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From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: "Theodore Y. Ts'o" <tytso@mit.edu>
Cc: Tony Luck <tony.luck@gmail.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] random: always use batched entropy for get_random_u{32,64}
Date: Sat, 22 Feb 2020 10:59:57 +0100	[thread overview]
Message-ID: <CAHmME9pJPhqX8kDCTiRQdqGMLctEZTWTaG0vTDPL0v5A9-rX2A@mail.gmail.com> (raw)
In-Reply-To: <20200222004133.GC873427@mit.edu>

Hi Ted,

On 2/22/20, Theodore Y. Ts'o <tytso@mit.edu> wrote:

> No, we can't; take a look at invalidate_batched_entropy(), where we
> need invalidate all of per-cpu batched entropy from a single CPU after
> we have initialized the the CRNG.
>
> Since most of the time after CRNG initialization, the spinlock for
> each CPU will be on that CPU's cacheline, the time to take and release
> the spinlock is not going to be material.

Ah, you're right. I hadn't looked in detail before, hence mentioning
"probably" and deferring to a new patch. Thanks for looking into it.

Regarding this patch here, can you apply the v2 that I posted to your
random.git tree?

Thanks,
Jason

  reply	other threads:[~2020-02-22 10:00 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-16 16:18 Jason A. Donenfeld
2020-02-16 18:23 ` Greg Kroah-Hartman
2020-02-20 22:20   ` Tony Luck
2020-02-20 22:29     ` Tony Luck
2020-02-21 20:08       ` Jason A. Donenfeld
2020-02-22  0:41         ` Theodore Y. Ts'o
2020-02-22  9:59           ` Jason A. Donenfeld [this message]
2020-02-24 20:41           ` Luck, Tony
2020-02-21 20:07     ` Jason A. Donenfeld
2020-02-21 20:10       ` [PATCH v2] " Jason A. Donenfeld
2020-02-28  4:09         ` Theodore Y. Ts'o
2020-04-01 13:08         ` Nicolai Stange

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