From: Matthew Wilcox <willy@infradead.org>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: akpm@linux-foundation.org, mhocko@suse.com, ak@linux.intel.com,
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
Date: Thu, 13 Apr 2017 05:46:33 -0700 [thread overview]
Message-ID: <20170413124633.GG784@bombadil.infradead.org> (raw)
In-Reply-To: <87wpaoq1zy.fsf@skywalker.in.ibm.com>
On Thu, Apr 13, 2017 at 11:32:09AM +0530, Aneesh Kumar K.V wrote:
> > +#define SHM_HUGE_SHIFT 26
> > +#define SHM_HUGE_MASK 0x3f
> > +#define SHM_HUGE_2MB (21 << SHM_HUGE_SHIFT)
> > +#define SHM_HUGE_8MB (23 << SHM_HUGE_SHIFT)
> > +#define SHM_HUGE_1GB (30 << SHM_HUGE_SHIFT)
> > +#define SHM_HUGE_16GB (34 << SHM_HUGE_SHIFT)
>
> This should be in arch/uapi like MAP_HUGE_2M ? That will let arch add
> #defines based on the hugepae size supported by them.
Well, what do we want to happen if source code contains SHM_HUGE_2MB?
Do we want it to fail to compile on ppc, or do we want it to request 2MB
pages and get ... hmm, looks like it fails at runtime (size_to_hstate
ends up returning NULL). So, yeah, looks like a compile-time failure
would be better.
But speaking of MAP_HUGE_, the only definitions so far are in arch/x86.
Are you going to add the ppc versions?
Also, which header file? I'm reluctant to add a new header, but
asm/shmbuf.h doesn't seem like a great place to put it.
next prev parent reply other threads:[~2017-04-13 12:46 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-08 17:06 [PATCH] mm,hugetlb: compute page_size_log properly Davidlohr Bueso
2017-03-08 19:39 ` Andi Kleen
2017-03-09 3:24 ` Anshuman Khandual
2017-03-09 8:55 ` Michal Hocko
2017-03-28 16:53 ` Davidlohr Bueso
2017-03-28 16:55 ` Davidlohr Bueso
2017-03-28 17:54 ` Matthew Wilcox
2017-03-29 8:06 ` Michal Hocko
2017-03-29 17:45 ` Andi Kleen
2017-03-30 6:12 ` Michal Hocko
2017-04-12 16:18 ` Davidlohr Bueso
2017-04-12 16:30 ` Andi Kleen
2017-04-12 17:21 ` Matthew Wilcox
2017-04-13 6:02 ` Aneesh Kumar K.V
2017-04-13 12:46 ` Matthew Wilcox [this message]
2017-07-17 22:27 ` Mike Kravetz
2017-07-17 22:27 ` [RFC PATCH 1/3] mm:hugetlb: Define system call hugetlb size encodings in single file Mike Kravetz
2017-07-18 0:00 ` Matthew Wilcox
2017-07-26 9:50 ` Michal Hocko
2017-07-17 22:28 ` [RFC PATCH 2/3] mm: arch: Use new hugetlb size encoding definitions Mike Kravetz
2017-07-26 9:52 ` Michal Hocko
2017-07-17 22:28 ` [RFC PATCH 3/3] mm: shm: " Mike Kravetz
2017-07-26 9:53 ` Michal Hocko
2017-07-26 10:07 ` Michal Hocko
2017-07-26 17:39 ` Mike Kravetz
2017-07-26 18:48 ` Matthew Wilcox
2017-07-27 7:50 ` Michal Hocko
2017-07-27 21:18 ` Mike Kravetz
2017-07-28 6:30 ` Michal Hocko
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