On Tue, Jun 25, 2019 at 7:10 AM Dave Hansen <dave.hansen@xxxxxxxxx> wrote: > > On 6/25/19 12:42 AM, David Hildenbrand wrote: > > On 20.06.19 00:32, Alexander Duyck wrote: > > I still *detest* the terminology, sorry. Can't you come up with a > > simpler terminology that makes more sense in the context of operating > > systems and pages we want to hint to the hypervisor? (that is the only > > use case you are using it for so far) > > It's a wee bit too cute for my taste as well. I could probably live > with it in the data structures, but having it show up out in places like > Kconfig and filenames goes too far. > > For instance, someone seeing memory_aeration.c will have no concept > what's in the file. Could we call it something like memory_paravirt.c? > Or even mm/paravirt.c. Well I couldn't come up with a better explanation of what this was doing, also I wanted to avoid mentioning hinting specifically because there have already been a few series that have been committed upstream that reference this for slightly different purposes such as the one by Wei Wang that was doing free memory tracking for migration purposes, https://lkml.org/lkml/2018/7/10/211. Basically what we are doing is inflating the memory size we can report by inserting voids into the free memory areas. In my mind that matches up very well with what "aeration" is. It is similar to balloon in functionality, however instead of inflating the balloon we are inflating the free_list for higher order free areas by creating voids where the madvised pages were. > Could you talk for a minute about why the straightforward naming like > "hinted/unhinted" wasn't used? Is there something else we could ever > use this infrastructure for that is not related to paravirtualized free > page hinting? I was hoping there might be something in the future that could use the infrastructure if it needed to go through and sort out used versus unused memory. The way things are designed right now for instance there is only really a define that is limiting the lowest order pages that are processed. So if we wanted to use this for another purpose we could replace the AERATOR_MIN_ORDER define with something that is specific to that use case.
