Rusty Russell wrote: > On Sun, 2007-07-08 at 15:48 +0200, Ingo Molnar wrote: > >> * Avi Kivity <[EMAIL PROTECTED]> 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? 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. >> > > OK, this patch is *ugly*. Not that there's anything wrong with a patch > which says "I'm going to preempt you", but making it kvm-specific is > ugly. ISTR times past where I wanted such a hook, although none spring > immediately into my pre-coffee brain. > > I think a "struct preempt_ops *" and a "void *preempt_ops_data" inside > every task struct is a better idea. Call the config option > PREEMPT_SCHED_HOOKS and now there's nothing kvm-specific about it... >
I considered that, but your proposal does not allow a single task to have multiple preemption hooks installed (hookers?!). Since in general there's no reason to suppose that users would be mutually exclusive, we need to have a struct hlist of these things. All in all this seemed to indicate that the second user should have the honor of figuring out that stuff. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
