On Wed, Jun 10, 2015 at 10:31:55AM -0500, Josh Poimboeuf wrote: > On Wed, Jun 10, 2015 at 05:04:12PM +0200, Andi Kleen wrote: > > It's not needed, but it's an optimization to optimize icache usage. > > It is optional (-freorder-blocks-and-partition) > > > > In this case gcc splits the function into two (hot and cold) > > > > It's actually a nice optimization and it would be sad from stopping > > the kernel from using it. > > Sorry if I wasn't clear, I was trying to ask for examples in kernel asm > code. > > Are you suggesting that we implement this gcc optimization in kernel asm > code? If you're wanting something like -freorder-blocks-and-partition for asm code, maybe we could implement something analagous to the likely()/unlikely() macros, to allow the hot and cold portions to be placed into different sections. (I could then teach asmvalidate how to validate such code.) Would that be useful? -- Josh -- 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
