Commit 8c793336 authored by Babu Moger's avatar Babu Moger Committed by Borislav Petkov (AMD)
Browse files

fs/resctrl: Add resctrl file to display number of assignable counters 



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.

Create 'num_mbm_cntrs' resctrl file that displays the number of counters
supported in each domain. 'num_mbm_cntrs' is only visible to user space when
the system supports "mbm_event" mode.

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 3b497c3f

Documentation/filesystems/resctrl.rst

+11 −0
Original line number Diff line number Diff line
@@ -288,6 +288,17 @@ with the following files: 
	result in misleading values or display "Unavailable" if no counter is assigned

	to the event.



"num_mbm_cntrs":

	The maximum number of counters (total of available and assigned counters) in

	each domain when the system supports mbm_event mode.



	For example, on a system with maximum of 32 memory bandwidth monitoring

	counters in each of its L3 domains:

	::



	  # cat /sys/fs/resctrl/info/L3_MON/num_mbm_cntrs

	  0=32;1=32



"max_threshold_occupancy":

		Read/write file provides the largest value (in

		bytes) at which a previously used LLC_occupancy

fs/resctrl/internal.h

+2 −0
Original line number Diff line number Diff line
@@ -386,6 +386,8 @@ void *rdt_kn_parent_priv(struct kernfs_node *kn); 


int resctrl_mbm_assign_mode_show(struct kernfs_open_file *of, struct seq_file *s, void *v);



int resctrl_num_mbm_cntrs_show(struct kernfs_open_file *of, struct seq_file *s, void *v);



#ifdef CONFIG_RESCTRL_FS_PSEUDO_LOCK

int rdtgroup_locksetup_enter(struct rdtgroup *rdtgrp);

fs/resctrl/monitor.c

+26 −0
Original line number Diff line number Diff line
@@ -912,6 +912,30 @@ int resctrl_mbm_assign_mode_show(struct kernfs_open_file *of, 
	return 0;

}



int resctrl_num_mbm_cntrs_show(struct kernfs_open_file *of,

			       struct seq_file *s, void *v)

{

	struct rdt_resource *r = rdt_kn_parent_priv(of->kn);

	struct rdt_mon_domain *dom;

	bool sep = false;



	cpus_read_lock();

	mutex_lock(&rdtgroup_mutex);



	list_for_each_entry(dom, &r->mon_domains, hdr.list) {

		if (sep)

			seq_putc(s, ';');



		seq_printf(s, "%d=%d", dom->hdr.id, r->mon.num_mbm_cntrs);

		sep = true;

	}

	seq_putc(s, '\n');



	mutex_unlock(&rdtgroup_mutex);

	cpus_read_unlock();

	return 0;

}



/**

 * resctrl_mon_resource_init() - Initialise global monitoring structures.

 *
@@ -957,6 +981,8 @@ int resctrl_mon_resource_init(void) 
			resctrl_enable_mon_event(QOS_L3_MBM_TOTAL_EVENT_ID);

		if (!resctrl_is_mon_event_enabled(QOS_L3_MBM_LOCAL_EVENT_ID))

			resctrl_enable_mon_event(QOS_L3_MBM_LOCAL_EVENT_ID);

		resctrl_file_fflags_init("num_mbm_cntrs",

					 RFTYPE_MON_INFO | RFTYPE_RES_CACHE);

	}



	return 0;

fs/resctrl/rdtgroup.c

+6 −0
Original line number Diff line number Diff line
@@ -1836,6 +1836,12 @@ static struct rftype res_common_files[] = { 
		.seq_show	= rdt_default_ctrl_show,

		.fflags		= RFTYPE_CTRL_INFO | RFTYPE_RES_CACHE,

	},

	{

		.name		= "num_mbm_cntrs",

		.mode		= 0444,

		.kf_ops		= &rdtgroup_kf_single_ops,

		.seq_show	= resctrl_num_mbm_cntrs_show,

	},

	{

		.name		= "min_cbm_bits",

		.mode		= 0444,