On Wed, Jan 27, 2016 at 09:51:12PM +1100, Balbir Singh wrote: > On Mon, 25 Jan 2016 16:38:48 +0100 > Torsten Duwe <duwe@xxxxxx> wrote: > > > Changes since v5: > > * extra "std r0,LRSAVE(r1)" for gcc-6 > > This makes the code compiler-agnostic. > > * Follow Petr Mladek's suggestion to avoid > > redefinition of HAVE_LIVEPATCH > > I looked at the patches - well mostly patches 1 and 2, some quick questions > > 1. I know -mprofile-kernel is a big optimization win, do we need it or can > we incrementally add it? There's a reason why these are first ;-) The following ones assume -mprofile-kernel is used. The disadvantage is all relevant registers need to be saved before calling further C code in between functions. On the Pro side, no stack frame has been created at that point. These are assumptions made all over the ftrace-with-regs and live patching code here. > 2. Some of the hardcoded checks for opcode are hard to review, I know they've > been there in similar forms for a while. May be as an iterative step we should > give the numbers some meaning and use proper helpers for it. Yes, Michael has already criticised that. No further literal hex constants, I promise. > I am going to give the patches a spin Thanks! Make sure you use a compiler that can disable -mprofile-kernel with "notrace". Torsten -- To unsubscribe from this list: send the line "unsubscribe live-patching" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
