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From: James Morse <james.morse@arm.com>
To: Jamie Iles <jamie@nuviainc.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
	Fenghua Yu <fenghua.yu@intel.com>,
	Reinette Chatre <reinette.chatre@intel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	H Peter Anvin <hpa@zytor.com>, Babu Moger <Babu.Moger@amd.com>,
	shameerali.kolothum.thodi@huawei.com,
	D Scott Phillips OS <scott@os.amperecomputing.com>,
	lcherian@marvell.com, bobo.shaobowang@huawei.com
Subject: Re: [PATCH v1 12/20] x86/recstrl: Add per-rmid arch private storage for overflow and chunks
Date: Tue, 31 Aug 2021 17:25:01 +0100	[thread overview]
Message-ID: <5caa74a5-a73d-a5ce-9169-396ad3727386@arm.com> (raw)
In-Reply-To: <YRQFY+/vwsfTBeTd@hazel>

Hi Jamie,

On 11/08/2021 18:14, Jamie Iles wrote:
> On Thu, Jul 29, 2021 at 10:36:02PM +0000, James Morse wrote:
>> resctrl_arch_rmid_read() is intended as the function that an
>> architecture agnostic resctrl filesystem driver can use to
>> read a value in bytes from a counter. Currently the function returns
>> the mbm values in chunks directly from hardware. For bandwidth
>> counters the resctrl filesystem provides the number of bytes
>> ever seen. Internally mba_sc uses a second prev_bw_msr to calculate
>> the bytes read since the last mba_sc invocation.
>>
>> MPAM's scaling of counters can be changed at runtime, reducing the
>> resolution but increasing the range. When this is changed the prev_msr
>> values need to be converted by the architecture code.
>>
>> Add storage for per-rmid private storage. The prev_msr and chunks
>> values will move here to allow resctrl_arch_rmid_read() to always
>> return the number of bytes read by this counter.

>> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
>> index 8a3c13c6c19f..27c93d12ca27 100644
>> --- a/arch/x86/kernel/cpu/resctrl/core.c
>> +++ b/arch/x86/kernel/cpu/resctrl/core.c
>> @@ -432,6 +432,28 @@ static int domain_setup_ctrlval(struct rdt_resource *r, struct rdt_domain *d)

>> +static int arch_domain_mbm_alloc(u32 num_rmid, struct rdt_hw_domain *hw_dom)
>> +{
>> +	size_t tsize;
>> +
>> +	if (is_mbm_total_enabled()) {
>> +		tsize = sizeof(*hw_dom->arch_mbm_total);
>> +		hw_dom->arch_mbm_total = kcalloc(num_rmid, tsize, GFP_KERNEL);
>> +		if (!hw_dom->arch_mbm_total)
>> +			return -ENOMEM;
>> +	}
>> +	if (is_mbm_local_enabled()) {
>> +		tsize = sizeof(*hw_dom->arch_mbm_local);
>> +		hw_dom->arch_mbm_local = kcalloc(num_rmid, tsize, GFP_KERNEL);
>> +		if (!hw_dom->arch_mbm_local) {
>> +			kfree(hw_dom->arch_mbm_total);
>> +			return -ENOMEM;
>> +		}
>> +	}
>> +
>> +	return 0;
>> +}
>> +

>> @@ -481,6 +503,11 @@ static void domain_add_cpu(int cpu, struct rdt_resource *r)
>>  		return;
>>  	}
>>  
>> +	if (r->mon_capable && arch_domain_mbm_alloc(r->num_rmid, hw_dom)) {
>> +		kfree(d);
> 
> Does this error path and subsequent ones in domain_add_cpu also need to 
> undo the allocations from arch_domain_mbm_alloc?

This one needs to free the ctrl_val array, as does the path from resctrl_online_domain().
Yes, resctrl_online_domain() needs to free the two mbm arrays. Thanks!

Its probably cleanest to add some helper in patch 3 that kfree()s anything that might have
been allocated, and add-to/remote-from that over time. The root structure is kzalloc()d ,
so shouldn't need an elaborate and verbose unwind/goto-nest.


Thanks,

James

  reply	other threads:[~2021-08-31 16:25 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-29 22:35 [PATCH v1 00/20] x86/resctrl: Make resctrl_arch_rmid_read() return values in bytes James Morse
2021-07-29 22:35 ` [PATCH v1 01/20] x86/resctrl: Kill off alloc_enabled James Morse
2021-08-11 12:12   ` Jamie Iles
2021-09-01 21:18   ` Reinette Chatre
2021-07-29 22:35 ` [PATCH v1 02/20] x86/resctrl: Merge mon_capable and mon_enabled James Morse
2021-08-11 12:15   ` Jamie Iles
2021-08-11 15:16     ` James Morse
2021-07-29 22:35 ` [PATCH v1 03/20] x86/resctrl: Add domain online callback for resctrl work James Morse
2021-09-01 21:19   ` Reinette Chatre
2021-09-17 16:57     ` James Morse
2021-07-29 22:35 ` [PATCH v1 04/20] x86/resctrl: Add domain offline " James Morse
2021-08-11 16:10   ` Jamie Iles
2021-09-01 21:21   ` Reinette Chatre
2021-07-29 22:35 ` [PATCH v1 05/20] x86/resctrl: Create mba_sc configuration in the rdt_domain James Morse
2021-08-11 16:32   ` Jamie Iles
2021-08-31 16:24     ` James Morse
2021-09-01 21:22   ` Reinette Chatre
2021-09-17 16:57     ` James Morse
2021-07-29 22:35 ` [PATCH v1 06/20] x86/resctrl: Switch over to the resctrl mbps_val list James Morse
2021-09-01 21:25   ` Reinette Chatre
2021-09-17 16:57     ` James Morse
2021-09-17 18:20       ` Reinette Chatre
2021-10-01 16:02         ` James Morse
2021-07-29 22:35 ` [PATCH v1 07/20] x86/resctrl: Remove architecture copy of mbps_val James Morse
2021-09-01 21:26   ` Reinette Chatre
2021-09-17 16:57     ` James Morse
2021-07-29 22:35 ` [PATCH v1 08/20] x86/resctrl: Remove set_mba_sc()s control array re-initialisation James Morse
2021-07-29 22:35 ` [PATCH v1 09/20] x86/resctrl: Abstract and use supports_mba_mbps() James Morse
2021-09-01 21:27   ` Reinette Chatre
2021-09-17 16:57     ` James Morse
2021-09-24  6:23   ` tan.shaopeng
2021-10-01 16:01     ` James Morse
2021-07-29 22:36 ` [PATCH v1 10/20] x86/resctrl: Allow update_mba_bw() to update controls directly James Morse
2021-09-01 21:28   ` Reinette Chatre
2021-07-29 22:36 ` [PATCH v1 11/20] x86/resctrl: Calculate bandwidth from the total bytes counter James Morse
2021-09-01 21:31   ` Reinette Chatre
2021-09-17 16:58     ` James Morse
2021-07-29 22:36 ` [PATCH v1 12/20] x86/recstrl: Add per-rmid arch private storage for overflow and chunks James Morse
2021-08-11 17:14   ` Jamie Iles
2021-08-31 16:25     ` James Morse [this message]
2021-07-29 22:36 ` [PATCH v1 13/20] x86/recstrl: Allow per-rmid arch private storage to be reset James Morse
2021-09-24  6:34   ` tan.shaopeng
2021-10-01 16:01     ` James Morse
2021-07-29 22:36 ` [PATCH v1 14/20] x86/resctrl: Abstract __rmid_read() James Morse
2021-07-29 22:36 ` [PATCH v1 15/20] x86/resctrl: Pass the required parameters into resctrl_arch_rmid_read() James Morse
2021-07-29 22:36 ` [PATCH v1 16/20] x86/resctrl: Move mbm_overflow_count() " James Morse
2021-07-29 22:36 ` [PATCH v1 17/20] x86/resctrl: Move get_corrected_mbm_count() " James Morse
2021-07-29 22:36 ` [PATCH v1 18/20] x86/resctrl: Rename and change the units of resctrl_cqm_threshold James Morse
2021-07-29 22:36 ` [PATCH v1 19/20] x86/resctrl: Add resctrl_rmid_realloc_limit to abstract x86's boot_cpu_data James Morse
2021-07-29 22:36 ` [PATCH v1 20/20] x86/resctrl: Make resctrl_arch_rmid_read() return values in bytes James Morse

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