From: Dan Williams <dan.j.williams@intel.com>
To: Matthew Wilcox <willy@linux.intel.com>
Cc: Ross Zwisler <zwisler@gmail.com>,
linux-nvdimm <linux-nvdimm@ml01.01.org>,
Dave Chinner <david@fromorbit.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Christoph Hellwig <hch@infradead.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Jan Kara <jack@suse.com>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences
Date: Sun, 31 Jan 2016 10:50:49 -0800 [thread overview]
Message-ID: <CAPcyv4gpGApe+gPhL=2qTdNM4FzZLc66K65AQyuweeMtdGpG1Q@mail.gmail.com> (raw)
In-Reply-To: <20160131182730.GC2948@linux.intel.com>
On Sun, Jan 31, 2016 at 10:27 AM, Matthew Wilcox <willy@linux.intel.com> wrote:
> On Sun, Jan 31, 2016 at 10:18:46AM -0800, Dan Williams wrote:
>> On Sun, Jan 31, 2016 at 10:07 AM, Matthew Wilcox <willy@linux.intel.com> wrote:
>> > Yes. This is just the default implementation of dax_map_pfn() which works
>> > for most situations. We can introduce more complex implementations of
>> > dax_map_pfn() as necessary. You make another excellent point for why
>> > we should store PFNs in the radix tree instead of kaddrs :-)
>>
>> How much complexity do we want to add in support of an fsync/msync
>> mechanism that is not the recommended way to use DAX?
>
> It actually makes the dax_io path much, much simpler. And it's not
> primarily about fixing fsync/msync. It also makes the fault path cheaper
> in the case where we're refaulting a page that's already been faulted
> by another process (or was previously faulted by this process and now
> needs to be faulted at a different address).
>
> And it fixes the problem with filesystems that use multiple block_devices.
> It also makes DAX much less reliant on buffer heads, which is good for
> the problem that Jared raised where he doesn't have a block_device in
> an embedded system.
Oh I thought we were talking about what goes in the radix. Sure,
de-emphasizing the usage of a block_device throughout the dax
implementation is interesting. It also has some synergy with the
LSF/MM topic I'm writing up "pmem as storage device vs pmem as
memory".
next prev parent reply other threads:[~2016-01-31 18:50 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-28 19:35 [PATCH 1/2] block: fix pfn_mkwrite() DAX fault handler Ross Zwisler
2016-01-28 19:35 ` Ross Zwisler
2016-01-28 19:35 ` [PATCH 2/2] dax: fix bdev NULL pointer dereferences Ross Zwisler
2016-01-28 19:35 ` Ross Zwisler
2016-01-28 20:21 ` Dan Williams
2016-01-28 20:21 ` Dan Williams
2016-01-28 21:38 ` Christoph Hellwig
2016-01-29 18:28 ` Ross Zwisler
2016-01-29 23:34 ` Ross Zwisler
2016-01-30 0:18 ` Dan Williams
2016-01-31 22:44 ` Dave Chinner
2016-01-30 5:28 ` Matthew Wilcox
2016-01-30 6:01 ` Dan Williams
2016-01-30 7:08 ` Jared Hulbert
2016-01-31 2:32 ` Matthew Wilcox
2016-01-31 6:12 ` Ross Zwisler
2016-01-31 10:55 ` Matthew Wilcox
2016-01-31 16:38 ` Dan Williams
2016-01-31 18:07 ` Matthew Wilcox
2016-01-31 18:18 ` Dan Williams
2016-01-31 18:27 ` Matthew Wilcox
2016-01-31 18:50 ` Dan Williams [this message]
2016-01-31 19:51 ` Dan Williams
2016-02-01 13:44 ` Matthew Wilcox
2016-02-01 14:51 ` Jan Kara
2016-02-01 20:49 ` Matthew Wilcox
2016-02-01 21:47 ` Dave Chinner
2016-02-02 6:06 ` Jared Hulbert
2016-02-02 6:46 ` Dan Williams
2016-02-02 8:05 ` Jared Hulbert
2016-02-02 16:51 ` Dan Williams
2016-02-02 21:46 ` Jared Hulbert
2016-02-03 0:34 ` Matthew Wilcox
2016-02-03 1:21 ` Jared Hulbert
2016-02-02 11:17 ` Jan Kara
2016-02-02 16:33 ` Dan Williams
2016-02-02 16:46 ` Jan Kara
2016-02-02 17:10 ` Dan Williams
2016-02-02 17:34 ` Ross Zwisler
2016-02-02 17:46 ` Dan Williams
2016-02-02 17:47 ` Dan Williams
2016-02-02 18:24 ` Ross Zwisler
2016-02-02 18:46 ` Matthew Wilcox
2016-02-02 18:59 ` Dan Williams
2016-02-02 20:14 ` Matthew Wilcox
2016-02-03 11:09 ` Jan Kara
2016-02-03 10:46 ` Jan Kara
2016-02-03 20:13 ` Ross Zwisler
2016-02-04 9:15 ` Jan Kara
2016-02-04 23:38 ` Ross Zwisler
2016-02-06 23:15 ` Dave Chinner
2016-02-07 5:27 ` Ross Zwisler
2016-02-04 19:56 ` Ross Zwisler
2016-02-04 20:29 ` Jan Kara
2016-02-04 22:19 ` Ross Zwisler
2016-02-05 22:25 ` Ross Zwisler
2016-02-06 23:40 ` Dave Chinner
2016-02-07 6:43 ` Ross Zwisler
2016-02-08 13:48 ` Jan Kara
2016-02-07 8:38 ` Christoph Hellwig
2016-02-08 15:55 ` Ross Zwisler
2016-02-02 18:41 ` Ross Zwisler
2016-02-02 18:53 ` Ross Zwisler
2016-02-02 0:02 ` Ross Zwisler
2016-02-02 7:10 ` Dave Chinner
2016-02-02 10:34 ` Jan Kara
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