KS2012: Lightning talks

The lightning talks on day 1 of the 2012 Kernel Summit were over in, one could say, a flash. There were just two very brief discussions.

Paul McKenney noted that a small number of read-copy update (RCU) users have for some time requested the ability to offload RCU callbacks. Normally, RCU callbacks are invoked on the CPU that registered them. This works well in most cases, but it can result in unwelcome variations in the execution times of user processes running on the same CPU. This kind of variation (also known as operating system jitter) can be reduced by offloading the callbacks—arranging for that CPU's RCU callbacks to be invoked on some other CPU. Paul asked if the ability to offload RCU callbacks was of interest to others in the room. A number of developers responded in the affirmative.

Dan Carpenter noted the existence of Smatch, his static analysis tool that detects various kinds of errors in C source code, pointing out that by now "many of you have received emails from me". (The emails that he referred to contained kernel patches and lists of bugs or potential bugs in kernel code. In the summary of his LPC 2011 presentation, Dan noted that Smatch has resulted in hundreds of kernel patches.) Dan's main point was simply to request other ideas from kernel developers on what checks to add to Smatch; he noted that there is a mailing list, smatch@vger.kernel.org, to which suggestions can be sent.