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Date: Fri, 3 Jan 2014 11:33:03 +0800
From: Han Pingtian <hanpt@linux.vnet.ibm.com>
Subject: Re: [RFC] mm: show message when updating min_free_kbytes in thp
Message-ID: <20140103033303.GB4106@localhost.localdomain>
References: <20140101002935.GA15683@localhost.localdomain>
 <52C5AA61.8060701@intel.com>
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To: linux-kernel@vger.kernel.org
Cc: Dave Hansen <dave.hansen@intel.com>, Andrea Arcangeli <aarcange@redhat.com>, Mel Gorman <mgorman@suse.de>, Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org, Michal Hocko <mhocko@suse.cz>

On Thu, Jan 02, 2014 at 10:05:21AM -0800, Dave Hansen wrote:
> On 12/31/2013 04:29 PM, Han Pingtian wrote:
> > min_free_kbytes may be updated during thp's initialization. Sometimes,
> > this will change the value being set by user. Showing message will
> > clarify this confusion.
> ...
> > -	if (recommended_min > min_free_kbytes)
> > +	if (recommended_min > min_free_kbytes) {
> >  		min_free_kbytes = recommended_min;
> > +		pr_info("min_free_kbytes is updated to %d by enabling transparent hugepage.\n",
> > +			min_free_kbytes);
> > +	}
> 
> "updated" doesn't tell us much.  It's also kinda nasty that if we enable
> then disable THP, we end up with an elevated min_free_kbytes.  Maybe we
> should at least put something in that tells the user how to get back
> where they were if they care:
> 
> "raising min_free_kbytes from %d to %d to help transparent hugepage
> allocations"
> 
Thanks. I have updated it according to your suggestion.