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Date:   Fri, 14 Apr 2023 12:09:57 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc:     linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Rick Edgecombe <rick.p.edgecombe@intel.com>
Subject: Re: [PATCH v2] mm/mmap: Regression fix for unmapped_area{_topdown}
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On Fri, 14 Apr 2023 14:59:19 -0400 "Liam R. Howlett" <Liam.Howlett@oracle.com> wrote:

> The maple tree limits the gap returned to a window that specifically
> fits what was asked.  This may not be optimal in the case of switching
> search directions or a gap that does not satisfy the requested space for
> other reasons.  Fix the search by retrying the operation and limiting
> the search window in the rare occasion that a conflict occurs.

This is a performance regression, yes?  Of what magnitude?