linux-kernel - Re: [patch 1/2] infrastructure to debug (dynamic) objects

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sat, 01 Mar 2008 23:42:57 +0100
From:	Peter Zijlstra <a.p.zijlstra@...llo.nl>
To:	Thomas Gleixner <tglx@...utronix.de>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>, Ingo Molnar <mingo@...e.hu>,
	Greg KH <greg@...ah.com>
Subject: Re: [patch 1/2] infrastructure to debug (dynamic) objects


On Sat, 2008-03-01 at 12:44 +0100, Thomas Gleixner wrote:
> On Sat, 1 Mar 2008, Andrew Morton wrote:

> > > +
> > > +#define ODEBUG_HASH_SIZE	4096
> > 
> > power-of-2 is said to be a very poor size for a hash table.
> 
> The hash is not a randomized hash as one would expect. It's purely
> generated from the object address to simplify the lookup during the
> free check. So the power of 2 size is a good thing :) /me adds
> comment.

Power of two buckets work when used along with a golden ratio based hash
map - as done by linux/hash.h.

Power of two hash maps otoh suck royally.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/