Re: Merging the Suspend2 freezer implementation.

[Pavel Machek <pavel@ucw.cz>]

Hi!

> > > The main change involves the introduction of a new SYNCTHREAD flag. We
> > > use this to avoid deadlocking over processes that are running sys_sync
> > > and siblings. Processes that enter those routines get the flag added,
> > > and it's removed when they exit the sync routine. We then freeze in four
> > > stages: 
> > 
> > Is SYNCTHREAD neccessary for me, too, or is it needed for suspend2, only?
> 
> It's necessary for reliable freezing under I/O load. Signalling the
> non-sync threads first removes the race involved in some threads
> submitting I/O while others are trying to sync. Try doing a dd and a
> sync at the same time. The sync can take ages to return, worst case,
> sometimes not until the dd is completed. (Actually, try doing anything
> while a dd is running :>)

Okay, just attach this explanation when you are merging it otherwise
I'll surely ask again...

> > > Finally I'd like to merge the support for freezer flags on workqueues.
> 
> No comment here? :>

:-). I forgot why it was neccessary, but I was too shy to ask
;-). Just attach nice explanation when you attempt to merge it.

								Pavel
-- 
People were complaining that M$ turns users into beta-testers...
...jr ghea gurz vagb qrirybcref, naq gurl frrz gb yvxr vg gung jnl!