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Date:   Wed, 5 Apr 2023 10:14:49 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     David Dai <davidai@google.com>
Cc:     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>,
        Daniel Bristot de Oliveira <bristot@redhat.com>,
        Valentin Schneider <vschneid@redhat.com>,
        Saravana Kannan <saravanak@google.com>,
        kernel-team@android.com, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 1/6] sched/fair: Add util_guest for tasks
Message-ID: <20230405081449.GX4253@hirez.programming.kicks-ass.net>
References: <20230330224348.1006691-1-davidai@google.com>
 <20230330224348.1006691-2-davidai@google.com>
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On Thu, Mar 30, 2023 at 03:43:36PM -0700, David Dai wrote:
> @@ -499,6 +509,7 @@ struct sched_avg {
>  	unsigned long			load_avg;
>  	unsigned long			runnable_avg;
>  	unsigned long			util_avg;
> +	unsigned long			util_guest;
>  	struct util_est			util_est;
>  } ____cacheline_aligned;
>  

Yeah, no... you'll have to make room first.

struct sched_avg {
	/* typedef u64 -> __u64 */ long long unsigned int     last_update_time;          /*     0     8 */
	/* typedef u64 -> __u64 */ long long unsigned int     load_sum;                  /*     8     8 */
	/* typedef u64 -> __u64 */ long long unsigned int     runnable_sum;              /*    16     8 */
	/* typedef u32 -> __u32 */ unsigned int               util_sum;                  /*    24     4 */
	/* typedef u32 -> __u32 */ unsigned int               period_contrib;            /*    28     4 */
	long unsigned int          load_avg;                                             /*    32     8 */
	long unsigned int          runnable_avg;                                         /*    40     8 */
	long unsigned int          util_avg;                                             /*    48     8 */
	struct util_est {
		unsigned int       enqueued;                                             /*    56     4 */
		unsigned int       ewma;                                                 /*    60     4 */
	} __attribute__((__aligned__(8)))util_est __attribute__((__aligned__(8))); /*    56     8 */

	/* size: 64, cachelines: 1, members: 9 */
	/* forced alignments: 1 */
} __attribute__((__aligned__(64)));