Re: [RFC/PATCH] Use mmu_gather for fork() instead of flush_tlb_mm()

Nick Piggin
2007-07-09T10:12:43Z

Benjamin Herrenschmidt wrote:
> On Mon, 2007-07-09 at 19:29 +1000, Nick Piggin wrote:
>
>>They could just #define one to the other though, there are only a
>>small
>>number of them. Is there a downside to not making them distinct? i386
>>for example probably would just keep doing a tlb flush for fork and
>>not
>>want to worry about touching the tlb gather stuff.
>
>
> But the tlb gather stuff just does ... a flush_tlb_mm() on x86 :-)

But it still does the get_cpu of the mmu gather data structure and
has to look in there and touch the cacheline. You're also having to
do more work when unlocking/relocking the ptl etc.

> I really think it's the right API

--
SUSE Labs, Novell Inc.