From: paulmck@kernel.org
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com,
mingo@kernel.org, jiangshanlai@gmail.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org,
"Paul E. McKenney" <paulmck@kernel.org>
Subject: [PATCH RFC tip/core/rcu 2/5] srcu: Provide internal interface to start a Tiny SRCU grace period
Date: Mon, 16 Nov 2020 16:40:49 -0800 [thread overview]
Message-ID: <20201117004052.14758-2-paulmck@kernel.org> (raw)
In-Reply-To: <20201117004017.GA7444@paulmck-ThinkPad-P72>
From: "Paul E. McKenney" <paulmck@kernel.org>
There is a need for a polling interface for SRCU grace periods.
This polling needs to initiate an SRCU grace period without
having to queue (and manage) a callback. This commit therefore
splits the Tiny SRCU call_srcu() function into callback-queuing and
start-grace-period portions, with the latter in a new function named
srcu_gp_start_if_needed().
Link: https://lore.kernel.org/rcu/20201112201547.GF3365678@moria.home.lan/
Reported-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
kernel/rcu/srcutiny.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c
index 5598cf6..3bac1db 100644
--- a/kernel/rcu/srcutiny.c
+++ b/kernel/rcu/srcutiny.c
@@ -152,6 +152,16 @@ void srcu_drive_gp(struct work_struct *wp)
}
EXPORT_SYMBOL_GPL(srcu_drive_gp);
+static void srcu_gp_start_if_needed(struct srcu_struct *ssp)
+{
+ if (!READ_ONCE(ssp->srcu_gp_running)) {
+ if (likely(srcu_init_done))
+ schedule_work(&ssp->srcu_work);
+ else if (list_empty(&ssp->srcu_work.entry))
+ list_add(&ssp->srcu_work.entry, &srcu_boot_list);
+ }
+}
+
/*
* Enqueue an SRCU callback on the specified srcu_struct structure,
* initiating grace-period processing if it is not already running.
@@ -167,12 +177,7 @@ void call_srcu(struct srcu_struct *ssp, struct rcu_head *rhp,
*ssp->srcu_cb_tail = rhp;
ssp->srcu_cb_tail = &rhp->next;
local_irq_restore(flags);
- if (!READ_ONCE(ssp->srcu_gp_running)) {
- if (likely(srcu_init_done))
- schedule_work(&ssp->srcu_work);
- else if (list_empty(&ssp->srcu_work.entry))
- list_add(&ssp->srcu_work.entry, &srcu_boot_list);
- }
+ srcu_gp_start_if_needed(ssp);
}
EXPORT_SYMBOL_GPL(call_srcu);
--
2.9.5
next prev parent reply other threads:[~2020-11-17 0:41 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-17 0:40 [PATCH tip/core/rcu 0/5] Provide SRCU polling grace-period interfaces Paul E. McKenney
2020-11-17 0:40 ` [PATCH RFC tip/core/rcu 1/5] srcu: Make Tiny SRCU use multi-bit grace-period counter paulmck
2020-11-19 8:14 ` Neeraj Upadhyay
2020-11-19 18:00 ` Paul E. McKenney
2020-11-17 0:40 ` paulmck [this message]
2020-11-20 11:36 ` [PATCH RFC tip/core/rcu 2/5] srcu: Provide internal interface to start a Tiny SRCU grace period Neeraj Upadhyay
2020-11-17 0:40 ` [PATCH RFC tip/core/rcu 3/5] srcu: Provide internal interface to start a Tree " paulmck
2020-11-20 11:36 ` Neeraj Upadhyay
2020-11-21 0:37 ` Paul E. McKenney
2020-11-17 0:40 ` [PATCH RFC tip/core/rcu 4/5] srcu: Provide polling interfaces for Tiny SRCU grace periods paulmck
2020-11-20 11:58 ` Neeraj Upadhyay
2020-11-21 0:13 ` Paul E. McKenney
2020-11-22 14:27 ` Neeraj Upadhyay
2020-11-22 18:01 ` Paul E. McKenney
2020-11-23 4:34 ` Neeraj Upadhyay
2020-11-23 21:07 ` Paul E. McKenney
2020-11-17 0:40 ` [PATCH RFC tip/core/rcu 5/5] srcu: Provide polling interfaces for Tree " paulmck
2020-11-20 12:01 ` Neeraj Upadhyay
2020-11-21 0:16 ` Paul E. McKenney
2020-11-22 14:22 ` Neeraj Upadhyay
2020-11-21 0:58 ` [PATCH tip/core/rcu 0/5] Provide SRCU polling grace-period interfaces Paul E. McKenney
2020-11-21 1:05 ` Steven Rostedt
2020-11-21 1:12 ` Paul E. McKenney
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