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From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Tue, 16 Nov 2010 17:50:41 -0800
Message-ID: <AANLkTi=ynv+TAB9a2-+9PDhYbmopMn+6FPxh4ZUdro2K@mail.gmail.com>
Subject: Re: [RFC/RFT PATCH v3] sched: automated per tty task groups
To: Kyle McMartin <kyle@mcmartin.ca>
Cc: Mike Galbraith <efault@gmx.de>, Oleg Nesterov <oleg@redhat.com>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Markus Trippelsdorf <markus@trippelsdorf.de>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Ingo Molnar <mingo@elte.hu>, LKML <linux-kernel@vger.kernel.org>
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On Tue, Nov 16, 2010 at 5:31 PM, Kyle McMartin <kyle@mcmartin.ca> wrote:
>
> This is a bit of a problem, as it's called in_atomic context and kmalloc's
> under GFP_KERNEL (which can sleep.) This results in sleep-under-spinlock
> prints when CONFIG_DEBUG_SPINLOCK_SLEEP=y.

Blame me, I threw that out as a single point where this can be done.

In fact, holding the signal spinlock was seen as a bonus, since that
was used to serialize the access to the signal->autogroup access.
Which I think is required.

But yes, it does create problems for the allocation. It could be done
as just a GFP_ATOMIC, of course, and on allocation failure you'd just
punt and not do it. Not pretty, but functional.

                  Linus
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