From: Benjamin Herrenschmidt <benh@au1.ibm.com>
To: Alexey Kardashevskiy <aik@ozlabs.ru>,
Michael Ellerman <mpe@ellerman.id.au>,
linuxppc-dev@lists.ozlabs.org
Cc: Gavin Shan <gwshan@linux.vnet.ibm.com>,
David Gibson <david@gibson.dropbear.id.au>
Subject: Re: [PATCH kernel] powerpc/powernv/ioda2: Gracefully fail if too many TCE levels requested
Date: Mon, 06 Mar 2017 14:36:09 +1100 [thread overview]
Message-ID: <1488771369.2870.123.camel@au1.ibm.com> (raw)
In-Reply-To: <cd84399e-73d6-72dd-8509-f45db5e47d31@ozlabs.ru>
On Mon, 2017-03-06 at 12:28 +1100, Alexey Kardashevskiy wrote:
> 8192*8192*8192*65536>>40 = 32768TB of addressable memory (but there is no
> good reason not to use huge pages);
No, 39 bits is half a TB. That's not enough.
> 8192*8192*8192*4096>>40 = 2048TB or addressable memory (even with 2
> indirect levels but we can have all 5 levels with 4K IOMMU pages).
>
> Looks enough to me...
>
> And in this particular patch I am not limiting anything, I just replace
> already existing EEH condition with -EINVAL. If it is this important to
> have all 5 levels, then we can switch from alloc_pages_node() to
> kmem_cache_alloc_node(), in a separate patch.
>
>
> --
next prev parent reply other threads:[~2017-03-06 3:37 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-22 4:43 [PATCH kernel] powerpc/powernv/ioda2: Gracefully fail if too many TCE levels requested Alexey Kardashevskiy
2017-02-27 0:53 ` Gavin Shan
2017-02-27 11:00 ` Michael Ellerman
2017-02-28 0:54 ` Alexey Kardashevskiy
2017-03-05 23:03 ` Benjamin Herrenschmidt
2017-03-06 1:28 ` Alexey Kardashevskiy
2017-03-06 3:36 ` Benjamin Herrenschmidt [this message]
2017-03-06 4:02 ` Alexey Kardashevskiy
2017-03-14 11:45 ` [kernel] " Michael Ellerman
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