Re: [PATCH] Remove process freezer from suspend to RAM pathway

From: Nigel Cunningham
Date: Fri Jul 06 2007 - 05:16:36 EST


Hi.

On Friday 06 July 2007 19:09:43 Miklos Szeredi wrote:
> > > > Moreover, if FUSE implements syncing, then the sync from within the
freezer
> > > > will almost certainly deadlock.
> > >
> > > Rafael, think positively: by the time fuse implements sync(), the
> > > freezer will be long gone ;)
> >
> > Now you are entering really dangerous territory.
> > If you can implement a meaningfull sync method, you must have dirty
> > pages in the page cache. That means you are in the page freeing path
> > of the vm. Then we are in real trouble. Don't even think about it.
>
> VM induced deadlocks are real nasty. I have thought about them a lot
> already. Suspend shouldn't introduce any big surprises.

Suspend isn't introducing the surprises. Fuse is. It creates the potential
deadlocks simply by existing (this isn't suspend or hibernate specific).

Nigel

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