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Date:   Wed, 20 Sep 2023 04:57:33 +0100
From:   Matthew Wilcox <willy@infradead.org>
To:     riel@surriel.com
Cc:     linux-kernel@vger.kernel.org, kernel-team@meta.com,
        linux-mm@kvack.org, akpm@linux-foundation.org,
        muchun.song@linux.dev, mike.kravetz@oracle.com, leit@meta.com
Subject: Re: [PATCH 1/2] hugetlbfs: extend hugetlb_vma_lock to private VMAs
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References: <20230920021811.3095089-1-riel@surriel.com>
 <20230920021811.3095089-2-riel@surriel.com>
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On Tue, Sep 19, 2023 at 10:16:09PM -0400, riel@surriel.com wrote:
> From: Rik van Riel <riel@surriel.com>
> 
> Extend the locking scheme used to protect shared hugetlb mappings
> from truncate vs page fault races, in order to protect private
> hugetlb mappings (with resv_map) against MADV_DONTNEED.
> 
> Add a read-write semaphore to the resv_map data structure, and
> use that from the hugetlb_vma_(un)lock_* functions, in preparation
> for closing the race between MADV_DONTNEED and page faults.

This feels an awful lot like the invalidate_lock in struct address_space
which was recently added by Jan Kara.