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| author | Frederic Weisbecker <frederic@kernel.org> | 2021-02-23 01:10:00 +0100 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2021-03-15 13:54:54 -0700 |
| commit | 76d00b494d7962e88d4bbd4135f34aba9019c67f (patch) | |
| tree | 82c01fb3a120706461a1f752d96b3baf7174ae13 /include/linux/rcu_segcblist.h | |
| parent | b2fcf2102049f6e56981e0ab3d9b633b8e2741da (diff) | |
| download | linux-stable-76d00b494d7962e88d4bbd4135f34aba9019c67f.tar.gz linux-stable-76d00b494d7962e88d4bbd4135f34aba9019c67f.tar.bz2 linux-stable-76d00b494d7962e88d4bbd4135f34aba9019c67f.zip | |
rcu/nocb: Disable bypass when CPU isn't completely offloaded
Currently, the bypass is flushed at the very last moment in the
deoffloading procedure. However, this approach leads to a larger state
space than would be preferred. This commit therefore disables the
bypass at soon as the deoffloading procedure begins, then flushes it.
This guarantees that the bypass remains empty and thus out of the way
of the deoffloading procedure.
Symmetrically, this commit waits to enable the bypass until the offloading
procedure has completed.
Reported-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'include/linux/rcu_segcblist.h')
| -rw-r--r-- | include/linux/rcu_segcblist.h | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/include/linux/rcu_segcblist.h b/include/linux/rcu_segcblist.h index 8afe886e85f1..3db96c4f45fd 100644 --- a/include/linux/rcu_segcblist.h +++ b/include/linux/rcu_segcblist.h @@ -109,7 +109,7 @@ struct rcu_cblist { * | SEGCBLIST_KTHREAD_GP | * | | * | Kthreads handle callbacks holding nocb_lock, local rcu_core() stops | - * | handling callbacks. | + * | handling callbacks. Enable bypass queueing. | * ---------------------------------------------------------------------------- */ @@ -125,7 +125,7 @@ struct rcu_cblist { * | SEGCBLIST_KTHREAD_GP | * | | * | CB/GP kthreads handle callbacks holding nocb_lock, local rcu_core() | - * | ignores callbacks. | + * | ignores callbacks. Bypass enqueue is enabled. | * ---------------------------------------------------------------------------- * | * v @@ -134,7 +134,8 @@ struct rcu_cblist { * | SEGCBLIST_KTHREAD_GP | * | | * | CB/GP kthreads and local rcu_core() handle callbacks concurrently | - * | holding nocb_lock. Wake up CB and GP kthreads if necessary. | + * | holding nocb_lock. Wake up CB and GP kthreads if necessary. Disable | + * | bypass enqueue. | * ---------------------------------------------------------------------------- * | * v |