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Date:   Sun, 21 May 2023 04:39:16 +0100
From:   Matthew Wilcox <willy@infradead.org>
To:     Wang Yugui <wangyugui@e16-tech.com>
Cc:     linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org,
        Dave Chinner <david@fromorbit.com>,
        Christoph Hellwig <hch@infradead.org>,
        "Darrick J . Wong" <djwong@kernel.org>
Subject: Re: [PATCH 1/3] filemap: Allow __filemap_get_folio to allocate large
 folios
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References: <20230521090235.4860.409509F4@e16-tech.com>
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On Sun, May 21, 2023 at 10:04:35AM +0800, Wang Yugui wrote:
> > I don't see it?
> > 
> > size == 1 << 20;
> > 
> > shift = 20;
> > return (20 - 12) << 26;
> > 
> > Looks like about 1 << 29 to me.
> 
> sorry that I wrongly
> 1) wrongly conside PAGE_SHIFT as 13 from arch/alpha/include/asm/page.h
> it should be 12 from arch/x86/include/asm/page_types.h.
> 
> 2) wrongly conside
> 	(20 - 12) << 26
> as
> 	1<< (20 - 12) << 26

Ah, no problem.  Glad I didn't miss something.