From: Frederic Weisbecker <frederic@kernel.org> To: Alex Belits <abelits@marvell.com> Cc: "rostedt@goodmis.org" <rostedt@goodmis.org>, "mingo@kernel.org" <mingo@kernel.org>, "peterz@infradead.org" <peterz@infradead.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Prasun Kapoor <pkapoor@marvell.com>, "tglx@linutronix.de" <tglx@linutronix.de>, "linux-api@vger.kernel.org" <linux-api@vger.kernel.org>, "linux-mm@vger.kernel.org" <linux-mm@vger.kernel.org>, "linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org> Subject: Re: [PATCH 03/12] task_isolation: userspace hard isolation from kernel Date: Fri, 6 Mar 2020 17:00:36 +0100 Message-ID: <20200306160035.GD8590@lenoir> (raw) In-Reply-To: <36d84b8dd168a38e6a56549dedc15dd6ebf8c09e.camel@marvell.com> On Wed, Mar 04, 2020 at 04:07:12PM +0000, Alex Belits wrote: > +#ifdef CONFIG_TASK_ISOLATION > +int try_stop_full_tick(void) > +{ > + int cpu = smp_processor_id(); > + struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched); > + > + /* For an unstable clock, we should return a permanent error code. */ > + if (atomic_read(&tick_dep_mask) & TICK_DEP_MASK_CLOCK_UNSTABLE) > + return -EINVAL; > + > + if (!can_stop_full_tick(cpu, ts)) > + return -EAGAIN; Note that the stop_tick naming in nohz can be misleading. It means we actually leave the periodic mode and we enter in dynamic tick mode. In practice it means that the tick is delayed until the next event, which in the worst case may well be in 1 ms and in the best case never. So what you probably want to check instead is whether the tick has been entirely stopped (ie: we called hrtimer_cancel(&ts->sched_timer)). Thanks. > + > + tick_nohz_stop_sched_tick(ts, cpu); > + return 0; > +} > +#endif > + > static bool can_stop_idle_tick(int cpu, struct tick_sched *ts) > { > /* > -- > 2.20.1 >
next prev parent reply index Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-03-04 16:01 [PATCH 00/12] "Task_isolation" mode Alex Belits 2020-03-04 16:03 ` [PATCH 01/12] task_isolation: vmstat: add quiet_vmstat_sync function Alex Belits 2020-03-04 16:04 ` [PATCH 02/12] task_isolation: vmstat: add vmstat_idle function Alex Belits 2020-03-04 16:07 ` [PATCH 03/12] task_isolation: userspace hard isolation from kernel Alex Belits 2020-03-05 18:33 ` Frederic Weisbecker 2020-03-08 5:32 ` [EXT] " Alex Belits 2020-04-28 14:12 ` Marcelo Tosatti 2020-03-06 15:26 ` Frederic Weisbecker 2020-03-08 6:06 ` [EXT] " Alex Belits 2020-03-06 16:00 ` Frederic Weisbecker [this message] 2020-03-08 7:16 ` Alex Belits 2020-03-04 16:08 ` [PATCH 04/12] task_isolation: Add task isolation hooks to arch-independent code Alex Belits 2020-03-04 16:09 ` [PATCH 05/12] task_isolation: arch/x86: enable task isolation functionality Alex Belits 2020-03-04 16:10 ` [PATCH 06/12] task_isolation: arch/arm64: " Alex Belits 2020-03-04 16:31 ` Mark Rutland 2020-03-08 4:48 ` [EXT] " Alex Belits 2020-03-04 16:11 ` [PATCH 07/12] task_isolation: arch/arm: " Alex Belits 2020-03-04 16:12 ` [PATCH 08/12] task_isolation: don't interrupt CPUs with tick_nohz_full_kick_cpu() Alex Belits 2020-03-06 16:03 ` Frederic Weisbecker 2020-03-08 7:28 ` [EXT] " Alex Belits 2020-03-09 2:38 ` Frederic Weisbecker 2020-03-04 16:13 ` [PATCH 09/12] task_isolation: net: don't flush backlog on CPUs running isolated tasks Alex Belits 2020-03-04 16:14 ` [PATCH 10/12] task_isolation: ringbuffer: don't interrupt CPUs running isolated tasks on buffer resize Alex Belits 2020-03-04 16:15 ` [PATCH 11/12] task_isolation: kick_all_cpus_sync: don't kick isolated cpus Alex Belits 2020-03-06 15:34 ` Frederic Weisbecker 2020-03-08 6:48 ` [EXT] " Alex Belits 2020-03-09 2:28 ` Frederic Weisbecker 2020-03-04 16:16 ` [PATCH 12/12] task_isolation: CONFIG_TASK_ISOLATION prevents distribution of jobs to non-housekeeping CPUs Alex Belits 2020-03-08 3:42 ` [PATCH v2 00/12] "Task_isolation" mode Alex Belits 2020-03-08 3:44 ` [PATCH v2 01/12] task_isolation: vmstat: add quiet_vmstat_sync function Alex Belits 2020-03-08 3:46 ` [PATCH v2 02/12] task_isolation: vmstat: add vmstat_idle function Alex Belits 2020-03-08 3:47 ` [PATCH v2 03/12] task_isolation: userspace hard isolation from kernel Alex Belits [not found] ` <20200307214254.7a8f6c22@hermes.lan> 2020-03-08 7:33 ` [EXT] " Alex Belits 2020-03-27 8:42 ` Marta Rybczynska 2020-04-06 4:31 ` Kevyn-Alexandre Paré 2020-04-06 4:43 ` Kevyn-Alexandre Paré 2020-03-08 3:48 ` [PATCH v2 04/12] task_isolation: Add task isolation hooks to arch-independent code Alex Belits 2020-03-08 3:49 ` [PATCH v2 05/12] task_isolation: arch/x86: enable task isolation functionality Alex Belits 2020-03-08 3:50 ` [PATCH v2 06/12] task_isolation: arch/arm64: " Alex Belits 2020-03-09 16:59 ` Mark Rutland 2020-03-08 3:52 ` [PATCH v2 07/12] task_isolation: arch/arm: " Alex Belits 2020-03-08 3:53 ` [PATCH v2 08/12] task_isolation: don't interrupt CPUs with tick_nohz_full_kick_cpu() Alex Belits 2020-03-08 3:54 ` [PATCH v2 09/12] task_isolation: net: don't flush backlog on CPUs running isolated tasks Alex Belits 2020-03-08 3:55 ` [PATCH v2 10/12] task_isolation: ringbuffer: don't interrupt CPUs running isolated tasks on buffer resize Alex Belits 2020-04-06 4:27 ` Kevyn-Alexandre Paré 2020-03-08 3:56 ` [PATCH v2 11/12] task_isolation: kick_all_cpus_sync: don't kick isolated cpus Alex Belits 2020-03-08 3:57 ` [PATCH v2 12/12] task_isolation: CONFIG_TASK_ISOLATION prevents distribution of jobs to non-housekeeping CPUs Alex Belits 2020-04-09 15:09 ` [PATCH v3 00/13] "Task_isolation" mode Alex Belits 2020-04-09 15:15 ` [PATCH 01/13] task_isolation: vmstat: add quiet_vmstat_sync function Alex Belits 2020-04-09 15:16 ` [PATCH 02/13] task_isolation: vmstat: add vmstat_idle function Alex Belits 2020-04-09 15:17 ` [PATCH v3 03/13] task_isolation: add instruction synchronization memory barrier Alex Belits 2020-04-15 12:44 ` Mark Rutland 2020-04-19 5:02 ` [EXT] " Alex Belits 2020-04-20 12:23 ` Will Deacon 2020-04-20 12:36 ` Mark Rutland 2020-04-20 13:55 ` Will Deacon 2020-04-21 7:41 ` Will Deacon 2020-04-20 12:45 ` Mark Rutland 2020-04-09 15:20 ` [PATCH v3 04/13] task_isolation: userspace hard isolation from kernel Alex Belits 2020-04-09 18:00 ` Andy Lutomirski 2020-04-19 5:07 ` Alex Belits 2020-04-09 15:21 ` [PATCH 05/13] task_isolation: Add task isolation hooks to arch-independent code Alex Belits 2020-04-09 15:22 ` [PATCH 06/13] task_isolation: arch/x86: enable task isolation functionality Alex Belits 2020-04-09 15:23 ` [PATCH v3 07/13] task_isolation: arch/arm64: " Alex Belits 2020-04-22 12:08 ` Catalin Marinas 2020-04-09 15:24 ` [PATCH v3 08/13] task_isolation: arch/arm: " Alex Belits 2020-04-09 15:25 ` [PATCH v3 09/13] task_isolation: don't interrupt CPUs with tick_nohz_full_kick_cpu() Alex Belits 2020-04-09 15:26 ` [PATCH v3 10/13] task_isolation: net: don't flush backlog on CPUs running isolated tasks Alex Belits 2020-04-09 15:27 ` [PATCH v3 11/13] task_isolation: ringbuffer: don't interrupt CPUs running isolated tasks on buffer resize Alex Belits 2020-04-09 15:27 ` [PATCH v3 12/13] task_isolation: kick_all_cpus_sync: don't kick isolated cpus Alex Belits 2020-04-09 15:28 ` [PATCH v3 13/13] task_isolation: CONFIG_TASK_ISOLATION prevents distribution of jobs to non-housekeeping CPUs Alex Belits
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