On Tue, 2011-04-12 at 11:13 +0530, Amit Shah wrote: > Sure, the only contention was on the commit message, where you stated > modern qemus set this... qemu doesn't, and it should. Care to do a > patch for that? If Rusty hasn't pushed the commit out anywhere, we can still amend the commit. Otherwise, we're in a _bit_ of a pickle since you can't patch git logs. :) Whatever is easiest for Rusty works for me. How about this for a replacement log? -- The virtio balloon driver has a VIRTIO_BALLOON_F_MUST_TELL_HOST feature bit. Whenever the bit is set, we must always tell the host before we free pages back to the allocator. Without this feature, we might free a page (and have another user touch it) while the hypervisor is unprepared for it. But, if the bit is _not_ set, we are under no obligation to reverse the order; we're under no obligation to do _anything_. That's the state of affairs in current qemu: #define VIRTIO_BALLOON_F_MUST_TELL_HOST 0 This patch makes the "tell host first" logic the only case. This should make everybody happy, and reduce the amount of untested or untestable code in the kernel. This _also_ means that we don't have to preserve a pfn list after the pages are freed, which should let us get rid of some temporary storage (vb->pfns) eventually. Signed-off-by: Dave Hansen <dave@xxxxxxxxxxxxxxxxxx> -- Dave _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/virtualization
