On 24/08/17 13:35, Jan Beulich wrote: >>>> On 24.08.17 at 13:13, <andrew.coop...@citrix.com> wrote: >> On 24/08/17 09:44, Jan Beulich wrote: >>> >>> On 23.08.17 at 21:09, <andrew.coop...@citrix.com> wrote: >>>> * These functions work in terms of linear addresses, not virtual addresses. >>>> Update the comments and parameter names. >>>> * Drop unnecessary inlines. >>>> * Drop vcpu parameter from guest_get_eff_kern_l1e(). Its sole caller >>>> passes >>>> current, and its callee strictly operates on current. >>> I'm not entirely convinced of this part, as I think the intention was >>> to save the re-latching of "current", but anyway: >> It'll be inlined anyway, given a sole caller. > But the inlining won't help with the re-fetching; the compiler can't > know it can re-use the earlier fetched value.
On that side of things, in the past I tried experimenting with attribute pure and const for things behind current. Such annotations should allow subexpression elimination and reordering, even across inlining boundaries, but I failed to get any change in generated code. I don't know if it was because I was annotating incorrectly, or GCC decided that elimination wasn't worth doing, but it might be something worth re-investigating. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
