On Mon 28-08-17 15:33:26, Michal Hocko wrote: > On Mon 28-08-17 18:08:32, Wei Wang wrote: > > This patch adds support to walk through the free page blocks in the > > system and report them via a callback function. Some page blocks may > > leave the free list after zone->lock is released, so it is the caller's > > responsibility to either detect or prevent the use of such pages. > > > > One use example of this patch is to accelerate live migration by skipping > > the transfer of free pages reported from the guest. A popular method used > > by the hypervisor to track which part of memory is written during live > > migration is to write-protect all the guest memory. So, those pages that > > are reported as free pages but are written after the report function > > returns will be captured by the hypervisor, and they will be added to the > > next round of memory transfer. > > OK, looks much better. I still have few nits. > > > +extern void walk_free_mem_block(void *opaque, > > + int min_order, > > + bool (*report_page_block)(void *, unsigned long, > > + unsigned long)); > > + > > please add names to arguments of the prototype And one more thing. Your callback returns bool and true usually means a success while you are using it to break out from the loop. This is rather confusing. I would expect iterating until false is returned so the opposite than what you have. You could also change this to int and return 0 on success and < 0 to break out. -- Michal Hocko SUSE Labs _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
