From: Paul E. McKenney Date: Wed, 11 Jan 2012 01:52:31 +0000 (-0800) Subject: rcu: Don't make callbacks go through second full grace period X-Git-Tag: v3.4-rc1~194^2^2~32 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a50c3af910e06f35bc0c68f89d8fef98c0fec0ea;p=pandora-kernel.git rcu: Don't make callbacks go through second full grace period RCU's current CPU-offline code path dumps all of the outgoing CPU's callbacks onto the RCU_NEXT_TAIL portion of the surviving CPU's callback list. This means that all the ready-to-invoke callbacks from the outgoing CPU must wait for another full RCU grace period. This was just fine when CPU-hotplug events were rare, but there is increasing evidence that users are planning to make increasing use of CPU hotplug. Therefore, this commit changes the callback-dumping procedure so that callbacks that are ready to invoke are moved to the RCU_DONE_TAIL portion of the surviving CPU's callback list. This avoids running these callbacks through a second unnecessary grace period. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney --- Reading git-diff-tree failed