linux-kernel - Re: [PATCH] mm: reduce tlb flush range when changing vma protection

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Message-Id: <87861C77-F203-40A5-814D-A3541081064E@gmail.com>
Date:   Tue, 8 Mar 2022 20:14:01 -0800
From:   Nadav Amit <nadav.amit@...il.com>
To:     Bibo Mao <maobibo@...ngson.cn>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Linux-MM <linux-mm@...ck.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm: reduce tlb flush range when changing vma protection



> On Mar 8, 2022, at 6:57 PM, Bibo Mao <maobibo@...ngson.cn> wrote:
> 
> numa worker will periodically change vma prot with PROT_NONE, by
> default it will scan 256M vma memory size with pmd stepping size.
> If there are fewer pages changed with PROT_NONE, tlb flush is called
> with pmd size. This patch will calculate flush range for those
> pages with pte prot changed, it will reduce size for tlb flush.
> 
> Signed-off-by: Bibo Mao <maobibo@...ngson.cn>

Hi Bibo,

I finally managed to make v3 of a patchiest, which I think does
something similar to what you are looking for (without introducing
yet another TLB batching mechanism).

Have a look at [1] and let me know if that would satisfy you.


[1] https://lore.kernel.org/linux-mm/20220309041043.302261-4-namit@vmware.com/T/#u