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Message-ID: <766ecc49-555e-6e14-c9c2-6abb076dfd5c@amd.com>
Date: Fri, 18 Oct 2024 09:22:57 -0500
From: "Moger, Babu" <bmoger@....com>
To: Reinette Chatre <reinette.chatre@...el.com>,
Babu Moger <babu.moger@....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 v8 19/25] x86/resctrl: Auto assign/unassign counters when
mbm_cntr_assign is enabled
Hi Reinette,
On 10/15/2024 10:30 PM, Reinette Chatre wrote:
> Hi Babu,
>
> On 10/9/24 10:39 AM, Babu Moger wrote:
>> Assign/unassign counters on resctrl group creation/deletion. Two counters
>> are required per group, one for MBM total event and one for MBM local
>> event.
>>
>> There are a limited number of counters available for assignment. If these
>> counters are exhausted, the kernel will display the error message: "Out of
>> MBM assignable counters". However, it is not necessary to fail the
>> creation of a group due to assignment failures. Users have the flexibility
>> to modify the assignments at a later time.
>>
>> Signed-off-by: Babu Moger <babu.moger@....com>
>> ---
> ...
>
>> ---
>> arch/x86/kernel/cpu/resctrl/rdtgroup.c | 64 ++++++++++++++++++++++++++
>> 1 file changed, 64 insertions(+)
>>
>> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> index 791258adcbda..cb2c60c0319e 100644
>> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>
> ...
>
>> static int rdt_get_tree(struct fs_context *fc)
>> {
>> struct rdt_fs_context *ctx = rdt_fc2context(fc);
>> @@ -2934,6 +2980,8 @@ static int rdt_get_tree(struct fs_context *fc)
>> if (ret < 0)
>> goto out_mongrp;
>> rdtgroup_default.mon.mon_data_kn = kn_mondata;
>> +
>> + rdtgroup_assign_cntrs(&rdtgroup_default);
>> }
>>
>> ret = rdt_pseudo_lock_init();
>> @@ -2964,6 +3012,7 @@ static int rdt_get_tree(struct fs_context *fc)
>> out_psl:
>> rdt_pseudo_lock_release();
>> out_mondata:
>> + rdtgroup_unassign_cntrs(&rdtgroup_default);
>> if (resctrl_arch_mon_capable())
>> kernfs_remove(kn_mondata);
>
> I think I mentioned this before ... this addition belongs within the
> "if (resctrl_arch_mon_capable())" to be symmetrical with where it was called from.
Sure.
>
>> out_mongrp:
>> @@ -3144,6 +3193,7 @@ static void free_all_child_rdtgrp(struct rdtgroup *rdtgrp)
>>
>> head = &rdtgrp->mon.crdtgrp_list;
>> list_for_each_entry_safe(sentry, stmp, head, mon.crdtgrp_list) {
>> + rdtgroup_unassign_cntrs(sentry);
>> free_rmid(sentry->closid, sentry->mon.rmid);
>> list_del(&sentry->mon.crdtgrp_list);
>>
>> @@ -3184,6 +3234,8 @@ static void rmdir_all_sub(void)
>> cpumask_or(&rdtgroup_default.cpu_mask,
>> &rdtgroup_default.cpu_mask, &rdtgrp->cpu_mask);
>>
>> + rdtgroup_unassign_cntrs(rdtgrp);
>> +
>> free_rmid(rdtgrp->closid, rdtgrp->mon.rmid);
>>
>> kernfs_remove(rdtgrp->kn);
>> @@ -3223,6 +3275,8 @@ static void rdt_kill_sb(struct super_block *sb)
>> resctrl_arch_disable_alloc();
>> if (resctrl_arch_mon_capable())
>> resctrl_arch_disable_mon();
>> +
>> + rdtgroup_unassign_cntrs(&rdtgroup_default);
>
> Unassigning counters after monitoring is completely disabled seems late. I
> think this can be moved earlier to be right after the counters of all the
> other groups are unassigned.
Sure. Right after rmdir_all_sub().
>
>> resctrl_mounted = false;
>> kernfs_kill_sb(sb);
>> mutex_unlock(&rdtgroup_mutex);
>> @@ -3814,6 +3868,8 @@ static int rdtgroup_mkdir_mon(struct kernfs_node *parent_kn,
>> goto out_unlock;
>> }
>>
>> + rdtgroup_assign_cntrs(rdtgrp);
>> +
>> kernfs_activate(rdtgrp->kn);
>>
>> /*
>> @@ -3858,6 +3914,8 @@ static int rdtgroup_mkdir_ctrl_mon(struct kernfs_node *parent_kn,
>> if (ret)
>> goto out_closid_free;
>>
>> + rdtgroup_assign_cntrs(rdtgrp);
>> +
>> kernfs_activate(rdtgrp->kn);
>>
>> ret = rdtgroup_init_alloc(rdtgrp);
>> @@ -3883,6 +3941,7 @@ static int rdtgroup_mkdir_ctrl_mon(struct kernfs_node *parent_kn,
>> out_del_list:
>> list_del(&rdtgrp->rdtgroup_list);
>> out_rmid_free:
>> + rdtgroup_unassign_cntrs(rdtgrp);
>> mkdir_rdt_prepare_rmid_free(rdtgrp);
>> out_closid_free:
>> closid_free(closid);
>> @@ -3953,6 +4012,9 @@ 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);
>>
>> /*
>> @@ -3999,6 +4061,8 @@ 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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