From: Peter Zijlstra <peterz@infradead.org>
To: Arjan van de Ven <arjan@linux.intel.com>,
lenb@kernel.org, rjw@rjwysocki.net,
Eliezer Tamir <eliezer.tamir@linux.intel.com>,
rui.zhang@intel.com, jacob.jun.pan@linux.intel.com,
Mike Galbraith <bitbucket@online.de>,
Ingo Molnar <mingo@kernel.org>,
hpa@zytor.com, paulmck@linux.vnet.ibm.com,
Thomas Gleixner <tglx@linutronix.de>,
John Stultz <john.stultz@linaro.org>,
Andy Lutomirski <luto@amacapital.net>,
Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH 14/15] sched, clock: Fixup clear_sched_clock_stable()
Date: Thu, 12 Dec 2013 15:08:49 +0100 [thread overview]
Message-ID: <20131212141655.423200708@infradead.org> (raw)
In-Reply-To: <20131212140835.729222186@infradead.org>
[-- Attachment #1: peterz-sched_clock_static_key-fixup.patch --]
[-- Type: text/plain, Size: 8195 bytes --]
The below tells us the static_key conversion has a problem; since the
exact point of clearing that flag isn't too important, delay the flip
and use a workqueue to process it.
[ ] TSC synchronization [CPU#0 -> CPU#22]:
[ ] Measured 8 cycles TSC warp between CPUs, turning off TSC clock.
[ ]
[ ] ======================================================
[ ] [ INFO: possible circular locking dependency detected ]
[ ] 3.13.0-rc3-01745-g848b0d0322cb-dirty #637 Not tainted
[ ] -------------------------------------------------------
[ ] swapper/0/1 is trying to acquire lock:
[ ] (jump_label_mutex){+.+...}, at: [<ffffffff8115a637>] jump_label_lock+0x17/0x20
[ ]
[ ] but task is already holding lock:
[ ] (cpu_hotplug.lock){+.+.+.}, at: [<ffffffff8109408b>] cpu_hotplug_begin+0x2b/0x60
[ ]
[ ] which lock already depends on the new lock.
[ ]
[ ]
[ ] the existing dependency chain (in reverse order) is:
[ ]
[ ] -> #1 (cpu_hotplug.lock){+.+.+.}:
[ ] [<ffffffff810def00>] lock_acquire+0x90/0x130
[ ] [<ffffffff81661f83>] mutex_lock_nested+0x63/0x3e0
[ ] [<ffffffff81093fdc>] get_online_cpus+0x3c/0x60
[ ] [<ffffffff8104cc67>] arch_jump_label_transform+0x37/0x130
[ ] [<ffffffff8115a3cf>] __jump_label_update+0x5f/0x80
[ ] [<ffffffff8115a48d>] jump_label_update+0x9d/0xb0
[ ] [<ffffffff8115aa6d>] static_key_slow_inc+0x9d/0xb0
[ ] [<ffffffff810c0f65>] sched_feat_set+0xf5/0x100
[ ] [<ffffffff810c5bdc>] set_numabalancing_state+0x2c/0x30
[ ] [<ffffffff81d12f3d>] numa_policy_init+0x1af/0x1b7
[ ] [<ffffffff81cebdf4>] start_kernel+0x35d/0x41f
[ ] [<ffffffff81ceb5a5>] x86_64_start_reservations+0x2a/0x2c
[ ] [<ffffffff81ceb6a2>] x86_64_start_kernel+0xfb/0xfe
[ ]
[ ] -> #0 (jump_label_mutex){+.+...}:
[ ] [<ffffffff810de141>] __lock_acquire+0x1701/0x1eb0
[ ] [<ffffffff810def00>] lock_acquire+0x90/0x130
[ ] [<ffffffff81661f83>] mutex_lock_nested+0x63/0x3e0
[ ] [<ffffffff8115a637>] jump_label_lock+0x17/0x20
[ ] [<ffffffff8115aa3b>] static_key_slow_inc+0x6b/0xb0
[ ] [<ffffffff810ca775>] clear_sched_clock_stable+0x15/0x20
[ ] [<ffffffff810503b3>] mark_tsc_unstable+0x23/0x70
[ ] [<ffffffff810772cb>] check_tsc_sync_source+0x14b/0x150
[ ] [<ffffffff81076612>] native_cpu_up+0x3a2/0x890
[ ] [<ffffffff810941cb>] _cpu_up+0xdb/0x160
[ ] [<ffffffff810942c9>] cpu_up+0x79/0x90
[ ] [<ffffffff81d0af6b>] smp_init+0x60/0x8c
[ ] [<ffffffff81cebf42>] kernel_init_freeable+0x8c/0x197
[ ] [<ffffffff8164e32e>] kernel_init+0xe/0x130
[ ] [<ffffffff8166beec>] ret_from_fork+0x7c/0xb0
[ ]
[ ] other info that might help us debug this:
[ ]
[ ] Possible unsafe locking scenario:
[ ]
[ ] CPU0 CPU1
[ ] ---- ----
[ ] lock(cpu_hotplug.lock);
[ ] lock(jump_label_mutex);
[ ] lock(cpu_hotplug.lock);
[ ] lock(jump_label_mutex);
[ ]
[ ] *** DEADLOCK ***
[ ]
[ ] 2 locks held by swapper/0/1:
[ ] #0: (cpu_add_remove_lock){+.+.+.}, at: [<ffffffff81094037>] cpu_maps_update_begin+0x17/0x20
[ ] #1: (cpu_hotplug.lock){+.+.+.}, at: [<ffffffff8109408b>] cpu_hotplug_begin+0x2b/0x60
[ ]
[ ] stack backtrace:
[ ] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.13.0-rc3-01745-g848b0d0322cb-dirty #637
[ ] Hardware name: Supermicro X8DTN/X8DTN, BIOS 4.6.3 01/08/2010
[ ] ffffffff82c9c270 ffff880236843bb8 ffffffff8165c5f5 ffffffff82c9c270
[ ] ffff880236843bf8 ffffffff81658c02 ffff880236843c80 ffff8802368586a0
[ ] ffff880236858678 0000000000000001 0000000000000002 ffff880236858000
[ ] Call Trace:
[ ] [<ffffffff8165c5f5>] dump_stack+0x4e/0x7a
[ ] [<ffffffff81658c02>] print_circular_bug+0x1f9/0x207
[ ] [<ffffffff810de141>] __lock_acquire+0x1701/0x1eb0
[ ] [<ffffffff816680ff>] ? __atomic_notifier_call_chain+0x8f/0xb0
[ ] [<ffffffff810def00>] lock_acquire+0x90/0x130
[ ] [<ffffffff8115a637>] ? jump_label_lock+0x17/0x20
[ ] [<ffffffff8115a637>] ? jump_label_lock+0x17/0x20
[ ] [<ffffffff81661f83>] mutex_lock_nested+0x63/0x3e0
[ ] [<ffffffff8115a637>] ? jump_label_lock+0x17/0x20
[ ] [<ffffffff8115a637>] jump_label_lock+0x17/0x20
[ ] [<ffffffff8115aa3b>] static_key_slow_inc+0x6b/0xb0
[ ] [<ffffffff810ca775>] clear_sched_clock_stable+0x15/0x20
[ ] [<ffffffff810503b3>] mark_tsc_unstable+0x23/0x70
[ ] [<ffffffff810772cb>] check_tsc_sync_source+0x14b/0x150
[ ] [<ffffffff81076612>] native_cpu_up+0x3a2/0x890
[ ] [<ffffffff810941cb>] _cpu_up+0xdb/0x160
[ ] [<ffffffff810942c9>] cpu_up+0x79/0x90
[ ] [<ffffffff81d0af6b>] smp_init+0x60/0x8c
[ ] [<ffffffff81cebf42>] kernel_init_freeable+0x8c/0x197
[ ] [<ffffffff8164e320>] ? rest_init+0xd0/0xd0
[ ] [<ffffffff8164e32e>] kernel_init+0xe/0x130
[ ] [<ffffffff8166beec>] ret_from_fork+0x7c/0xb0
[ ] [<ffffffff8164e320>] ? rest_init+0xd0/0xd0
[ ] ------------[ cut here ]------------
[ ] WARNING: CPU: 0 PID: 1 at /usr/src/linux-2.6/kernel/smp.c:374 smp_call_function_many+0xad/0x300()
[ ] Modules linked in:
[ ] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.13.0-rc3-01745-g848b0d0322cb-dirty #637
[ ] Hardware name: Supermicro X8DTN/X8DTN, BIOS 4.6.3 01/08/2010
[ ] 0000000000000009 ffff880236843be0 ffffffff8165c5f5 0000000000000000
[ ] ffff880236843c18 ffffffff81093d8c 0000000000000000 0000000000000000
[ ] ffffffff81ccd1a0 ffffffff810ca951 0000000000000000 ffff880236843c28
[ ] Call Trace:
[ ] [<ffffffff8165c5f5>] dump_stack+0x4e/0x7a
[ ] [<ffffffff81093d8c>] warn_slowpath_common+0x8c/0xc0
[ ] [<ffffffff810ca951>] ? sched_clock_tick+0x1/0xa0
[ ] [<ffffffff81093dda>] warn_slowpath_null+0x1a/0x20
[ ] [<ffffffff8110b72d>] smp_call_function_many+0xad/0x300
[ ] [<ffffffff8104f200>] ? arch_unregister_cpu+0x30/0x30
[ ] [<ffffffff8104f200>] ? arch_unregister_cpu+0x30/0x30
[ ] [<ffffffff810ca951>] ? sched_clock_tick+0x1/0xa0
[ ] [<ffffffff8110ba96>] smp_call_function+0x46/0x80
[ ] [<ffffffff8104f200>] ? arch_unregister_cpu+0x30/0x30
[ ] [<ffffffff8110bb3c>] on_each_cpu+0x3c/0xa0
[ ] [<ffffffff810ca950>] ? sched_clock_idle_sleep_event+0x20/0x20
[ ] [<ffffffff810ca951>] ? sched_clock_tick+0x1/0xa0
[ ] [<ffffffff8104f964>] text_poke_bp+0x64/0xd0
[ ] [<ffffffff810ca950>] ? sched_clock_idle_sleep_event+0x20/0x20
[ ] [<ffffffff8104ccde>] arch_jump_label_transform+0xae/0x130
[ ] [<ffffffff8115a3cf>] __jump_label_update+0x5f/0x80
[ ] [<ffffffff8115a48d>] jump_label_update+0x9d/0xb0
[ ] [<ffffffff8115aa6d>] static_key_slow_inc+0x9d/0xb0
[ ] [<ffffffff810ca775>] clear_sched_clock_stable+0x15/0x20
[ ] [<ffffffff810503b3>] mark_tsc_unstable+0x23/0x70
[ ] [<ffffffff810772cb>] check_tsc_sync_source+0x14b/0x150
[ ] [<ffffffff81076612>] native_cpu_up+0x3a2/0x890
[ ] [<ffffffff810941cb>] _cpu_up+0xdb/0x160
[ ] [<ffffffff810942c9>] cpu_up+0x79/0x90
[ ] [<ffffffff81d0af6b>] smp_init+0x60/0x8c
[ ] [<ffffffff81cebf42>] kernel_init_freeable+0x8c/0x197
[ ] [<ffffffff8164e320>] ? rest_init+0xd0/0xd0
[ ] [<ffffffff8164e32e>] kernel_init+0xe/0x130
[ ] [<ffffffff8166beec>] ret_from_fork+0x7c/0xb0
[ ] [<ffffffff8164e320>] ? rest_init+0xd0/0xd0
[ ] ---[ end trace 6ff1df5620c49d26 ]---
[ ] tsc: Marking TSC unstable due to check_tsc_sync_source failed
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
---
kernel/sched/clock.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
--- a/kernel/sched/clock.c
+++ b/kernel/sched/clock.c
@@ -59,6 +59,7 @@
#include <linux/ktime.h>
#include <linux/sched.h>
#include <linux/static_key.h>
+#include <linux/workqueue.h>
/*
* Scheduler clock - returns current time in nanosec units.
@@ -90,13 +91,20 @@ void set_sched_clock_stable(void)
static_key_slow_dec(&__sched_clock_stable);
}
-void clear_sched_clock_stable(void)
+static void __clear_sched_clock_stable(struct work_struct *work)
{
/* XXX worry about clock continuity */
if (sched_clock_stable())
static_key_slow_inc(&__sched_clock_stable);
}
+static DECLARE_WORK(sched_clock_work, __clear_sched_clock_stable);
+
+void clear_sched_clock_stable(void)
+{
+ schedule_work(&sched_clock_work);
+}
+
struct sched_clock_data {
u64 tick_raw;
u64 tick_gtod;
next prev parent reply other threads:[~2013-12-12 14:24 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-12 14:08 [PATCH 00/15] cleanups and optimizations Peter Zijlstra
2013-12-12 14:08 ` [PATCH 01/15] x86, acpi, idle: Restructure the mwait idle routines Peter Zijlstra
2013-12-19 20:09 ` [tip:x86/idle] " tip-bot for Peter Zijlstra
2013-12-19 20:13 ` H. Peter Anvin
2013-12-19 20:16 ` Peter Zijlstra
2013-12-12 14:08 ` [PATCH 02/15] sched, preempt: Fixup missed PREEMPT_NEED_RESCHED folding Peter Zijlstra
2013-12-12 14:08 ` [PATCH 03/15] preempt, locking: Rework local_bh_{dis,en}able() Peter Zijlstra
2013-12-12 14:08 ` [PATCH 04/15] locking: Optimize lock_bh functions Peter Zijlstra
2013-12-12 14:08 ` [PATCH 05/15] sched, net: Clean up preempt_enable_no_resched() abuse Peter Zijlstra
2013-12-12 14:08 ` [PATCH 06/15] sched, net: Fixup busy_loop_us_clock() Peter Zijlstra
2013-12-12 14:08 ` [PATCH 07/15] sched, thermal: Clean up preempt_enable_no_resched() abuse Peter Zijlstra
2013-12-12 14:08 ` [PATCH 08/15] preempt: Take away preempt_enable_no_resched() from modules Peter Zijlstra
2013-12-12 14:08 ` [PATCH 09/15] x86: Use mul_u64_u32_shr() for native_sched_clock() Peter Zijlstra
2013-12-12 14:08 ` [PATCH 10/15] x86: Move some code around Peter Zijlstra
2013-12-12 14:08 ` [PATCH 11/15] x86: Rewrite cyc2ns to avoid the need to disable IRQs Peter Zijlstra
2014-06-16 17:13 ` Viresh Kumar
2014-06-17 12:15 ` Peter Zijlstra
2014-06-17 12:42 ` Viresh Kumar
2014-06-17 16:32 ` Mauro
2014-06-17 12:47 ` Mauro
2013-12-12 14:08 ` [PATCH 12/15] sched: Remove local_irq_disable() from the clocks Peter Zijlstra
2013-12-12 14:08 ` [PATCH 13/15] sched: Use a static_key for sched_clock_stable Peter Zijlstra
2014-01-21 22:28 ` Sasha Levin
2014-01-22 10:45 ` Peter Zijlstra
2014-01-22 11:59 ` Peter Zijlstra
2014-01-23 1:53 ` Dave Young
2014-01-23 16:46 ` [tip:sched/urgent] sched/clock: Fixup early initialization tip-bot for Peter Zijlstra
2014-01-22 12:00 ` [PATCH 13/15] sched: Use a static_key for sched_clock_stable Markus Trippelsdorf
2014-01-22 12:07 ` Peter Zijlstra
2014-01-22 12:16 ` Peter Zijlstra
2014-01-22 12:26 ` Markus Trippelsdorf
2014-01-22 12:30 ` Peter Zijlstra
2014-01-22 13:14 ` Markus Trippelsdorf
2014-01-22 14:26 ` Sasha Levin
2014-01-22 18:35 ` Markus Trippelsdorf
2014-01-22 18:42 ` Peter Zijlstra
2014-01-22 18:45 ` Markus Trippelsdorf
2014-01-22 19:17 ` Josh Boyer
2014-01-22 19:09 ` Markus Trippelsdorf
2014-01-22 19:12 ` Markus Trippelsdorf
2014-01-22 20:16 ` Peter Zijlstra
2014-01-22 21:08 ` Peter Zijlstra
2014-01-22 21:17 ` Markus Trippelsdorf
2014-01-23 9:48 ` Peter Zijlstra
2014-01-23 10:01 ` Markus Trippelsdorf
2014-01-23 10:04 ` Peter Zijlstra
2014-01-23 13:32 ` Josh Boyer
2014-01-23 16:46 ` [tip:sched/urgent] sched/x86/tsc: Initialize multiplier to 0 tip-bot for Peter Zijlstra
2014-01-22 23:53 ` [PATCH 13/15] sched: Use a static_key for sched_clock_stable Josh Boyer
2014-01-23 1:53 ` Dave Young
2014-01-23 2:10 ` Dave Young
2014-01-23 16:56 ` Peter Zijlstra
2014-01-24 3:15 ` Dave Young
2014-01-24 7:58 ` Ingo Molnar
2014-01-22 17:14 ` Peter Zijlstra
2014-01-22 22:31 ` Sasha Levin
2013-12-12 14:08 ` Peter Zijlstra [this message]
2013-12-12 14:08 ` [PATCH 15/15] x86: Avoid a runtime condition in native_sched_clock() Peter Zijlstra
2013-12-13 3:30 ` [PATCH 00/15] cleanups and optimizations Mike Galbraith
2013-12-13 10:49 ` Eliezer Tamir
2013-12-13 13:56 ` Peter Zijlstra
2013-12-16 17:48 ` Eliezer Tamir
2013-12-17 13:32 ` Peter Zijlstra
2013-12-17 14:03 ` Eliezer Tamir
2013-12-17 15:13 ` Peter Zijlstra
2013-12-17 18:19 ` Eliezer Tamir
2013-12-17 22:11 ` Thomas Gleixner
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