Re: [PATCH] mm: show stats for non-default hugepage sizes in /proc/meminfo

From: Mike Kravetz <mike.kravetz@oracle.com>
To: Johannes Weiner <hannes@cmpxchg.org>, Roman Gushchin <guro@fb.com>
Cc: Dave Hansen <dave.hansen@intel.com>,
	linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
	Michal Hocko <mhocko@suse.com>,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	kernel-team@fb.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: show stats for non-default hugepage sizes in /proc/meminfo
Date: Mon, 13 Nov 2017 11:25:21 -0800	[thread overview]
Message-ID: <0842738c-1c6f-9a29-b9a6-21e5af898c31@oracle.com> (raw)
In-Reply-To: <20171113191056.GA28749@cmpxchg.org>

On 11/13/2017 11:10 AM, Johannes Weiner wrote:
> On Mon, Nov 13, 2017 at 06:45:01PM +0000, Roman Gushchin wrote:
>> Or, at least, some total counter, e.g. how much memory is consumed
>> by hugetlb pages?
> 
> I'm not a big fan of the verbose breakdown for every huge page size.
> As others have pointed out such detail exists elswhere.
> 
> But I do think we should have a summary counter for memory consumed by
> hugetlb that lets you know how much is missing from MemTotal. This can
> be large parts of overall memory, and right now /proc/meminfo will
> give the impression we are leaking those pages.
> 
> Maybe a simple summary counter for everything set aside by the hugetlb
> subsystem - default and non-default page sizes, whether they're used
> or only reserved etc.?
> 
> Hugetlb 12345 kB

I would prefer this approach.  The 'trick' is coming up with a name or
description that is not confusing.  Unfortunately, we have to leave the
existing entries.  So, this new entry will be greater than or equal to
HugePages_Total. :(  I guess Hugetlb is as good of a name as any?

-- 
Mike Kravetz