From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E062C18E2C; Fri, 12 Jan 2024 23:20:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="njIy9xgk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BEF69C433F1; Fri, 12 Jan 2024 23:20:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1705101617; bh=BVDuigBYTOkL1XAi3KeGeioizo6Ea+Fj47cSJCEZh/Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=njIy9xgkfwRBZ6Q+Ga0emA3HhdJKPpEFX6/XysqgdoxSNxKTnRs9h5//+TNuZYOa2 gJZp1lDAfRuhKvhNFXKIe6EAcff62F0eLMeLw4vftgJTd3M8Mugb/2u1wmaH8FYFt0 olA8fT7ZYG5v9PD3YaWHVIyo6ILHEhsEg7KFB8WPRS6nDCJnY0wd5Jkw7tUc5Y9I06 wcYUhzkFhNv2QUFOHFjVWhGh2Fi0Urqi57CBO/TmktnGgw2n7RMdSg/StJ5Hj74RsP G730Kw/l2sf2PG1e7m1xYFyCEbyP6qmdK88X1RH6mrCbsKxSpZ3JF33lxJ4uPrn3Jc wLbujrtPs3+5w== Date: Sat, 13 Jan 2024 00:20:14 +0100 From: Frederic Weisbecker To: "Uladzislau Rezki (Sony)" Cc: "Paul E . McKenney" , RCU , Neeraj upadhyay , Boqun Feng , Hillf Danton , Joel Fernandes , LKML , Oleksiy Avramchenko Subject: Re: [PATCH v4 2/4] rcu: Add a trace event for synchronize_rcu_normal() Message-ID: References: <20240104162510.72773-1-urezki@gmail.com> <20240104162510.72773-3-urezki@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20240104162510.72773-3-urezki@gmail.com> Le Thu, Jan 04, 2024 at 05:25:08PM +0100, Uladzislau Rezki (Sony) a écrit : > Add an rcu_sr_normal() trace event. It takes three arguments > first one is the name of RCU flavour, second one is a user id > which triggeres synchronize_rcu_normal() and last one is an > event. > > There are two traces in the synchronize_rcu_normal(). On entry, > when a new request is registered and on exit point when request > is completed. > > Please note, CONFIG_RCU_TRACE=y is required to activate traces. > > Signed-off-by: Uladzislau Rezki (Sony) > --- > include/trace/events/rcu.h | 27 +++++++++++++++++++++++++++ > kernel/rcu/tree.c | 7 ++++++- > 2 files changed, 33 insertions(+), 1 deletion(-) > > diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h > index 2ef9c719772a..31b3e0d3e65f 100644 > --- a/include/trace/events/rcu.h > +++ b/include/trace/events/rcu.h > @@ -707,6 +707,33 @@ TRACE_EVENT_RCU(rcu_invoke_kfree_bulk_callback, > __entry->rcuname, __entry->p, __entry->nr_records) > ); > > +/* > + * Tracepoint for a normal synchronize_rcu() states. The first argument > + * is the RCU flavor, the second argument is a pointer to rcu_head the > + * last one is an event. > + */ > +TRACE_EVENT_RCU(rcu_sr_normal, Can we call this "synchronize_rcu" instead? So people really know what it's about. Then should the need arise, we can still add "synchronize_rcu_expedited" trace events later. Thanks. > + > + TP_PROTO(const char *rcuname, struct rcu_head *rhp, const char *srevent), > + > + TP_ARGS(rcuname, rhp, srevent), > + > + TP_STRUCT__entry( > + __field(const char *, rcuname) > + __field(void *, rhp) > + __field(const char *, srevent) > + ), > + > + TP_fast_assign( > + __entry->rcuname = rcuname; > + __entry->rhp = rhp; > + __entry->srevent = srevent; > + ), > + > + TP_printk("%s rhp=0x%p event=%s", > + __entry->rcuname, __entry->rhp, __entry->srevent) > +); > + > /* > * Tracepoint for exiting rcu_do_batch after RCU callbacks have been > * invoked. The first argument is the name of the RCU flavor, > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > index b756c40e4960..7d2ed89efcb3 100644 > --- a/kernel/rcu/tree.c > +++ b/kernel/rcu/tree.c > @@ -3672,9 +3672,11 @@ static void synchronize_rcu_normal(void) > { > struct rcu_synchronize rs; > > + trace_rcu_sr_normal(rcu_state.name, &rs.head, TPS("request")); > + > if (!READ_ONCE(rcu_normal_wake_from_gp)) { > wait_rcu_gp(call_rcu_hurry); > - return; > + goto trace_complete_out; > } > > init_rcu_head_on_stack(&rs.head); > @@ -3695,6 +3697,9 @@ static void synchronize_rcu_normal(void) > /* Now we can wait. */ > wait_for_completion(&rs.completion); > destroy_rcu_head_on_stack(&rs.head); > + > +trace_complete_out: > + trace_rcu_sr_normal(rcu_state.name, &rs.head, TPS("complete")); > } > > /** > -- > 2.39.2 >