Re: x86 ptep_get_and_clear question

From: Linus Torvalds (
Date: Fri Feb 16 2001 - 14:00:41 EST

On Fri, 16 Feb 2001, Manfred Spraul wrote:
> That leaves msync() - it currently does a flush_tlb_page() for every
> single dirty page.
> Is it possible to integrate that into the mmu gather code?

Not even necessary.

The D bit does not have to be coherent. We need to make sure that we flush
the TLB before we start the IO on the pages which clears the per-physical
D bit (so that no CPU will have done any modifications that didn't show up
in one of the D bits - whther virtual in the page tables or physical in
the memory map), but there are no other real requirements.

So you don't strictly need to gather them at all, although right now with
the type of setup we have I suspect it's hard to actually implement any
other way (because msync doesn't necessarily know when the IO has been
physically started and has no good way of hooking into it..).


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This archive was generated by hypermail 2b29 : Fri Feb 23 2001 - 21:00:13 EST