From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, mingo@kernel.org,
jiangshanlai@gmail.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, tglx@linutronix.de, rostedt@goodmis.org,
dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com,
oleg@redhat.com, joel@joelfernandes.org
Subject: Re: [PATCH tip/core/rcu 13/22] rcu: Fix grace-period hangs due to race with CPU offline
Date: Tue, 26 Jun 2018 13:40:33 -0700 [thread overview]
Message-ID: <20180626204033.GM3593@linux.vnet.ibm.com> (raw)
In-Reply-To: <20180626194807.GQ2494@hirez.programming.kicks-ass.net>
On Tue, Jun 26, 2018 at 09:48:07PM +0200, Peter Zijlstra wrote:
> On Tue, Jun 26, 2018 at 11:19:37AM -0700, Paul E. McKenney wrote:
> > The initial reason for ____cacheline_internodealigned_in_smp was that
> > some of the fields can be accessed by random CPUs, while others are
> > used more locally, give or take our usual contention over the handling
> > of CPU numbers. ;-)
>
> So that whole internode thing only matters for the insane VSMP case,
> where they take node to mean a cluster node, not a numa node.
>
> VSMP is a networked shared memory machine where, by necessity, the MESI
> protocol operates on page granularity.
>
> In general I tend to completely and utterly ignore that and let the VSMP
> people worry about things.
Sounds like I should queue a patch to replace them all with
____cacheline_aligned_in_smp.
Any objections?
(I don't consider this an emergency, so I would queue it for the merge
window following the next one.)
Thanx, Paul
next prev parent reply other threads:[~2018-06-26 20:38 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-26 0:20 [PATCH tip/core/rcu 0/22] Grace-period fixes for v4.19 Paul E. McKenney
2018-06-26 17:10 ` [PATCH tip/core/rcu 01/22] rcu: Clean up handling of tasks blocked across full-rcu_node offline Paul E. McKenney
2018-06-26 17:10 ` [PATCH tip/core/rcu 02/22] rcu: Fix an obsolete ->qsmaskinit comment Paul E. McKenney
2018-06-26 17:10 ` [PATCH tip/core/rcu 03/22] rcu: Make rcu_init_new_rnp() stop upon already-set bit Paul E. McKenney
2018-06-26 17:10 ` [PATCH tip/core/rcu 04/22] rcu: Make rcu_report_unblock_qs_rnp() warn on violated preconditions Paul E. McKenney
2018-06-26 17:10 ` [PATCH tip/core/rcu 05/22] rcu: Fix typo and add additional debug Paul E. McKenney
2018-06-26 17:10 ` [PATCH tip/core/rcu 06/22] rcu: Replace smp_wmb() with smp_store_release() for stall check Paul E. McKenney
2018-06-26 17:10 ` [PATCH tip/core/rcu 07/22] rcu: Prevent useless FQS scan after all CPUs have checked in Paul E. McKenney
2018-06-26 17:10 ` [PATCH tip/core/rcu 08/22] rcu: Suppress false-positive offline-CPU lockdep-RCU splat Paul E. McKenney
2018-06-26 17:10 ` [PATCH tip/core/rcu 09/22] rcu: Suppress false-positive preempted-task splats Paul E. McKenney
2018-06-26 17:10 ` [PATCH tip/core/rcu 10/22] rcu: Suppress more involved " Paul E. McKenney
2018-06-26 17:10 ` [PATCH tip/core/rcu 11/22] rcu: Suppress false-positive splats from mid-init task resume Paul E. McKenney
2018-06-26 17:10 ` [PATCH tip/core/rcu 12/22] rcu: Fix grace-period hangs " Paul E. McKenney
2018-06-26 17:10 ` [PATCH tip/core/rcu 13/22] rcu: Fix grace-period hangs due to race with CPU offline Paul E. McKenney
2018-06-26 17:44 ` Peter Zijlstra
2018-06-26 18:19 ` Paul E. McKenney
2018-06-26 19:48 ` Peter Zijlstra
2018-06-26 20:40 ` Paul E. McKenney [this message]
2018-06-26 17:51 ` Peter Zijlstra
2018-06-26 18:29 ` Paul E. McKenney
2018-06-26 20:07 ` Peter Zijlstra
2018-06-26 20:26 ` Paul E. McKenney
2018-06-26 20:32 ` Peter Zijlstra
2018-06-26 23:40 ` Paul E. McKenney
2018-06-27 8:33 ` Peter Zijlstra
2018-06-27 15:43 ` Paul E. McKenney
2018-06-27 9:11 ` Peter Zijlstra
2018-06-27 9:46 ` Peter Zijlstra
2018-06-27 15:57 ` Paul E. McKenney
2018-06-27 17:51 ` Peter Zijlstra
2018-06-28 5:13 ` Paul E. McKenney
2018-06-28 8:26 ` Peter Zijlstra
2018-06-28 12:38 ` Paul E. McKenney
2018-06-28 13:06 ` Peter Zijlstra
2018-06-29 4:30 ` Paul E. McKenney
2018-06-27 15:53 ` Paul E. McKenney
2018-06-26 17:10 ` [PATCH tip/core/rcu 14/22] rcu: Add RCU-preempt check for waiting on newly onlined CPU Paul E. McKenney
2018-06-26 17:10 ` [PATCH tip/core/rcu 15/22] rcu: Move grace-period pre-init delay after pre-init Paul E. McKenney
2018-06-26 17:10 ` [PATCH tip/core/rcu 16/22] rcu: Remove failsafe check for lost quiescent state Paul E. McKenney
2018-06-26 17:10 ` [PATCH tip/core/rcu 17/22] rcutorture: Change units of onoff_interval to jiffies Paul E. McKenney
2018-06-26 17:10 ` [PATCH tip/core/rcu 18/22] rcu: Remove CPU-hotplug failsafe from force-quiescent-state code path Paul E. McKenney
2018-06-26 17:10 ` [PATCH tip/core/rcu 19/22] rcu: Add up-tree information to dump_blkd_tasks() diagnostics Paul E. McKenney
2018-06-26 17:10 ` [PATCH tip/core/rcu 20/22] rcu: Add CPU online/offline state to dump_blkd_tasks() Paul E. McKenney
2018-06-26 17:10 ` [PATCH tip/core/rcu 21/22] rcu: Record ->gp_state for both phases of grace-period initialization Paul E. McKenney
2018-06-26 17:10 ` [PATCH tip/core/rcu 22/22] rcu: Add diagnostics for offline CPUs failing to report QS Paul E. McKenney
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