Re: [RFC PATCH 00/11] Avoid synchronous TLB invalidation for intermediate page-table entries on arm64

From: Jon Masters
Date: Thu Sep 13 2018 - 12:53:33 EST


Computer Architect

> On Sep 13, 2018, at 11:52, Will Deacon <will.deacon@xxxxxxx> wrote:
>> On Fri, Sep 07, 2018 at 02:36:08AM -0400, Jon Masters wrote:
>>> On 09/05/2018 08:28 AM, Will Deacon wrote:
>>>> On Tue, Sep 04, 2018 at 02:38:02PM -0400, Jon Masters wrote:
>>>>> On 08/24/2018 11:52 AM, Will Deacon wrote:
>>>>> I hacked up this RFC on the back of the recent changes to the mmu_gather
>>>>> stuff in mainline. It's had a bit of testing and it looks pretty good so
>>>>> far.
>>>> I will request the server folks go and test this. You'll probably
>>>> remember a couple of parts we've seen where aggressive walker caches
>>>> ended up (correctly) seeing stale page table entries and we had all
>>>> manner of horrifically hard to debug problems. We have some fairly nice
>>>> reproducers that were able to find this last time that we can test.
>>> Cheers, Jon, that would be very helpful. You're probably best off using
>>> my (rebasing) tlb branch rather than picking the RFC:
>>> git:// tlb
>>> Let me know if you'd prefer something stable (I can tag it with a date).
>> That would be useful. I've prodded each of the Arm server SoC vendors I
>> work with via our weekly call to have them each specifically check this.
>> A tag would be helpful to that effort I expect. They all claim to be
>> watching this thread now, so we'll see if they see cabbages here.
> This is now all queued up in the (stable) arm64 for-next/core branch:
> so that's the best place to grab the patches.
> Will