Message-ID: <52FC98A6.1000701@linux.vnet.ibm.com>
Date: Thu, 13 Feb 2014 15:34:22 +0530
From: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Organization: IBM
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To: David Rientjes <rientjes@google.com>
CC: Andrew Morton <akpm@linux-foundation.org>,
        Fengguang Wu <fengguang.wu@intel.com>,
        David Cohen <david.a.cohen@linux.intel.com>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Damien Ramonda <damien.ramonda@intel.com>, Jan Kara <jack@suse.cz>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Nishanth Aravamudan <nacc@linux.vnet.ibm.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH V5] mm readahead: Fix readahead fail for no local
 memory and limit readahead pages
References: <1390388025-1418-1-git-send-email-raghavendra.kt@linux.vnet.ibm.com> <20140206145105.27dec37b16f24e4ac5fd90ce@linux-foundation.org> <alpine.DEB.2.02.1402061456290.31828@chino.kir.corp.google.com> <20140206152219.45c2039e5092c8ea1c31fd38@linux-foundation.org> <alpine.DEB.2.02.1402061537180.3441@chino.kir.corp.google.com> <alpine.DEB.2.02.1402061557210.5061@chino.kir.corp.google.com> <52F4B8A4.70405@linux.vnet.ibm.com> <alpine.DEB.2.02.1402071239301.4212@chino.kir.corp.google.com> <52F88C16.70204@linux.vnet.ibm.com> <alpine.DEB.2.02.1402100200420.30650@chino.kir.corp.google.com> <52F8C556.6090006@linux.vnet.ibm.com> <alpine.DEB.2.02.1402101333160.15624@chino.kir.corp.google.com> <52FC6F2A.30905@linux.vnet.ibm.com> <alpine.DEB.2.02.1402130003320.11689@chino.kir.corp.google.com>
In-Reply-To: <alpine.DEB.2.02.1402130003320.11689@chino.kir.corp.google.com>
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Sender: linux-kernel-owner@vger.kernel.org

On 02/13/2014 01:35 PM, David Rientjes wrote:
> On Thu, 13 Feb 2014, Raghavendra K T wrote:
>
>> I was able to test (1) implementation on the system where readahead problem
>> occurred. Unfortunately it did not help.
>>
>> Reason seem to be that CONFIG_HAVE_MEMORYLESS_NODES dependency of
>> numa_mem_id(). The PPC machine I am facing problem has topology like
>> this:
[...]
>>
>> So it seems numa_mem_id() does not help for all the configs..
>> Am I missing something ?
>>
>
> You need the patch from http://marc.info/?l=linux-mm&m=139093411119013
> first.

Thanks David, unfortunately even after applying that patch, I do not see
the improvement.

Interestingly numa_mem_id() seem to still return the value of a
memoryless node.
May be  per cpu _numa_mem_ values are not set properly. Need to dig out ....

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