On Friday, 20 July 2007 17:36, [EMAIL PROTECTED] wrote: > On Fri, 20 Jul 2007, Jim Crilly wrote: > > >>> has > >>> requested the image to be not greater than 50% of RAM. In that case you > >>> have > >>> to free some memory _before_ identifying memory to save and you must not > >>> race with applications that attempt to allocate memory while you're doing > >>> it. > >> > >> I disagree a little bit. > >> > >> first off, only the suspending kernel can know what can be freed and what > >> is needed to do so (remember this is kernel internals, it can change from > >> patch to patch, let alone version to version) > >> > >> second, if you have a lot of memory to free, and you can't just throw away > >> caches to do so, you don't know what is going to be involved in freeing > >> the memory, it's very possilbe that it is going to involve userspace, so > >> you can't freeze any significant portion of the system, so you can't > >> eliminate all chance of races > >> > >> what you can do is > >> > >> 1. try to free stuff > >> 2. stop the system and account for memory, is enough free > >> if not goto 1 > >> > >> if userspace is dirtying memory fast enough, or is just useing enough > >> memory that you can't meet your limit you just won't be able to suspend. > >> > >> but under any other conditions you will eventually get enough memory free. > >> > >> so try several times and if you still fail tell the user they have too > >> much stuff running and they need to kill something. > > > > Which would be a pretty big regression from what we have now. With the > > current implementation I can hibernate under virtually any workload because > > the freezer stops everything and there's no competition for resources. > > as long as what you are trying to save is <=50% of ram (at least with some > implementations). if you are trying to save more then 50% of ram with some > current implmenetations you just can't
With some, you can't, with the others, you can. :-) The argument given was about the freezer and IMO it was valid. Why didn't you address it directly? Greetings, Rafael -- "Premature optimization is the root of all evil." - Donald Knuth - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
