From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753723AbaHMRYY (ORCPT ); Wed, 13 Aug 2014 13:24:24 -0400 Received: from casper.infradead.org ([85.118.1.10]:45632 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750913AbaHMRYX (ORCPT ); Wed, 13 Aug 2014 13:24:23 -0400 Date: Wed, 13 Aug 2014 19:24:07 +0200 From: Peter Zijlstra To: "Paul E. McKenney" Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, dvhart@linux.intel.com, fweisbec@gmail.com, oleg@redhat.com, bobby.prani@gmail.com, rafael@kernel.org Subject: Re: [PATCH v5 tip/core/rcu 15/16] rcu: Make RCU-tasks wait for idle tasks Message-ID: <20140813172407.GM3588@twins.programming.kicks-ass.net> References: <20140811224840.GA25594@linux.vnet.ibm.com> <1407797345-28227-1-git-send-email-paulmck@linux.vnet.ibm.com> <1407797345-28227-15-git-send-email-paulmck@linux.vnet.ibm.com> <20140813081215.GB9918@twins.programming.kicks-ass.net> <20140813124818.GQ4752@linux.vnet.ibm.com> <20140813134025.GN9918@twins.programming.kicks-ass.net> <20140813141217.GU4752@linux.vnet.ibm.com> <20140813144219.GQ9918@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="GN/IAAAoV4GJoJGS" Content-Disposition: inline In-Reply-To: <20140813144219.GQ9918@twins.programming.kicks-ass.net> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --GN/IAAAoV4GJoJGS Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Aug 13, 2014 at 04:42:19PM +0200, Peter Zijlstra wrote: > Auditing all idle functions will be somewhat of a pain, but its entirely > doable. Looking at this stuff, it appears we can clean it up massively; > see how the generic cpuidle code already has the broadcast logic in, so > we can remove that from the drivers by setting the right flags. >=20 > We can similarly pull out the leave_mm() call by adding a > CPUIDLE_FLAG_TLB_FLUSH. At which point all we'd need to do is mark the > intel_idle (and all other cpuidle_state::enter functions with __notrace. This removes the broadcast stuff from intel_idle.c; processor_idle.c hurts my brain, but something similar should be possible. --- drivers/idle/intel_idle.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index 4d140bbbe100..6613d4ee60ce 100644 --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -508,11 +508,8 @@ static int intel_idle(struct cpuidle_device *dev, unsigned long ecx =3D 1; /* break on interrupt flag */ struct cpuidle_state *state =3D &drv->states[index]; unsigned long eax =3D flg2MWAIT(state->flags); - unsigned int cstate; int cpu =3D smp_processor_id(); =20 - cstate =3D (((eax) >> MWAIT_SUBSTATE_SIZE) & MWAIT_CSTATE_MASK) + 1; - /* * leave_mm() to avoid costly and often unnecessary wakeups * for flushing the user TLB's associated with the active mm. @@ -520,14 +517,8 @@ static int intel_idle(struct cpuidle_device *dev, if (state->flags & CPUIDLE_FLAG_TLB_FLUSHED) leave_mm(cpu); =20 - if (!(lapic_timer_reliable_states & (1 << (cstate)))) - clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu); - mwait_idle_with_hints(eax, ecx); =20 - if (!(lapic_timer_reliable_states & (1 << (cstate)))) - clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu); - return index; } =20 @@ -670,6 +661,7 @@ static int __init intel_idle_probe(void) { unsigned int eax, ebx, ecx; const struct x86_cpu_id *id; + int i; =20 if (max_cstate =3D=3D 0) { pr_debug(PREFIX "disabled\n"); @@ -705,6 +697,15 @@ static int __init intel_idle_probe(void) else on_each_cpu(__setup_broadcast_timer, (void *)true, 1); =20 + for (i =3D 0; cpuidle_state_table[i].enter; i++) { + struct cpuidle_state *state =3D &cpuidle_state_table[i]; + int cstate =3D ((flg2MWAIT(state->flags) >> MWAIT_SUBSTATE_SIZE) &=20 + MWAIT_CSTATE_MASK) + 1; + + if (!(lapic_timer_reliable_states & (1 << cstate))) + state->flags |=3D CPUIDLE_FLAG_TIMER_STOP; + } + pr_debug(PREFIX "v" INTEL_IDLE_VERSION " model 0x%X\n", boot_cpu_data.x86_model); =20 --GN/IAAAoV4GJoJGS Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJT6582AAoJEHZH4aRLwOS6n74QAIzMrbTgNbn81md5M0Mijz2F +ZTh/y4Ex1wekZW2K+g2pvNF9D0LwxypPNb085CSXXzlXYfWtdxQebWYIUEO3Ac5 PmKNBPXkuI6YH0/psQkay4tvOBFk/IZOu9puMmx2vczJxHWElOErnOe9lUUc2K6V 7EDMmU7vNZrhsHnHzJqna5yaLoiznxZ849+9eVug+XWMSLEhbm+5vGUH3a4udcS+ zQJGtKwCUHmJ9sRAOmU1CmdWrVmbA8WLT5cQw3yGoHMPZybl+JcgLskGh6ifEqpt d/VPR+utmCudhYNwWhELqn8YKf5P0F6e+IGOUyNS4WlHSLZvZa0EnSdS4GVP7K/U z8ijJ7f3/YsEbVvt9lOWyWE7tlxRobHQnUyAeMubFsAzVBc/rwWAMUQBmnFxO6BF 6qviyd/KdRDUutscWjV9AKA0q3WMmHotqbFbjphfghlH6B11fiAFa8Wr7x/DxR13 tC9wj3L0H1lUYDfoX+5QvKtiRSib6Xeq1muzrhmhJbjcAoksZ+GZymtt2NB0skOC 7lJFJWIKmuI5GDauiJtIXnIs1kZbJSC9a2tlBScBQB1JALc0vhXLdLf9ZU0PgfZQ JlVsNbO3v2CEYWRlIdUK6euJw8CHo440QLrk/eAaXtLD6OkJzCTOWlZRSdR0yHrl Exzc+t1cfSVxZVhOrUg2 =Znus -----END PGP SIGNATURE----- --GN/IAAAoV4GJoJGS--