On Sat, Feb 28, 2009 at 2:53 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote: > On Saturday 28 February 2009, Arve Hjønnevåg wrote: >> Can you summarize what the problems with my current api are? I get the >> impression that you think the overhead of using a list is too high, >> and that timeout support should be removed because you think all >> drivers that use it are broken. > > In no particular order: > 1. One user space process can create an unlimited number of wakelocks. This > shouldn't be possible. Moreover, it is not even necessary for any process > to have more than one wakelock held at any time. This has been addressed. A user space process cannot create more wakelocks than it has filedescriptors. > 2. Timeouts are wrong, because they don't really _solve_ any problem. They are > useful for working around the fact that you can't or you don't want to > modify every piece of code that in principle should take a wakelock and > that's it. Yes, timeouts are sometimes wrong, but they are not always wrong. I gave two examples where the use of timeouts was not incorrect. > However, entire concept of having one code path acting on > behalf of another one on a hunch that it might be doing something making > suspend undesirable is conceptually broken IMO. OK. Do you have an alternative? I my opinion this is how the entire system works if you do autosuspend without a mechanism like wakelocks. > 3. The overhead of using a list is unnecessary and _therefore_ too high (not > just too high). It is only unnecessary if you do not want accounting or timeouts. The overhead of a timer going off when it is not needed (if you push timeouts to the drivers) is way higher then the overhead putting wakelocks on a list. > 4. There seems to be a race between user space wakelocks and the freezer > (perhaps I overlooked something, in which case please disregard this item). You are missing something. Wakelocks overlap. > 5. The name "wakelocks" is confusing, because they aren't locks and they > affect suspend, not wake. I can change the name. Currently suspend_blocker seems to be acceptable many people, but some don't like this name either. > 6. Last time I saw the patches they were barely commented and the changelogs > didn't describe the code well (if at all). I have not added many inline comments, but I did add the kerneldoc comments you requested, and a lot of documentation since the first patches. > 7. There's no clear distinction between debug/stats code and the basic > functionality. I don't think this is still true. -- Arve Hjønnevåg _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
