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From:   Barry Song <21cnbao@gmail.com>
Date:   Thu, 16 Nov 2023 04:49:11 +0800
Message-ID: <CAGsJ_4wD9Ug=CLi6Cdw3Ve5q8-1u7MmipLtEGQTfWmU9BJFJOQ@mail.gmail.com>
Subject: Re: [RFC V3 PATCH] arm64: mm: swap: save and restore mte tags for
 large folios
To:     David Hildenbrand <david@redhat.com>
Cc:     steven.price@arm.com, akpm@linux-foundation.org,
        ryan.roberts@arm.com, catalin.marinas@arm.com, will@kernel.org,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org, mhocko@suse.com,
        shy828301@gmail.com, v-songbaohua@oppo.com,
        wangkefeng.wang@huawei.com, willy@infradead.org, xiang@kernel.org,
        ying.huang@intel.com, yuzhao@google.com
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On Wed, Nov 15, 2023 at 11:16=E2=80=AFPM David Hildenbrand <david@redhat.co=
m> wrote:
>
> On 14.11.23 02:43, Barry Song wrote:
> > This patch makes MTE tags saving and restoring support large folios,
> > then we don't need to split them into base pages for swapping out
> > on ARM64 SoCs with MTE.
> >
> > arch_prepare_to_swap() should take folio rather than page as parameter
> > because we support THP swap-out as a whole.
> >
> > Meanwhile, arch_swap_restore() should use page parameter rather than
> > folio as swap-in always works at the granularity of base pages right
> > now.
>
> ... but then we always have order-0 folios and can pass a folio, or what
> am I missing?

Hi David,
you missed the discussion here:

https://lore.kernel.org/lkml/CAGsJ_4yXjex8txgEGt7+WMKp4uDQTn-fR06ijv4Ac68Mk=
hjMDw@mail.gmail.com/
https://lore.kernel.org/lkml/CAGsJ_4xmBAcApyK8NgVQeX_Znp5e8D4fbbhGguOkNzmh1=
Veocg@mail.gmail.com/

>
> >
> > arch_thp_swp_supported() is dropped since ARM64 MTE was the only one
> > who needed it.
>
> Can we do that separately?

i think it is ok.

>
> --
> Cheers,
>
> David / dhildenb
>

Thanks
Barry