Re: [PATCH 4/4] block: Optionally snapshot page contents to provide stable pages during write

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Fri, Dec 14, 2012 at 06:06:50PM -0800, Andy Lutomirski wrote:
> On Fri, Dec 14, 2012 at 6:01 PM, Darrick J. Wong
> <darrick.wong@xxxxxxxxxx> wrote:
> > On Fri, Dec 14, 2012 at 05:12:37PM -0800, Andy Lutomirski wrote:
> >> It survived.  I hit at least one mm bug, but I really don't think it's
> >> a problem with your code.  (I have not tried this workload on Linux
> >> 3.7 at all before.  It normally runs on 3.5.)  The box in question is
> >
> > Would you mind sending along the bug report so I can make sure?
> 
> http://marc.info/?l=linux-mm&m=135553342803210&w=2

Hm, this looks like a hugepages thing, which (afaik) doesn't touch fs code at
all.  Looks like this patchset is in the clear.

> >
> >> ext4 on LVM on dm-crypt on (hardware) RAID 5 on hpsa, which should not
> >> need stable pages.
> >>
> >> The majority of the data written (that wasn't unlinked before it was
> >> dropped from cache) was checksummed when written and verified later.
> >> Most of this data was written using mmap.  This workload hammers the
> >> vm concurrently in several threads, and it frequently stalls when
> >> stable pages are enabled, so it's probably exercising the code
> >> decently well.
> >
> > Did you observe any change in performance?
> 
> No.  But I'm comparing to 3.5 + butchery to remove stable pages.  With
> stable pages on, this workload performs terribly.  (It's a soft
> real-time thing, as you can possibly guess from my domain name, and
> various latency monitoring things go nuts when stable pages are
> active.)

Well, I guess that's good. :)

> Actually, performance appears to be improved, probably due to
> https://lkml.org/lkml/2012/12/14/14, which I tested concurrently.
> 
> >
> >> Feel free to add Tested-by: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
> >
> > Will do!  Thanks for the testing!
> 
> My pleasure.  When these changes go in to an upstream kernel, they'll
> represent a significant reduction in how much our kernel differs from
> kernel.org's :)  Thanks for fixing this.

No problem!

--D
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [Reiser Filesystem Development]     [Ceph FS]     [Kernel Newbies]     [Security]     [Netfilter]     [Bugtraq]     [Linux FS]     [Yosemite National Park]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Samba]     [Device Mapper]     [Linux Media]

  Powered by Linux