Re: [PATCH] Add a page cache-backed balloon device driver.
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On 06/26/2012 04:32 PM, 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<fes@xxxxxxxxxx>
It is a great idea, but how can this memory balancing possibly work if someone uses memory cgroups inside a guest? Having said that, we currently do not have proper memory reclaim balancing between cgroups at all, so requiring that of this balloon driver would be unreasonable. The code looks good to me, my only worry is the code duplication. We now have 5 balloon drivers, for 4 hypervisors, all implementing everything from scratch... _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization