On Thursday, 9 November 2006 22:41, Pavel Machek wrote: > Hi! > > > > > This is from a work queue, so in fact from a process context, but from > > > > a process that is running with PF_NOFREEZE. > > > > > > Why not simply &~ PF_NOFREEZE on that particular process? Filesystems > > > are free to use threads/work queues/whatever, but refrigerator should > > > mean "no writes to filesystem" for them... > > > > But how we differentiate worker_threads used by filesystems from the > > other ones? > > I'd expect filesystems to do &~ PF_NOFREEZE by hand. > > > BTW, I think that worker_threads run with PF_NOFREEZE for a reason, > > but what exactly is it? > > I do not think we had particulary good reasons... Well, it looks like quite a lot of drivers depend on them, including libata. I think we can add a flag to __create_workqueue() that will indicate if this one is to be running with PF_NOFREEZE and a corresponding macro like create_freezable_workqueue() to be used wherever we want the worker thread to freeze (in which case it should be calling try_to_freeze() somewhere). Then, we can teach filesystems to use this macro instead of create_workqueue(). Having done that we'd be able to drop the freezing of bdevs patch and forget about the dm-related complexity. [Still I wonder if the sys_sync() in freeze_processes() is actually safe if there's a suspended dm device somewhere in the stack, because in the other case the freezing of bdevs would be no more dangerous than the thing that we're already doing.] Greetings, Rafael -- You never change things by fighting the existing reality. R. Buckminster Fuller -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
