From: Benjamin Herrenschmidt <benh@kernel•crashing.org>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux•vnet.ibm.com>,
paulus@samba•org, mpe@ellerman•id.au
Cc: linuxppc-dev@lists•ozlabs.org
Subject: Re: [RFC PATCH 5/5] powerpc/mm/hash: Increase VA range to 256TB
Date: Tue, 07 Feb 2017 15:46:00 +1100 [thread overview]
Message-ID: <1486442760.4850.121.camel@kernel.crashing.org> (raw)
In-Reply-To: <87lgtir5wa.fsf@skywalker.in.ibm.com>
On Tue, 2017-02-07 at 09:47 +0530, Aneesh Kumar K.V wrote:
> > Benjamin Herrenschmidt <benh@kernel•crashing.org> writes:
>
> > That's 48 bits. I would keep the limit at 47 without some explicit
> > opt-in by applications. That's what users get on x86 and we know
> > some GPUs have limits there.
>
> The idea is to have linux personality values that will limit the
> effective address to different memory range. By default max effective
> address will be limited to 64TB. Applications can then extend this to
> 128TB or 512TB. So we will have two personality values PER_LINUX_128TB
> and PER_LINUX_512TB ?
No. I think we can go up to 47-bits without any personality
requirement. For above, a single personality indicating that the
application has no limit.
Check what Intel is doing for 5-level trees
Cheers,
Ben.
prev parent reply other threads:[~2017-02-07 4:46 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-07 3:48 [RFC PATCH 0/5] Add support for larger address space for ppc64 Aneesh Kumar K.V
2017-02-07 3:48 ` [RFC PATCH 1/5] powerpc/mm/slice: Convert slice_mask high slice to a bitmap Aneesh Kumar K.V
2017-02-08 10:30 ` Balbir Singh
2017-02-07 3:48 ` [RFC PATCH 2/5] powerpc/mm/slice: Update the function prototype Aneesh Kumar K.V
2017-02-07 3:48 ` [RFC PATCH 3/5] powerpc/mm/hash: Move kernel context to the starting of context range Aneesh Kumar K.V
2017-02-07 3:48 ` [RFC PATCH 4/5] powerpc/mm/hash: Support 68 bit VA Aneesh Kumar K.V
2017-02-07 3:48 ` [RFC PATCH 5/5] powerpc/mm/hash: Increase VA range to 256TB Aneesh Kumar K.V
2017-02-07 4:06 ` Benjamin Herrenschmidt
2017-02-07 4:17 ` Aneesh Kumar K.V
2017-02-07 4:46 ` Benjamin Herrenschmidt [this message]
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