Re: [PATCH 1/1] Page Table cleanup patch
Hi Nick On Wed, 24 Jan 2007, Nick Piggin wrote: Paul Davies wrote: This patch is a proposed cleanup of the current page table organisation. Such a cleanup would be a logical first step towards introducing at least a partial clean page table interface, geared towards providing enhanced virtualization oportunities for x86. It is also a common sense cleanup in its own right. * Creates mlpt.c to hold the page table implementation currently held in memory.c. * Adjust Makefile * Move implementation dependent page table code out of include/linux/mm.h into include/linux/mlpt-mm.h * Move implementation dependent page table code out of include/asm-generic/pgtable.h to include/asm-generic/pgtable-mlpt.h mlpt stands from multi level page table. Hi Paul, I'm not sure that I see the point of this patch alone, as there is still all the mlpt implementation details in all the page table walkers. Or did you have a scheme to change implementations somehow just using the p*d_addr_next? This patch alone doesn't acheive nearly enough. Separating out as much implementation (without tackling the walkers) would be a start though. The MLPT appears to be intrinsic to the kernel owing to its open coding, and starting to isolate its implementation (even partially) is an important step towards destroying this misconception. I strongly prefer not to go down the path of using a scheme to change implementations with p*d_addr_next. I tried this kind of thing early on and it was horribly ugly. There are far cleaner ways to do it. Cheers Paul Davies - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 1/1] Page Table cleanup patch
Hi Nick On Wed, 24 Jan 2007, Nick Piggin wrote: Paul Davies wrote: This patch is a proposed cleanup of the current page table organisation. Such a cleanup would be a logical first step towards introducing at least a partial clean page table interface, geared towards providing enhanced virtualization oportunities for x86. It is also a common sense cleanup in its own right. * Creates mlpt.c to hold the page table implementation currently held in memory.c. * Adjust Makefile * Move implementation dependent page table code out of include/linux/mm.h into include/linux/mlpt-mm.h * Move implementation dependent page table code out of include/asm-generic/pgtable.h to include/asm-generic/pgtable-mlpt.h mlpt stands from multi level page table. Hi Paul, I'm not sure that I see the point of this patch alone, as there is still all the mlpt implementation details in all the page table walkers. Or did you have a scheme to change implementations somehow just using the p*d_addr_next? This patch alone doesn't acheive nearly enough. Separating out as much implementation (without tackling the walkers) would be a start though. The MLPT appears to be intrinsic to the kernel owing to its open coding, and starting to isolate its implementation (even partially) is an important step towards destroying this misconception. I strongly prefer not to go down the path of using a scheme to change implementations with p*d_addr_next. I tried this kind of thing early on and it was horribly ugly. There are far cleaner ways to do it. Cheers Paul Davies - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 1/1] Page Table cleanup patch
Paul Davies wrote:
This patch is a proposed cleanup of the current page table organisation.
Such a cleanup would be a logical first step towards introducing at least
a partial clean page table interface, geared towards providing enhanced
virtualization oportunities for x86. It is also a common sense cleanup
in its own right.
* Creates mlpt.c to hold the page table implementation currently held
in memory.c.
* Adjust Makefile
* Move implementation dependent page table code out of
include/linux/mm.h into include/linux/mlpt-mm.h
* Move implementation dependent page table code out of
include/asm-generic/pgtable.h to include/asm-generic/pgtable-mlpt.h
mlpt stands from multi level page table.
Hi Paul,
I'm not sure that I see the point of this patch alone, as there is still
all the mlpt implementation details in all the page table walkers. Or
did you have a scheme to change implementations somehow just using the
p*d_addr_next?
-#ifndef __PAGETABLE_PUD_FOLDED
-/*
- * Allocate page upper directory.
- * We've already handled the fast-path in-line.
- */
-int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
-{
- pud_t *new = pud_alloc_one(mm, address);
- if (!new)
- return -ENOMEM;
-
- spin_lock(>page_table_lock);
- if (pgd_present(*pgd)) /* Another has populated it */
- pud_free(new);
- else
- pgd_populate(mm, pgd, new);
- spin_unlock(>page_table_lock);
- return 0;
-}
-#else
-/* Workaround for gcc 2.96 */
-int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
-{
- return 0;
-}
-#endif /* __PAGETABLE_PUD_FOLDED */
...
-/* Workaround for gcc 2.96 */
-int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
-{
- return 0;
-}
-#endif /* __PAGETABLE_PMD_FOLDED */
Hmm, we're gcc-3.2 minimum now -- let's get rid of that crud?
--
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com
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Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 1/1] Page Table cleanup patch
Paul Davies wrote:
This patch is a proposed cleanup of the current page table organisation.
Such a cleanup would be a logical first step towards introducing at least
a partial clean page table interface, geared towards providing enhanced
virtualization oportunities for x86. It is also a common sense cleanup
in its own right.
* Creates mlpt.c to hold the page table implementation currently held
in memory.c.
* Adjust Makefile
* Move implementation dependent page table code out of
include/linux/mm.h into include/linux/mlpt-mm.h
* Move implementation dependent page table code out of
include/asm-generic/pgtable.h to include/asm-generic/pgtable-mlpt.h
mlpt stands from multi level page table.
Hi Paul,
I'm not sure that I see the point of this patch alone, as there is still
all the mlpt implementation details in all the page table walkers. Or
did you have a scheme to change implementations somehow just using the
p*d_addr_next?
-#ifndef __PAGETABLE_PUD_FOLDED
-/*
- * Allocate page upper directory.
- * We've already handled the fast-path in-line.
- */
-int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
-{
- pud_t *new = pud_alloc_one(mm, address);
- if (!new)
- return -ENOMEM;
-
- spin_lock(mm-page_table_lock);
- if (pgd_present(*pgd)) /* Another has populated it */
- pud_free(new);
- else
- pgd_populate(mm, pgd, new);
- spin_unlock(mm-page_table_lock);
- return 0;
-}
-#else
-/* Workaround for gcc 2.96 */
-int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
-{
- return 0;
-}
-#endif /* __PAGETABLE_PUD_FOLDED */
...
-/* Workaround for gcc 2.96 */
-int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
-{
- return 0;
-}
-#endif /* __PAGETABLE_PMD_FOLDED */
Hmm, we're gcc-3.2 minimum now -- let's get rid of that crud?
--
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com
-
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
