From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
linux-mips@linux-mips.org, linux-mm@kvack.org,
WireGuard mailing list <wireguard@lists.zx2c4.com>,
k@vodka.home.kg
Subject: Re: Proposal: HAVE_SEPARATE_IRQ_STACK?
Date: Thu, 10 Nov 2016 00:34:54 +0100 [thread overview]
Message-ID: <CAHmME9pGoRogjHSSy-G-sB4-cHMGcjCeW9PSrNw1h5FsKzfWAw@mail.gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.20.1611092227200.3501@nanos>
Hey Thomas,
On Wed, Nov 9, 2016 at 10:40 PM, Thomas Gleixner <tglx@linutronix.de> wrote:
> That preempt_disable() prevents merily preemption as the name says, but it
> wont prevent softirq handlers from running on return from interrupt. So
> what's the point?
Oh, interesting. Okay, then in that case the proposed define wouldn't
be useful for my purposes. What clever tricks do I have at my
disposal, then?
>> If not, do you have a better solution for me (which doesn't
>> involve using kmalloc or choosing a different crypto primitive)?
>
> What's wrong with using kmalloc?
It's cumbersome and potentially slow. This is crypto code, where speed
matters a lot. Avoiding allocations is usually the lowest hanging
fruit among optimizations. To give you some idea, here's a somewhat
horrible solution using kmalloc I hacked together: [1]. I'm not to
happy with what it looks like, code-wise, and there's around a 16%
slowdown, which isn't nice either.
[1] https://git.zx2c4.com/WireGuard/commit/?h=jd/curve25519-kmalloc
next prev parent reply other threads:[~2016-11-09 23:35 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-09 21:27 Proposal: HAVE_SEPARATE_IRQ_STACK? Jason A. Donenfeld
2016-11-09 21:40 ` Thomas Gleixner
2016-11-09 23:34 ` Jason A. Donenfeld [this message]
2016-11-10 9:03 ` Thomas Gleixner
2016-11-10 11:41 ` Jason A. Donenfeld
2016-11-10 13:00 ` Thomas Gleixner
2016-11-10 17:39 ` Jason A. Donenfeld
2016-11-10 16:36 ` Matt Redfearn
2016-11-10 17:37 ` Jason A. Donenfeld
2016-11-10 0:17 ` David Daney
2016-11-10 1:47 ` Jason A. Donenfeld
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