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| author |   Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2020-12-15 15:16:49 +0100 |
|---|---|---|
| committer |   Paul E. McKenney <paulmck@kernel.org> | 2021-01-06 16:10:44 -0800 |
| commit | 81ad58be2f83f9bd675f67ca5b8f420358ddf13c (patch) | |
| tree | f19bfb3c94119f67a107d15bb80762dbd0c6773b /Documentation/RCU/whatisRCU.rst | |
| parent | doc: Update RCU's requirements page about the PREEMPT_RT wiki (diff) | |
| download | linux-dev-81ad58be2f83f9bd675f67ca5b8f420358ddf13c.tar.xz linux-dev-81ad58be2f83f9bd675f67ca5b8f420358ddf13c.zip | |
doc: Use CONFIG_PREEMPTION
CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by CONFIG_PREEMPT_RT.
Both PREEMPT and PREEMPT_RT require the same functionality which today
depends on CONFIG_PREEMPT.
Update the documents and mention CONFIG_PREEMPTION. Spell out
CONFIG_PREEMPT_RT (instead PREEMPT_RT) since it is an option now.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'Documentation/RCU/whatisRCU.rst')
| -rw-r--r-- | Documentation/RCU/whatisRCU.rst | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/Documentation/RCU/whatisRCU.rst b/Documentation/RCU/whatisRCU.rst index 1a4723f48bd9..17e95ab2a201 100644 --- a/Documentation/RCU/whatisRCU.rst +++ b/Documentation/RCU/whatisRCU.rst @@ -683,7 +683,7 @@ Quick Quiz #1: ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This section presents a "toy" RCU implementation that is based on "classic RCU". It is also short on performance (but only for updates) and -on features such as hotplug CPU and the ability to run in CONFIG_PREEMPT +on features such as hotplug CPU and the ability to run in CONFIG_PREEMPTION kernels. The definitions of rcu_dereference() and rcu_assign_pointer() are the same as those shown in the preceding section, so they are omitted. :: @@ -739,7 +739,7 @@ Quick Quiz #2: Quick Quiz #3: If it is illegal to block in an RCU read-side critical section, what the heck do you do in - PREEMPT_RT, where normal spinlocks can block??? + CONFIG_PREEMPT_RT, where normal spinlocks can block??? :ref:`Answers to Quick Quiz <8_whatisRCU>` @@ -1093,7 +1093,7 @@ Quick Quiz #2: overhead is **negative**. Answer: - Imagine a single-CPU system with a non-CONFIG_PREEMPT + Imagine a single-CPU system with a non-CONFIG_PREEMPTION kernel where a routing table is used by process-context code, but can be updated by irq-context code (for example, by an "ICMP REDIRECT" packet). The usual way of handling @@ -1120,10 +1120,10 @@ Answer: Quick Quiz #3: If it is illegal to block in an RCU read-side critical section, what the heck do you do in - PREEMPT_RT, where normal spinlocks can block??? + CONFIG_PREEMPT_RT, where normal spinlocks can block??? Answer: - Just as PREEMPT_RT permits preemption of spinlock + Just as CONFIG_PREEMPT_RT permits preemption of spinlock critical sections, it permits preemption of RCU read-side critical sections. It also permits spinlocks blocking while in RCU read-side critical |