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From: Peter Zijlstra <peterz@infradead.org>
To: K Prateek Nayak <kprateek.nayak@amd.com>
Cc: Steve Wahl <steve.wahl@hpe.com>, Russ Anderson <rja@hpe.com>,
	Dimitri Sivanich <sivanich@hpe.com>,
	Ingo Molnar <mingo@redhat.com>,
	Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
	Valentin Schneider <vschneid@redhat.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] sched/topology: improve topology_span_sane speed
Date: Tue, 15 Oct 2024 13:05:44 +0200	[thread overview]
Message-ID: <20241015110544.GQ16066@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <60473622-e6f9-561b-a269-9da64add4966@amd.com>

On Tue, Oct 15, 2024 at 03:50:49PM +0530, K Prateek Nayak wrote:

> > +	masks = kmalloc_array(num_possible_cpus(), sizeof(struct cpumask *), GFP_KERNEL);
> > +	if (!masks)
> > +		return ret;
> 
> That looks like a very large array that seems unnecessary. Instead, is
> it possible to use "tl->mask(id)" down blow to check for equality? (I'll
> elaborate more below)

drive-by comments, haven't got time atm to read this, but
num_possible_cpus() is wrong, this should be nr_cpu_ids.

The CPU mask must not be assumed dense.

  reply	other threads:[~2024-10-15 11:05 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-10 15:51 [PATCH] sched/topology: improve topology_span_sane speed Steve Wahl
2024-10-15 10:20 ` K Prateek Nayak
2024-10-15 11:05   ` Peter Zijlstra [this message]
2024-10-15 22:32     ` Steve Wahl
2024-10-15 22:19   ` Steve Wahl
2024-10-15 14:37 ` Valentin Schneider
2024-10-16  8:10   ` Valentin Schneider
2024-10-16 16:08     ` Steve Wahl
2024-10-25 15:06   ` Steve Wahl
2024-10-25 17:21     ` Valentin Schneider
2024-10-18 11:35 ` Vishal Chourasia
2024-10-21 16:20   ` Steve Wahl
2024-10-23 13:19     ` Vishal Chourasia
2024-10-23 15:16 ` Shrikanth Hegde
2024-10-29 17:34 ` samir
2024-11-01 20:05   ` Steve Wahl

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