From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ig0-f169.google.com (mail-ig0-f169.google.com [209.85.213.169]) by kanga.kvack.org (Postfix) with ESMTP id 8EDC46B0253 for ; Mon, 14 Sep 2015 07:38:47 -0400 (EDT) Received: by igxx6 with SMTP id x6so79351959igx.1 for ; Mon, 14 Sep 2015 04:38:47 -0700 (PDT) Received: from e23smtp09.au.ibm.com (e23smtp09.au.ibm.com. [202.81.31.142]) by mx.google.com with ESMTPS id uw4si22846700pac.106.2015.09.14.04.38.45 for (version=TLSv1 cipher=AES128-SHA bits=128/128); Mon, 14 Sep 2015 04:38:46 -0700 (PDT) Received: from /spool/local by e23smtp09.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 14 Sep 2015 21:38:42 +1000 Received: from d23relay09.au.ibm.com (d23relay09.au.ibm.com [9.185.63.181]) by d23dlp03.au.ibm.com (Postfix) with ESMTP id 517083578052 for ; Mon, 14 Sep 2015 21:38:40 +1000 (EST) Received: from d23av04.au.ibm.com (d23av04.au.ibm.com [9.190.235.139]) by d23relay09.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t8EBcVZQ57409694 for ; Mon, 14 Sep 2015 21:38:40 +1000 Received: from d23av04.au.ibm.com (localhost [127.0.0.1]) by d23av04.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t8EBc7fg016225 for ; Mon, 14 Sep 2015 21:38:07 +1000 Message-ID: <55F6B1F3.1010702@linux.vnet.ibm.com> Date: Mon, 14 Sep 2015 17:09:31 +0530 From: Raghavendra K T MIME-Version: 1.0 Subject: Re: [PATCH 1/2] mm: Replace nr_node_ids for loop with for_each_node in list lru References: <1441737107-23103-1-git-send-email-raghavendra.kt@linux.vnet.ibm.com> <1441737107-23103-2-git-send-email-raghavendra.kt@linux.vnet.ibm.com> <20150914090010.GB30743@esperanza> In-Reply-To: <20150914090010.GB30743@esperanza> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Vladimir Davydov Cc: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, anton@samba.org, akpm@linux-foundation.org, nacc@linux.vnet.ibm.com, gkurz@linux.vnet.ibm.com, zhong@linux.vnet.ibm.com, grant.likely@linaro.org, nikunj@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org On 09/14/2015 02:30 PM, Vladimir Davydov wrote: > Hi, > > On Wed, Sep 09, 2015 at 12:01:46AM +0530, Raghavendra K T wrote: >> The functions used in the patch are in slowpath, which gets called >> whenever alloc_super is called during mounts. >> >> Though this should not make difference for the architectures with >> sequential numa node ids, for the powerpc which can potentially have >> sparse node ids (for e.g., 4 node system having numa ids, 0,1,16,17 >> is common), this patch saves some unnecessary allocations for >> non existing numa nodes. >> >> Even without that saving, perhaps patch makes code more readable. > > Do I understand correctly that node 0 must always be in > node_possible_map? I ask, because we currently test > lru->node[0].memcg_lrus to determine if the list is memcg aware. > Yes, node 0 is always there. So it should not be a problem. >> >> Signed-off-by: Raghavendra K T >> --- >> mm/list_lru.c | 23 +++++++++++++++-------- >> 1 file changed, 15 insertions(+), 8 deletions(-) >> >> diff --git a/mm/list_lru.c b/mm/list_lru.c >> index 909eca2..5a97f83 100644 >> --- a/mm/list_lru.c >> +++ b/mm/list_lru.c >> @@ -377,7 +377,7 @@ static int memcg_init_list_lru(struct list_lru *lru, bool memcg_aware) >> { >> int i; >> >> - for (i = 0; i < nr_node_ids; i++) { >> + for_each_node(i) { >> if (!memcg_aware) >> lru->node[i].memcg_lrus = NULL; > > So, we don't explicitly initialize memcg_lrus for nodes that are not in > node_possible_map. That's OK, because we allocate lru->node using > kzalloc. However, this partial nullifying in case !memcg_aware looks > confusing IMO. Let's drop it, I mean something like this: Yes, you are right. and we do not have to have memcg_aware check inside for loop too. Will change as per your suggestion and send V2. Thanks for the review. > > static int memcg_init_list_lru(struct list_lru *lru, bool memcg_aware) > { > int i; > > if (!memcg_aware) > return 0; > > for_each_node(i) { > if (memcg_init_list_lru_node(&lru->node[i])) > goto fail; > } > -- 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