From: Dan Williams <dan.j.williams@intel.com>
To: Boaz Harrosh <boaz@plexistor.com>
Cc: Christoph Hellwig <hch@infradead.org>,
"Rudoff, Andy" <andy.rudoff@intel.com>,
Dave Chinner <david@fromorbit.com>,
Jeff Moyer <jmoyer@redhat.com>, Arnd Bergmann <arnd@arndb.de>,
linux-nvdimm <linux-nvdimm@ml01.01.org>,
Oleg Nesterov <oleg@redhat.com>, linux-mm <linux-mm@kvack.org>,
Mel Gorman <mgorman@suse.de>,
Johannes Weiner <hannes@cmpxchg.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [RFC 0/2] New MAP_PMEM_AWARE mmap flag
Date: Tue, 23 Feb 2016 15:23:23 -0800 [thread overview]
Message-ID: <CAPcyv4gLoQm818BzQSqkCbNPztr0JVihmvuhb=d-kSgbrmYFzQ@mail.gmail.com> (raw)
In-Reply-To: <56CCE647.70408@plexistor.com>
On Tue, Feb 23, 2016 at 3:07 PM, Boaz Harrosh <boaz@plexistor.com> wrote:
> On 02/24/2016 12:33 AM, Dan Williams wrote:
>> The crux of the problem, in my opinion, is that we're asking for an "I
>> know what I'm doing" flag, and I expect that's an impossible statement
>> for a filesystem to trust generically. If you can get MAP_PMEM_AWARE
>> in, great, but I'm more and more of the opinion that the "I know what
>> I'm doing" interface should be something separate from today's trusted
>> filesystems.
>>
>
> I disagree. I'm not saying any "trust me I know what I'm doing" flag.
> the FS reveals nothing and trusts nothing.
> All I'm saying is that the libc library I'm using as the new pmem_memecpy()
> and I'm using that instead of the old memecpy(). So the FS does not need to
> wipe my face after I eat. Failing to do so just means a bug in the application
"just means a bug in the application"
Who gets the bug report when an app gets its cache syncing wrong and
data corruption ensues, and why isn't the fix for that bug that the
filesystem simply stops trusting MAP_PMEM_AWARE and synching
cachelines on behalf of the app when it calls sync as it must for
metadata consistency. Problem solved globally for all broken usages
of MAP_PMEM_AWARE and the flag loses all meaning as a result.
This is the takeaway I've internalized from Dave's pushback of these
new mmap flags.
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next prev parent reply other threads:[~2016-02-23 23:23 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
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 [this message]
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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