rcu.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: "Paul E. McKenney" <paulmck@kernel.org>,
	"Xu, Yanfei" <yanfei.xu@windriver.com>,
	Sasha Levin <sashal@kernel.org>,
	rcu@vger.kernel.org
Subject: [PATCH AUTOSEL 5.13 06/19] rcu-tasks: Don't delete holdouts within trc_wait_for_one_reader()
Date: Thu, 22 Jul 2021 23:57:07 -0400	[thread overview]
Message-ID: <20210723035721.531372-6-sashal@kernel.org> (raw)
In-Reply-To: <20210723035721.531372-1-sashal@kernel.org>

From: "Paul E. McKenney" <paulmck@kernel.org>

[ Upstream commit a9ab9cce9367a2cc02a3c7eb57a004dc0b8f380d ]

Invoking trc_del_holdout() from within trc_wait_for_one_reader() is
only a performance optimization because the RCU Tasks Trace grace-period
kthread will eventually do this within check_all_holdout_tasks_trace().
But it is not a particularly important performance optimization because
it only applies to the grace-period kthread, of which there is but one.
This commit therefore removes this invocation of trc_del_holdout() in
favor of the one in check_all_holdout_tasks_trace() in the grace-period
kthread.

Reported-by: "Xu, Yanfei" <yanfei.xu@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/rcu/tasks.h | 1 -
 1 file changed, 1 deletion(-)

diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index 71e9d625371a..fcef5f0c60b8 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -937,7 +937,6 @@ static void trc_wait_for_one_reader(struct task_struct *t,
 	// The current task had better be in a quiescent state.
 	if (t == current) {
 		t->trc_reader_checked = true;
-		trc_del_holdout(t);
 		WARN_ON_ONCE(t->trc_reader_nesting);
 		return;
 	}
-- 
2.30.2


      parent reply	other threads:[~2021-07-23  3:57 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20210723035721.531372-1-sashal@kernel.org>
2021-07-23  3:57 ` [PATCH AUTOSEL 5.13 05/19] rcu-tasks: Don't delete holdouts within trc_inspect_reader() Sasha Levin
2021-07-23  3:57 ` Sasha Levin [this message]

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=20210723035721.531372-6-sashal@kernel.org \
    --to=sashal@kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=paulmck@kernel.org \
    --cc=rcu@vger.kernel.org \
    --cc=stable@vger.kernel.org \
    --cc=yanfei.xu@windriver.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).