diff for duplicates of <20170816162731.GA22978@linux.vnet.ibm.com> diff --git a/a/1.txt b/N1/1.txt index c4622a6..1c0e7d6 100644 --- a/a/1.txt +++ b/N1/1.txt @@ -59,24 +59,23 @@ task_struct ->state field. The immediately preceding dmesg line is as follows: -[ 1602.063851] (detected by 53, t=2603 jiffies, g=7275, c=7274, q=608) +[ 1602.063851] (detected by 53, t&03 jiffies, gr75, cr74, q`8) In other words, the rcu_sched grace-period kthread has been starved for the entire duration of the current grace period, as shown by the -t=2603. +t&03. Lets turn now to the trace output, looking for the last bit of the rcu_sched task's activity: - rcu_sched-9 [054] d... 1576.030096: timer_start: timer=c0000007fae1bc20 function=process_timeout expires=4295094922 [timeout=1] cpu=54 idx=0 flags= - ksoftirqd/53-276 [053] ..s. 1576.030097: rcu_invoke_callback: rcu_sched rhp=c000000fcf8c4eb0 func=__d_free + rcu_sched-9 [054] d... 1576.030096: timer_start: timerÀ000007fae1bc20 function=process_timeout expiresB95094922 [timeout=1] cpuT idx=0 flags ksoftirqd/53-276 [053] ..s. 1576.030097: rcu_invoke_callback: rcu_sched rhpÀ00000fcf8c4eb0 func=__d_free rcu_sched-9 [054] d... 1576.030097: rcu_utilization: Start context switch - ksoftirqd/53-276 [053] ..s. 1576.030098: rcu_invoke_callback: rcu_sched rhp=c000000fcff74ee0 func=proc_i_callback + ksoftirqd/53-276 [053] ..s. 1576.030098: rcu_invoke_callback: rcu_sched rhpÀ00000fcff74ee0 func=proc_i_callback rcu_sched-9 [054] d... 1576.030098: rcu_grace_period: rcu_sched 7275 cpuqs rcu_sched-9 [054] d... 1576.030099: rcu_utilization: End context switch So this task set up a timer ("timer_start:") for one jiffy ("[timeout=1]", -but what is with "expires=4295094922"?) and blocked ("rcu_utilization: +but what is with "expiresB95094922"?) and blocked ("rcu_utilization: Start context switch" and "rcu_utilization: End context switch"), recording its CPU's quiescent state in the process ("rcu_grace_period: rcu_sched 7275 cpuqs"). @@ -89,8 +88,8 @@ to earlier uses of this timer by rcu_sched). So the timer never did fire. The next question is "what did CPU 054 do next?" We find it entering idle: <idle>-0 [054] d... 1576.030167: tick_stop: success=1 dependency=NONE - <idle>-0 [054] d... 1576.030167: hrtimer_cancel: hrtimer=c000000fff88c680 - <idle>-0 [054] d... 1576.030168: hrtimer_start: hrtimer=c000000fff88c680 function=tick_sched_timer expires=1610710000000 softexpires=1610710000000 + <idle>-0 [054] d... 1576.030167: hrtimer_cancel: hrtimerÀ00000fff88c680 + <idle>-0 [054] d... 1576.030168: hrtimer_start: hrtimerÀ00000fff88c680 function=tick_sched_timer expires\x1610710000000 softexpires\x1610710000000 <idle>-0 [054] d... 1576.030170: __tick_nohz_idle_enter: tick_nohz_stop_sched_tick: 34469831 <idle>-0 [054] d... 1576.030171: rcu_dyntick: Start 140000000000000 0 diff --git a/a/content_digest b/N1/content_digest index b69c150..1c51761 100644 --- a/a/content_digest +++ b/N1/content_digest @@ -10,21 +10,8 @@ "ref\020170816125617.GY7017@linux.vnet.ibm.com\0" "From\0Paul E. McKenney <paulmck@linux.vnet.ibm.com>\0" "Subject\0Re: RCU lockup issues when CONFIG_SOFTLOCKUP_DETECTOR=n - any one else seeing this?\0" - "Date\0Wed, 16 Aug 2017 09:27:31 -0700\0" - "To\0Michael Ellerman <mpe@ellerman.id.au>\0" - "Cc\0Jonathan Cameron <Jonathan.Cameron@huawei.com>" - dzickus@redhat.com - sfr@canb.auug.org.au - linuxarm@huawei.com - Nicholas Piggin <npiggin@gmail.com> - abdhalee@linux.vnet.ibm.com - tglx@linutronix.de - sparclinux@vger.kernel.org - akpm@linux-foundation.org - linuxppc-dev@lists.ozlabs.org - David Miller <davem@davemloft.net> - linux-arm-kernel@lists.infradead.org - " john.stultz@linaro.org\0" + "Date\0Wed, 16 Aug 2017 16:27:31 +0000\0" + "To\0linux-arm-kernel@lists.infradead.org\0" "\00:1\0" "b\0" "On Wed, Aug 16, 2017 at 05:56:17AM -0700, Paul E. McKenney wrote:\n" @@ -88,24 +75,23 @@ "\n" "The immediately preceding dmesg line is as follows:\n" "\n" - "[ 1602.063851] (detected by 53, t=2603 jiffies, g=7275, c=7274, q=608)\n" + "[ 1602.063851] (detected by 53, t&03 jiffies, gr75, cr74, q`8)\n" "\n" "In other words, the rcu_sched grace-period kthread has been starved\n" "for the entire duration of the current grace period, as shown by the\n" - "t=2603.\n" + "t&03.\n" "\n" "Lets turn now to the trace output, looking for the last bit of the\n" "rcu_sched task's activity:\n" "\n" - " rcu_sched-9 [054] d... 1576.030096: timer_start: timer=c0000007fae1bc20 function=process_timeout expires=4295094922 [timeout=1] cpu=54 idx=0 flags=\n" - " ksoftirqd/53-276 [053] ..s. 1576.030097: rcu_invoke_callback: rcu_sched rhp=c000000fcf8c4eb0 func=__d_free\n" + " rcu_sched-9 [054] d... 1576.030096: timer_start: timer\303\200000007fae1bc20 function=process_timeout expiresB95094922 [timeout=1] cpuT idx=0 flags ksoftirqd/53-276 [053] ..s. 1576.030097: rcu_invoke_callback: rcu_sched rhp\303\20000000fcf8c4eb0 func=__d_free\n" " rcu_sched-9 [054] d... 1576.030097: rcu_utilization: Start context switch\n" - " ksoftirqd/53-276 [053] ..s. 1576.030098: rcu_invoke_callback: rcu_sched rhp=c000000fcff74ee0 func=proc_i_callback\n" + " ksoftirqd/53-276 [053] ..s. 1576.030098: rcu_invoke_callback: rcu_sched rhp\303\20000000fcff74ee0 func=proc_i_callback\n" " rcu_sched-9 [054] d... 1576.030098: rcu_grace_period: rcu_sched 7275 cpuqs\n" " rcu_sched-9 [054] d... 1576.030099: rcu_utilization: End context switch\n" "\n" "So this task set up a timer (\"timer_start:\") for one jiffy (\"[timeout=1]\",\n" - "but what is with \"expires=4295094922\"?) and blocked (\"rcu_utilization:\n" + "but what is with \"expiresB95094922\"?) and blocked (\"rcu_utilization:\n" "Start context switch\" and \"rcu_utilization: End context switch\"),\n" "recording its CPU's quiescent state in the process (\"rcu_grace_period:\n" "rcu_sched 7275 cpuqs\").\n" @@ -118,8 +104,8 @@ "The next question is \"what did CPU 054 do next?\" We find it entering idle:\n" "\n" " <idle>-0 [054] d... 1576.030167: tick_stop: success=1 dependency=NONE\n" - " <idle>-0 [054] d... 1576.030167: hrtimer_cancel: hrtimer=c000000fff88c680\n" - " <idle>-0 [054] d... 1576.030168: hrtimer_start: hrtimer=c000000fff88c680 function=tick_sched_timer expires=1610710000000 softexpires=1610710000000\n" + " <idle>-0 [054] d... 1576.030167: hrtimer_cancel: hrtimer\303\20000000fff88c680\n" + " <idle>-0 [054] d... 1576.030168: hrtimer_start: hrtimer\303\20000000fff88c680 function=tick_sched_timer expires\02610710000000 softexpires\02610710000000\n" " <idle>-0 [054] d... 1576.030170: __tick_nohz_idle_enter: tick_nohz_stop_sched_tick: 34469831\n" " <idle>-0 [054] d... 1576.030171: rcu_dyntick: Start 140000000000000 0\n" "\n" @@ -134,4 +120,4 @@ "\n" "\t\t\t\t\t\t\tThanx, Paul" -cc4d0c418366d56697073a4eae86de47116c881d435c72b3e4242c28b92c0b07 +f64b9ea5f97973c2d4c19cae6f888f94c08df026db9ce9840188b289ce3e3fe7
diff --git a/a/content_digest b/N2/content_digest index b69c150..e2dbd61 100644 --- a/a/content_digest +++ b/N2/content_digest @@ -8,23 +8,10 @@ "ref\020170815154743.GK7017@linux.vnet.ibm.com\0" "ref\087wp63smwn.fsf@concordia.ellerman.id.au\0" "ref\020170816125617.GY7017@linux.vnet.ibm.com\0" - "From\0Paul E. McKenney <paulmck@linux.vnet.ibm.com>\0" - "Subject\0Re: RCU lockup issues when CONFIG_SOFTLOCKUP_DETECTOR=n - any one else seeing this?\0" + "From\0paulmck@linux.vnet.ibm.com (Paul E. McKenney)\0" + "Subject\0RCU lockup issues when CONFIG_SOFTLOCKUP_DETECTOR=n - any one else seeing this?\0" "Date\0Wed, 16 Aug 2017 09:27:31 -0700\0" - "To\0Michael Ellerman <mpe@ellerman.id.au>\0" - "Cc\0Jonathan Cameron <Jonathan.Cameron@huawei.com>" - dzickus@redhat.com - sfr@canb.auug.org.au - linuxarm@huawei.com - Nicholas Piggin <npiggin@gmail.com> - abdhalee@linux.vnet.ibm.com - tglx@linutronix.de - sparclinux@vger.kernel.org - akpm@linux-foundation.org - linuxppc-dev@lists.ozlabs.org - David Miller <davem@davemloft.net> - linux-arm-kernel@lists.infradead.org - " john.stultz@linaro.org\0" + "To\0linux-arm-kernel@lists.infradead.org\0" "\00:1\0" "b\0" "On Wed, Aug 16, 2017 at 05:56:17AM -0700, Paul E. McKenney wrote:\n" @@ -134,4 +121,4 @@ "\n" "\t\t\t\t\t\t\tThanx, Paul" -cc4d0c418366d56697073a4eae86de47116c881d435c72b3e4242c28b92c0b07 +d964b90dbde57841901f14cd17cbab7714fc4031ca05aa0f9286b5782ab9c2d0
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