linux/kernel/rcu
Paul E. McKenney db13710a03 rcu-tasks: Cancel callback laziness if too many callbacks
The various RCU Tasks flavors now do lazy grace periods when there are
only asynchronous grace period requests.  By default, the system will let
250 milliseconds elapse after the first call_rcu_tasks*() callbacki is
queued before starting a grace period.  In contrast, synchronous grace
period requests such as synchronize_rcu_tasks*() will start a grace
period immediately.

However, invoking one of the call_rcu_tasks*() functions in a too-tight
loop can result in a callback flood, which in turn can exhaust memory
if grace periods are delayed for too long.

This commit therefore sets a limit so that the grace-period kthread
will be awakened when any CPU's callback list expands to contain
rcupdate.rcu_task_lazy_lim callbacks elements (defaulting to 32, set to -1
to disable), the grace-period kthread will be awakened, thus cancelling
any ongoing laziness and getting out in front of the potential callback
flood.

Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2023-07-14 15:00:12 -07:00
..
Kconfig rcu: Employ jiffies-based backstop to callback time limit 2023-05-11 13:42:39 -07:00
Kconfig.debug rcu: Allow up to five minutes expedited RCU CPU stall-warning timeouts 2023-01-09 12:09:52 -08:00
Makefile rcuperf: Change rcuperf to rcuscale 2020-08-24 18:39:24 -07:00
rcu_segcblist.c rcu: Throttle callback invocation based on number of ready callbacks 2023-01-03 17:28:34 -08:00
rcu_segcblist.h rcu: Throttle callback invocation based on number of ready callbacks 2023-01-03 17:28:34 -08:00
rcu.h rcu-tasks: Stop rcu_tasks_invoke_cbs() from using never-onlined CPUs 2023-05-11 13:42:39 -07:00
rcuscale.c rcu/rcuscale: Stop kfree_scale_thread thread(s) after unloading rcuscale 2023-05-11 13:48:50 -07:00
rcutorture.c Merge branches 'rcu/staging-core', 'rcu/staging-docs' and 'rcu/staging-kfree', remote-tracking branches 'paul/srcu-cf.2023.04.04a', 'fbq/rcu/lockdep.2023.03.27a' and 'fbq/rcu/rcutorture.2023.03.20a' into rcu/staging 2023-04-05 13:50:37 +00:00
refscale.c refscale: Move shutdown from wait_event() to wait_event_idle() 2023-03-20 11:12:16 -07:00
srcutiny.c rcu: Annotate SRCU's update-side lockdep dependencies 2023-03-27 11:15:59 -07:00
srcutree.c Merge branches 'rcu/staging-core', 'rcu/staging-docs' and 'rcu/staging-kfree', remote-tracking branches 'paul/srcu-cf.2023.04.04a', 'fbq/rcu/lockdep.2023.03.27a' and 'fbq/rcu/rcutorture.2023.03.20a' into rcu/staging 2023-04-05 13:50:37 +00:00
sync.c rcu/sync: Use call_rcu_hurry() instead of call_rcu 2022-11-29 14:04:33 -08:00
tasks.h rcu-tasks: Cancel callback laziness if too many callbacks 2023-07-14 15:00:12 -07:00
tiny.c rcu: Refactor kvfree_call_rcu() and high-level helpers 2023-01-03 17:48:40 -08:00
tree_exp.h rcu: Mark additional concurrent load from ->cpu_no_qs.b.exp 2023-05-11 13:42:39 -07:00
tree_nocb.h rcu/nocb: Make shrinker iterate only over NOCB CPUs 2023-05-11 13:44:50 -07:00
tree_plugin.h rcu: Mark additional concurrent load from ->cpu_no_qs.b.exp 2023-05-11 13:42:39 -07:00
tree_stall.h rcu: Allow up to five minutes expedited RCU CPU stall-warning timeouts 2023-01-09 12:09:52 -08:00
tree.c Merge branches 'doc.2023.05.10a', 'fixes.2023.05.11a', 'kvfree.2023.05.10a', 'nocb.2023.05.11a', 'rcu-tasks.2023.05.10a', 'torture.2023.05.15a' and 'rcu-urgent.2023.06.06a' into HEAD 2023-06-07 13:44:06 -07:00
tree.h rcu: Add RCU stall diagnosis information 2023-01-05 12:21:11 -08:00
update.c Merge branch 'stall.2023.01.09a' into HEAD 2023-02-02 16:40:07 -08:00