On Sat, Feb 6, 2021 at 8:12 AM Pavel Raiskup <praiskup@xxxxxxxxxx> wrote: > > I'm trying to overcommit storage space on one our hypervisors (and reclaim > space if possible after memory peak times) and it seems like kernel in > Fedora 33 isn't doing automatic discard on swap partitions? You might ask about it on linux-mm@xxxxxxxxx > $ swapon --discard /dev/sda --discard without options enables both available options, so you get an initial discard and then an async discard when pages are freed. Quite a lot of applications don't seem to free their dirty pages until they quit, which might also be worth asking about. > The 'fstrim -av' isn't propagated to SWAP mount points (expected > probably). It's not a file system so that doesn't work. > But otherwise, freeing the guest memory manually, minimizing the swap usage, > etc. (experiments with tmpfs) doesn't result in freeing the allocated storage > blocks on host. I think it's up to the application to free the pages, if they aren't freed somehow then the kernel can't know what blocks to issue discards for. -- Chris Murphy _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@xxxxxxxxxxxxxxxxxxxxxxx
