Mike Waychison <mi...@google.com> writes: > On Mon, Sep 10, 2012 at 3:59 PM, Michael S. Tsirkin <m...@redhat.com> wrote: >> On Mon, Sep 10, 2012 at 01:37:06PM -0400, Mike Waychison wrote: >>> On Mon, Sep 10, 2012 at 5:05 AM, Michael S. Tsirkin <m...@redhat.com> wrote: >>> > On Tue, Jun 26, 2012 at 01:32:58PM -0700, Frank Swiderski wrote: >>> >> This implementation of a virtio balloon driver uses the page cache to >>> >> "store" pages that have been released to the host. The communication >>> >> (outside of target counts) is one way--the guest notifies the host when >>> >> it adds a page to the page cache, allowing the host to madvise(2) with >>> >> MADV_DONTNEED. Reclaim in the guest is therefore automatic and implicit >>> >> (via the regular page reclaim). This means that inflating the balloon >>> >> is similar to the existing balloon mechanism, but the deflate is >>> >> different--it re-uses existing Linux kernel functionality to >>> >> automatically reclaim. >>> >> >>> >> Signed-off-by: Frank Swiderski <f...@google.com> >>> >>> Hi Michael, >>> >>> I'm very sorry that Frank and I have been silent on these threads. >>> I've been out of the office and Frank has been been swamped :) >>> >>> I'll take a stab at answering some of your questions below, and >>> hopefully we can end up on the same page.
Hi Mike, Frank, Michael, Thanks for the explanation and discussion. I like that this implementation is more dynamic: the guest can use more pages for a while (and the balloon kthread will furiously start trying to grab more pages to give back). This part is a completely reasonable implementation, and more sophisticated that what we have. It doesn't *quite* meet the spec, because we don't notify the host when we pull a page from the balloon, but I think that is quite possible. If this is a performance waster, we should add a "SILENT_DEFLATE" feature to tell the driver that it doesn't need to, though we should stll support the !SILENT_DEFLATE case. And Michael: thanks again for doing the heavy lifting on this! Cheers, Rusty. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html