Re: [kvm-devel] [PATCH] kvm balloon guest driver (v2)

[Akio T. <tak...@jp...>]

Hi, Marcelo

>> >+static int kvm_balloon_inflate(struct virtballoon *v, int32_t npages)
>> >+{
>> >+	LIST_HEAD(tmp_list);
>> >+	struct page *page, *tmp;
>> >+	struct balloon_buf *buf;
>> >+	u32 *pfn;
>> >+	int allocated = 0;
>> >+	int i, r = -ENOMEM;
>> >+
>> >+	buf = alloc_balloon_buf(v->vdev, GFP_KERNEL);
>> When does balloon driver free the buf?
>
>Hi Akio,
>
>The buffers are passed from the virtio handling routine to the balloon_thread
>through the balloon_work list, and then freed here:
>
>+               spin_lock_irq(&v->queue_lock);
>+               while (!list_empty(&v->balloon_work)) {
>+                       struct balloon_work *work;
>+                       struct balloon_buf *buf;
>+
>+                       work = list_entry(v->balloon_work.next,
>+                                        struct balloon_work, list);
>+                       list_del(&work->list);
>+                       spin_unlock_irq(&v->queue_lock);
>+                       buf = work->buf;
>+                       kfree(work);
>+
>+                       switch(buf->hdr.cmd) {
>+                       case CMD_BALLOON_DEFLATE:
>+                               deflate_done(v, buf);
>+                               break;
>+                       case CMD_BALLOON_INFLATE:
>+                               inflate_done(v, buf);
>+                               break;
>+                       default:
>+                               printk("%s: unknown cmd 0x%x\n", __func__,
>+                                       buf->hdr.cmd);
>+                       }
>+                       kfree(buf);
Thank you for your exlanation.
Does balloon free the buf when kvm_balloon_xflate() retrun -ENOMEM?

Best Regards,

Akio Takebe