From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
dvhart@linux.intel.com, fweisbec@gmail.com, oleg@redhat.com,
bobby.prani@gmail.com,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 09/10] documentation: Emphasize the call_rcu() is illegal from idle
Date: Tue, 12 Apr 2016 08:18:20 -0700 [thread overview]
Message-ID: <1460474301-22998-9-git-send-email-paulmck@linux.vnet.ibm.com> (raw)
In-Reply-To: <20160412151755.GA22416@linux.vnet.ibm.com>
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 <paulmck@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
next prev parent reply other threads:[~2016-04-12 15:18 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-12 15:17 [PATCH tip/core/rcu 0/10] Documentation updates for 4.7 Paul E. McKenney
2016-04-12 15:18 ` [PATCH tip/core/rcu 01/10] documentation: Make sample code and documentation consistent Paul E. McKenney
2016-04-12 15:18 ` [PATCH tip/core/rcu 02/10] documentation: Add real-time requirements from CPU-bound workloads Paul E. McKenney
2016-04-12 15:18 ` [PATCH tip/core/rcu 03/10] documentation: Add synchronize_rcu_mult() to the requirements Paul E. McKenney
2016-04-12 15:18 ` [PATCH tip/core/rcu 04/10] documentation: Explain why rcu_read_lock() needs no barrier() Paul E. McKenney
2016-04-12 15:18 ` [PATCH tip/core/rcu 05/10] documentation: Document illegality of call_rcu() from offline CPUs Paul E. McKenney
2016-04-12 15:18 ` [PATCH tip/core/rcu 06/10] documentation: Remove unnecessary images from requirements Paul E. McKenney
2016-04-12 15:18 ` [PATCH tip/core/rcu 07/10] documentation: Get rid of duplicate .htmlx file Paul E. McKenney
2016-04-12 15:18 ` [PATCH tip/core/rcu 08/10] documentation: Sharpen up the no-readers quick quiz Paul E. McKenney
2016-04-12 15:18 ` Paul E. McKenney [this message]
2016-04-12 15:18 ` [PATCH tip/core/rcu 10/10] documentation: Add documentation for RCU's major data structures Paul E. McKenney
2016-04-16 14:52 ` Boqun Feng
2016-04-17 2:33 ` Paul E. McKenney
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