From: Waiman Long <longman@redhat.com>
To: Davidlohr Bueso <dave@stgolabs.net>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Will Deacon <will.deacon@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-kernel@vger.kernel.org, x86@kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Tim Chen <tim.c.chen@linux.intel.com>
Subject: Re: [PATCH-tip v2 06/12] locking/rwsem: Wake up almost all readers in wait queue
Date: Wed, 10 Apr 2019 13:53:06 -0400 [thread overview]
Message-ID: <f5facb9a-59ce-d59e-9e7d-4c167cf0ca32@redhat.com> (raw)
In-Reply-To: <20190410172254.ivgcgehjhqgwjtda@linux-r8p5>
On 04/10/2019 01:22 PM, Davidlohr Bueso wrote:
> On Wed, 10 Apr 2019, Waiman Long wrote:
>> There are 2 major reasons why there is a limit.
>>
>> 1) It will be unfair to the task that needs to spend so much of its own
>> CPU time to wake up too many readers.
>
> This has never been a problem before.
>
In real workloads, you seldom have more than a couple dozens of readers
waiting in the queue.
Cheers,
Longman
next prev parent reply other threads:[~2019-04-10 17:53 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-05 19:21 [PATCH-tip v2 00/12] locking/rwsem: Rwsem rearchitecture part 2 Waiman Long
2019-04-05 19:21 ` [PATCH-tip v2 01/12] locking/rwsem: Implement a new locking scheme Waiman Long
2019-04-05 19:21 ` [PATCH-tip v2 02/12] locking/rwsem: Implement lock handoff to prevent lock starvation Waiman Long
2019-04-10 15:07 ` Peter Zijlstra
2019-04-10 15:28 ` Waiman Long
2019-04-10 15:10 ` Peter Zijlstra
2019-04-10 15:29 ` Waiman Long
2019-04-10 18:44 ` Peter Zijlstra
2019-04-11 2:25 ` Waiman Long
2019-04-11 7:16 ` Peter Zijlstra
2019-04-05 19:21 ` [PATCH-tip v2 03/12] locking/rwsem: Remove rwsem_wake() wakeup optimization Waiman Long
2019-04-10 18:38 ` Davidlohr Bueso
2019-04-05 19:21 ` [PATCH-tip v2 04/12] locking/rwsem: Make rwsem_spin_on_owner() return owner state Waiman Long
2019-04-05 19:21 ` [PATCH-tip v2 05/12] locking/rwsem: Ensure an RT task will not spin on reader Waiman Long
2019-04-05 19:21 ` [PATCH-tip v2 06/12] locking/rwsem: Wake up almost all readers in wait queue Waiman Long
2019-04-10 16:50 ` Davidlohr Bueso
2019-04-10 17:08 ` Waiman Long
2019-04-10 17:22 ` Davidlohr Bueso
2019-04-10 17:31 ` Davidlohr Bueso
2019-04-10 17:54 ` Waiman Long
2019-04-10 17:53 ` Waiman Long [this message]
2019-04-05 19:21 ` [PATCH-tip v2 07/12] locking/rwsem: Enable readers spinning on writer Waiman Long
2019-04-05 19:21 ` [PATCH-tip v2 08/12] locking/rwsem: Enable time-based spinning on reader-owned rwsem Waiman Long
2019-04-05 19:21 ` [PATCH-tip v2 09/12] locking/rwsem: Add more rwsem owner access helpers Waiman Long
2019-04-05 19:21 ` [PATCH-tip v2 10/12] locking/rwsem: Guard against making count negative Waiman Long
2019-04-05 19:21 ` [PATCH-tip v2 11/12] locking/rwsem: Merge owner into count on x86-64 Waiman Long
2019-04-05 19:21 ` [PATCH-tip v2 12/12] locking/rwsem: Remove redundant computation of writer lock word Waiman Long
2019-04-05 23:27 ` [PATCH-tip v2 00/12] locking/rwsem: Rwsem rearchitecture part 2 Linus Torvalds
2019-04-10 10:00 ` Ingo Molnar
2019-04-10 12:38 ` Waiman Long
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