From: Paul E. McKenney Date: Mon, 4 Jan 2010 23:09:02 +0000 (-0800) Subject: rcu: Prohibit starting new grace periods while forcing quiescent states X-Git-Tag: v2.6.34-rc1~265^2~42 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=07079d5357a4d53c2b13126c4a38fb40e6e04966;p=pandora-kernel.git rcu: Prohibit starting new grace periods while forcing quiescent states Reduce the number and variety of race conditions by prohibiting the start of a new grace period while force_quiescent_state() is active. A new fqs_active flag in the rcu_state structure is used to trace whether or not force_quiescent_state() is active, and this new flag is tested by rcu_start_gp(). If the CPU that closed out the last grace period needs another grace period, this new grace period may be delayed up to one scheduling-clock tick, but it will eventually get started. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <126264655052-git-send-email-> Signed-off-by: Ingo Molnar --- Reading git-diff-tree failed