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Message-ID: <ad4cfa10-21e2-414b-81e6-3c5c86650529@amd.com>
Date: Tue, 16 Jul 2024 15:58:30 -0500
From: "Moger, Babu" <babu.moger@....com>
To: Reinette Chatre <reinette.chatre@...el.com>, corbet@....net,
fenghua.yu@...el.com, tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
dave.hansen@...ux.intel.com
Cc: x86@...nel.org, hpa@...or.com, paulmck@...nel.org, rdunlap@...radead.org,
tj@...nel.org, peterz@...radead.org, yanjiewtw@...il.com,
kim.phillips@....com, lukas.bulwahn@...il.com, seanjc@...gle.com,
jmattson@...gle.com, leitao@...ian.org, jpoimboe@...nel.org,
rick.p.edgecombe@...el.com, kirill.shutemov@...ux.intel.com,
jithu.joseph@...el.com, kai.huang@...el.com, kan.liang@...ux.intel.com,
daniel.sneddon@...ux.intel.com, pbonzini@...hat.com, sandipan.das@....com,
ilpo.jarvinen@...ux.intel.com, peternewman@...gle.com,
maciej.wieczor-retman@...el.com, linux-doc@...r.kernel.org,
linux-kernel@...r.kernel.org, eranian@...gle.com, james.morse@....com
Subject: Re: [PATCH v5 15/20] x86/resctrl: Assign/unassign counters by default
when ABMC is enabled
Hi Reinette,
On 7/12/24 17:10, Reinette Chatre wrote:
> Hi Babu,
>
> On 7/3/24 2:48 PM, Babu Moger wrote:
>> Assign/unassign counters on resctrl group creation/deletion. If the
>> counters are exhausted, report the warnings and continue. It is not
>> required to fail group creation for assignment failures. Users have
>> the option to modify the assignments later.
>>
>> Signed-off-by: Babu Moger <babu.moger@....com>
>> ---
>> v5: Removed the code to enable/disable ABMC during the mount.
>> That will be another patch.
>> Added arch callers to get the arch specific data.
>> Renamed fuctions to match the other abmc function.
>> Added code comments for assignment failures.
>>
>> v4: Few name changes based on the upstream discussion.
>> Commit message update.
>>
>> v3: This is a new patch. Patch addresses the upstream comment to enable
>> ABMC feature by default if the feature is available.
>> ---
>> arch/x86/kernel/cpu/resctrl/rdtgroup.c | 78 ++++++++++++++++++++++++++
>> 1 file changed, 78 insertions(+)
>>
>> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> index ffde30b36c1a..475a0c7b2a25 100644
>> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> @@ -2910,6 +2910,46 @@ static void schemata_list_destroy(void)
>> }
>> }
>> +/*
>> + * Called when new group is created. Assign the counters if ABMC is
>> + * already enabled. Two counters are required per group, one for total
>> + * event and one for local event. With limited number of counters,
>> + * the assignments can fail in some cases. But, it is not required to
>> + * fail the group creation. Users have the option to modify the
>> + * assignments after the group creation.
>> + */
>> +static int rdtgroup_assign_cntrs(struct rdtgroup *rdtgrp)
>> +{
>> + int ret = 0;
>> +
>> + if (!resctrl_arch_get_abmc_enabled())
>> + return 0;
>> +
>> + if (is_mbm_total_enabled())
>> + ret = rdtgroup_assign_cntr(rdtgrp, QOS_L3_MBM_TOTAL_EVENT_ID);
>> +
>> + if (!ret && is_mbm_local_enabled())
>> + ret = rdtgroup_assign_cntr(rdtgrp, QOS_L3_MBM_LOCAL_EVENT_ID);
>> +
>> + return ret;
>> +}
>> +
>> +static int rdtgroup_unassign_cntrs(struct rdtgroup *rdtgrp)
>> +{
>> + int ret = 0;
>> +
>> + if (!resctrl_arch_get_abmc_enabled())
>> + return 0;
>> +
>> + if (is_mbm_total_enabled())
>> + ret = rdtgroup_unassign_cntr(rdtgrp, QOS_L3_MBM_TOTAL_EVENT_ID);
>> +
>> + if (!ret && is_mbm_local_enabled())
>> + ret = rdtgroup_unassign_cntr(rdtgrp, QOS_L3_MBM_LOCAL_EVENT_ID);
>> +
>> + return ret;
>> +}
>> +
>> static int rdt_get_tree(struct fs_context *fc)
>> {
>> struct rdt_resource *r =
>> &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
>> @@ -2972,6 +3012,16 @@ static int rdt_get_tree(struct fs_context *fc)
>> if (ret < 0)
>> goto out_mongrp;
>> rdtgroup_default.mon.mon_data_kn = kn_mondata;
>> +
>> + /*
>> + * Assign the counters if ABMC is already enabled.
>> + * With limited number of counters, the assignments can
>> + * fail in some cases. But, it is not required to fail
>> + * the group creation. Users have the option to modify
>> + * the assignments after the group creation.
>> + */
>
> The function has detailed comments - it seems unnecessary to me that the
> same comments are duplicated at each call site.
Sure. Will remove duplicates.
>
>> + if (rdtgroup_assign_cntrs(&rdtgroup_default) < 0)
>> + rdt_last_cmd_puts("Monitor assignment failed\n");
>
> rdtgroup_assign_cntrs() already prints message, why print another? Error
> handling can then be dropped.
Sure.
>
>> }
>> ret = rdt_pseudo_lock_init();
>> @@ -3246,6 +3296,8 @@ static void rdt_kill_sb(struct super_block *sb)
>> cpus_read_lock();
>> mutex_lock(&rdtgroup_mutex);
>> + rdtgroup_unassign_cntrs(&rdtgroup_default);
>> +
>
> This seems appropriate to be in the "Put everything back to default values"
> section.
Sure. Will move it down.
>
>> rdt_disable_ctx();
>> /*Put everything back to default values. */
>> @@ -3850,6 +3902,16 @@ static int rdtgroup_mkdir_mon(struct kernfs_node
>> *parent_kn,
>> goto out_unlock;
>> }
>> + /*
>> + * Assign the counters if ABMC is already enabled.
>> + * With the limited number of counters, there can be cases
>> + * only on assignment succeed. It is not required to fail
>> + * here in that case. Users have the option to modify the
>> + * assignments later.
>> + */
>> + if (rdtgroup_assign_cntrs(rdtgrp) < 0)
>> + rdt_last_cmd_puts("Monitor assignment failed\n");
>> +
>> kernfs_activate(rdtgrp->kn);
>> /*
>> @@ -3894,6 +3956,17 @@ static int rdtgroup_mkdir_ctrl_mon(struct
>> kernfs_node *parent_kn,
>> if (ret)
>> goto out_closid_free;
>> + /*
>> + * Assign the counters if ABMC is already enabled.
>> + * With the limited number of counters, there can be cases
>> + * only on assignment succeed. It is not required to fail
>> + * here in that case. Users have the option to assign the
>> + * counter later.
>> + */
>> +
>> + if (rdtgroup_assign_cntrs(rdtgrp) < 0)
>> + rdt_last_cmd_puts("Monitor assignment failed\n");
>> +
>> kernfs_activate(rdtgrp->kn);
>> ret = rdtgroup_init_alloc(rdtgrp);
>> @@ -3989,6 +4062,9 @@ static int rdtgroup_rmdir_mon(struct rdtgroup
>> *rdtgrp, cpumask_var_t tmpmask)
>> update_closid_rmid(tmpmask, NULL);
>> rdtgrp->flags = RDT_DELETED;
>> +
>> + rdtgroup_unassign_cntrs(rdtgrp);
>> +
>> free_rmid(rdtgrp->closid, rdtgrp->mon.rmid);
>> /*
>> @@ -4035,6 +4111,8 @@ static int rdtgroup_rmdir_ctrl(struct rdtgroup
>> *rdtgrp, cpumask_var_t tmpmask)
>> cpumask_or(tmpmask, tmpmask, &rdtgrp->cpu_mask);
>> update_closid_rmid(tmpmask, NULL);
>> + rdtgroup_unassign_cntrs(rdtgrp);
>> +
>> free_rmid(rdtgrp->closid, rdtgrp->mon.rmid);
>> closid_free(rdtgrp->closid);
>>
>
> Reinette
>
--
Thanks
Babu Moger
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