On Wed, 7 Nov 2012 01:05:52 -0200
Rafael Aquini <aquini@xxxxxxxxxx> wrote:
> Memory fragmentation introduced by ballooning might reduce significantly
> the number of 2MB contiguous memory blocks that can be used within a guest,
> thus imposing performance penalties associated with the reduced number of
> transparent huge pages that could be used by the guest workload.
>
> Besides making balloon pages movable at allocation time and introducing
> the necessary primitives to perform balloon page migration/compaction,
> this patch also introduces the following locking scheme, in order to
> enhance the syncronization methods for accessing elements of struct
> virtio_balloon, thus providing protection against concurrent access
> introduced by parallel memory migration threads.
>
> ...
>
> @@ -122,18 +128,25 @@ static void set_page_pfns(u32 pfns[], struct page *page)
>
> static void fill_balloon(struct virtio_balloon *vb, size_t num)
> {
> + struct balloon_dev_info *vb_dev_info = vb->vb_dev_info;
> +
> + static DEFINE_RATELIMIT_STATE(fill_balloon_rs,
> + DEFAULT_RATELIMIT_INTERVAL,
> + DEFAULT_RATELIMIT_BURST);
> +
> /* We can only do one array worth at a time. */
> num = min(num, ARRAY_SIZE(vb->pfns));
>
> + mutex_lock(&vb->balloon_lock);
> for (vb->num_pfns = 0; vb->num_pfns < num;
> vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) {
> - struct page *page = alloc_page(GFP_HIGHUSER | __GFP_NORETRY |
> - __GFP_NOMEMALLOC | __GFP_NOWARN);
> + struct page *page = balloon_page_enqueue(vb_dev_info);
> +
> if (!page) {
> - if (printk_ratelimit())
> + if (__ratelimit(&fill_balloon_rs))
> dev_printk(KERN_INFO, &vb->vdev->dev,
> "Out of puff! Can't get %zu pages\n",
> - num);
> + VIRTIO_BALLOON_PAGES_PER_PAGE);
> /* Sleep for at least 1/5 of a second before retry. */
> msleep(200);
> break;
linux-next's fill_balloon() has already been converted to
dev_info_ratelimited(). I fixed everything up. Please check the result.
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