From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <48B2FD8F.4000808@sgi.com> Date: Mon, 25 Aug 2008 11:44:31 -0700 From: Mike Travis MIME-Version: 1.0 Subject: Re: [RFC][PATCH 2/2] quicklist shouldn't be proportional to # of CPUs References: <20080820195021.12E7.KOSAKI.MOTOHIRO@jp.fujitsu.com> <20080820200709.12F0.KOSAKI.MOTOHIRO@jp.fujitsu.com> <20080820234615.258a9c04.akpm@linux-foundation.org> <20080821.001322.236658980.davem@davemloft.net> <20080821002757.b7c807ad.akpm@linux-foundation.org> <1219311154.8651.96.camel@twins> In-Reply-To: <1219311154.8651.96.camel@twins> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Peter Zijlstra Cc: Andrew Morton , David Miller , kosaki.motohiro@jp.fujitsu.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, cl@linux-foundation.org, tokunaga.keiich@jp.fujitsu.com List-ID: Peter Zijlstra wrote: > On Thu, 2008-08-21 at 00:27 -0700, Andrew Morton wrote: >> On Thu, 21 Aug 2008 00:13:22 -0700 (PDT) David Miller wrote: >> >>> From: Andrew Morton >>> Date: Wed, 20 Aug 2008 23:46:15 -0700 >>> >>>> On Wed, 20 Aug 2008 20:08:13 +0900 KOSAKI Motohiro wrote: >>>> >>>>> + num_cpus_per_node = cpus_weight_nr(node_to_cpumask(node)); >>>> sparc64 allmodconfig: >>>> >>>> mm/quicklist.c: In function `max_pages': >>>> mm/quicklist.c:44: error: invalid lvalue in unary `&' >>>> >>>> we seem to have a made a spectacular mess of cpumasks lately. >>> It should explode similarly on x86, since it also defines node_to_cpumask() >>> as an inline function. >>> >>> IA64 seems to be one of the few platforms to define this as a macro >>> evaluating to the node-to-cpumask array entry, so it's clear what >>> platform Motohiro-san did build testing on :-) >> Seems to compile OK on x86_32, x86_64, ia64 and powerpc for some reason. >> >> This seems to fix things on sparc64: >> >> --- a/mm/quicklist.c~mm-quicklist-shouldnt-be-proportional-to-number-of-cpus-fix >> +++ a/mm/quicklist.c >> @@ -28,7 +28,7 @@ static unsigned long max_pages(unsigned >> unsigned long node_free_pages, max; >> int node = numa_node_id(); >> struct zone *zones = NODE_DATA(node)->node_zones; >> - int num_cpus_per_node; >> + cpumask_t node_cpumask; >> >> node_free_pages = >> #ifdef CONFIG_ZONE_DMA >> @@ -41,8 +41,8 @@ static unsigned long max_pages(unsigned >> >> max = node_free_pages / FRACTION_OF_NODE_MEM; >> >> - num_cpus_per_node = cpus_weight_nr(node_to_cpumask(node)); >> - max /= num_cpus_per_node; >> + node_cpumask = node_to_cpumask(node); >> + max /= cpus_weight_nr(node_cpumask); >> >> return max(max, min_pages); >> } > > humm, I thought we wanted to keep cpumask_t stuff away from our stack - > since on insanely large SGI boxen (/me looks at mike) the thing becomes > 512 bytes. Yes, thanks for pointing that out! I did send out an alternate coding that should keep the cpumask_t off the stack for those arch's that need to worry about it (using the node_to_cpumask_ptr function). I should probably devote some time to documenting some of these gotcha's in one of the Doc.../ files. Mike -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org