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From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: "Michal Suchánek" <msuchanek@suse.de>, linuxppc-dev@lists.ozlabs.org
Cc: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au
Subject: Re: [PATCH V3 08/10] powerpc/mm/hash: Increase VA range to 128TB
Date: Mon, 06 Mar 2017 09:07:48 +0530	[thread overview]
Message-ID: <87y3wjcbxv.fsf@skywalker.in.ibm.com> (raw)
In-Reply-To: <8760jndt6v.fsf@skywalker.in.ibm.com>

"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> writes:

> Michal Such=C3=A1nek <msuchanek@suse.de> writes:
>
>> Hello,
>>
>> On Sun, 19 Feb 2017 15:37:15 +0530
>> "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> wrote:
>>
>>> We update the hash linux page table layout such that we can support
>>> 512TB. But we limit the TASK_SIZE to 128TB. We can switch to 128TB by
>>> default without conditional because that is the max virtual address
>>> supported by other architectures. We will later add a mechanism to
>>> on-demand increase the application's effective address range to 512TB.
>>>=20
>>> Having the page table layout changed to accommodate 512TB  makes
>>> testing large memory configuration easier with less code changes to
>>> kernel
>>>=20
>>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
>
> ....
>
>> index b64daf124fee..c7ca70dc3ba5 100644
>>> --- a/arch/powerpc/kernel/paca.c
>>> +++ b/arch/powerpc/kernel/paca.c
>>> @@ -253,8 +253,15 @@ void copy_mm_to_paca(struct mm_struct *mm)
>>>  	get_paca()->mm_ctx_id =3D context->id;
>>>  #ifdef CONFIG_PPC_MM_SLICES
>>>  	get_paca()->mm_ctx_low_slices_psize =3D
>>> context->low_slices_psize;
>>> +	/*
>>> +	 * We support upto 128TB for now. Hence copy only 128/2
>>> bytes.
>>> +	 * Later when we support tasks with different max effective
>>> +	 * address, we can optimize this based on mm->task_size.
>>> +	 */
>>> +	BUILD_BUG_ON(TASK_SIZE_USER64 !=3D TASK_SIZE_128TB);
>>
>> Can this be handled by KConfig?
>> Above I see=20
>
> I am reworking the series so that we depend on mm->task_size. Will send
> a new version soon.
>
>
>
>>> +#ifdef CONFIG_PPC_BOOK3S_64
>>> +#define TASK_SIZE_USER64 TASK_SIZE_128TB
>>> +#else
>>> +#define TASK_SIZE_USER64 TASK_SIZE_64TB
>>> +#endif
>> and=20
>>> #ifdef CONFIG_PPC_MM_SLICES
>>> ILD_BUG_ON(TASK_SIZE_USER64 !=3D TASK_SIZE_128TB)
>>
>> which boils down to
>> #ifndef CONFIG_PPC_BOOK3S_64
>> #ifdef CONFIG_PPC_MM_SLICES
>> #error TASK_SIZE_USER64 !=3D TASK_SIZE_128TB
>>
>>
>>>  	memcpy(&get_paca()->mm_ctx_high_slices_psize,
>>> -	       &context->high_slices_psize, SLICE_ARRAY_SIZE);
>>> +	       &context->high_slices_psize, TASK_SIZE_128TB >> 41);
>>
>> Can we avoid magic numbers, please?
>>
>
> Since array is 4 bytes per each TB which is documented else where.

4 bits per teach TB.


-aneesh

  reply	other threads:[~2017-03-06  3:39 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-19 10:07 [PATCH V3 00/10] powerpc/mm/ppc64: Add 128TB support Aneesh Kumar K.V
2017-02-19 10:07 ` [PATCH V3 01/10] powerpc/mm/slice: Convert slice_mask high slice to a bitmap Aneesh Kumar K.V
2017-02-21  4:43   ` Balbir Singh
2017-02-21  6:56     ` Aneesh Kumar K.V
2017-02-22  0:16       ` Balbir Singh
2017-02-19 10:07 ` [PATCH V3 02/10] powerpc/mm/slice: Update the function prototype Aneesh Kumar K.V
2017-02-21  4:44   ` Balbir Singh
2017-02-19 10:07 ` [PATCH V3 03/10] powerpc/mm/hash: Move kernel context to the starting of context range Aneesh Kumar K.V
2017-02-21  4:51   ` Balbir Singh
2017-02-19 10:07 ` [PATCH V3 04/10] powerpc/mm/hash: Support 68 bit VA Aneesh Kumar K.V
2017-02-22  0:15   ` Balbir Singh
2017-02-19 10:07 ` [PATCH V3 05/10] powerpc/mm: Move copy_mm_to_paca to paca.c Aneesh Kumar K.V
2017-02-19 10:07 ` [PATCH V3 06/10] powerpc/mm: Remove redundant TASK_SIZE_USER64 checks Aneesh Kumar K.V
2017-02-22  0:17   ` Balbir Singh
2017-02-19 10:07 ` [PATCH V3 07/10] powerpc/mm/slice: Use mm task_size as max value of slice index Aneesh Kumar K.V
2017-02-19 10:07 ` [PATCH V3 08/10] powerpc/mm/hash: Increase VA range to 128TB Aneesh Kumar K.V
2017-03-03 16:00   ` Michal Suchánek
2017-03-06  2:39     ` Aneesh Kumar K.V
2017-03-06  3:37       ` Aneesh Kumar K.V [this message]
2017-03-06 15:20         ` Michal Suchánek
2017-02-19 10:07 ` [PATCH V3 09/10] powerpc/mm/slice: Move slice_mask struct definition to slice.c Aneesh Kumar K.V
2017-03-03 15:44   ` Michal Suchánek
2017-02-19 10:07 ` [PATCH V3 10/10] powerpc/mm/slice: Update slice mask printing to use bitmap printing Aneesh Kumar K.V
2017-02-22  0:20   ` Balbir Singh

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