On Wednesday, July 17, 2019 7:21 PM, Michael S. Tsirkin wrote: > > Wei, others, > > ATM virtio_balloon_shrinker_scan will only get registered when deflate on > oom feature bit is set. > > Not sure whether that's intentional. Yes, we wanted to follow the old oom behavior, which allows the oom notifier to deflate pages only when this feature bit has been negotiated. > Assuming it is: > > virtio_balloon_shrinker_scan will try to locate and free pages that are > processed by host. > The above seems broken in several ways: > - count ignores the free page list completely Do you mean virtio_balloon_shrinker_count()? It just reports to do_shrink_slab the amount of freeable memory that balloon has. (vb->num_pages and vb->num_free_page_blocks are all included ) > - if free pages are being reported, pages freed > by shrinker will just get re-allocated again fill_balloon will re-try the allocation after sleeping 200ms once allocation fails. > I was unable to make this part of code behave in any reasonable way - was > shrinker usage tested? What's a good way to test that? Please see the example that I tested before : https://lkml.org/lkml/2018/8/6/29 (just the first one: *1. V3 patches) What problem did you see? I just tried the latest code, and find ballooning reports a #GP (seems caused by 418a3ab1e). I'll take a look at the details in the office tomorrow. Best, Wei
