From: Boaz Harrosh <boaz@plexistor.com>
To: Jeff Moyer <jmoyer@redhat.com>
Cc: "Wilcox, Matthew R" <matthew.r.wilcox@intel.com>,
"linda.knippers@hp.com" <linda.knippers@hp.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>
Subject: Re: regression introduced by "block: Add support for DAX reads/writes to block devices"
Date: Thu, 13 Aug 2015 08:32:10 +0300 [thread overview]
Message-ID: <55CC2BDA.3080906@plexistor.com> (raw)
In-Reply-To: <x49k2t05i0n.fsf@segfault.boston.devel.redhat.com>
On 08/13/2015 12:11 AM, Jeff Moyer wrote:
> Boaz Harrosh <boaz@plexistor.com> writes:
>
>> On 08/07/2015 11:41 PM, Jeff Moyer wrote:
>> <>
>>>
>>>> We need to cope with the case where the end of a partition isn't on a
>>>> page boundary though.
>>>
>>> Well, that's usually done by falling back to buffered I/O. I gave that
>>> a try and panicked the box. :) I'll keep looking into it, but probably
>>> won't have another patch until next week.
>>>
>>
>> lets slow down for a sec, please.
>>
>> We have all established that an unaligned partition start is BAD and not supported?
>
> No. Unaligned partitions on RAID arrays or 512e devices are bad because
> they result in suboptimal performance. They are most certainly still
> supported, though.
>
What ?
I meant for dax on pmem or brd. I meant that we *do not* support dax access
on an unaligned partition start. (None dax is perfectly supported)
We did it this way because of the direct_access API that returns a pfn
with is PAGE_SIZE. We could introduce a pfn+offset but we thought it is
not worth it, and that dax should be page aligned for code simplicity
Cheers
Boaz
> -Jeff
>
next prev parent reply other threads:[~2015-08-13 5:32 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-05 20:19 regression introduced by "block: Add support for DAX reads/writes to block devices" Jeff Moyer
2015-08-05 22:01 ` Dave Chinner
2015-08-06 1:42 ` Linda Knippers
2015-08-06 3:24 ` Dave Chinner
2015-08-06 7:52 ` Boaz Harrosh
2015-08-06 20:34 ` Dave Chinner
2015-08-09 8:52 ` Boaz Harrosh
2015-08-10 16:32 ` Linda Knippers
2015-08-10 21:27 ` Dave Chinner
2015-08-10 23:04 ` Linda Knippers
2015-08-06 14:21 ` Wilcox, Matthew R
2015-08-06 15:33 ` Jeff Moyer
2015-08-06 15:51 ` Wilcox, Matthew R
2015-08-06 21:30 ` Jeff Moyer
2015-08-07 18:11 ` Wilcox, Matthew R
2015-08-07 20:41 ` Jeff Moyer
2015-08-10 7:42 ` Boaz Harrosh
2015-08-12 21:11 ` Jeff Moyer
2015-08-13 5:32 ` Boaz Harrosh [this message]
2015-08-13 14:00 ` Jeff Moyer
2015-08-13 16:42 ` Linda Knippers
2015-08-13 17:14 ` Jeff Moyer
2015-08-13 17:52 ` Linda Knippers
2015-08-13 18:19 ` Jeff Moyer
2015-08-13 19:32 ` Wilcox, Matthew R
2015-08-14 16:28 ` Dan Williams
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