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* [RFC/PATCH 0/12] WIP mmu_gather and PTE accessors work
@ 2007-08-07  7:19 Benjamin Herrenschmidt
  2007-08-07  7:19 ` [RFC/PATCH 1/12] remove frv usage of flush_tlb_pgtables() Benjamin Herrenschmidt
                   ` (11 more replies)
  0 siblings, 12 replies; 13+ messages in thread
From: Benjamin Herrenschmidt @ 2007-08-07  7:19 UTC (permalink / raw)
  To: Linux Memory Management; +Cc: linux-kernel

This is a snapshot of my current work on PTE accessors and
mmu_gather. It's not complete but it should show the direction
I'm heading toward.

The main goals are:

 - Make mmu_gather used for all page table walk operations that
also need to invalidate TLB entries, thus obsoleting flush_tlb_range()
and flush_tlb_mm() as generic APIs to the TLB flushing.

 - Make mmu_gather stack based. The cleans quite a bit of stuff up,
and once fully done, should allow to reduce latencies caused by the
need to use get_cpu() for a long time.

 - Make mmu_gather more flexible so that archs who need to do more than
what the standard implementation does don't have to copy all of it and
do their own implementation.

 - Make mmu_gather suitable for batching on powerpc :-) This involves
mostly adding a hook before PTE pages are unlocked and some work on
the interaction between PTE accessors and tlb_remove_tlb_entry()

 - Remove other remaings of flush_tlb_*, keeping only for now
flush_tlb_kernel_range() which will be harder to "fix" (provided we
want to do it at all)

 - Go through all remaining page table accessors, remove all the unused
ones (there's still a few), there should be only a handful left and redo
the documentation accordingly.

These goals are _NOT_ yet met by this patch serie and some of the bits
in there may want to be done a bit differently. As I did the patches,
and hacked various archs, I got a better visibility on what is done and
why and thus some of my initial directions end up not looking so good.

Most notably, the MMF_DEAD flag doesn't sound like such a good idea
anymore and I'm considering instead replacing ptep_get_and_clear()
and tlb_remove_tlb_entry() with a version that takes the batch as an
argument.

Also, I haven't fully moved the batch off the per-cpu, only "part 1" is
there at this stage.

However, I'll be travelling for a while and won't have much time to work
on it until I'm back mid september, so I decided now was a good time to
post what I have for comments and discussions on the approach taken.

Cheers,
Ben.

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^ permalink raw reply	[flat|nested] 13+ messages in thread

end of thread, other threads:[~2007-08-07  7:19 UTC | newest]

Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2007-08-07  7:19 [RFC/PATCH 0/12] WIP mmu_gather and PTE accessors work Benjamin Herrenschmidt
2007-08-07  7:19 ` [RFC/PATCH 1/12] remove frv usage of flush_tlb_pgtables() Benjamin Herrenschmidt
2007-08-07  7:19 ` [RFC/PATCH 2/12] remove flush_tlb_pgtables Benjamin Herrenschmidt
2007-08-07  7:19 ` [RFC/PATCH 3/12] Add MMF_DEAD flag to mm_struct being torn down Benjamin Herrenschmidt
2007-08-07  7:19 ` [RFC/PATCH 4/12] disconnect sparc64 tlb flush from mmu_gather Benjamin Herrenschmidt
2007-08-07  7:19 ` [RFC/PATCH 5/12] Add mm argument to pte/pmd/pud/pgd_free Benjamin Herrenschmidt
2007-08-07  7:19 ` [RFC/PATCH 6/12] Add "address" argument to pte/pmd/pud_free_tlb() Benjamin Herrenschmidt
2007-08-07  7:19 ` [RFC/PATCH 7/12] ia64 tracks freed page tables addresses Benjamin Herrenschmidt
2007-08-07  7:19 ` [RFC/PATCH 8/12] remove ptep_get_and_clear_full Benjamin Herrenschmidt
2007-08-07  7:19 ` [RFC/PATCH 9/12] mmu_gather on stack, part 1 Benjamin Herrenschmidt
2007-08-07  7:19 ` [RFC/PATCH 10/12] remove call to flush_tlb_page() from handle_pte_fault() Benjamin Herrenschmidt
2007-08-07  7:19 ` [RFC/PATCH 11/12] Use mmu_gather for fork() instead of flush_tlb_mm() Benjamin Herrenschmidt
2007-08-07  7:19 ` [RFC/PATCH 12/12] Use mmu_gather for fs/proc/task_mmu.c Benjamin Herrenschmidt

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