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Message-ID: <7b2d6bf91d30c007e19a7d2cbddcb2460e72d163.camel@redhat.com>
Subject: Re: [patch 1/4] add basic task isolation prctl interface
From:   nsaenzju@redhat.com
To:     Marcelo Tosatti <mtosatti@redhat.com>, linux-kernel@vger.kernel.org
Cc:     Nitesh Lal <nilal@redhat.com>,
        Frederic Weisbecker <frederic@kernel.org>,
        Christoph Lameter <cl@linux.com>,
        Juri Lelli <juri.lelli@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Alex Belits <abelits@marvell.com>, Peter Xu <peterx@redhat.com>
Date:   Tue, 27 Jul 2021 12:48:33 +0200
In-Reply-To: <20210727104119.551607458@fuller.cnet>
References: <20210727103803.464432924@fuller.cnet>
         <20210727104119.551607458@fuller.cnet>
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On Tue, 2021-07-27 at 07:38 -0300, Marcelo Tosatti wrote:
> +Isolation mode (PR_ISOL_MODE):
> +------------------------------
> +
> +- PR_ISOL_MODE_NONE (arg4): no per-task isolation (default mode).
> +  PR_ISOL_EXIT sets mode to PR_ISOL_MODE_NONE.
> +
> +- PR_ISOL_MODE_NORMAL (arg4): applications can perform system calls normally,
> +  and in case of interruption events, the notifications can be collected
> +  by BPF programs.
> +  In this mode, if system calls are performed, deferred actions initiated
> +  by the system call will be executed before return to userspace.
> +
> +Other modes, which for example send signals upon interruptions events,
> +can be implemented.

Shouldn't this be a set of flags that enable specific isolation features?
Something the likes of 'PR_ISOL_QUIESCE_ON_EXIT'. Modes seem more restrictive
and too much of a commitment. If we merge MODE_NORMAL as is, we won't be able
to tweak/extend its behaviour in the future.

-- 
Nicolás Sáenz