From: "Paul E. McKenney" <paulmck@kernel.org>
To: Frederic Weisbecker <frederic@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Uladzislau Rezki <urezki@gmail.com>,
Boqun Feng <boqun.feng@gmail.com>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Neeraj Upadhyay <neeraju@codeaurora.org>,
Josh Triplett <josh@joshtriplett.org>,
Joel Fernandes <joel@joelfernandes.org>
Subject: Re: [PATCH 1/3] srcu: Remove superfluous ssp initialization on deferred work queue
Date: Thu, 1 Apr 2021 18:01:21 -0700 [thread overview]
Message-ID: <20210402010121.GA7355@paulmck-ThinkPad-P72> (raw)
In-Reply-To: <20210402004856.GM2696@paulmck-ThinkPad-P72>
On Thu, Apr 01, 2021 at 05:48:56PM -0700, Paul E. McKenney wrote:
> On Fri, Apr 02, 2021 at 01:47:02AM +0200, Frederic Weisbecker wrote:
> > When an ssp has already started a grace period and queued an early work
> > to flush after SRCU workqueues are created, we expect the ssp to be
> > properly initialized already. So we can skip this step at this stage.
> >
> > Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
> > Cc: Boqun Feng <boqun.feng@gmail.com>
> > Cc: Lai Jiangshan <jiangshanlai@gmail.com>
> > Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
> > Cc: Josh Triplett <josh@joshtriplett.org>
> > Cc: Joel Fernandes <joel@joelfernandes.org>
> > Cc: Uladzislau Rezki <urezki@gmail.com>
> > ---
> > kernel/rcu/srcutree.c | 1 -
> > 1 file changed, 1 deletion(-)
> >
> > diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
> > index 036ff5499ad5..7197156418e4 100644
> > --- a/kernel/rcu/srcutree.c
> > +++ b/kernel/rcu/srcutree.c
> > @@ -1396,7 +1396,6 @@ void __init srcu_init(void)
> > while (!list_empty(&srcu_boot_list)) {
> > ssp = list_first_entry(&srcu_boot_list, struct srcu_struct,
> > work.work.entry);
> > - check_init_srcu_struct(ssp);
>
> You lost me on this one. What happens if the only pre-initialization
> invocation on the statically allocated srcu_struct pointed to by ssp
> was call_srcu()? I am not seeing how the initialization has already
> happened in that case.
>
> What am I missing here?
Idiot here was looking at Tiny SRCU's call_srcu(), not that of Tree SRCU.
Never mind, I will queue this one as well.
Thanx, Paul
> > list_del_init(&ssp->work.work.entry);
> > queue_work(rcu_gp_wq, &ssp->work.work);
> > }
> > --
> > 2.25.1
> >
next prev parent reply other threads:[~2021-04-02 1:01 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-01 23:47 [PATCH 0/3] srcu: Fix boot stall Frederic Weisbecker
2021-04-01 23:47 ` [PATCH 1/3] srcu: Remove superfluous ssp initialization on deferred work queue Frederic Weisbecker
2021-04-02 0:48 ` Paul E. McKenney
2021-04-02 0:58 ` Frederic Weisbecker
2021-04-02 1:19 ` Paul E. McKenney
2021-04-02 1:01 ` Paul E. McKenney [this message]
2021-04-01 23:47 ` [PATCH 2/3] srcu: Remove superfluous sdp->srcu_lock_count zero filling Frederic Weisbecker
2021-04-02 0:58 ` Paul E. McKenney
2021-04-01 23:47 ` [PATCH 3/3] srcu: Fix broken node geometry after early ssp init Frederic Weisbecker
2021-04-02 1:12 ` Paul E. McKenney
2021-04-02 10:02 ` Frederic Weisbecker
2021-04-02 15:03 ` Paul E. McKenney
2021-04-02 20:50 ` Frederic Weisbecker
2021-04-02 22:12 ` Paul E. McKenney
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210402010121.GA7355@paulmck-ThinkPad-P72 \
--to=paulmck@kernel.org \
--cc=boqun.feng@gmail.com \
--cc=frederic@kernel.org \
--cc=jiangshanlai@gmail.com \
--cc=joel@joelfernandes.org \
--cc=josh@joshtriplett.org \
--cc=linux-kernel@vger.kernel.org \
--cc=neeraju@codeaurora.org \
--cc=urezki@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).