Re: Kernel 2.6.19.2 New RAID 5 Bug (oops when writing Samba -> RAID5)

[Justin Piszcz <jpiszcz@xxxxxxxxxxxxxxx>]

On Tue, 23 Jan 2007, Michael Tokarev wrote:

> Justin Piszcz wrote:
> > 
> > On Tue, 23 Jan 2007, Michael Tokarev wrote:
> > 
> >> Disabling pre-emption on critical and/or server machines seems to be a good
> >> idea in the first place.  IMHO anyway.. ;)
> >
> > So bottom line is make sure not to use preemption on servers or else you 
> > will get weird spinlock/deadlocks on RAID devices--GOOD To know!
> 
> This is not a reason.  The reason is that preemption usually works worse
> on servers, esp. high-loaded servers - the more often you interrupt a
> (kernel) work, the more nedleess context switches you'll have, and the
> more slow the whole thing works.
> 
> Another point is that with preemption enabled, we have more chances to
> hit one or another bug somewhere.  Those bugs should be found and fixed
> for sure, but important servers/data isn't a place usually for bughunting.
> 
> /mjt
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Thanks for the update/info.

Justin.