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Commit 0c7d10e4 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

documentation: Emphasize the call_rcu() is illegal from idle 



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: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 5413e24c

Documentation/RCU/Design/Requirements/Requirements.html

+1 −1
Original line number Diff line number Diff line
@@ -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,