On Sat, Sep 20, 2014 at 08:41:21PM +0000, Paul Zimmerman wrote: > > From: linux-usb-owner@xxxxxxxxxxxxxxx [mailto:linux-usb-owner@xxxxxxxxxxxxxxx] On Behalf Of Alan Stern > > Sent: Friday, September 19, 2014 12:39 PM > > > > On Fri, 19 Sep 2014, Petr Mladek wrote: > > > > > The 3rd version of the patchset is slightly reordered and refactored > > > as suggested earlier. See below for more details. > > > > > > IMHO, the result is more clean. But feel free to ask me to revert it. > > > I do not want to make the review more complicated. Well, I double checked > > > the diff of patches files between v2 and v3. It is pretty small and only > > > the expected changes are there. > > > > > > Changes in: > > > + v3: > > > + split the optimization of hub->hdev reference counting > > > into separate patch; usable standalone (1st patch) > > > > > > + switch order of the two patches that convert the kthread > > > and that remove the while cycle in hub_event(); it is > > > cleaner (2nd and 3rd patch) > > > > > > + use ordered workqueue by default; it makes it compatible > > > with the original kthread solution (3rd patch) > > > > > > + added optional patch that allows to process events > > > in parallel (6th patch) > > > > > > + fixed the suggested stylistic problems (2nd and 3rd patch) > > > > > > > > > + v2: > > > + solved potential races: > > > + get hub->kref in kick_hub_wq() > > > + call usb_get_dev(hdev) in hub_probe() > > > and usb_put_dev(hdev) in hub_release() > > > + INIT_WORK only once in hub_probe() > > > > > > + do not call cancel_work_sync() in hub_disconnect() > > > to keep it fast > > > > > > + rename kick_khubd() to kick_hub_wq() already > > > in the first patch; IMHO, it is cleaner while > > > adding only very few changes > > > > > > > > > The workqueue API is well defined and tested. It has many options > > > that could be used to tune the scheduling. The code is usually > > > easier and thus more safe. It allows to avoid the extra thread > > > in most cases. It has has clearly defined behavior vrt. system suspend. > > > > > > This patchset converts khubd into the workqueue. It saves one thread, > > > lock, and list. > > > > > > It looks huge but the main change is in the first patch. The rest is > > > simple renaming of functions, comments and documentation. > > > > > > > > > Thanks a lot Alan Stern and Tejun Heo for hints and guidance. > > > > > > The patches can be applied either against Linus' tree or linux-next. > > > > Very nice work. I haven't tried it out, but it all looks good. No > > doubt we will be able to sort out unforeseen troubles if any arise, > > without much difficulty. > > Hmm. What are the odds that some old kernel monitoring program, in an > ancient Fedora distribution let's say, will be checking for 'khubd' in > the kernel process list? Pretty high I would think. I really doubt it, what would that tell them? thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
