19 May, 2008

1 commit


26 Jan, 2008

1 commit

  • This patch implements a new version of RCU which allows its read-side
    critical sections to be preempted. It uses a set of counter pairs
    to keep track of the read-side critical sections and flips them
    when all tasks exit read-side critical section. The details
    of this implementation can be found in this paper -

    http://www.rdrop.com/users/paulmck/RCU/OLSrtRCU.2006.08.11a.pdf

    and the article-

    http://lwn.net/Articles/253651/

    This patch was developed as a part of the -rt kernel development and
    meant to provide better latencies when read-side critical sections of
    RCU don't disable preemption. As a consequence of keeping track of RCU
    readers, the readers have a slight overhead (optimizations in the paper).
    This implementation co-exists with the "classic" RCU implementations
    and can be switched to at compiler.

    Also includes RCU tracing summarized in debugfs.

    [ akpm@linux-foundation.org: build fixes on non-preempt architectures ]

    Signed-off-by: Gautham R Shenoy
    Signed-off-by: Dipankar Sarma
    Signed-off-by: Paul E. McKenney
    Reviewed-by: Steven Rostedt
    Signed-off-by: Ingo Molnar

    Paul E. McKenney