Re: [PATCH 2/2] arm64: mte: Defer disabling of TCO until user_access_begin/end

From: Carl Worth

Date: Wed Jan 14 2026 - 15:27:51 EST


Catalin Marinas <catalin.marinas@xxxxxxx> writes:
> On Fri, Jan 09, 2026 at 11:29:29PM -0600, Taehyun Noh wrote:
>> Our team agrees with Catalin’s TCMA1 solution. It disables every kernel
>> tag checking but the user address will get tag checked as far as TCO is
>> clear. Also, Carl’s initial testing confirms that
>> `mem_access_checked*:k` counters drop with the TCMA1 patch. While we
>> haven’t run the memcached benchmark yet, we will follow up with those
>> results shortly.
>
> That's great. Carl, could you please respin the patch with just setting
> the TCMA1 bit? Just add a suggested-by me (I could post the patch as
> well but I don't have the data to back it up and include in the commit
> log).

Will do. I'm just running the final benchmark numbers and then will send
this out.

-Carl