From: Gautham R Shenoy <ego@linux.vnet.ibm.com>
To: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Cc: mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org,
linux-kernel@vger.kernel.org,
Anju T Sudhakar <anju@linux.vnet.ibm.com>,
"Gautham R . Shenoy" <ego@linux.vnet.ibm.com>,
Balbir Singh <bsingharora@gmail.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Anton Blanchard <anton@samba.org>,
Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>,
Michael Neuling <mikey@neuling.org>,
Stewart Smith <stewart@linux.vnet.ibm.com>,
Daniel Axtens <dja@axtens.net>,
Stephane Eranian <eranian@google.com>
Subject: Re: [PATCH 12/13] powerpc/perf: Thread imc cpuhotplug support
Date: Thu, 23 Mar 2017 22:45:11 +0530 [thread overview]
Message-ID: <20170323171511.GA4148@in.ibm.com> (raw)
In-Reply-To: <1489649707-8021-13-git-send-email-maddy@linux.vnet.ibm.com>
Hi Maddy, Anju,
On Thu, Mar 16, 2017 at 01:05:06PM +0530, Madhavan Srinivasan wrote:
> From: Anju T Sudhakar <anju@linux.vnet.ibm.com>
>
> This patch adds support for thread IMC on cpuhotplug.
>
> When a cpu goes offline, the LDBAR for that cpu is disabled, and when it comes
> back online the previous ldbar value is written back to the LDBAR for that cpu.
>
> To register the hotplug functions for thread_imc, a new state
> CPUHP_AP_PERF_POWERPC_THREADIMC_ONLINE is added to the list of existing
> states.
>
> Cc: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
> Cc: Balbir Singh <bsingharora@gmail.com>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Anton Blanchard <anton@samba.org>
> Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
> Cc: Michael Neuling <mikey@neuling.org>
> Cc: Stewart Smith <stewart@linux.vnet.ibm.com>
> Cc: Daniel Axtens <dja@axtens.net>
> Cc: Stephane Eranian <eranian@google.com>
> Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com>
> Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
> ---
> arch/powerpc/perf/imc-pmu.c | 33 ++++++++++++++++++++++++++++-----
> include/linux/cpuhotplug.h | 1 +
> 2 files changed, 29 insertions(+), 5 deletions(-)
>
> diff --git a/arch/powerpc/perf/imc-pmu.c b/arch/powerpc/perf/imc-pmu.c
> index 6802960db51c..2ff39fe2a5ce 100644
> --- a/arch/powerpc/perf/imc-pmu.c
> +++ b/arch/powerpc/perf/imc-pmu.c
> @@ -687,6 +687,16 @@ static void cleanup_all_thread_imc_memory(void)
> on_each_cpu(cleanup_thread_imc_memory, NULL, 1);
> }
>
> +static void thread_imc_update_ldbar(unsigned int cpu_id)
> +{
> + u64 ldbar_addr, ldbar_value;
> +
> + ldbar_addr = (u64)virt_to_phys((void *)per_cpu_add[cpu_id]);
> + ldbar_value = (ldbar_addr & (u64)THREAD_IMC_LDBAR_MASK) |
> + (u64)THREAD_IMC_ENABLE;
> + mtspr(SPRN_LDBAR, ldbar_value);
> +}
> +
> /*
> * Allocates a page of memory for each of the online cpus, and, writes the
> * physical base address of that page to the LDBAR for that cpu. This starts
> @@ -694,20 +704,33 @@ static void cleanup_all_thread_imc_memory(void)
> */
> static void thread_imc_mem_alloc(void *dummy)
> {
> - u64 ldbar_addr, ldbar_value;
> int cpu_id = smp_processor_id();
>
> per_cpu_add[cpu_id] = (u64)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
> 0);
> - ldbar_addr = (u64)virt_to_phys((void *)per_cpu_add[cpu_id]);
> - ldbar_value = (ldbar_addr & (u64)THREAD_IMC_LDBAR_MASK) |
> - (u64)THREAD_IMC_ENABLE;
> - mtspr(SPRN_LDBAR, ldbar_value);
> + thread_imc_update_ldbar(cpu_id);
> +}
> +
> +static int ppc_thread_imc_cpu_online(unsigned int cpu)
> +{
> + thread_imc_update_ldbar(cpu);
> + return 0;
> +
> +}
> +
> +static int ppc_thread_imc_cpu_offline(unsigned int cpu)
> +{
> + mtspr(SPRN_LDBAR, 0);
> + return 0;
> }
This patch looks ok to me.
So it appears that in case of a full-core deep stop entry/exit you
will need to save/restore LDBAR as well. But I will take it up for the
next set of stop cleanups.
For this patch,
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
>
> void thread_imc_cpu_init(void)
> {
> on_each_cpu(thread_imc_mem_alloc, NULL, 1);
> + cpuhp_setup_state(CPUHP_AP_PERF_POWERPC_THREADIMC_ONLINE,
> + "POWER_THREAD_IMC_ONLINE",
> + ppc_thread_imc_cpu_online,
> + ppc_thread_imc_cpu_offline);
> }
>
> static void thread_imc_ldbar_disable(void *dummy)
> diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
> index abde85d9511a..724df46b2c3c 100644
> --- a/include/linux/cpuhotplug.h
> +++ b/include/linux/cpuhotplug.h
> @@ -138,6 +138,7 @@ enum cpuhp_state {
> CPUHP_AP_PERF_ARM_L2X0_ONLINE,
> CPUHP_AP_PERF_POWERPC_NEST_ONLINE,
> CPUHP_AP_PERF_POWERPC_COREIMC_ONLINE,
> + CPUHP_AP_PERF_POWERPC_THREADIMC_ONLINE,
> CPUHP_AP_PERF_ARM_QCOM_L2_ONLINE,
> CPUHP_AP_WORKQUEUE_ONLINE,
> CPUHP_AP_RCUTREE_ONLINE,
> --
> 2.7.4
>
--
Thanks and Regards
gautham.
next prev parent reply other threads:[~2017-03-23 17:15 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-16 7:34 [PATCH v5 00/13] IMC Instrumentation Support Madhavan Srinivasan
2017-03-16 7:34 ` [PATCH v5 01/13] powerpc/powernv: Data structure and macros definitions Madhavan Srinivasan
2017-03-16 7:34 ` [PATCH v5 02/13] powerpc/powernv: Autoload IMC device driver module Madhavan Srinivasan
2017-03-16 7:34 ` [PATCH v5 03/13] powerpc/powernv: Detect supported IMC units and its events Madhavan Srinivasan
2017-03-16 7:34 ` [PATCH v5 04/13] powerpc/perf: Add event attribute and group to IMC pmus Madhavan Srinivasan
2017-03-16 7:34 ` [PATCH v5 05/13] powerpc/perf: Generic imc pmu event functions Madhavan Srinivasan
2017-03-16 7:35 ` [PATCH v5 06/13] powerpc/perf: IMC pmu cpumask and cpu hotplug support Madhavan Srinivasan
2017-03-23 11:52 ` Gautham R Shenoy
2017-03-27 10:34 ` Anju T Sudhakar
2017-03-16 7:35 ` [PATCH v5 07/13] powerpc/powernv: Core IMC events detection Madhavan Srinivasan
2017-03-16 7:35 ` [PATCH v5 08/13] powerpc/perf: PMU functions for Core IMC and hotplugging Madhavan Srinivasan
2017-03-23 13:09 ` Gautham R Shenoy
2017-03-28 4:41 ` Madhavan Srinivasan
2017-03-16 7:35 ` [PATCH v5 09/13] powerpc/powernv: Thread IMC events detection Madhavan Srinivasan
2017-03-16 7:35 ` [PATCH v5 10/13] powerpc/perf: Thread IMC PMU functions Madhavan Srinivasan
2017-03-16 7:35 ` [PATCH 11/13] powerpc/powernv: Add device shutdown function for Core IMC Madhavan Srinivasan
2017-03-16 7:35 ` [PATCH 12/13] powerpc/perf: Thread imc cpuhotplug support Madhavan Srinivasan
2017-03-23 17:15 ` Gautham R Shenoy [this message]
2017-03-27 10:35 ` Anju T Sudhakar
2017-03-16 7:35 ` [PATCH 13/13] powerpc/perf: Enable/disable core engine during cpuhotplug Madhavan Srinivasan
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