From patchwork Tue Nov 8 13:33:28 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Akshay Adiga X-Patchwork-Id: 9417413 X-Patchwork-Delegate: rjw@sisk.pl Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 95C0460585 for ; Tue, 8 Nov 2016 13:33:58 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8423428AD9 for ; Tue, 8 Nov 2016 13:33:58 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7704428B71; Tue, 8 Nov 2016 13:33:58 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BB81B28AD9 for ; Tue, 8 Nov 2016 13:33:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751455AbcKHNd4 (ORCPT ); Tue, 8 Nov 2016 08:33:56 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:35131 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751243AbcKHNd4 (ORCPT ); Tue, 8 Nov 2016 08:33:56 -0500 Received: from pps.filterd (m0098413.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id uA8DXoIf000749 for ; Tue, 8 Nov 2016 08:33:55 -0500 Received: from e23smtp06.au.ibm.com (e23smtp06.au.ibm.com [202.81.31.148]) by mx0b-001b2d01.pphosted.com with ESMTP id 26keg967a0-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 08 Nov 2016 08:33:54 -0500 Received: from localhost by e23smtp06.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Tue, 8 Nov 2016 23:33:50 +1000 Received: from d23relay08.au.ibm.com (d23relay08.au.ibm.com [9.185.71.33]) by d23dlp03.au.ibm.com (Postfix) with ESMTP id 9A8143578052; Wed, 9 Nov 2016 00:33:49 +1100 (EST) Received: from d23av03.au.ibm.com (d23av03.au.ibm.com [9.190.234.97]) by d23relay08.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id uA8DXnBC17760392; Wed, 9 Nov 2016 00:33:49 +1100 Received: from d23av03.au.ibm.com (localhost [127.0.0.1]) by d23av03.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id uA8DXmpf025787; Wed, 9 Nov 2016 00:33:49 +1100 Received: from aksadiga.in.ibm.com (aksadiga.in.ibm.com [9.124.35.197]) by d23av03.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id uA8DXhDM025666; Wed, 9 Nov 2016 00:33:46 +1100 From: Akshay Adiga To: rjw@rjwysocki.net, ego@linux.vnet.ibm.com, shilpa.bhat@linux.vnet.ibm.com, viresh.kumar@linaro.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Cc: Akshay Adiga Subject: [PATCH v3 2/2] cpufreq: powernv: Use PMCR to verify global and local pstate Date: Tue, 8 Nov 2016 19:03:28 +0530 X-Mailer: git-send-email 2.5.5 In-Reply-To: <1478612008-20703-1-git-send-email-akshay.adiga@linux.vnet.ibm.com> References: <1478612008-20703-1-git-send-email-akshay.adiga@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16110813-0040-0000-0000-000001FC0328 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16110813-0041-0000-0000-00000ADD0E40 Message-Id: <1478612008-20703-2-git-send-email-akshay.adiga@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2016-11-08_04:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1609300000 definitions=main-1611080244 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP As fast_switch() may get called with interrupt disable mode, we cannot hold a mutex to update the global_pstate_info. So currently, fast_switch() does not update the global_pstate_info and it will end up with stale data whenever pstate is updated through fast_switch(). As the gpstate_timer can fire after fast_switch() has updated the pstates, the timer handler cannot rely on the cached values of local and global pstate and needs to read it from the PMCR. Only gpstate_timer_handler() is affected by the stale cached pstate data beacause either fast_switch() or target_index() routines will be called for a given govenor, but gpstate_timer can fire after the governor has changed to schedutil. Signed-off-by: Akshay Adiga Reviewed-by: Gautham R. Shenoy Acked-by: Viresh Kumar --- Changes from v2 : - Added generic macros GET_LPSTATE and GET_GPSTATE instead of making it specific to PMCR. Changes from v1 : - Corrected Commit message - Type cast pstate values read from PMCR to type s8 - Added Macros to get local and global pstates from PMCR drivers/cpufreq/powernv-cpufreq.c | 36 ++++++++++++++++++++++++++---------- 1 file changed, 26 insertions(+), 10 deletions(-) diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c index 4a4380d..c82304b 100644 --- a/drivers/cpufreq/powernv-cpufreq.c +++ b/drivers/cpufreq/powernv-cpufreq.c @@ -42,6 +42,10 @@ #define PMSR_PSAFE_ENABLE (1UL << 30) #define PMSR_SPR_EM_DISABLE (1UL << 31) #define PMSR_MAX(x) ((x >> 32) & 0xFF) +#define LPSTATE_SHIFT 48 +#define GPSTATE_SHIFT 56 +#define GET_LPSTATE(x) (((x) >> LPSTATE_SHIFT) & 0xFF) +#define GET_GPSTATE(x) (((x) >> GPSTATE_SHIFT) & 0xFF) #define MAX_RAMP_DOWN_TIME 5120 /* @@ -592,7 +596,8 @@ void gpstate_timer_handler(unsigned long data) { struct cpufreq_policy *policy = (struct cpufreq_policy *)data; struct global_pstate_info *gpstates = policy->driver_data; - int gpstate_idx; + int gpstate_idx, lpstate_idx; + unsigned long val; unsigned int time_diff = jiffies_to_msecs(jiffies) - gpstates->last_sampled_time; struct powernv_smp_call_data freq_data; @@ -600,21 +605,36 @@ void gpstate_timer_handler(unsigned long data) if (!spin_trylock(&gpstates->gpstate_lock)) return; + /* + * If PMCR was last updated was using fast_swtich then + * We may have wrong in gpstate->last_lpstate_idx + * value. Hence, read from PMCR to get correct data. + */ + val = get_pmspr(SPRN_PMCR); + freq_data.gpstate_id = (s8)GET_GPSTATE(val); + freq_data.pstate_id = (s8)GET_LPSTATE(val); + if (freq_data.gpstate_id == freq_data.pstate_id) { + reset_gpstates(policy); + spin_unlock(&gpstates->gpstate_lock); + return; + } + gpstates->last_sampled_time += time_diff; gpstates->elapsed_time += time_diff; - freq_data.pstate_id = idx_to_pstate(gpstates->last_lpstate_idx); - if ((gpstates->last_gpstate_idx == gpstates->last_lpstate_idx) || - (gpstates->elapsed_time > MAX_RAMP_DOWN_TIME)) { + if (gpstates->elapsed_time > MAX_RAMP_DOWN_TIME) { gpstate_idx = pstate_to_idx(freq_data.pstate_id); reset_gpstates(policy); gpstates->highest_lpstate_idx = gpstate_idx; } else { + lpstate_idx = pstate_to_idx(freq_data.pstate_id); gpstate_idx = calc_global_pstate(gpstates->elapsed_time, gpstates->highest_lpstate_idx, - gpstates->last_lpstate_idx); + lpstate_idx); } - + freq_data.gpstate_id = idx_to_pstate(gpstate_idx); + gpstates->last_gpstate_idx = gpstate_idx; + gpstates->last_lpstate_idx = lpstate_idx; /* * If local pstate is equal to global pstate, rampdown is over * So timer is not required to be queued. @@ -622,10 +642,6 @@ void gpstate_timer_handler(unsigned long data) if (gpstate_idx != gpstates->last_lpstate_idx) queue_gpstate_timer(gpstates); - freq_data.gpstate_id = idx_to_pstate(gpstate_idx); - gpstates->last_gpstate_idx = pstate_to_idx(freq_data.gpstate_id); - gpstates->last_lpstate_idx = pstate_to_idx(freq_data.pstate_id); - spin_unlock(&gpstates->gpstate_lock); /* Timer may get migrated to a different cpu on cpu hot unplug */