linux-kernel - Re: [PATCH v5 1/4]: perf/core: use rb trees for pinned/flexible groups

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Date:   Tue, 18 Jul 2017 16:38:48 +0300
From:   Alexey Budankov <alexey.budankov@...ux.intel.com>
To:     Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Andi Kleen <ak@...ux.intel.com>, Kan Liang <kan.liang@...el.com>,
        Dmitri Prokhorov <Dmitry.Prohorov@...el.com>,
        Valery Cherepennikov <valery.cherepennikov@...el.com>,
        Mark Rutland <mark.rutland@....com>,
        David Carrillo-Cisneros <davidcc@...gle.com>,
        Stephane Eranian <eranian@...gle.com>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v5 1/4]: perf/core: use rb trees for pinned/flexible
 groups

Hi,

On 18.07.2017 15:02, Alexander Shishkin wrote:
> Alexey Budankov <alexey.budankov@...ux.intel.com> writes:
> 
>> +static void
>> +perf_event_groups_rotate(struct perf_event_groups *groups, int cpu)
>> +{
>> +	struct rb_node *node;
>> +	struct perf_event *node_event;
>> +
>> +	WARN_ON_ONCE(!groups);
> 
> This seems redundant.

Used that for debugging.

> 
>> +
>> +	list_rotate_left(&groups->list);
>> +
>> +	/* will replace rotation above in patch v5 3/4
>> +
>> +	node = groups->tree.rb_node;
>> +
>> +	while (node) {
>> +		node_event = container_of(node,
>> +				struct perf_event, group_node);
>> +
>> +		if (cpu < node_event->cpu) {
>> +			node = node->rb_left;
>> +		} else if (cpu > node_event->cpu) {
>> +			node = node->rb_right;
>> +		} else {
>> +			list_rotate_left(&node_event->group_list);
>> +			break;
>> +		}
>> +	}
>> +
>> +	*/
> 
> Please don't do this, it doesn't add clarity.

Accepted. Put it here just for review process simplification.

> 
>> +static int
>> +perf_event_groups_iterate(struct perf_event_groups *groups,
>> +		perf_event_groups_iterate_f callback, void *data)
>> +{
>> +	int ret = 0;
>> +	struct perf_event *event;
>> +
>> +	WARN_ON_ONCE(!groups);
>> +
>> +	list_for_each_entry(event, &groups->list, group_list_entry) {
>> +		ret = callback(event, data);
>> +		if (ret)
>> +			break;
>> +	}
>> +
>> +	/* will replace itration above in patch v5 4/4
>> +
>> +	for (node = rb_first(groups); node; node = rb_next(node)) {
>> +		node_event = container_of(node,	struct perf_event, group_node);
>> +		list_for_each_entry(event, &node_event->group_list,
>> +				group_list_entry) {
>> +			WARN_ON_ONCE(!(event->cpu == node_event->cpu));
>> +			ret = callback(event, data);
>> +			if (ret) {
>> +				return ret;
>> +			}
>> +		}
>> +	}
>> +
>> +	*/
> 
> Ditto.
> 
> Regards,
> --
> Alex
> 

Thanks,
Alexey