From: Paul E. McKenney Date: Sun, 13 Sep 2009 16:15:10 +0000 (-0700) Subject: rcu: Simplify rcu_read_unlock_special() quiescent-state accounting X-Git-Tag: v2.6.32-rc1~612^2~5 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c3422bea5f09b0e85704f51f2b01271630b8940b;p=pandora-kernel.git rcu: Simplify rcu_read_unlock_special() quiescent-state accounting The earlier approach required two scheduling-clock ticks to note an preemptable-RCU quiescent state in the situation in which the scheduling-clock interrupt is unlucky enough to always interrupt an RCU read-side critical section. With this change, the quiescent state is instead noted by the outermost rcu_read_unlock() immediately following the first scheduling-clock tick, or, alternatively, by the first subsequent context switch. Therefore, this change also speeds up grace periods. Suggested-by: Josh Triplett Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu LKML-Reference: <12528585111945-git-send-email-> Signed-off-by: Ingo Molnar --- Reading git-diff-tree failed