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x86/resctrl: Add helper for setting CPU default properties

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rdtgroup_rmdir_ctrl() and rdtgroup_rmdir_mon() set the per-CPU pqr_state for
CPUs that were part of the rmdir()'d group.

Another architecture might not have a 'pqr_state', its hardware may need the
values in a different format. MPAM's equivalent of RMID values are not unique,
and always need the CLOSID to be provided too.

There is only one caller that modifies a single value, (rdtgroup_rmdir_mon()).
MPAM always needs both CLOSID and RMID for the hardware value as these are
written to the same system register.

As rdtgroup_rmdir_mon() has the CLOSID on hand, only provide a helper to set
both values. These values are read by __resctrl_sched_in(), but may be written
by a different CPU without any locking, add READ/WRTE_ONCE() to avoid torn
values.

Co-developed-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Fenghua Yu <fenghuay@nvidia.com>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Tested-by: Carl Worth <carl@os.amperecomputing.com> # arm64
Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Amit Singh Tomar <amitsinght@marvell.com> # arm64
Tested-by: Shanker Donthineni <sdonthineni@nvidia.com> # arm64
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/20250311183715.16445-10-james.morse@arm.com
This commit is contained in:
James Morse 2025-03-11 18:36:54 +00:00 committed by Borislav Petkov (AMD)
parent dbc58f7eec
commit aebd5354dd
2 changed files with 25 additions and 9 deletions
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14
arch/x86/include/asm/resctrl.h
View File

@ -4,8 +4,9 @@
#ifdef CONFIG_X86_CPU_RESCTRL
#include <linux/sched.h>
#include <linux/jump_label.h>
#include <linux/percpu.h>
#include <linux/sched.h>
/*
* This value can never be a valid CLOSID, and is used when mapping a
@ -96,8 +97,8 @@ static inline void resctrl_arch_disable_mon(void)
static inline void __resctrl_sched_in(struct task_struct *tsk)
{
struct resctrl_pqr_state *state = this_cpu_ptr(&pqr_state);
u32 closid = state->default_closid;
u32 rmid = state->default_rmid;
u32 closid = READ_ONCE(state->default_closid);
u32 rmid = READ_ONCE(state->default_rmid);
u32 tmp;
/*
@ -132,6 +133,13 @@ static inline unsigned int resctrl_arch_round_mon_val(unsigned int val)
return val * scale;
}
static inline void resctrl_arch_set_cpu_default_closid_rmid(int cpu, u32 closid,
u32 rmid)
{
WRITE_ONCE(per_cpu(pqr_state.default_closid, cpu), closid);
WRITE_ONCE(per_cpu(pqr_state.default_rmid, cpu), rmid);
}
static inline void resctrl_arch_set_closid_rmid(struct task_struct *tsk,
u32 closid, u32 rmid)
{

20
arch/x86/kernel/cpu/resctrl/rdtgroup.c
View File

@ -3731,14 +3731,21 @@ static int rdtgroup_mkdir(struct kernfs_node *parent_kn, const char *name,
static int rdtgroup_rmdir_mon(struct rdtgroup *rdtgrp, cpumask_var_t tmpmask)
{
struct rdtgroup *prdtgrp = rdtgrp->mon.parent;
u32 closid, rmid;
int cpu;
/* Give any tasks back to the parent group */
rdt_move_group_tasks(rdtgrp, prdtgrp, tmpmask);
/* Update per cpu rmid of the moved CPUs first */
/*
* Update per cpu closid/rmid of the moved CPUs first.
* Note: the closid will not change, but the arch code still needs it.
*/
closid = prdtgrp->closid;
rmid = prdtgrp->mon.rmid;
for_each_cpu(cpu, &rdtgrp->cpu_mask)
per_cpu(pqr_state.default_rmid, cpu) = prdtgrp->mon.rmid;
resctrl_arch_set_cpu_default_closid_rmid(cpu, closid, rmid);
/*
* Update the MSR on moved CPUs and CPUs which have moved
* task running on them.
@ -3771,6 +3778,7 @@ static int rdtgroup_ctrl_remove(struct rdtgroup *rdtgrp)
static int rdtgroup_rmdir_ctrl(struct rdtgroup *rdtgrp, cpumask_var_t tmpmask)
{
u32 closid, rmid;
int cpu;
/* Give any tasks back to the default group */
@ -3781,10 +3789,10 @@ static int rdtgroup_rmdir_ctrl(struct rdtgroup *rdtgrp, cpumask_var_t tmpmask)
&rdtgroup_default.cpu_mask, &rdtgrp->cpu_mask);
/* Update per cpu closid and rmid of the moved CPUs first */
for_each_cpu(cpu, &rdtgrp->cpu_mask) {
per_cpu(pqr_state.default_closid, cpu) = rdtgroup_default.closid;
per_cpu(pqr_state.default_rmid, cpu) = rdtgroup_default.mon.rmid;
}
closid = rdtgroup_default.closid;
rmid = rdtgroup_default.mon.rmid;
for_each_cpu(cpu, &rdtgrp->cpu_mask)
resctrl_arch_set_cpu_default_closid_rmid(cpu, closid, rmid);
/*
* Update the MSR on moved CPUs and CPUs which have moved