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Date:   Mon, 31 May 2021 08:36:58 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     palmerdabbelt@google.com
Cc:     Christoph Hellwig <hch@lst.de>, guoren@kernel.org,
        Anup Patel <Anup.Patel@wdc.com>, Arnd Bergmann <arnd@arndb.de>,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-arch@vger.kernel.org, linux-sunxi@lists.linux.dev,
        guoren@linux.alibaba.com
Subject: Re: [PATCH V4 2/2] riscv: Use use_asid_allocator flush TLB
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References: <20210527070903.GA32653@lst.de> <mhng-cfb5a043-4b59-4698-b732-5cf5ceb49114@palmerdabbelt-glaptop>
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On Sat, May 29, 2021 at 04:42:37PM -0700, palmerdabbelt@google.com wrote:
>>
>> Also the non-ASID code switches to a global flush once flushing more
>> than a single page.  It might be worth documenting the tradeoff in the
>> code.
>
> For some reason I thought we'd written this down in the commentary of teh 
> ISA manual as the suggested huersitic here, but I can't find it so maybe 
> I'm wrong.  If it's actually there it would be good to point that out, 
> otherwise some documentation seems fine as it'll probably become a tunable 
> at some point anyway.

The real question is why is the heuristic different for the ASID vs
non-ASID case?  I think that really need a comment.

> LGTM.  I took the first one as IMO they're really distnict issues, LMK if 
> you want to re-spin this one or if I should just take what's here.

What distinct issue?  The fact that the new code is buggy and uses rather
non-optimal calling conventions?