From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: David Gibson <dwg@au1.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org, paulus@samba.org, linux-mm@kvack.org
Subject: Re: [PATCH -V7 01/18] mm/THP: HPAGE_SHIFT is not a #define on some arch
Date: Sat, 04 May 2013 00:21:47 +0530 [thread overview]
Message-ID: <87obcr522k.fsf@linux.vnet.ibm.com> (raw)
In-Reply-To: <20130430050101.GY20202@truffula.fritz.box>
David Gibson <dwg@au1.ibm.com> writes:
> On Tue, Apr 30, 2013 at 09:12:09AM +0530, Aneesh Kumar K.V wrote:
>> David Gibson <dwg@au1.ibm.com> writes:
>>
>> > On Mon, Apr 29, 2013 at 01:07:22AM +0530, Aneesh Kumar K.V wrote:
>> >> From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
>> >>
>> >> On archs like powerpc that support different hugepage sizes, HPAGE_SHIFT
>> >> and other derived values like HPAGE_PMD_ORDER are not constants. So move
>> >> that to hugepage_init
>> >
>> > These seems to miss the point. Those variables may be defined in
>> > terms of HPAGE_SHIFT right now, but that is of itself kind of broken.
>> > The transparent hugepage mechanism only works if the hugepage size is
>> > equal to the PMD size - and PMD_SHIFT remains a compile time constant.
>> >
>> > There's no reason having transparent hugepage should force the PMD
>> > size of hugepage to be the default for other purposes - it should be
>> > possible to do THP as long as PMD-sized is a possible hugepage size.
>> >
>>
>> THP code does
>>
>> #define HPAGE_PMD_SHIFT HPAGE_SHIFT
>> #define HPAGE_PMD_MASK HPAGE_MASK
>> #define HPAGE_PMD_SIZE HPAGE_SIZE
>>
>> I had two options, one to move all those in terms of PMD_SHIFT
>
> This is a much better option that you've taken now, and really
> shouldn't be that hard. The THP code is much more strongly tied to
> the fact that it is a PMD than the fact that it's the same size as
> explicit huge pages.
>
Ok I tried the above and that turned out to be much simpler. I will have
to make sure i didn't break other archs that support THP.
-aneesh
next prev parent reply other threads:[~2013-05-03 18:51 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-28 19:37 [PATCH -V7 00/18] THP support for PPC64 (Patchset 1) Aneesh Kumar K.V
2013-04-28 19:37 ` [PATCH -V7 01/18] mm/THP: HPAGE_SHIFT is not a #define on some arch Aneesh Kumar K.V
2013-04-30 2:21 ` David Gibson
2013-04-30 2:24 ` David Gibson
2013-04-30 3:42 ` Aneesh Kumar K.V
2013-04-30 5:01 ` David Gibson
2013-05-03 18:51 ` Aneesh Kumar K.V [this message]
2013-04-28 19:37 ` [PATCH -V7 02/18] mm/THP: Add pmd args to pgtable deposit and withdraw APIs Aneesh Kumar K.V
2013-04-28 19:37 ` [PATCH -V7 03/18] mm/THP: withdraw the pgtable after pmdp related operations Aneesh Kumar K.V
2013-04-28 19:37 ` [PATCH -V7 04/18] powerpc: Use signed formatting when printing error Aneesh Kumar K.V
2013-04-28 19:37 ` [PATCH -V7 05/18] powerpc: Save DAR and DSISR in pt_regs on MCE Aneesh Kumar K.V
2013-04-28 19:37 ` [PATCH -V7 06/18] powerpc: Don't hard code the size of pte page Aneesh Kumar K.V
2013-04-28 19:37 ` [PATCH -V7 07/18] powerpc: Don't truncate pgd_index wrongly Aneesh Kumar K.V
2013-04-28 19:37 ` [PATCH -V7 08/18] powerpc: New hugepage directory format Aneesh Kumar K.V
2013-04-30 5:16 ` David Gibson
2013-04-28 19:37 ` [PATCH -V7 09/18] powerpc: Switch 16GB and 16MB explicit hugepages to a different page table format Aneesh Kumar K.V
2013-04-30 5:17 ` David Gibson
2013-06-06 22:42 ` Scott Wood
2013-06-07 3:55 ` Aneesh Kumar K.V
2013-06-07 19:17 ` Scott Wood
2013-06-08 16:57 ` Aneesh Kumar K.V
2013-06-11 20:53 ` Scott Wood
2013-06-11 22:50 ` Scott Wood
2013-06-12 6:30 ` Aneesh Kumar K.V
2013-04-28 19:37 ` [PATCH -V7 10/18] powerpc: Reduce the PTE_INDEX_SIZE Aneesh Kumar K.V
2013-04-28 19:37 ` [PATCH -V7 11/18] powerpc: Move the pte free routines from common header Aneesh Kumar K.V
2013-04-28 19:37 ` [PATCH -V7 12/18] powerpc: Reduce PTE table memory wastage Aneesh Kumar K.V
2013-04-28 19:37 ` [PATCH -V7 13/18] powerpc: Use encode avpn where we need only avpn values Aneesh Kumar K.V
2013-04-28 19:37 ` [PATCH -V7 14/18] powerpc: Decode the pte-lp-encoding bits correctly Aneesh Kumar K.V
2013-04-28 19:37 ` [PATCH -V7 15/18] powerpc: Fix hpte_decode to use the correct decoding for page sizes Aneesh Kumar K.V
2013-04-28 19:37 ` [PATCH -V7 16/18] powerpc: print both base and actual page size on hash failure Aneesh Kumar K.V
2013-04-28 19:37 ` [PATCH -V7 17/18] powerpc: Print page size info during boot Aneesh Kumar K.V
2013-04-28 19:37 ` [PATCH -V7 18/18] powerpc: Update tlbie/tlbiel as per ISA doc Aneesh Kumar K.V
2013-04-30 6:15 ` David Gibson
2013-04-30 17:21 ` Aneesh Kumar K.V
2013-05-01 5:26 ` David Gibson
2013-05-01 7:47 ` Aneesh Kumar K.V
2013-05-01 7:52 ` Simon Jeons
2013-05-01 11:36 ` David Gibson
2013-05-02 5:23 ` David Gibson
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