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Date:   Sat, 20 Mar 2021 16:51:27 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     "Joel Fernandes (Google)" <joel@joelfernandes.org>
Cc:     Nishanth Aravamudan <naravamudan@digitalocean.com>,
        Julien Desfossez <jdesfossez@digitalocean.com>,
        Tim Chen <tim.c.chen@linux.intel.com>,
        Vineeth Pillai <viremana@linux.microsoft.com>,
        Aaron Lu <aaron.lwe@gmail.com>,
        Aubrey Li <aubrey.intel@gmail.com>, tglx@linutronix.de,
        linux-kernel@vger.kernel.org, mingo@kernel.org,
        torvalds@linux-foundation.org, fweisbec@gmail.com,
        keescook@chromium.org, Phil Auld <pauld@redhat.com>,
        Valentin Schneider <valentin.schneider@arm.com>,
        Mel Gorman <mgorman@techsingularity.net>,
        Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
        Paolo Bonzini <pbonzini@redhat.com>, vineeth@bitbyteword.org,
        Chen Yu <yu.c.chen@intel.com>,
        Christian Brauner <christian.brauner@ubuntu.com>,
        Agata Gruza <agata.gruza@intel.com>,
        Antonio Gomez Iglesias <antonio.gomez.iglesias@intel.com>,
        graf@amazon.com, konrad.wilk@oracle.com, dfaggioli@suse.com,
        rostedt@goodmis.org, benbjiang@tencent.com,
        Alexandre Chartre <alexandre.chartre@oracle.com>,
        James.Bottomley@hansenpartnership.com, OWeisse@umich.edu,
        Dhaval Giani <dhaval.giani@oracle.com>, chris.hyser@oracle.com,
        Josh Don <joshdon@google.com>, Hao Luo <haoluo@google.com>,
        Tom Lendacky <thomas.lendacky@amd.com>
Subject: Re: [PATCH 3/6] sched: prctl() cookie manipulation for core
 scheduling.
Message-ID: <20210320155127.GA4746@worktop.programming.kicks-ass.net>
References: <20210319203253.3352417-1-joel@joelfernandes.org>
 <20210319203253.3352417-4-joel@joelfernandes.org>
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In-Reply-To: <20210319203253.3352417-4-joel@joelfernandes.org>
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On Fri, Mar 19, 2021 at 04:32:50PM -0400, Joel Fernandes (Google) wrote:

>  include/linux/sched.h            |   7 ++
>  include/linux/sched/task.h       |   4 +-
>  include/uapi/linux/prctl.h       |   7 ++
>  kernel/sched/core.c              |  11 +-
>  kernel/sched/coretag.c           | 197 +++++++++++++++++++++++++++++--
>  kernel/sched/sched.h             |   2 +
>  kernel/sys.c                     |   7 ++
>  tools/include/uapi/linux/prctl.h |   7 ++
>  8 files changed, 230 insertions(+), 12 deletions(-)
> 

> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 2e3024a6f6e1..a62e8ad5ce58 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -4654,11 +4654,17 @@ unsigned long nr_iowait(void)
>   * sched_exec - execve() is a valuable balancing opportunity, because at
>   * this point the task has the smallest effective memory and cache footprint.
>   */
> -void sched_exec(void)
> +int sched_exec(void)
>  {
>  	struct task_struct *p = current;
>  	unsigned long flags;
>  	int dest_cpu;
> +	int ret;
> +
> +	/* this may change what tasks current can share a core with */
> +	ret = sched_core_exec();
> +	if (ret)
> +		return ret;

Did the hunk for fs/exec.c go missing?