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Date:   Tue, 8 Nov 2022 14:00:18 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc:     linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        "Paul E . McKenney" <paulmck@kernel.org>,
        Boqun Feng <boqun.feng@gmail.com>,
        "H . Peter Anvin" <hpa@zytor.com>, Paul Turner <pjt@google.com>,
        linux-api@vger.kernel.org, Christian Brauner <brauner@kernel.org>,
        Florian Weimer <fw@deneb.enyo.de>, David.Laight@aculab.com,
        carlos@redhat.com, Peter Oskolkov <posk@posk.io>,
        Alexander Mikhalitsyn <alexander@mihalicyn.com>,
        Chris Kennelly <ckennelly@google.com>
Subject: Re: [PATCH v5 08/24] sched: Introduce per memory space current
 virtual cpu id
Message-ID: <Y2pS4gC1MHw+mX3x@hirez.programming.kicks-ass.net>
References: <20221103200359.328736-1-mathieu.desnoyers@efficios.com>
 <20221103200359.328736-9-mathieu.desnoyers@efficios.com>
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On Thu, Nov 03, 2022 at 04:03:43PM -0400, Mathieu Desnoyers wrote:

> diff --git a/fs/exec.c b/fs/exec.c
> index 349a5da91efe..93eb88f4053b 100644
> --- a/fs/exec.c
> +++ b/fs/exec.c
> @@ -1013,6 +1013,9 @@ static int exec_mmap(struct mm_struct *mm)
>  	tsk->active_mm = mm;
>  	tsk->mm = mm;
>  	lru_gen_add_mm(mm);
> +	mm_init_vcpu_lock(mm);
> +	mm_init_vcpumask(mm);
> +	mm_init_node_vcpumask(mm);
>  	/*
>  	 * This prevents preemption while active_mm is being loaded and
>  	 * it and mm are being updated, which could cause problems for

> @@ -1150,6 +1154,9 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
>  
>  	mm->user_ns = get_user_ns(user_ns);
>  	lru_gen_init_mm(mm);
> +	mm_init_vcpu_lock(mm);
> +	mm_init_vcpumask(mm);
> +	mm_init_node_vcpumask(mm);
>  	return mm;
>  
>  fail_nocontext:

Why isn't all that a single mm_init_vcpu(mm) or something ?