linux-kernel - Re: [rfc][patch 1/3] slub: fix small HWCACHE

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]

Message-ID: <20080307023223.GD21185@wotan.suse.de>
Date:	Fri, 7 Mar 2008 03:32:23 +0100
From:	Nick Piggin <npiggin@...e.de>
To:	Christoph Lameter <clameter@....com>
Cc:	David Miller <davem@...emloft.net>, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org, yanmin_zhang@...ux.intel.com,
	dada1@...mosbay.com
Subject: Re: [rfc][patch 1/3] slub: fix small HWCACHE_ALIGN alignment

On Thu, Mar 06, 2008 at 06:26:49PM -0800, Christoph Lameter wrote:
> On Fri, 7 Mar 2008, Nick Piggin wrote:
> 
> > That's just because you (apparently still) have a misconception about what
> > the flag is supposed to be for. It is not for aligning things to the start
> > of a cacheline boundary. It is not for avoiding false sharing on SMP. It
> 
> The alignment of the object to the start of a cacheline is the obvious 
> meaning and that is also reflected in the comment in slab.h.

It doesn't say start of cache line. It says align them *on* cachelines.
2 32 byte objects on a 64 byte cacheline are aligned on the cacheline.
2.67 24 bytes objects on a 64 byte cacheline are not aligned on the
cacheline.

Anyway, if you want to be myopic about it, then good luck with that.

--
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/