dequeue_task_fair
[ 249.148009] s2disk-3327 2d... 48550429us : update_curr <-dequeue_task_fair
[ 249.148009] s2disk-3327 2d... 48550429us : update_cfs_rq_blocked_load <-dequeue_task_fair
[ 249.148009] s2disk-3327 2d... 48550429us : clear_buddies <-dequeue_task_fair
[ 249.148009] s2disk-3327 2d... 48550429us : account_entity_dequeue <-dequeue_task_fair
[ 249.148009] s2disk-3327 2d... 48550430us : update_min_vruntime <-dequeue_task_fair
[ 249.148009] s2disk-3327 2d... 48550430us : update_cfs_shares <-dequeue_task_fair
[ 249.148009] s2disk-3327 2d... 48550430us : hrtick_update <-__schedule
[ 249.148009] s2disk-3327 2d... 48550430us : put_prev_task_fair <-__schedule
[ 249.148009] s2disk-3327 2d... 48550430us : pick_next_task_fair <-pick_next_task
[ 249.148009] s2disk-3327 2d... 48550430us : clear_buddies <-pick_next_task_fair
[ 249.148009] s2disk-3327 2d... 48550431us : __dequeue_entity <-pick_next_task_fair
but the worker wakeup doesn't actually do anything:
[ 249.148009] kworker/-3466 2d... 48550431us : finish_task_switch <-__schedule
[ 249.148009] kworker/-3466 2.... 48550431us : _raw_spin_lock_irq <-worker_thread
[ 249.148009] kworker/-3466 2d... 48550431us : need_to_create_worker <-worker_thread
[ 249.148009] kworker/-3466 2d... 48550432us : worker_enter_idle <-worker_thread
[ 249.148009] kworker/-3466 2d... 48550432us : too_many_workers <-worker_enter_idle
[ 249.148009] kworker/-3466 2.... 48550432us : schedule <-worker_thread
[ 249.148009] kworker/-3466 2.... 48550432us : __schedule <-worker_thread
My suspicion is that this fails because the bdi_wq is frozen at this
point and so the flush work never runs until resume, whereas before my
patch the effective dirty limit was high enough so that image could be
written in one go without being throttled; followed by an fsync() that
then writes the pages in the context of the unfrozen s2disk.
Does this make sense? Rafael? Tejun?
Well, it does seem to make sense to me.
Thanks,
Rafael
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>