Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: [ 00/10] [Suspend2] Modules support. | Date | Sat, 4 Feb 2006 14:09:42 +0100 |
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Hi,
On Saturday 04 February 2006 12:41, Nigel Cunningham wrote: > On Saturday 04 February 2006 21:38, Rafael J. Wysocki wrote: > > > > My personal view is that: > > > > 1) turning the freezing of kernel threads upside-down is not > > > > necessary and would cause problems in the long run, > > > > > > Upside down? > > > > I mean now they should freeze voluntarily and your patches change that > > so they would have to be created as non-freezeable if need be, AFAICT. > > Ah. Now I'm on the same page. Lost the context. > > > > > 2) the todo lists are not necessary and add a lot of complexity, > > > > > > Sorry. Forgot about this. I liked it for solving the SMP problem, but > > > IIRC, we're downing other cpus before this now, so that issue has gone > > > away. I should check whether I'm right there. > > > > > > > 3) trying to treat uninterruptible tasks as non-freezeable should > > > > better be avoided (I tried to implement this in swsusp last year but > > > > it caused vigorous opposition to appear, and it was not Pavel ;-)) > > > > > > I'm not suggesting treating them as unfreezeable in the fullest sense. > > > I still signal them, but don't mind if they don't respond. This way, > > > if they do leave that state for some reason (timeout?) at some point, > > > they still get frozen. > > > > Yes, that's exactly what I wanted to do in swsusp. ;-) > > Oh. What's Pavel's solution? Fail freezing if uninterruptible threads don't > freeze? > > > > > > A couple of possible exceptions might be (1) freezing bdevs, > > > > > because you don't care so much about making xfs really sync and > > > > > really stop it's activity > > > > > > > > As I have already stated, in my view this one is at least worth > > > > considering in the long run. > > > > > > > > > and (2) the ability to thaw kernel space without thawing > > > > > userspace. I want this for eating memory, to avoid deadlocking > > > > > against kjournald etc. I haven't checked carefully as to why you > > > > > don't need it in vanilla. > > > > > > > > Because it does not deadlock? I will say we need this if I see a > > > > testcase showing such a deadlock clearly. > > > > > > I've been surprised that you haven't already seen them while eating > > > memory such that filesystems come into play. Perhaps you guys only use > > > swap partitions, and something like a swapfile with some memory > > > pressure might trigger this? Or it could be a side effect of one of > > > the other changes. > > > > In fact, we only use swap partitions, so this will be needed if we are > > going to use files, I guess. Nice to know in advance, thanks. ;-) > > k. Just so you don't confuse me, can I ask you not to refer to swapfiles as > 'files'? I support swap partitions, swapfiles and ordinary files, so the > latter will come to mind first for me.
Sure. In fact I was referring to both swapfiles and regular files as just "files".
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