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author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2018-04-05 17:19:17 -0700 |
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committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2018-05-15 10:27:56 -0700 |
commit | f7194ac32ca241d28765a98e42a7fe13debc85a7 (patch) | |
tree | 788cdde1d2f7abe01e14b37004e89734cc642835 /kernel/rcu | |
parent | 17672480fb1e953f999623b598a98130f8aacfbc (diff) | |
download | op-kernel-dev-f7194ac32ca241d28765a98e42a7fe13debc85a7.zip op-kernel-dev-f7194ac32ca241d28765a98e42a7fe13debc85a7.tar.gz |
srcu: Add cleanup_srcu_struct_quiesced()
The current cleanup_srcu_struct() flushes work, which prevents it
from being invoked from some workqueue contexts, as well as from
atomic (non-blocking) contexts. This patch therefore introduced a
cleanup_srcu_struct_quiesced(), which can be invoked only after all
activity on the specified srcu_struct has completed. This restriction
allows cleanup_srcu_struct_quiesced() to be invoked from workqueue
contexts as well as from atomic contexts.
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Nitzan Carmi <nitzanc@mellanox.com>
Tested-by: Nicholas Piggin <npiggin@gmail.com>
Diffstat (limited to 'kernel/rcu')
-rw-r--r-- | kernel/rcu/rcutorture.c | 7 | ||||
-rw-r--r-- | kernel/rcu/srcutiny.c | 9 | ||||
-rw-r--r-- | kernel/rcu/srcutree.c | 30 |
3 files changed, 29 insertions, 17 deletions
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index 680c96d..f0e1d44 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -593,7 +593,12 @@ static void srcu_torture_init(void) static void srcu_torture_cleanup(void) { - cleanup_srcu_struct(&srcu_ctld); + static DEFINE_TORTURE_RANDOM(rand); + + if (torture_random(&rand) & 0x800) + cleanup_srcu_struct(&srcu_ctld); + else + cleanup_srcu_struct_quiesced(&srcu_ctld); srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */ } diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c index 76ac5f5..622792a 100644 --- a/kernel/rcu/srcutiny.c +++ b/kernel/rcu/srcutiny.c @@ -86,16 +86,19 @@ EXPORT_SYMBOL_GPL(init_srcu_struct); * Must invoke this after you are finished using a given srcu_struct that * was initialized via init_srcu_struct(), else you leak memory. */ -void cleanup_srcu_struct(struct srcu_struct *sp) +void _cleanup_srcu_struct(struct srcu_struct *sp, bool quiesced) { WARN_ON(sp->srcu_lock_nesting[0] || sp->srcu_lock_nesting[1]); - flush_work(&sp->srcu_work); + if (quiesced) + WARN_ON(work_pending(&sp->srcu_work)); + else + flush_work(&sp->srcu_work); WARN_ON(sp->srcu_gp_running); WARN_ON(sp->srcu_gp_waiting); WARN_ON(sp->srcu_cb_head); WARN_ON(&sp->srcu_cb_head != sp->srcu_cb_tail); } -EXPORT_SYMBOL_GPL(cleanup_srcu_struct); +EXPORT_SYMBOL_GPL(_cleanup_srcu_struct); /* * Removes the count for the old reader from the appropriate element of diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index fb560fc..b4123d7 100644 --- a/kernel/rcu/srcutree.c +++ b/kernel/rcu/srcutree.c @@ -366,24 +366,28 @@ static unsigned long srcu_get_delay(struct srcu_struct *sp) return SRCU_INTERVAL; } -/** - * cleanup_srcu_struct - deconstruct a sleep-RCU structure - * @sp: structure to clean up. - * - * Must invoke this after you are finished using a given srcu_struct that - * was initialized via init_srcu_struct(), else you leak memory. - */ -void cleanup_srcu_struct(struct srcu_struct *sp) +/* Helper for cleanup_srcu_struct() and cleanup_srcu_struct_quiesced(). */ +void _cleanup_srcu_struct(struct srcu_struct *sp, bool quiesced) { int cpu; if (WARN_ON(!srcu_get_delay(sp))) - return; /* Leakage unless caller handles error. */ + return; /* Just leak it! */ if (WARN_ON(srcu_readers_active(sp))) - return; /* Leakage unless caller handles error. */ - flush_delayed_work(&sp->work); + return; /* Just leak it! */ + if (quiesced) { + if (WARN_ON(delayed_work_pending(&sp->work))) + return; /* Just leak it! */ + } else { + flush_delayed_work(&sp->work); + } for_each_possible_cpu(cpu) - flush_delayed_work(&per_cpu_ptr(sp->sda, cpu)->work); + if (quiesced) { + if (WARN_ON(delayed_work_pending(&per_cpu_ptr(sp->sda, cpu)->work))) + return; /* Just leak it! */ + } else { + flush_delayed_work(&per_cpu_ptr(sp->sda, cpu)->work); + } if (WARN_ON(rcu_seq_state(READ_ONCE(sp->srcu_gp_seq)) != SRCU_STATE_IDLE) || WARN_ON(srcu_readers_active(sp))) { pr_info("%s: Active srcu_struct %p state: %d\n", __func__, sp, rcu_seq_state(READ_ONCE(sp->srcu_gp_seq))); @@ -392,7 +396,7 @@ void cleanup_srcu_struct(struct srcu_struct *sp) free_percpu(sp->sda); sp->sda = NULL; } -EXPORT_SYMBOL_GPL(cleanup_srcu_struct); +EXPORT_SYMBOL_GPL(_cleanup_srcu_struct); /* * Counts the new reader in the appropriate per-CPU element of the |