linux-kernel - Re: [PATCH] hugetlbfs: add O

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Message-ID: <766b4370-ba71-85a2-5a57-ca9ed7dc7870@oracle.com>
Date:   Tue, 15 Oct 2019 16:37:00 -0700
From:   Mike Kravetz <mike.kravetz@...cle.com>
To:     Michal Hocko <mhocko@...nel.org>, Piotr Sarna <p.sarna@...n.pl>
Cc:     linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        viro@...iv.linux.org.uk, linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH] hugetlbfs: add O_TMPFILE support

On 10/15/19 3:50 AM, Michal Hocko wrote:
> On Tue 15-10-19 11:01:12, Piotr Sarna wrote:
>> With hugetlbfs, a common pattern for mapping anonymous huge pages
>> is to create a temporary file first.
> 
> Really? I though that this is normally done by shmget(SHM_HUGETLB) or
> mmap(MAP_HUGETLB). Or maybe I misunderstood your definition on anonymous
> huge pages.
> 
>> Currently libraries like
>> libhugetlbfs and seastar create these with a standard mkstemp+unlink
>> trick,

I would guess that much of libhugetlbfs was writen before MAP_HUGETLB
was implemented.  So, that is why it does not make (more) use of that
option.

The implementation looks to be straight forward.  However, I really do
not want to add more functionality to hugetlbfs unless there is specific
use case that needs it.
-- 
Mike Kravetz