From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pawel Moll Subject: Re: [PATCH] bus: arm-ccn: Use hrtimer_start() Date: Wed, 13 May 2015 16:47:07 +0100 Message-ID: <1431532027.3285.107.camel@arm.com> References: <1431530484-3389-1-git-send-email-pawel.moll@arm.com> <2646197.ZVRR8xztig@wuerfel> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from foss.arm.com ([217.140.101.70]:36592 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964839AbbEMPrJ (ORCPT ); Wed, 13 May 2015 11:47:09 -0400 In-Reply-To: <2646197.ZVRR8xztig@wuerfel> Sender: linux-next-owner@vger.kernel.org List-ID: To: Arnd Bergmann Cc: "kernel-build-reports@lists.linaro.org" , "arm@kernel.org" , "linaro-kernel@lists.linaro.org" , "linux-next@vger.kernel.org" , Thomas Gleixner , "linux-arm-kernel@lists.infradead.org" On Wed, 2015-05-13 at 16:32 +0100, Arnd Bergmann wrote: > On Wednesday 13 May 2015 16:21:24 Pawel Moll wrote: > > diff --git a/drivers/bus/arm-ccn.c b/drivers/bus/arm-ccn.c > > index df5f307..7d9879e 100644 > > --- a/drivers/bus/arm-ccn.c > > +++ b/drivers/bus/arm-ccn.c > > @@ -921,9 +921,8 @@ static void arm_ccn_pmu_event_start(struct perf_event *event, int flags) > > * attribute). > > */ > > if (!ccn->irq) > > - __hrtimer_start_range_ns(&ccn->dt.hrtimer, > > - arm_ccn_pmu_timer_period(), 0, > > - HRTIMER_MODE_REL_PINNED, 0); > > + hrtimer_start(&ccn->dt.hrtimer, arm_ccn_pmu_timer_period(), > > + HRTIMER_MODE_REL_PINNED); > > > > /* Set the DT bus input, engaging the counter */ > > arm_ccn_pmu_xp_dt_config(event, 1); > > Is this correct by itself, or do we need to pull in the branch that > contains c6eb3f70d44828 ("hrtimer: Get rid of hrtimer softirq") > from Thomas? The other similar patches that Thomas did contain a > comment about the conversion being safe after hrtimer_start() > no longer uses a softirq, but it is still in use in 4.1-rc3. That's why I asked who should carry this patch ;-) Now, the answer to your question is: the result will not be worse than the what was there before you pulled my updates, as the code was using normal hrtimer_start(). It's just when I realised that it should be pinned I looked at what x86 uncore pmu is doing and shamelessly (and probably a bit mindlessly) copied the "do not wakeup" version from there. Pawel