On Fri 2015-10-30 11:29:08, Alan Stern wrote: > On Fri, 30 Oct 2015, Jiri Kosina wrote: > > > This series is a followup to my proposal I brought up on Kernel Summit in > > Seoul. Noone seemed to had any principal objections, so let's have wider > > audience look into it. > > > > In a nuthsell: freezing of kernel threads is horrible interface with > > unclear semantics and guarantees, and I am surprised it ever worked > > properly. Plus there are a lot of places that simply use it in a > > completely wrong way (which is not suprising, given the lack of defined > > semantics and requirements). > > > > I've tested this over a series of suspend/resume cycles on several > > machines with at least ext4, btrfs and xfs, and it survived the testing > > without any harm. > > > > Patch 1/3 implements the actual change, and has a more detailed > > explanation on "why?" and "how?" questions in the changelog > > This patch talks about freezing in relation to hibernation. What about > other forms of suspend? > > Also, it replaces kthread freezing with filesystem freezing. What > about kthreads performing I/O that doesn't go through a filesystem? > You write: > > > the only facility that is needed during suspend: "no persistent fs > > changes are allowed from now on" > > I would say instead "no I/O is allowed from now on". Maybe that's an > overstatement, but I think it comes closer to the truth. Exactly. And I'm pretty sure hardware drivers do use kernel threads, and do I/O from them. LEDs are just one example Best regards, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
