[RFC PATCH 2/2] mm/mmu_gather: Avoid multiple page walk cache flush

[Aneesh Kumar K.V]

On 12/17/19 2:28 PM, Peter Zijlstra wrote:
> On Tue, Dec 17, 2019 at 12:47:13PM +0530, Aneesh Kumar K.V wrote:
>> On tlb_finish_mmu() kernel does a tlb flush before  mmu gather table invalidate.
>> The mmu gather table invalidate depending on kernel config also does another
>> TLBI. Avoid the later on tlb_finish_mmu().
> 
> That is already avoided, if you look at tlb_flush_mmu_tlbonly() it does
> __tlb_range_reset(), which results in ->end = 0, which then triggers the
> early exit on the next invocation:
> 
> 	if (!tlb->end)
> 		return;
> 

Is that true for tlb->fulmm flush?

-aneesh