From: Paul E. McKenney Date: Wed, 14 Oct 2009 17:15:55 +0000 (-0700) Subject: rcu: Prevent RCU IPI storms in presence of high call_rcu() load X-Git-Tag: v2.6.32-rc6~55^2~3 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=37c72e56f6b234ea7387ba530434a80abf2658d8;p=pandora-kernel.git rcu: Prevent RCU IPI storms in presence of high call_rcu() load As the number of callbacks on a given CPU rises, invoke force_quiescent_state() only every blimit number of callbacks (defaults to 10,000), and even then only if no other CPU has invoked force_quiescent_state() in the meantime. This should fix the performance regression reported by Nick. Reported-by: Nick Piggin 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 Cc: jens.axboe@oracle.com LKML-Reference: <12555405592133-git-send-email-> Signed-off-by: Ingo Molnar --- Reading git-diff-tree failed