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Date:   Thu, 28 Apr 2022 18:21:32 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     NeilBrown <neilb@suse.de>
Cc:     Geert Uytterhoeven <geert+renesas@glider.be>,
        Christoph Hellwig <hch@lst.de>,
        Miaohe Lin <linmiaohe@huawei.com>, linux-nfs@vger.kernel.org,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] MM: handle THP in swap_*page_fs()
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On Fri, 29 Apr 2022 10:43:34 +1000 NeilBrown <neilb@suse.de> wrote:

> Pages passed to swap_readpage()/swap_writepage() are not necessarily all
> the same size - there may be transparent-huge-pages involves.
> 
> The BIO paths of swap_*page() handle this correctly, but the SWP_FS_OPS
> path does not.
> 
> So we need to use thp_size() to find the size, not just assume
> PAGE_SIZE, and we need to track the total length of the request, not
> just assume it is "page * PAGE_SIZE".

Cool.  I added this in the series after
mm-submit-multipage-write-for-swp_fs_ops-swap-space.patch.  I could
later squash it into that patch if you think that's more logical.