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

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Date:   Tue, 14 Nov 2017 12:48:07 +0000
From:   Roman Gushchin <guro@...com>
To:     Mike Kravetz <mike.kravetz@...cle.com>
CC:     Johannes Weiner <hannes@...xchg.org>,
        Dave Hansen <dave.hansen@...el.com>, <linux-mm@...ck.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Michal Hocko <mhocko@...e.com>,
        "Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>,
        Andrea Arcangeli <aarcange@...hat.com>, <kernel-team@...com>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] mm: show stats for non-default hugepage sizes in
 /proc/meminfo

On Mon, Nov 13, 2017 at 11:25:21AM -0800, Mike Kravetz wrote:
> 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?

Yes, I like this approach too, and Hugetlb (in kB) sounds reasonable.
I'll post a new patch soon.