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Date: Fri, 17 Jul 2015 21:23:48 +0200
From: Ingo Molnar <mingo@kernel.org>
To: linux-kernel@vger.kernel.org, Dave Hansen <dave@sr71.net>
Cc: Andy Lutomirski <luto@amacapital.net>,
        Andrew Morton <akpm@linux-foundation.org>, Dave Hansen <dave@sr71.net>,
        Denys Vlasenko <dvlasenk@redhat.com>, Brian Gerst <brgerst@gmail.com>,
        Peter Zijlstra <peterz@infradead.org>, Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Oleg Nesterov <oleg@redhat.com>, Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 1/2] x86/fpu, fork: Dynamically allocate 'struct fpu'
Message-ID: <20150717192348.GB24300@gmail.com>
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* Ingo Molnar <mingo@kernel.org> wrote:

> From: Dave Hansen <dave@sr71.net>
> 
> The FPU rewrite removed the dynamic allocations of 'struct fpu'.
> But, this potentially wastes massive amounts of memory (2k per
> task on systems that do not have AVX-512 for instance).
> 
> Instead of having a separate slab, this patch just appends the
> space that we need to the 'task_struct' which we dynamically
> allocate already.  This saves from doing an extra slab
> allocation at fork().
> 
> The only real downside here is that we have to stick everything
> and the end of the task_struct.  But, I think the BUILD_BUG_ON()s
> I stuck in there should keep that from being too fragile.
> 
> Cc: Andy Lutomirski <luto@amacapital.net>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: H. Peter Anvin <hpa@zytor.com>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: dave@sr71.net
> Link: http://lkml.kernel.org/r/20150716191437.A334FF2E@viggo.jf.intel.com
> Signed-off-by: Ingo Molnar <mingo@kernel.org>

Dave, can I put your Signed-off-by into this patch? I have already tested these 
two patches and they are looking good here - so unless you can see some breakage 
or other problem I'd prefer it to keep it two patches.

Thanks,

	Ingo