From: David Gibson <david@gibson.dropbear.id.au>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: paulus@samba.org, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org
Subject: Re: [RFC PATCH -V2 05/21] powerpc: Reduce PTE table memory wastage
Date: Fri, 22 Feb 2013 11:32:35 +1100 [thread overview]
Message-ID: <20130222003235.GJ21011@truffula.fritz.box> (raw)
In-Reply-To: <1361465248-10867-6-git-send-email-aneesh.kumar@linux.vnet.ibm.com>
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On Thu, Feb 21, 2013 at 10:17:12PM +0530, Aneesh Kumar K.V wrote:
> From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
>
> We now have PTE page consuming only 2K of the 64K page.This is in order to
> facilitate transparent huge page support, which works much better if our PMDs
> cover 16MB instead of 256MB.
>
> Inorder to reduce the wastage, we now have multiple PTE page fragment
> from the same PTE page.
This needs a much better description of what you're doing here to
manage the allocations. It's certainly not easy to figure out from
the code.
[snip]
> +#ifdef CONFIG_PPC_64K_PAGES
> +typedef pte_t *pgtable_t;
> +#else
> typedef struct page *pgtable_t;
> +#endif
This looks really bogus. A pgtable_t is a pointer to PTEs on 64K, but
a pointer to a struct page on 4k.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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next prev parent reply other threads:[~2013-02-22 0:32 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-21 16:47 [RFC PATCH -V2 00/21] THP support for PPC64 Aneesh Kumar K.V
2013-02-21 16:47 ` [RFC PATCH -V2 01/21] powerpc: Use signed formatting when printing error Aneesh Kumar K.V
2013-02-22 5:00 ` Paul Mackerras
2013-02-21 16:47 ` [RFC PATCH -V2 02/21] powerpc: Save DAR and DSISR in pt_regs on MCE Aneesh Kumar K.V
2013-02-22 5:03 ` Paul Mackerras
2013-02-21 16:47 ` [RFC PATCH -V2 03/21] powerpc: Don't hard code the size of pte page Aneesh Kumar K.V
2013-02-22 5:06 ` Paul Mackerras
2013-02-23 16:17 ` Aneesh Kumar K.V
2013-02-21 16:47 ` [RFC PATCH -V2 04/21] powerpc: Reduce the PTE_INDEX_SIZE Aneesh Kumar K.V
2013-02-22 5:07 ` Paul Mackerras
2013-02-21 16:47 ` [RFC PATCH -V2 05/21] powerpc: Reduce PTE table memory wastage Aneesh Kumar K.V
2013-02-22 0:32 ` David Gibson [this message]
2013-02-22 5:14 ` Aneesh Kumar K.V
2013-02-22 5:23 ` Paul Mackerras
2013-02-22 17:20 ` Aneesh Kumar K.V
2013-02-23 16:38 ` Aneesh Kumar K.V
2013-02-21 16:47 ` [RFC PATCH -V2 06/21] powerpc: Add size argument to pgtable_cache_add Aneesh Kumar K.V
2013-02-22 5:27 ` Paul Mackerras
2013-02-21 16:47 ` [RFC PATCH -V2 07/21] powerpc: Use encode avpn where we need only avpn values Aneesh Kumar K.V
2013-02-22 5:28 ` Paul Mackerras
2013-02-21 16:47 ` [RFC PATCH -V2 08/21] powerpc: Decode the pte-lp-encoding bits correctly Aneesh Kumar K.V
2013-02-22 5:37 ` Paul Mackerras
2013-02-24 16:51 ` Aneesh Kumar K.V
2013-02-24 17:45 ` Aneesh Kumar K.V
2013-02-21 16:47 ` [RFC PATCH -V2 09/21] powerpc: Update tlbie/tlbiel as per ISA doc Aneesh Kumar K.V
2013-02-21 16:47 ` [RFC PATCH -V2 10/21] powerpc: print both base and actual page size on hash failure Aneesh Kumar K.V
2013-02-21 16:47 ` [RFC PATCH -V2 11/21] powerpc: Print page size info during boot Aneesh Kumar K.V
2013-02-21 16:47 ` [RFC PATCH -V2 12/21] powerpc: Fix hpte_decode to use the correct decoding for page sizes Aneesh Kumar K.V
2013-02-21 16:47 ` [RFC PATCH -V2 13/21] mm/THP: HPAGE_SHIFT is not a #define on some arch Aneesh Kumar K.V
2013-02-21 16:47 ` [RFC PATCH -V2 14/21] mm/THP: Add pmd args to pgtable deposit and withdraw APIs Aneesh Kumar K.V
2013-02-21 16:47 ` [RFC PATCH -V2 15/21] mm/THP: support for zerout withdraw Aneesh Kumar K.V
2013-02-21 16:47 ` [RFC PATCH -V2 16/21] powerpc/THP: Implement transparent huge pages for ppc64 Aneesh Kumar K.V
2013-02-21 16:47 ` [RFC PATCH -V2 17/21] powerpc/THP: Differentiate THP PMD entries from HUGETLB PMD entries Aneesh Kumar K.V
2013-02-21 16:47 ` [RFC PATCH -V2 18/21] powerpc/THP: Add code to handle HPTE faults for large pages Aneesh Kumar K.V
2013-02-21 16:47 ` [RFC PATCH -V2 19/21] powerpc/THP: hypervisor require few WIMG bit set Aneesh Kumar K.V
2013-02-21 16:47 ` [RFC PATCH -V2 20/21] powerpc/THP: get_user_pages_fast changes Aneesh Kumar K.V
2013-02-21 16:47 ` [RFC PATCH -V2 21/21] powerpc/THP: Enable THP on PPC64 Aneesh Kumar K.V
2013-03-21 8:17 ` [RFC PATCH -V2 00/21] THP support for PPC64 Simon Jeons
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