[lkml]   [2007]   [Jul]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Subjectremoving refrigerator does not help with s2ram vs. fuse deadlocks (was Re: [linux-pm] Re: [PATCH] Remove process freezer from suspend to RAM pathway)

> > The fact remains that lots of drivers would still need to be changed.
> > In the read and write methods someone would have to add code amounting
> > to this:
> >
> > if (suspend_is_under_way()) {
> > mutex_unlock(...);
> > block_until_resume();
> > goto restart;
> > }
> >
> > Freezing userspace is a small amount of code by comparison.
> Normally devices have some sort of queue of pending operations. So
> all that is required on suspend is to stop processing the queue and
> wait for any currently-underway operations to complete. The blocking
> then happens naturally using the normal I/O wait mechanisms.

So... instead of one big freezer (we know it is problematic), you have
100 small freezers, problematic in same way :-(.

Let's take current FUSE problems, and see if they have problem on PPC,

Let's say FUSE thread touches one of those "blocking" devices. It is
now in D state, somewhere in kernel.... exactly same way refrigerator

Now, if kernel needs FUSE services for some reason (that's the problem
we hit in s2ram case, right?), we have a deadlock.

So main problem still seems to be "kernel should not depend on
userland services during suspend", refrigerator or not.
(cesky, pictures)
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2007-07-05 11:17    [W:0.103 / U:0.412 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site