From: Paolo Bonzini <pbonzini@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>,
Josh Don <joshdon@google.com>,
g@hirez.programming.kicks-ass.net
Cc: Ingo Molnar <mingo@redhat.com>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
Eric Dumazet <edumazet@google.com>,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
kvm@vger.kernel.org, Xi Wang <xii@google.com>
Subject: Re: [PATCH 1/3] sched: better handling for busy polling loops
Date: Fri, 23 Oct 2020 11:33:09 +0200 [thread overview]
Message-ID: <ef03ceac-e7dc-f17a-8d4d-28adf90f6ded@redhat.com> (raw)
In-Reply-To: <20201023071905.GL2611@hirez.programming.kicks-ass.net>
On 23/10/20 09:19, Peter Zijlstra wrote:
>> + /*
>> + * preemption needs to be kept disabled between prepare_to_busy_poll()
>> + * and end_busy_poll().
>> + */
>> + BUG_ON(preemptible());
>> + if (allow_resched)
>> + preempt_enable();
>> + else
>> + preempt_enable_no_resched();
> NAK on @allow_resched
>
Since KVM is the one passing false, indeed I see no reason for the
argument; you can just use preempt_enable(). There is no impact for
example on the tracking of how much time was spent polling; that
ktime_get() for the end of the polling period is done before calling
end_busy_poll().
Paolo
next prev parent reply other threads:[~2020-10-23 9:33 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-23 3:29 [PATCH 1/3] sched: better handling for busy polling loops Josh Don
2020-10-23 3:29 ` [PATCH 2/3] kvm: better handling for kvm halt polling Josh Don
2020-10-23 3:29 ` [PATCH 3/3] net: better handling for network busy poll Josh Don
2020-10-23 7:19 ` [PATCH 1/3] sched: better handling for busy polling loops Peter Zijlstra
2020-10-23 9:33 ` Paolo Bonzini [this message]
2020-10-27 23:58 ` Josh Don
2020-10-23 7:33 ` Vincent Guittot
2020-10-23 17:48 ` Jakub Kicinski
2020-10-28 0:29 ` Josh Don
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