On Tue, 17 Mar 2015 00:56:51 -0500 (CDT) Christoph Lameter <c...@linux.com> wrote:
> On Mon, 16 Mar 2015, Steven Rostedt wrote: > > > It has come to my attention that this_cpu_read/write are horrible on > > architectures other than x86. Worse yet, they actually disable > > preemption or interrupts! This caused some unexpected tracing results > > on ARM. > > Well its just been 7 years or so. Took a long time it seems. The code that I added was not 7 years old. And not all people send me reports like this. > > These would need to be implemented on the architectures to > have comparable performance. > > > I may go and remove all this_cpu_read,write() calls from my code > > because of this. > > You could do that with __this_cpo_* but not this_cpu_*(). Doing > it to this_cpu_* would make the operations no longer per cpu atomic. If > they do not need per cpu atomicity then you could have used __this_cpu_* > instead. And __this_cpu_* do not disable preemption or interrupts. I do not need it to be atomic. > > So please do not send patches based on gut reactions. What else would you like me to do? It was an RFC, and it worked. > > NAK For this particular patch, I may override the NAK as I do not see a downside for it. Why should x86 get an advantage at the expense of ARM? -- 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/
