Re: [PATCH][RFC] kvm-scheduler integration

From: Avi Kivity
Date: Sun Jul 08 2007 - 09:53:18 EST


Ingo Molnar wrote:
* Avi Kivity <avi@xxxxxxxxxxxx> wrote:

+#ifdef CONFIG_SCHED_KVM
+static __read_mostly struct sched_kvm_hooks kvm_hooks;
+#endif
please just add a current->put_vcpu() function pointer instead of this hooks thing.
Won't that increase task_struct (16 bytes on 64-bit) unnecessarily? The function pointers are common to all virtual machines.

well, this function pointer could then be reused by other virtual machines as well, couldnt it?

I don't get this. If we add a couple of members to task_struct, it can't be reused. The values will be the same across all tasks, but the memory will be gone (including tasks which aren't virtual machines).

If the task struct overhead is a problem (it really isnt, and it's dependent on CONFIG_KVM) then we could switch it around to a notifier-alike mechanism.

I'm hoping that CONFIG_KVM will be enabled on most distro kernels, so we need to optimize for that case as well.

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

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