[ Thanks to Linux User &
Developer magazine for this link. ]
“This month saw the final release of kernel 2.6.36, and
the closing of the following ‘merge window’ for new features to be
merged into what will become the 2.6.37 kernel (more details about
the latter in a moment). The 2.6.36 kernel features
concurrency-managed workqueues, preliminary support for the
fanotify mechanism discussed here in the past, final merging of the
AppArmor security system used by some distributions for many years,
and support for a new architecture, among many dozens of other
significant improvements. The new kernel received patches from over
1,100 engineers for a total of nearly 11,000 changesets
(collections of related changes to various kernel files) overall.“Concurrency-managed workqueues
“Workqueues are one of the not particularly sexy but necessary
pieces of kernel infrastructure code that provide a means for
developers to schedule execution of some function at a more
convenient time. They run that function within a special kernel
thread – visible using the ‘top’ and ‘ps’ commands – in
what is known as ‘process’ context (Linux has historically
differentiated more between the limited ‘interrupt’ and ‘process’
context for what features code could use at the time, but this is
changing slowly with the mixture of newer threaded interrupt
support). Over the years, workqueue use has become so profuse
within drivers and other kernel code that a typical system may have
many hundreds – or even thousands – of kernel threads
dedicated to them, often competing at unfortunate times for the
CPU, and at other times doing nothing other than existing and
clogging up lists of running processes.”