From: Dan Williams <dan.j.williams@intel.com>
To: Boaz Harrosh <boaz@plexistor.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>,
linux-nvdimm <linux-nvdimm@ml01.01.org>,
Matthew Wilcox <willy@linux.intel.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Dave Chinner <david@fromorbit.com>,
Oleg Nesterov <oleg@redhat.com>, Mel Gorman <mgorman@suse.de>,
Johannes Weiner <hannes@cmpxchg.org>,
linux-mm <linux-mm@kvack.org>, Arnd Bergmann <arnd@arndb.de>
Subject: Re: [RFC 0/2] New MAP_PMEM_AWARE mmap flag
Date: Sun, 21 Feb 2016 12:57:31 -0800 [thread overview]
Message-ID: <CAPcyv4hpxab=c1g83ARJvrnk_5HFkqS-t3sXpwaRBiXzehFwWQ@mail.gmail.com> (raw)
In-Reply-To: <56CA1CE7.6050309@plexistor.com>
On Sun, Feb 21, 2016 at 12:24 PM, Boaz Harrosh <boaz@plexistor.com> wrote:
> On 02/21/2016 09:51 PM, Dan Williams wrote:
> <>
>>> Please advise?
>>
>> When this came up a couple weeks ago [1], the conclusion I came away
>> with is
>
> I think I saw that talk, no this was not suggested. What was suggested
> was an FS / mount knob. That would break semantics, this here does not
> break anything.
No, it was a MAP_DAX mmap flag, similar to this proposal. The
difference being that MAP_DAX was all or nothing (DAX vs page cache)
to address MAP_SHARED semantics.
>
>> that if an application wants to avoid the overhead of DAX
>> semantics it needs to use an alternative to DAX access methods. Maybe
>> a new pmem aware fs like Nova [2], or some other mechanism that
>> bypasses the semantics that existing applications on top of ext4 and
>> xfs expect.
>>
>
> But my suggestion does not break any "existing applications" and does
> not break any semantics of ext4 or xfs. (That I can see)
>
> As I said above it perfectly co exists with existing applications and
> is the best of both worlds. The both applications can write to the
> same page and will not break any of application's expectation. Old or
> new.
>
> Please point me to where I'm wrong in the code submitted?
>
> Besides even an FS like Nova will need a flag per vma like this,
> it will need to sort out the different type of application. So
> here is how this is communicated, on the mmap call, how else?
> And also works for xfs or ext4
>
> Do you not see how this is entirely different then what was
> proposed? or am I totally missing something? Again please show
> me how this breaks anything's expectations.
>
What happens for MAP_SHARED mappings with mixed pmem aware/unaware
applications? Does MAP_PMEM_AWARE also imply awareness of other
applications that may be dirtying cachelines without taking
responsibility for making them persistent?
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next prev parent reply other threads:[~2016-02-21 20:57 UTC|newest]
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-21 17:03 Boaz Harrosh
2016-02-21 17:04 ` [RFC 1/2] mmap: Define a new " Boaz Harrosh
2016-02-21 17:06 ` [RFC 2/2] dax: Support " Boaz Harrosh
2016-02-21 19:51 ` [RFC 0/2] New " Dan Williams
2016-02-21 20:24 ` Boaz Harrosh
2016-02-21 20:57 ` Dan Williams [this message]
2016-02-21 21:23 ` Boaz Harrosh
2016-02-21 22:03 ` Dan Williams
2016-02-21 22:31 ` Dave Chinner
2016-02-22 9:57 ` Boaz Harrosh
2016-02-22 15:34 ` Jeff Moyer
2016-02-22 17:44 ` Christoph Hellwig
2016-02-22 17:58 ` Jeff Moyer
2016-02-22 18:03 ` Christoph Hellwig
2016-02-22 18:52 ` Jeff Moyer
2016-02-23 9:45 ` Christoph Hellwig
2016-02-22 20:05 ` Rudoff, Andy
2016-02-23 9:52 ` Christoph Hellwig
2016-02-23 10:07 ` Rudoff, Andy
2016-02-23 12:06 ` Dave Chinner
2016-02-23 17:10 ` Ross Zwisler
2016-02-23 21:47 ` Dave Chinner
2016-02-23 22:15 ` Boaz Harrosh
2016-02-23 23:28 ` Dave Chinner
2016-02-24 0:08 ` Boaz Harrosh
2016-02-23 14:10 ` Boaz Harrosh
2016-02-23 16:56 ` Dan Williams
2016-02-23 17:05 ` Ross Zwisler
2016-02-23 17:26 ` Dan Williams
2016-02-23 21:55 ` Boaz Harrosh
2016-02-23 22:33 ` Dan Williams
2016-02-23 23:07 ` Boaz Harrosh
2016-02-23 23:23 ` Dan Williams
2016-02-23 23:40 ` Boaz Harrosh
2016-02-24 0:08 ` Dave Chinner
2016-02-23 23:28 ` Jeff Moyer
2016-02-23 23:34 ` Dan Williams
2016-02-23 23:43 ` Jeff Moyer
2016-02-23 23:56 ` Dan Williams
2016-02-24 4:09 ` Ross Zwisler
2016-02-24 19:30 ` Ross Zwisler
2016-02-25 9:46 ` Jan Kara
2016-02-25 7:44 ` Boaz Harrosh
2016-02-24 15:02 ` Jeff Moyer
2016-02-24 22:56 ` Dave Chinner
2016-02-25 16:24 ` Jeff Moyer
2016-02-25 19:11 ` Jeff Moyer
2016-02-25 20:15 ` Dave Chinner
2016-02-25 20:57 ` Jeff Moyer
2016-02-25 22:27 ` Dave Chinner
2016-02-26 4:02 ` Dan Williams
2016-02-26 10:04 ` Thanumalayan Sankaranarayana Pillai
2016-02-28 10:17 ` Boaz Harrosh
2016-03-03 17:38 ` Howard Chu
2016-02-29 20:25 ` Jeff Moyer
2016-02-25 21:08 ` Phil Terry
2016-02-25 21:39 ` Dave Chinner
2016-02-25 21:20 ` Dave Chinner
2016-02-29 20:32 ` Jeff Moyer
2016-02-23 17:25 ` Ross Zwisler
2016-02-23 22:47 ` Boaz Harrosh
2016-02-22 21:50 ` Dave Chinner
2016-02-23 13:51 ` Boaz Harrosh
2016-02-23 14:22 ` Jeff Moyer
2016-02-22 11:05 ` Boaz Harrosh
2016-03-11 6:44 ` Andy Lutomirski
2016-03-11 19:07 ` Dan Williams
2016-03-11 19:10 ` Andy Lutomirski
2016-03-11 23:02 ` Rudoff, Andy
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