Re: [PATCH][RF C/T/D] Unmapped page cache control - via boot parameter

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 03/15/2010 08:48 PM, Anthony Liguori wrote:
On 03/15/2010 04:27 AM, Avi Kivity wrote:

That's only beneficial if the cache is shared. Otherwise, you could use the balloon to evict cache when memory is tight.

Shared cache is mostly a desktop thing where users run similar workloads. For servers, it's much less likely. So a modified-guest doesn't help a lot here.

Not really. In many cloud environments, there's a set of common images that are instantiated on each node. Usually this is because you're running a horizontally scalable application or because you're supporting an ephemeral storage model.

But will these servers actually benefit from shared cache? So the images are shared, they boot up, what then?

- apache really won't like serving static files from the host pagecache
- dynamic content (java, cgi) will be mostly in anonymous memory, not pagecache
- ditto for application servers
- what else are people doing?

In fact, with ephemeral storage, you typically want to use cache=writeback since you aren't providing data guarantees across shutdown/failure.

Interesting point.

We'd need a cache=volatile for this use case to avoid the fdatasync()s we do now. Also useful for -snapshot. In fact I have a patch for this somewhere I can dig out.

--
error compiling committee.c: too many arguments to function

--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[Index of Archives]     [KVM ARM]     [KVM ia64]     [KVM ppc]     [Virtualization Tools]     [Spice Development]     [Libvirt]     [Libvirt Users]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite Questions]     [Linux Kernel]     [Linux SCSI]     [XFree86]
  Powered by Linux