From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with ESMTP id 2A6565F0001 for ; Wed, 15 Apr 2009 04:47:16 -0400 (EDT) Received: from d23relay01.au.ibm.com (d23relay01.au.ibm.com [202.81.31.243]) by e23smtp07.au.ibm.com (8.13.1/8.13.1) with ESMTP id n3F8lsFN010142 for ; Wed, 15 Apr 2009 18:47:54 +1000 Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by d23relay01.au.ibm.com (8.13.8/8.13.8/NCO v9.2) with ESMTP id n3F8lqHS528540 for ; Wed, 15 Apr 2009 18:47:54 +1000 Received: from d23av01.au.ibm.com (loopback [127.0.0.1]) by d23av01.au.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id n3F8lpcb000926 for ; Wed, 15 Apr 2009 18:47:51 +1000 Date: Wed, 15 Apr 2009 14:17:13 +0530 From: Balbir Singh Subject: Re: meminfo Committed_AS underflows Message-ID: <20090415084713.GU7082@balbir.in.ibm.com> Reply-To: balbir@linux.vnet.ibm.com References: <20090415105033.AC29.A69D9226@jp.fujitsu.com> <20090415033455.GS7082@balbir.in.ibm.com> <20090415130042.AC3D.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20090415130042.AC3D.A69D9226@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: Dave Hansen , linux-mm , "linux-kernel@vger.kernel.org" , Eric B Munson , Mel Gorman , Christoph Lameter List-ID: * KOSAKI Motohiro [2009-04-15 13:10:06]: > > * KOSAKI Motohiro [2009-04-15 11:04:59]: > > > > > committed = atomic_long_read(&vm_committed_space); > > > + if (committed < 0) > > > + committed = 0; > > > > Isn't this like pushing the problem under the rug? > > global_page_state() already has same logic. > IOW almost meminfo filed has this one (except Commited_AS). > OK > > > > allowed = ((totalram_pages - hugetlb_total_pages()) > > > * sysctl_overcommit_ratio / 100) + total_swap_pages; > > > > > > Index: b/mm/swap.c > > > =================================================================== > > > --- a/mm/swap.c > > > +++ b/mm/swap.c > > > @@ -519,7 +519,7 @@ EXPORT_SYMBOL(pagevec_lookup_tag); > > > * We tolerate a little inaccuracy to avoid ping-ponging the counter between > > > * CPUs > > > */ > > > -#define ACCT_THRESHOLD max(16, NR_CPUS * 2) > > > +#define ACCT_THRESHOLD max_t(long, 16, num_online_cpus() * 2) > > > > > > > Hmm.. this is a one time expansion, free of CPU hotplug. > > > > Should we use nr_cpu_ids or num_possible_cpus()? > > #define num_online_cpus() cpumask_weight(cpu_online_mask) > #define num_possible_cpus() cpumask_weight(cpu_possible_mask) > > num_possible_cpus() have the same calculation cost. > nr_cpu_ids isn't proper value. > it point to valid cpu-id range, no related number of online nor possible cpus. > Since the value is just a basis for thresholds, num_online_cpus() might work. -- Balbir -- 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