From: Michal Hocko <mhocko@suse.cz>
To: Ric Mason <ric.masonn@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>,
linux-mm@kvack.org, Hillf Danton <dhillf@gmail.com>
Subject: Re: Support variable-sized huge pages
Date: Tue, 5 Feb 2013 10:51:32 +0100 [thread overview]
Message-ID: <20130205095120.GA22808@dhcp22.suse.cz> (raw)
In-Reply-To: <1360043326.2403.2.camel@kernel.cn.ibm.com>
On Mon 04-02-13 23:48:46, Ric Mason wrote:
> Hi Andi,
> On Thu, 2013-01-31 at 11:52 +0100, Andi Kleen wrote:
> > On Thu, Jan 31, 2013 at 02:23:10AM -0600, Ric Mason wrote:
> > > Hi all,
> > >
> > > It seems that Andi's "Support more pagesizes for
> > > MAP_HUGETLB/SHM_HUGETLB" patch has already merged. According to the
> > > patch, x86 will support 2MB and 1GB huge pages. But I just see
> > > hugepages-2048kB under /sys/kernel/mm/hugepages/ on my x86_32 PAE desktop.
> > > Where is 1GB huge pages?
> >
> > 1GB pages are only supported under 64bit kernels, and also
> > only if you allocate them explicitely with boot options.
>
> I am curious about how can buddy system alloc 1GB huge pages? the most
> order buddy system supports is 10. Could you explain to me?
Have a look at setup_hugepagesz & hugetlb_nrpages_setup (in x86 arch code).
A short answer is. Bootmem is used for allocation > MAX_ORDER.
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2013-02-05 9:51 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-31 8:23 Ric Mason
2013-01-31 8:57 ` Jianguo Wu
2013-01-31 10:52 ` Andi Kleen
2013-02-05 5:48 ` Ric Mason
2013-02-05 9:51 ` Michal Hocko [this message]
2013-02-05 14:08 ` Andi Kleen
2013-02-24 7:00 ` Ric Mason
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