Commit 2a3c79c6 authored by James Morse's avatar James Morse
Browse files

arm_mpam: resctrl: Allow resctrl to allocate monitors 



When resctrl wants to read a domain's 'QOS_L3_OCCUP', it needs to allocate
a monitor on the corresponding resource. Monitors are allocated by class
instead of component.

Add helpers to allocate a CSU monitor. These helper return an out of range
value for MBM counters.

Allocating a montitor context is expected to block until hardware resources
become available. This only makes sense for QOS_L3_OCCUP as unallocated MBM
counters are losing data.

Tested-by: default avatarGavin Shan <gshan@redhat.com>
Tested-by: default avatarShaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: default avatarPeter Newman <peternewman@google.com>
Tested-by: default avatarZeng Heng <zengheng4@huawei.com>
Tested-by: default avatarPunit Agrawal <punit.agrawal@oss.qualcomm.com>
Tested-by: default avatarJesse Chick <jessechick@os.amperecomputing.com>
Reviewed-by: default avatarZeng Heng <zengheng4@huawei.com>
Reviewed-by: default avatarShaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: default avatarJonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: default avatarGavin Shan <gshan@redhat.com>
Co-developed-by: default avatarBen Horgan <ben.horgan@arm.com>
Signed-off-by: default avatarBen Horgan <ben.horgan@arm.com>
Signed-off-by: default avatarJames Morse <james.morse@arm.com>
parent 1458c4f0

drivers/resctrl/mpam_internal.h

+13 −1
Original line number Diff line number Diff line
@@ -29,6 +29,14 @@ struct platform_device; 
#define PACKED_FOR_KUNIT

#endif



/*

 * This 'mon' values must not alias an actual monitor, so must be larger than

 * U16_MAX, but not be confused with an errno value, so smaller than

 * (u32)-SZ_4K.

 * USE_PRE_ALLOCATED is used to avoid confusion with an actual monitor.

 */

#define USE_PRE_ALLOCATED	(U16_MAX + 1)



static inline bool mpam_is_enabled(void)

{

	return static_branch_likely(&mpam_enabled);
@@ -216,7 +224,11 @@ enum mon_filter_options { 
};



struct mon_cfg {

	u16			mon;

	/*

	 * mon must be large enough to hold out of range values like

	 * USE_PRE_ALLOCATED

	 */

	u32			mon;

	u8			pmg;

	bool			match_pmg;

	bool			csu_exclude_clean;

drivers/resctrl/mpam_resctrl.c

+67 −0
Original line number Diff line number Diff line
@@ -22,6 +22,8 @@ 


#include "mpam_internal.h"



DECLARE_WAIT_QUEUE_HEAD(resctrl_mon_ctx_waiters);



/*

 * The classes we've picked to map to resctrl resources, wrapped

 * in with their resctrl structure.
@@ -289,6 +291,71 @@ struct rdt_resource *resctrl_arch_get_resource(enum resctrl_res_level l) 
	return &mpam_resctrl_controls[l].resctrl_res;

}



static int resctrl_arch_mon_ctx_alloc_no_wait(enum resctrl_event_id evtid)

{

	struct mpam_resctrl_mon *mon = &mpam_resctrl_counters[evtid];



	if (!mon->class)

		return -EINVAL;



	switch (evtid) {

	case QOS_L3_OCCUP_EVENT_ID:

		/* With CDP, one monitor gets used for both code/data reads */

		return mpam_alloc_csu_mon(mon->class);

	case QOS_L3_MBM_LOCAL_EVENT_ID:

	case QOS_L3_MBM_TOTAL_EVENT_ID:

		return USE_PRE_ALLOCATED;

	default:

		return -EOPNOTSUPP;

	}

}



void *resctrl_arch_mon_ctx_alloc(struct rdt_resource *r,

				 enum resctrl_event_id evtid)

{

	DEFINE_WAIT(wait);

	int *ret;



	ret = kmalloc_obj(*ret);

	if (!ret)

		return ERR_PTR(-ENOMEM);



	do {

		prepare_to_wait(&resctrl_mon_ctx_waiters, &wait,

				TASK_INTERRUPTIBLE);

		*ret = resctrl_arch_mon_ctx_alloc_no_wait(evtid);

		if (*ret == -ENOSPC)

			schedule();

	} while (*ret == -ENOSPC && !signal_pending(current));

	finish_wait(&resctrl_mon_ctx_waiters, &wait);



	return ret;

}



static void resctrl_arch_mon_ctx_free_no_wait(enum resctrl_event_id evtid,

					      u32 mon_idx)

{

	struct mpam_resctrl_mon *mon = &mpam_resctrl_counters[evtid];



	if (!mon->class)

		return;



	if (evtid == QOS_L3_OCCUP_EVENT_ID)

		mpam_free_csu_mon(mon->class, mon_idx);



	wake_up(&resctrl_mon_ctx_waiters);

}



void resctrl_arch_mon_ctx_free(struct rdt_resource *r,

			       enum resctrl_event_id evtid, void *arch_mon_ctx)

{

	u32 mon_idx = *(u32 *)arch_mon_ctx;



	kfree(arch_mon_ctx);



	resctrl_arch_mon_ctx_free_no_wait(evtid, mon_idx);

}



static bool cache_has_usable_cpor(struct mpam_class *class)

{

	struct mpam_props *cprops = &class->props;

include/linux/arm_mpam.h

+5 −0
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
#define __LINUX_ARM_MPAM_H



#include <linux/acpi.h>

#include <linux/resctrl_types.h>

#include <linux/types.h>



struct mpam_msc;
@@ -62,6 +63,10 @@ u32 resctrl_arch_rmid_idx_encode(u32 closid, u32 rmid); 
void resctrl_arch_rmid_idx_decode(u32 idx, u32 *closid, u32 *rmid);

u32 resctrl_arch_system_num_rmid_idx(void);



struct rdt_resource;

void *resctrl_arch_mon_ctx_alloc(struct rdt_resource *r, enum resctrl_event_id evtid);

void resctrl_arch_mon_ctx_free(struct rdt_resource *r, enum resctrl_event_id evtid, void *ctx);



/**

 * mpam_register_requestor() - Register a requestor with the MPAM driver

 * @partid_max:		The maximum PARTID value the requestor can generate.