Commit 4d32c24a authored by Babu Moger's avatar Babu Moger Committed by Borislav Petkov (AMD)
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fs/resctrl: Introduce mbm_cntr_cfg to track assignable counters per domain 



The "mbm_event" counter assignment mode allows users to assign a hardware
counter to an RMID, event pair and monitor bandwidth usage as long as it is
assigned.  The hardware continues to track the assigned counter until it is
explicitly unassigned by the user. Counters are assigned/unassigned at
monitoring domain level.

Manage a monitoring domain's hardware counters using a per monitoring
domain array of struct mbm_cntr_cfg that is indexed by the hardware
counter ID. A hardware counter's configuration contains the MBM event
ID and points to the monitoring group that it is assigned to, with a NULL
pointer meaning that the hardware counter is available for assignment.

There is no direct way to determine which hardware counters are assigned
to a particular monitoring group. Check every entry of every hardware
counter configuration array in every monitoring domain to query which
MBM events of a monitoring group is tracked by hardware. Such queries are
acceptable because of a very small number of assignable counters (32
to 64).

Suggested-by: default avatarPeter Newman <peternewman@google.com>
Signed-off-by: default avatarBabu Moger <babu.moger@amd.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: default avatarReinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
parent 8c793336

fs/resctrl/rdtgroup.c

+8 −0
Original line number Diff line number Diff line
@@ -4029,6 +4029,7 @@ static void domain_destroy_mon_state(struct rdt_mon_domain *d) 
{

	int idx;



	kfree(d->cntr_cfg);

	bitmap_free(d->rmid_busy_llc);

	for_each_mbm_idx(idx) {

		kfree(d->mbm_states[idx]);
@@ -4112,6 +4113,13 @@ static int domain_setup_mon_state(struct rdt_resource *r, struct rdt_mon_domain 
			goto cleanup;

	}



	if (resctrl_is_mbm_enabled() && r->mon.mbm_cntr_assignable) {

		tsize = sizeof(*d->cntr_cfg);

		d->cntr_cfg = kcalloc(r->mon.num_mbm_cntrs, tsize, GFP_KERNEL);

		if (!d->cntr_cfg)

			goto cleanup;

	}



	return 0;

cleanup:

	bitmap_free(d->rmid_busy_llc);

include/linux/resctrl.h

+15 −0
Original line number Diff line number Diff line
@@ -156,6 +156,18 @@ struct rdt_ctrl_domain { 
	u32				*mbps_val;

};



/**

 * struct mbm_cntr_cfg - Assignable counter configuration.

 * @evtid:		MBM event to which the counter is assigned. Only valid

 *			if @rdtgroup is not NULL.

 * @rdtgrp:		resctrl group assigned to the counter. NULL if the

 *			counter is free.

 */

struct mbm_cntr_cfg {

	enum resctrl_event_id	evtid;

	struct rdtgroup		*rdtgrp;

};



/**

 * struct rdt_mon_domain - group of CPUs sharing a resctrl monitor resource

 * @hdr:		common header for different domain types
@@ -168,6 +180,8 @@ struct rdt_ctrl_domain { 
 * @cqm_limbo:		worker to periodically read CQM h/w counters

 * @mbm_work_cpu:	worker CPU for MBM h/w counters

 * @cqm_work_cpu:	worker CPU for CQM h/w counters

 * @cntr_cfg:		array of assignable counters' configuration (indexed

 *			by counter ID)

 */

struct rdt_mon_domain {

	struct rdt_domain_hdr		hdr;
@@ -178,6 +192,7 @@ struct rdt_mon_domain { 
	struct delayed_work		cqm_limbo;

	int				mbm_work_cpu;

	int				cqm_work_cpu;

	struct mbm_cntr_cfg		*cntr_cfg;

};



/**