On Mon, May 02, 2011 at 11:25:28PM -0700, Paul E. McKenney wrote: > > > > How significantly? As I wrote in other mail I compiled two TINY_RCU > > > > kernel with and without the patch and I didn't see memory footprint > > > > increase at all. May be I measure it incorrectly, but what I see is that > > > > with out of line function + export text section becomes 64 byte bigger, but > > > > data section becomes 64 byte smaller: > > > > > > > > text data bss dec hex filename > > > > 4544134 590596 2023424 7158154 6d398a vmlinux inline > > > > 4544198 590532 2023424 7158154 6d398a vmlinux.ol out of line > > > > > > Did you add the exports that would be needed to allow KVM to call > > > the functions in the inline case? > > > > > Yes, this is with and without patch applied. When patch is applied the > > function is out of line and exported. > > OK, here is what I am suggesting -- create a separate API for virtualization, > make it be an empty static inline function for TINY, and make it a wrapper > for TREE. This gets rid of the export in the TINY case, and takes advantage > of the single-CPU constraint in the TINY case. So this gains the benefit > of uninlining rcu_note_context_switch(), but avoids paying the cost of the > EXPORT_SYMBOL_GPL(). > > Then you call rcu_virt_note_context_switch() in place of > rcu_note_context_switch() from KVM. > > Does this make sense? > If TINY RCU has such strict code size requirement then yes. I will make another patch based on this and resend. -- Gleb. -- 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
