[Thomas, thanks for pinging me on this.] Hi Cyril Please CC linux-api on changes that affect kernel-user-space ABI/API. On Thu, May 22, 2014 at 12:35 AM, Cyrill Gorcunov <gorcunov@xxxxxxxxx> wrote: > On Thu, May 22, 2014 at 07:12:30AM +0900, Thomas Gleixner wrote: >> >> There is a world outside of checkpoint/restore, really. > > Yes, I simply don't know who else might use this write() > functionality for other purpose, I mean i don't see a > point to use it for anything else. Nevertheless, when making API changes like this, we should be thinking as generally as possible, rather than looking from the perspective of a single use case. >> So what's the semantics of that write function? We really want to have >> that agreed on and documented in the man page. > > The idea was to provide a way to setup @ticks into (nonzero) value > which we get from show_fdinfo output. Then when we restore it > we setup the timer and set @ticks to the value it had at dump > moment. > >> Right now the write will just update the ticks and nothing else. So >> what if there is a waiter already? What if there is a timer armed? >> >> Can you please describe how checkpoint/restore is going to use all of >> this. How is the timer restored and how/when is the reader which was >> waiting in read/poll at the time of suspend reattached to it. > > Thomas, I see what you mean. Need to think (I must admit I forgot about > polling of timerfds :( I were to restore timerfds like this > > - fetch data from fdinfo > - use timer_create/settime to arm it > - write @ticks then > > but i didn't try restore polling waiters, my bad. Letme rework this > trying addressing your comments. Great. Please CC me and linux-api@ on the next round. Cheers, Michael > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Author of "The Linux Programming Interface", http://blog.man7.org/ -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
