Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759543AbYBSPWS (ORCPT ); Tue, 19 Feb 2008 10:22:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758274AbYBSPV7 (ORCPT ); Tue, 19 Feb 2008 10:21:59 -0500 Received: from yoi5.greathalifaxhome.com ([66.180.172.116]:33108 "HELO vps1.tull.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with SMTP id S1753041AbYBSPV5 (ORCPT ); Tue, 19 Feb 2008 10:21:57 -0500 X-Spam-Check-By: mail.local.tull.net Date: Wed, 20 Feb 2008 02:21:17 +1100 From: Nick Andrew To: trivial@kernel.org Cc: linux-kernel@vger.kernel.org Subject: Improve init/Kconfig help descriptions [PATCH 8/9] Message-ID: <20080219152117.GF27352@tull.net> References: <20080219140609.GA26619@tull.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080219140609.GA26619@tull.net> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) X-SMTPD: qpsmtpd/0.26, http://develooper.com/code/qpsmtpd/ Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3535 Lines: 101 On Wed, Feb 20, 2008 at 01:06:09AM +1100, Nick Andrew wrote: > Here is a series of 9 patches to init/Kconfig intended to improve the > usefulness and consistency of the help descriptions. The patches are > against linux-2.6.24.2. > [...] > Patch 8 > SLUB_DEBUG > SLAB > SLUB > SLOB Changelog: Improve usefulness and consistency of kernel configuration help messages. Signed-off-by: Nick Andrew --- a/init/Kconfig 2008-02-20 00:45:07.000000000 +1100 +++ b/init/Kconfig 2008-02-20 00:52:07.000000000 +1100 @@ -616,31 +616,48 @@ config SLUB_DEBUG bool "Enable SLUB debugging support" if EMBEDDED depends on SLUB help + Enable debugging on the "SLUB" slab allocator. + SLUB has extensive debug support features. Disabling these can result in significant savings in code size. This also disables SLUB sysfs support. /sys/slab will not exist and there will be no support for cache validation etc. + If unsure, say N. + choice prompt "Choose SLAB allocator" default SLUB help - This option allows to select a slab allocator. + This option selects a slab allocator. + + A slab is a contiguous area of kernel memory. Slabs are of + fixed size (1 or more times the page size) and are used as + the container for allocation of kernel data structures. This + reduces memory fragmentation and makes allocation very fast, + improving kernel performance. + + "SLUB" is the default slab allocator. + + See wikipedia:Slab_allocation for more details. config SLAB bool "SLAB" help - The regular slab allocator that is established and known to work - well in all environments. It organizes cache hot objects in - per cpu and per node queues. SLAB is the default choice for - a slab allocator. + SLAB is the original slab allocator that is established and + known to work well in all environments. It organizes cache + hot objects in per-CPU and per-node queues. + + SLAB has been superseded by SLUB. config SLUB bool "SLUB (Unqueued Allocator)" help SLUB is a slab allocator that minimizes cache line usage - instead of managing queues of cached objects (SLAB approach). - Per cpu caching is realized using slabs of objects instead + instead of managing queues of cached objects (the SLAB + approach). + + Per-CPU caching is realized using slabs of objects instead of queues of objects. SLUB can use memory efficiently and has enhanced diagnostics. @@ -648,11 +665,14 @@ config SLOB depends on EMBEDDED bool "SLOB (Simple Allocator)" help - SLOB replaces the SLAB allocator with a drastically simpler - allocator. SLOB is more space efficient than SLAB but does not - scale well (single lock for all operations) and is also highly - susceptible to fragmentation. SLUB can accomplish a higher object - density. It is usually better to use SLUB instead of SLOB. + SLOB is a drastically simpler allocator for use in embedded + systems. + + SLOB is more space efficient than SLAB but does not scale well + (it uses a single lock for all operations) and is also highly + susceptible to fragmentation. SLUB can accomplish a higher + object density. It is usually better to use SLUB instead + of SLOB. endchoice -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/