From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH -V3 11/11] arch/powerpc: Add 64TB support
Date: Mon, 23 Jul 2012 14:19:32 +0530 [thread overview]
Message-ID: <87wr1uhnfn.fsf@skywalker.in.ibm.com> (raw)
In-Reply-To: <20120723001539.GI17790@bloggs.ozlabs.ibm.com>
Paul Mackerras <paulus@samba.org> writes:
> On Mon, Jul 09, 2012 at 06:43:41PM +0530, Aneesh Kumar K.V wrote:
>> From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
>>
>> Increase max addressable range to 64TB. This is not tested on
>> real hardware yet.
>>
>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
>> ---
>> arch/powerpc/include/asm/mmu-hash64.h | 8 ++++----
>> arch/powerpc/include/asm/pgtable-ppc64-4k.h | 2 +-
>> arch/powerpc/include/asm/pgtable-ppc64-64k.h | 2 +-
>> arch/powerpc/include/asm/processor.h | 4 ++--
>> arch/powerpc/include/asm/sparsemem.h | 4 ++--
>> 5 files changed, 10 insertions(+), 10 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/mmu-hash64.h b/arch/powerpc/include/asm/mmu-hash64.h
>> index aa0d560..a227ba7 100644
>> --- a/arch/powerpc/include/asm/mmu-hash64.h
>> +++ b/arch/powerpc/include/asm/mmu-hash64.h
>> @@ -374,16 +374,16 @@ extern void slb_set_size(u16 size);
>> */
>>
>> #define VSID_MULTIPLIER_256M ASM_CONST(200730139) /* 28-bit prime */
>> -#define VSID_BITS_256M 36
>> +#define VSID_BITS_256M 38
>> #define VSID_MODULUS_256M ((1UL<<VSID_BITS_256M)-1)
>
> With these settings, the multiplication in ASM_VSID_SCRAMBLE could
> overflow, leading to incorrect results (which would cause occasional
> corruption of user processes under heavy load). You will need to
> reduce the multiplier to be less than 2^26, and it will need to be
> co-prime with 2^38 - 1. (Probably, the same value as we use in the 1T
> case would be OK.)
I ended up using the same value as VSID_MULTIPLIER_1T.
(gdb) p/d 1ull << 38
$1 = 274877906944
(gdb) p/d 274877906943/12538073
$2 = 21923
(gdb) p/d 12538073ll*21923
$5 = 274872174379
next prev parent reply other threads:[~2012-07-23 8:49 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-09 13:13 [PATCH -V3 0/11] arch/powerpc: Add 64TB support to ppc64 Aneesh Kumar K.V
2012-07-09 13:13 ` [PATCH -V3 01/11] arch/powerpc: Use hpt_va to compute virtual address Aneesh Kumar K.V
2012-07-22 23:17 ` Paul Mackerras
2012-07-09 13:13 ` [PATCH -V3 02/11] arch/powerpc: Simplify hpte_decode Aneesh Kumar K.V
2012-07-22 23:26 ` Paul Mackerras
2012-07-23 5:41 ` Aneesh Kumar K.V
2012-07-09 13:13 ` [PATCH -V3 03/11] arch/powerpc: Convert virtual address to vpn Aneesh Kumar K.V
2012-07-09 22:41 ` Stephen Rothwell
2012-07-10 6:12 ` Aneesh Kumar K.V
2012-07-09 23:06 ` Stephen Rothwell
2012-07-10 6:15 ` Aneesh Kumar K.V
2012-07-22 23:42 ` Paul Mackerras
2012-07-23 5:54 ` Aneesh Kumar K.V
2012-07-09 13:13 ` [PATCH -V3 04/11] arch/powerpc: Rename va " Aneesh Kumar K.V
2012-07-22 23:46 ` Paul Mackerras
2012-07-23 6:14 ` Aneesh Kumar K.V
2012-07-09 13:13 ` [PATCH -V3 05/11] arch/powerpc: remove masking top 16 bit of va in tlb invalidate Aneesh Kumar K.V
2012-07-22 23:56 ` Paul Mackerras
2012-07-23 1:22 ` Benjamin Herrenschmidt
2012-07-23 3:49 ` Paul Mackerras
2012-07-23 6:44 ` Aneesh Kumar K.V
2012-07-23 6:48 ` Benjamin Herrenschmidt
2012-07-09 13:13 ` [PATCH -V3 06/11] arch/powerpc: Make KERN_VIRT_SIZE not dependend on PGTABLE_RANGE Aneesh Kumar K.V
2012-07-22 23:57 ` Paul Mackerras
2012-07-09 13:13 ` [PATCH -V3 07/11] arch/powerpc: Increase the slice range to 64TB Aneesh Kumar K.V
2012-07-23 0:00 ` Paul Mackerras
2012-07-23 7:13 ` Aneesh Kumar K.V
2012-07-09 13:13 ` [PATCH -V3 08/11] arch/powerpc: Make some of the PGTABLE_RANGE dependency explicit Aneesh Kumar K.V
2012-07-23 0:20 ` Paul Mackerras
2012-07-23 7:29 ` Aneesh Kumar K.V
2012-07-09 13:13 ` [PATCH -V3 09/11] arch/powerpc: Use 50 bits of VSID in slbmte Aneesh Kumar K.V
2012-07-23 0:06 ` Paul Mackerras
2012-07-23 8:21 ` Aneesh Kumar K.V
2012-07-23 9:36 ` Paul Mackerras
2012-07-23 10:22 ` Aneesh Kumar K.V
2012-07-09 13:13 ` [PATCH -V3 10/11] arch/powerpc: Use 32bit array for slb cache Aneesh Kumar K.V
2012-07-23 0:27 ` Paul Mackerras
2012-07-23 8:25 ` Aneesh Kumar K.V
2012-07-09 13:13 ` [PATCH -V3 11/11] arch/powerpc: Add 64TB support Aneesh Kumar K.V
2012-07-23 0:15 ` Paul Mackerras
2012-07-23 8:49 ` Aneesh Kumar K.V [this message]
2012-07-23 9:39 ` Paul Mackerras
2012-07-23 10:22 ` Aneesh Kumar K.V
2012-07-23 11:06 ` Paul Mackerras
2012-07-24 8:37 ` Aneesh Kumar K.V
2012-07-24 9:14 ` Aneesh Kumar K.V
2012-07-24 19:50 ` Aneesh Kumar K.V
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