From: Tejun Heo Date: Tue, 23 Nov 2010 05:36:11 +0000 (-0800) Subject: rcu: increase synchronize_sched_expedited() batching X-Git-Tag: v2.6.38-rc1~492^2^2~7 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e27fc9641e8ddc8146f8e01f06e5eba2469698de;p=pandora-kernel.git rcu: increase synchronize_sched_expedited() batching The fix in commit #6a0cc49 requires more than three concurrent instances of synchronize_sched_expedited() before batching is possible. This patch uses a ticket-counter-like approach that is also not unrelated to Lai Jiangshan's Ring RCU to allow sharing of expedited grace periods even when there are only two concurrent instances of synchronize_sched_expedited(). This commit builds on Tejun's original posting, which may be found at http://lkml.org/lkml/2010/11/9/204, adding memory barriers, avoiding overflow of signed integers (other than via atomic_t), and fixing the detection of batching. Signed-off-by: Tejun Heo Signed-off-by: Paul E. McKenney --- Reading git-diff-tree failed