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

From: Nick Piggin
Date: Mon Jul 09 2007 - 06:12:43 EST


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.
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