> Von: Jens Axboe [axboe@xxxxxxxxx]
> Gesendet: Sonntag, 29. Juli 2018 00:22
> An: Markus Stockhausen; linux-block@xxxxxxxxxxxxxxx
> Betreff: Re: [PATCH 0/2] direct IO: respect backing device max IO size
>
> On 7/28/18 1:17 PM, stockhausen@xxxxxxxxxxx wrote:
> > Running older FusionIO cards with newer linux kernels turns out to be
> > a headache. First of all their driver is a mix of open sources and
> > proprietary object parts. Second we get only support for kernels up
> > to ~4.0. Trying to get this to work with 4.9 longterm was successful
> > but 4.14 renders the driver totally useless.
> >
> > Searching the reason for lost data it turned out that the driver has
> > a hard 1024K or 257 page IO limit and silently drops any request that
> > is too large. Of course this might be a driver only problem but at
> > least it discloses the real source of a bad chain reaction.
> >
> > blkdev_direct_IO() sets the maximum allowed IO size to BIO_MAX_PAGES.
> > With 225311a4 ("mm: test code to write THP to swap device as a whole")
> > its value changed from 256 to 512. Indepedant of its value the choice
> > is arbitrary and can be driver agnostic as long as breakdown of bios
> > happens later on.
> >
> > We already have sufficent info about backing device properties and
> > can packetize the IO into sane values to avoid hassle later on. If
> > bdi->io_pages is set and lower than BIO_MAX_PAGES reduce the package
> > size appropriately.
> >
> > Ths patch consists of two parts. The first is only a cosmetic change
> > to avoid double coding in the second one.
>
> Sounds to me like the fusion driver isn't calling split like it is
> supposed to. That's what you get when it's unmaintained for years.
> Add a:
>
> blk_queue_split(queue, &bio);
>
> to kblock.c:kfio_make_request() and see if that helps.
> --
> Jens Axboe
I guess You know the driver and got my only by a few minutes.
Was just comparing iomemory 3.2.x with 4.3.x. And tadaaa: New
driver has a split.
Thanks a lot.
Markus
****************************************************************************
Diese E-Mail enthält vertrauliche und/oder rechtlich geschützte
Informationen. Wenn Sie nicht der richtige Adressat sind oder diese E-Mail
irrtümlich erhalten haben, informieren Sie bitte sofort den Absender und
vernichten Sie diese Mail. Das unerlaubte Kopieren sowie die unbefugte
Weitergabe dieser Mail ist nicht gestattet.
�ber das Internet versandte E-Mails können unter fremden Namen erstellt oder
manipuliert werden. Deshalb ist diese als E-Mail verschickte Nachricht keine
rechtsverbindliche Willenserklärung.
Collogia AG
Ubierring 11
D-50678 Köln
Vorstand:
Kadir Akin
Dr. Michael Höhnerbach
Vorsitzender des Aufsichtsrates:
Hans Kristian Langva
Registergericht: Amtsgericht Köln
Registernummer: HRB 52 497
This e-mail may contain confidential and/or privileged information. If you
are not the intended recipient (or have received this e-mail in error)
please notify the sender immediately and destroy this e-mail. Any
unauthorized copying, disclosure or distribution of the material in this
e-mail is strictly forbidden.
e-mails sent over the internet may have been written under a wrong name or
been manipulated. That is why this message sent as an e-mail is not a
legally binding declaration of intention.
Collogia AG
Ubierring 11
D-50678 Köln
executive board:
Kadir Akin
Dr. Michael Höhnerbach
President of the supervisory board:
Hans Kristian Langva
Registry office: district court Cologne
Register number: HRB 52 497
****************************************************************************
