From: "George Spelvin" <linux@horizon.com>
To: dborkman@redhat.com, hannes@stressinduktion.org
Cc: davem@davemloft.net, linux-kernel@vger.kernel.org,
linux@horizon.com, shemminger@osdl.org, tytso@mit.edu
Subject: Re: [PATCH 5/7] lib/random32.c: Make prandom_u32_max efficient for powers of 2
Date: 8 Jun 2014 20:28:25 -0400 [thread overview]
Message-ID: <20140609002825.20757.qmail@ns.horizon.com> (raw)
In-Reply-To: <5394C15D.3020507@redhat.com>
Daniel Borkmann wrote:
> On 06/08/2014 07:34 PM, Hannes Frederic Sowa wrote:
>> Please check this as it makes the code more complicated and I doubt it is worth it.
>
> Agreed.
Just to clarify, the goal is to be able to replace "prandom_u32() %
range" all over the kernel with "prandom_u32_max(range)" and promise
people that it's guaranteed to be just as good.
My goal is a one-time cleanup to eliminate "prandom_u32() % range" so
people will stop cutting and pasting it into new code.
(FIXME: Add a kdoc update on the subject.)
It uglifies the random32 code for sure, but by encapsulating the cleverness
it lets all the call sites be simpler and reduces arguments about the change.
E.g. have a look at all the prandom_u32 calls in net/core/pktgen.c.
next prev parent reply other threads:[~2014-06-09 0:28 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-07 8:18 [PATCH 0/7] random32: Various minor cleanups George Spelvin
2014-06-07 8:19 ` [PATCH 1/7] lib/random32.c: Mark self-test data as __initconst George Spelvin
2014-06-08 12:06 ` Daniel Borkmann
2014-06-07 8:20 ` [PATCH 2/7] lib/random32.c: Remove excess calls to prandom_u32_state in initialization George Spelvin
2014-06-08 12:11 ` Daniel Borkmann
2014-06-08 12:19 ` George Spelvin
2014-06-07 8:22 ` [PATCH 3/7] lib/random32.c: Replace an #ifdef with a stub prandom_state_selftest() George Spelvin
2014-06-08 12:16 ` Daniel Borkmann
2014-06-08 12:27 ` George Spelvin
2014-06-07 8:25 ` [PATCH 4/7] lib/random32.c: Use <asm/unaligned.h> instead of hand-rolling it George Spelvin
2014-06-08 12:25 ` Daniel Borkmann
2014-06-08 12:40 ` George Spelvin
2014-06-08 20:26 ` Hannes Frederic Sowa
2014-06-10 15:13 ` Daniel Borkmann
2014-06-07 8:28 ` [PATCH 5/7] lib/random32.c: Make prandom_u32_max efficient for powers of 2 George Spelvin
2014-06-08 12:03 ` Daniel Borkmann
2014-06-08 17:34 ` Hannes Frederic Sowa
2014-06-08 20:02 ` Daniel Borkmann
2014-06-09 0:28 ` George Spelvin [this message]
2014-06-08 20:48 ` George Spelvin
2014-06-09 10:30 ` Hannes Frederic Sowa
2014-06-07 8:28 ` [PATCH 6/7] lib/random32.c: Randomize timeout to the millisecond, not the second George Spelvin
2014-06-08 10:43 ` Daniel Borkmann
2014-06-08 11:30 ` George Spelvin
2014-06-08 12:28 ` Daniel Borkmann
2014-06-08 12:42 ` George Spelvin
2014-06-08 20:01 ` Daniel Borkmann
2014-06-07 8:31 ` [PATCH 7/7] lib/random32.c: Remove redundant U suffixes on integers George Spelvin
2014-06-08 10:36 ` Daniel Borkmann
2014-06-08 11:14 ` George Spelvin
2014-06-08 12:05 ` Daniel Borkmann
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