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author | David Vernet <void@manifault.com> | 2022-03-30 01:26:13 +0300 |
---|---|---|
committer | Paul E. McKenney <paulmck@kernel.org> | 2022-04-21 02:51:11 +0300 |
commit | f1efe84d6fd2af163989025bc285ff9b3b0c764f (patch) | |
tree | 6e882fa8778f703f3c037285441f3158e479b9b6 /kernel/rcu/sync.c | |
parent | 88ca472f80604c070526eb58b977ea0a9c3c2e1f (diff) | |
download | linux-f1efe84d6fd2af163989025bc285ff9b3b0c764f.tar.xz |
rcu_sync: Fix comment to properly reflect rcu_sync_exit() behavior
The rcu_sync_enter() function is used by updaters to force RCU readers
(e.g. percpu-rwsem) to use their slow paths during an update. This is
accomplished by setting the ->gp_state of the rcu_sync structure to
GP_ENTER. In the case of percpu-rwsem, the readers' slow path waits on
a semaphore instead of just incrementing a reader count. Each updater
invokes the rcu_sync_exit() function to signal to readers that they
may again take their fastpaths. The rcu_sync_exit() function sets the
->gp_state of the rcu_sync structure to GP_EXIT, and if all goes well,
after a grace period the ->gp_state reverts back to GP_IDLE.
Unfortunately, the rcu_sync_enter() function currently has a comment
incorrectly stating that rcu_sync_exit() (by an updater) will re-enable
reader "slowpaths". This patch changes the comment to state that this
function re-enables reader fastpaths.
Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/rcu/sync.c')
-rw-r--r-- | kernel/rcu/sync.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/rcu/sync.c b/kernel/rcu/sync.c index 33d896d85902..5cefc702158f 100644 --- a/kernel/rcu/sync.c +++ b/kernel/rcu/sync.c @@ -111,7 +111,7 @@ static void rcu_sync_func(struct rcu_head *rhp) * a slowpath during the update. After this function returns, all * subsequent calls to rcu_sync_is_idle() will return false, which * tells readers to stay off their fastpaths. A later call to - * rcu_sync_exit() re-enables reader slowpaths. + * rcu_sync_exit() re-enables reader fastpaths. * * When called in isolation, rcu_sync_enter() must wait for a grace * period, however, closely spaced calls to rcu_sync_enter() can |