On Tue, Mar 23, 2010 at 12:06:50PM -0400, Jeff Squyres wrote: > IBM has found a resource that they think will be able to progress Roland's > ummunotify work. > > After a few discussions in Sonoma last week and some off-list emails, here's > what we decided: > > 1. Take Roland's last code drop (Roland: can you re-send the last copy of > your code?). > > 2. Do not convert it to the perf events kernel framework as the Linux kernel > community requested. Instead, migrate the functionality into the ibv code > base. Roland thinks that most of the code should be adaptable without too > many changes. Here's the highlights of the new functionality: > > a. Add a new flag to ibv_reg_mr() that does the same function as > UMMUNOTIFY_REGISTER_REGION > b. ibv_dereg_mr() always performs the equivalent of > UMMUNOTIFY_UNREGISTER_REGION (if necessary)
> c. Make a new device somewhere (under /dev/infiniband?) that > performs the same functions as /dev/ummunotify (open it to mmap > the counter into user space, and read events when something > "interesting" happens) I would prefer to do this by adding a new verbs call that returns a fd directly. Ie use ib_uverbs_alloc_event_file and act like ibv_create_comp_channel. The main reason for the new FD is so it can be polled on.. You can also avoid the mmap scheme by doing what perf events does, pass in a pointer from userspace and have the kernel pin that page it is on. So, I'd suggest fd = ibv_create_mmu_monitor(verbs, &counter); [..] poll(fd); [..] if (counter != last_counter) [..] close(fd); Refuse to create more than one mmu_monitor for each verbs for now. I looked at this for a little while at Sonoma and I think it is quite straightforward, I'm happy to look over anything. Jason -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
