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, firstname.lastname@example.org, to which suggestions
can be sent.
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