Although call_rcu()'s fastpath works just fine on an idle CPU, some branches of the slowpath invoke the scheduler, which uses RCU. Therefore, this commit emphasizes the fact that call_rcu() must not be invoked from an idle CPU.
Signed-off-by: Paul E. McKenney <paul...@linux.vnet.ibm.com> --- Documentation/RCU/Design/Requirements/Requirements.html | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Documentation/RCU/Design/Requirements/Requirements.html b/Documentation/RCU/Design/Requirements/Requirements.html index 85cf2238fd08..e7e24b3e86e2 100644 --- a/Documentation/RCU/Design/Requirements/Requirements.html +++ b/Documentation/RCU/Design/Requirements/Requirements.html @@ -1650,7 +1650,7 @@ situations where neither <tt>synchronize_rcu()</tt> nor including within preempt-disable code, <tt>local_bh_disable()</tt> code, interrupt-disable code, and interrupt handlers. However, even <tt>call_rcu()</tt> is illegal within NMI handlers -and from offline CPUs. +and from idle and offline CPUs. The callback function (<tt>remove_gp_cb()</tt> in this case) will be executed within softirq (software interrupt) environment within the Linux kernel, -- 2.5.2
