Date: Wed, 29 Mar 2017 10:45:14 -0700
From: Andi Kleen <ak@linux.intel.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>, akpm@linux-foundation.org,
        mtk.manpages@gmail.com, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, Davidlohr Bueso <dbueso@suse.de>,
        khandual@linux.vnet.ibm.com
Subject: Re: [PATCH] mm,hugetlb: compute page_size_log properly
Message-ID: <20170329174514.GB4543@tassilo.jf.intel.com>
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 <20170328175408.GD7838@bombadil.infradead.org>
 <20170329080625.GC27994@dhcp22.suse.cz>
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On Wed, Mar 29, 2017 at 10:06:25AM +0200, Michal Hocko wrote:
> On Tue 28-03-17 10:54:08, Matthew Wilcox wrote:
> > On Tue, Mar 28, 2017 at 09:55:13AM -0700, Davidlohr Bueso wrote:
> > > Do we have any consensus here? Keeping SHM_HUGE_* is currently
> > > winning 2-1. If there are in fact users out there computing the
> > > value manually, then I am ok with keeping it and properly exporting
> > > it. Michal?
> > 
> > Well, let's see what it looks like to do that.  I went down the rabbit
> > hole trying to understand why some of the SHM_ flags had the same value
> > as each other until I realised some of them were internal flags, some
> > were flags to shmat() and others were flags to shmget().  Hopefully I
> > disambiguated them nicely in this patch.  I also added 8MB and 16GB sizes.
> > Any more architectures with a pet favourite huge/giant page size we
> > should add convenience defines for?
> 
> Do we actually have any users?

Yes this feature is widely used.

-Andi