From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Matthew Wilcox <willy@linux.intel.com>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: linux-mm@kvack.org
Subject: Re: pagewalk API
Date: Mon, 4 Jan 2016 22:47:27 +0200 [thread overview]
Message-ID: <20160104204727.GE13515@node.shutemov.name> (raw)
In-Reply-To: <20160104182939.GA27351@linux.intel.com>
On Mon, Jan 04, 2016 at 01:29:39PM -0500, Matthew Wilcox wrote:
>
> I find myself in the position of needing to expand the pagewalk API to
> allow PUDs to be passed to pagewalk handlers.
>
> The problem with the current pagewalk API is that it requires the callers
> to implement a lot of boilerplate, and the further up the hierarchy we
> intercept the pagewalk, the more boilerplate has to be implemented in each
> caller, to the point where it's not worth using the pagewalk API any more.
>
> Compare and contrast mincore's pud_entry that only has to handle PUDs
> which are guaranteed to be (1) present, (2) huge, (3) locked versus the
> PMD code which has to take care of checking all three things itself.
>
> (http://marc.info/?l=linux-mm&m=145097405229181&w=2)
>
> Kirill's point is that it's confusing to have the PMD and PUD handling
> be different, and I agree. But it certainly saves a lot of code in the
> callers. So should we convert the PMD code to be similar? Or put a
> subptimal API in for the PUD case?
Naoya, if I remember correctly, we had something like this on early stage
of you pagewalk rework. Is it correct? If yes, why it was changed to what
we have now?
>
> --
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--
Kirill A. Shutemov
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next prev parent reply other threads:[~2016-01-04 20:47 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-04 18:29 pagewalk API Matthew Wilcox
2016-01-04 20:47 ` Kirill A. Shutemov [this message]
2016-01-05 0:26 ` Naoya Horiguchi
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