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From: Ross Zwisler <ross.zwisler@linux.intel.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>,
	Konstantin Khlebnikov <koct9i@gmail.com>,
	Ross Zwisler <ross.zwisler@linux.intel.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH RFC 1/4] lib/radix: add universal radix_tree_fill_range
Date: Tue, 30 Aug 2016 16:03:53 -0600	[thread overview]
Message-ID: <20160830220353.GB20121@linux.intel.com> (raw)
In-Reply-To: <CAA9_cmeHzubEwpEGELo2FLf+MBdHbN4J=-TAe-P-M+OoxHAWyw@mail.gmail.com>

On Tue, Aug 30, 2016 at 02:56:17PM -0700, Dan Williams wrote:
> On Mon, Aug 29, 2016 at 11:52 AM, Matthew Wilcox <mawilcox@microsoft.com> wrote:
> > It may be protected by the mapping lock in the current code, but I would it expect it to become an RCU lookup + lock eventually.  No mapping lock, just like the page cache.
> >
> > Even if we can work around it, why do we want to?  What's the compelling reason to change from the current radix tree representation of order-N entries to an arbitrary range?  There are no in-kernel users right now; is there a performance reason to change?  We don't usually change an API in anticipation of future users appearing, particularly when the API makes it harder for the existing users to use it.
> 
> I'd use a fill range api for the radix backing get_dev_pagemap() and
> potentially another use in device-dax.  It centralizes the common
> routine of breaking down a range into its constituent power-of-2
> ranges.

Does your usage not work with the current sibling & canonical entry model?

  reply	other threads:[~2016-08-30 22:03 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-27 14:14 [PATCH RFC 1/4] lib/radix: add universal radix_tree_fill_range Konstantin Khlebnikov
2016-08-27 14:16 ` [PATCH RFC 2/4] lib/radix-tree: remove sibling entries Konstantin Khlebnikov
2016-08-27 14:16 ` [PATCH RFC 3/4] testing/radix-tree: replace multi-order with range operations Konstantin Khlebnikov
2016-08-27 14:16 ` [PATCH RFC 4/4] testing/radix-tree: benchmark for iterator Konstantin Khlebnikov
     [not found] ` <20160827180927.GA22919@linux.intel.com>
2016-08-29 15:21   ` [PATCH RFC 1/4] lib/radix: add universal radix_tree_fill_range Matthew Wilcox
2016-08-29 16:14     ` Konstantin Khlebnikov
2016-08-29 18:08       ` Matthew Wilcox
2016-08-29 18:15         ` Konstantin Khlebnikov
2016-08-29 18:52           ` Matthew Wilcox
2016-08-30 21:56             ` Dan Williams
2016-08-30 22:03               ` Ross Zwisler [this message]
2016-08-30 22:21                 ` Dan Williams
2016-08-30 22:53                   ` Ross Zwisler
2016-09-01  6:12                     ` Konstantin Khlebnikov
2016-09-02 17:59                       ` Matthew Wilcox
2016-09-03  4:50                         ` Konstantin Khlebnikov
2016-08-31 14:57                   ` Matthew Wilcox
2016-08-31 16:36                     ` Dan Williams
2016-09-01  6:16                       ` Konstantin Khlebnikov
2016-08-30 22:00             ` Ross Zwisler
2016-08-30 22:39 ` Ross Zwisler

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