On Sun, Nov 2, 2014 at 10:38 PM, Konstantin Belousov <kostik...@gmail.com> wrote: > On Sun, Nov 02, 2014 at 10:17:26PM +0100, Attilio Rao wrote: >> On Sun, Nov 2, 2014 at 8:10 PM, Konstantin Belousov <kostik...@gmail.com> >> wrote: >> > On Sun, Nov 02, 2014 at 06:53:44PM +0100, Attilio Rao wrote: >> >> > I did not proposed to verify owner chain. I said that it is easy to >> >> > record the locks owned by current thread, only for current thread >> >> > consumption. Below is the prototype. >> >> >> >> I think it is too expensive, think that this must happen for every shared >> >> lock. >> >> I know we may not be using too many shared locks on lockmgr right now, >> >> but it is not a good reason to make shared lock bloated and more >> >> expensive on lockmgr. >> > >> > It can be significantly simplified, if the array of lock pointers is >> > kept dense. Then the only non-trivial operation is unlock out of order, >> > when the array have to be compacted. >> > >> > The code adds one write and n reads on shared lock, where n is the >> > number of shared-locked locks already owned by thread. Typical n is 0 >> > or 1. On unlock, if done in order, the code adds one read; unordered >> > unlock shuffles array elements. Again, for typical lock nesting of 2, >> > this means one read and one write, and even this is rare. All reads and >> > writes are for thread-local memory. >> > >> > I am not going to spend any more time on this if people do not consider >> > the lock tracking worth it. Otherwise, I will benchmark the patch. >> >> I think that your initial patch (what is in head now) is a better approach. >> I would just make it a lockinit() flag to make it less alien to the KPI. >> > > Ok. > > Can you explain what would the proposed lockinit() flag do ? What should > it change comparing with the current code ?
You now provide LK_NODDLKTREAT on a call basis. The lockinit() flag would embed this into the lock attribute and make it always real, without the need for the callers to provide LK_NODDLKTREAT on a call basis. Attilio -- Peace can only be achieved by understanding - A. Einstein _______________________________________________ svn-src-all@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
