From: Paul E. McKenney Date: Wed, 2 Dec 2009 20:10:14 +0000 (-0800) Subject: rcu: Enable fourth level of TREE_RCU hierarchy X-Git-Tag: v2.6.33-rc1~405^2~2 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cf244dc01bf68e1ad338b82447f8686d24ea4435;p=pandora-kernel.git rcu: Enable fourth level of TREE_RCU hierarchy Enable a fourth level of rcu_node hierarchy for TREE_RCU and TREE_PREEMPT_RCU. This is for stress-testing and experiemental purposes only, although in theory this would enable 16,777,216 CPUs on 64-bit systems, though only 1,048,576 CPUs on 32-bit systems. Normal experimental use of this fourth level will normally set CONFIG_RCU_FANOUT=2, requiring a 16-CPU system, though the more adventurous (and more fortunate) experimenters may wish to chose CONFIG_RCU_FANOUT=3 for 81-CPU systems or even CONFIG_RCU_FANOUT=4 for 256-CPU systems. Signed-off-by: Paul E. McKenney Acked-by: Josh Triplett Acked-by: Lai Jiangshan Cc: dipankar@in.ibm.com 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 Cc: dhowells@redhat.com LKML-Reference: <12597846161257-git-send-email-> Signed-off-by: Ingo Molnar --- Reading git-diff-tree failed