On Fri, 08 Nov 2013 21:04:26 +0900 Masami Hiramatsu <masami.hiramatsu...@hitachi.com> wrote:
> (2013/11/08 18:12), Petr Mladek wrote: > > This change is inspired by the int3-based patching code used in > > ftrace. See the commit fd4363fff3d9 (x86: Introduce int3 > > (breakpoint)-based instruction patching). > > > > When trying to use text_poke_bp in ftrace, the result was slower than > > the original implementation. > > > > It turned out that one difference was in text_poke vs. ftrace_write. > > text_poke did many extra operations to make sure that the change > > was atomic. > > AFAIK, the main reason why text_poke is used is avoiding > RODATA protection (by alias mapping). That is correct, and the reason ftrace didn't do that is because it would be quite expensive to map 22,000 addresses for each change. -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
