From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 5A2E3DDF6F for ; Thu, 25 Sep 2008 00:05:08 +1000 (EST) Message-Id: From: Kumar Gala To: Johannes Berg In-Reply-To: <1222262654.4257.4.camel@johannes.berg> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Mime-Version: 1.0 (Apple Message framework v929.2) Subject: Re: [PATCH] powerpc: enforce sane MAX_ORDER Date: Wed, 24 Sep 2008 09:05:01 -0500 References: <1222262654.4257.4.camel@johannes.berg> Cc: linuxppc-dev list , Paul Mackerras List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Sep 24, 2008, at 8:24 AM, Johannes Berg wrote: > powerpc uses CONFIG_FORCE_MAX_ZONEORDER, and some things depend on it > being at least 10 when 64k pages are not configured (notably the dart > iommu code with CONFIG_PM). The defaults are fine, but when going > from a > 64K pages config to one without 64K pages, MAX_ORDER stays at 9 > which is > too low for 4K pages. > > This patch makes the Kconfig enforce at least the defaults, I used 999 > as the upper bound for no particular reason other than that it's > plenty. > > Signed-off-by: Johannes Berg > --- > > --- a/arch/powerpc/Kconfig > +++ b/arch/powerpc/Kconfig > @@ -415,8 +415,11 @@ config PPC_64K_PAGES > > config FORCE_MAX_ZONEORDER > int "Maximum zone order" > + range 9 999 if PPC_64K_PAGES > default "9" if PPC_64K_PAGES > + range 13 999 if PPC64 && !PPC_64K_PAGES > default "13" if PPC64 && !PPC_64K_PAGES > + range 11 999 > default "11" > help > The kernel memory allocator divides physically contiguous memory Hope about setting the upper bound to 32 or 64. Since I believe this in effect 2^FORCE_MAX_ZONEORDER, so 999 is just insane. I'd almost prefer something like 16 since that might still be in the realm of reasonable and able to work. - k