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Date:   Sun, 21 Nov 2021 04:35:43 +0000
From:   Matthew Wilcox <willy@infradead.org>
To:     Shakeel Butt <shakeelb@google.com>
Cc:     David Hildenbrand <david@redhat.com>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
        Yang Shi <shy828301@gmail.com>, Zi Yan <ziy@nvidia.com>,
        Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: split thp synchronously on MADV_DONTNEED
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On Sat, Nov 20, 2021 at 12:12:30PM -0800, Shakeel Butt wrote:
> This patch let such applications not worry about the low level handling
> of THPs in the kernel and splits the THPs synchronously on
> MADV_DONTNEED.

I don't mind the synchronous split, but I have concerns about the
implementation.  I don't think it's worth another pointer in task_struct.
It's also the case that splitting is likely to succeed, so I think a
better implementation would try to split and then put the page on the
global deferred list if splitting fails.