From: Waiman Long <waiman.long@hpe.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Wanpeng Li <kernellwp@gmail.com>, <linux-kernel@vger.kernel.org>,
Wanpeng Li <wanpeng.li@hotmail.com>,
Ingo Molnar <mingo@kernel.org>,
Davidlohr Bueso <dave@stgolabs.net>
Subject: Re: [PATCH v2] locking/pvqspinlock: restore/set vcpu_hashed state after failing adaptive locking spinning
Date: Thu, 14 Jul 2016 10:56:30 -0400 [thread overview]
Message-ID: <5787A81E.7080700@hpe.com> (raw)
In-Reply-To: <20160714112648.GG30909@twins.programming.kicks-ass.net>
On 07/14/2016 07:26 AM, Peter Zijlstra wrote:
> On Thu, Jul 14, 2016 at 04:15:56PM +0800, Wanpeng Li wrote:
>> In this case, lock holder inserts the pv_node of queue head into the
>> hash table and set _Q_SLOW_VAL unnecessary. This patch avoids it by
>> restoring/setting vcpu_halted state after failing adaptive locking
> ^^^^^^
>> spinning.
>>
>> - WRITE_ONCE(pn->state, vcpu_halted);
>> + WRITE_ONCE(pn->state, vcpu_hashed);
> ^^^^^^
>
> The Changelog meant so say vcpu_hashed, surely?
Do you have chance to review the "Fix missed PV wakeup & support PPC"
patch (https://lkml.org/lkml/2016/5/31/677) that I had sent out a while
ago? That patch addressed a similar pv_hash leakage and collision problem.
Cheers,
Longman
next prev parent reply other threads:[~2016-07-14 14:56 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-14 8:15 [PATCH v2] locking/pvqspinlock: restore/set vcpu_hashed state after failing adaptive locking spinning Wanpeng Li
2016-07-14 11:26 ` Peter Zijlstra
2016-07-14 11:28 ` Wanpeng Li
2016-07-14 14:56 ` Waiman Long [this message]
2016-08-10 18:05 ` [tip:locking/core] locking/pvqspinlock: Fix double hash race tip-bot for Wanpeng Li
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