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Date:   Mon, 30 Aug 2021 10:11:04 +0100
From:   Mel Gorman <mgorman@suse.com>
To:     NeilBrown <neilb@suse.de>
Cc:     Chuck Lever III <chuck.lever@oracle.com>,
        Mike Javorski <mike.javorski@gmail.com>,
        Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
        linux-mm@kvack.org
Subject: Re: [PATCH] MM: clarify effort used in alloc_pages_bulk_*()
Message-ID: <20210830091104.GA3997@suse.com>
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On Mon, Aug 30, 2021 at 08:28:15AM +1000, NeilBrown wrote:
> 
> The alloc_pages_bulk_*() interfaces do not make it clear what degree
> of success can be expected.
> 
> The code appears to allocate at least one page with the same effort as
> alloc_page() when used with the same GFP flags, and then to allocate any
> more only opportunistically.  So a caller should not *expect* to get a
> full allocation, but should not be *surprised* by one either.
> 
> Add text to the comment clarifying this.
> 
> Also fix a bug.  When alloc_pages_bulk_array() is called on an array
> that is partially allocated, the level of effort to get a single page is
> less than when the array was completely unallocated.  This behaviour is
> inconsistent, but now fixed.
> 
> Fixes: 0f87d9d30f21 ("mm/page_alloc: add an array-based interface to the bulk page allocator")
> Signed-off-by: NeilBrown <neilb@suse.de>

Acked-by: Mel Gorman <mgorman@suse.com>

-- 
Mel Gorman
SUSE Labs