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// SPDX-License-Identifier: GPL-2.0-only/* * Resource Director Technology(RDT) * - Monitoring code * * Copyright (C) 2017 Intel Corporation * * Author: *    Vikas Shivappa <vikas.shivappa@intel.com> * * This replaces the cqm.c based on perf but we reuse a lot of * code and datastructures originally from Peter Zijlstra and Matt Fleming. * * More information about RDT be found in the Intel (R) x86 Architecture * Software Developer Manual June 2016, volume 3, section 17.17. */ #define pr_fmt(fmt)	"resctrl: " fmt #include <linux/cpu.h>#include <linux/resctrl.h>#include <linux/sizes.h>#include <linux/slab.h> #include "internal.h" #define CREATE_TRACE_POINTS #include "monitor_trace.h" /** * struct rmid_entry - dirty tracking for all RMID. * @closid:	The CLOSID for this entry. * @rmid:	The RMID for this entry. * @busy:	The number of domains with cached data using this RMID. * @list:	Member of the rmid_free_lru list when busy == 0. * * Depending on the architecture the correct monitor is accessed using * both @closid and @rmid, or @rmid only. * * Take the rdtgroup_mutex when accessing. */struct rmid_entry {	u32				closid;	u32				rmid;	int				busy;	struct list_head		list;}; /* * @rmid_free_lru - A least recently used list of free RMIDs *     These RMIDs are guaranteed to have an occupancy less than the *     threshold occupancy */static LIST_HEAD(rmid_free_lru); /* * @closid_num_dirty_rmid    The number of dirty RMID each CLOSID has. *     Only allocated when CONFIG_RESCTRL_RMID_DEPENDS_ON_CLOSID is defined. *     Indexed by CLOSID. Protected by rdtgroup_mutex. */static u32 *closid_num_dirty_rmid; /* * @rmid_limbo_count - count of currently unused but (potentially) *     dirty RMIDs. *     This counts RMIDs that no one is currently using but that *     may have a occupancy value > resctrl_rmid_realloc_threshold. User can *     change the threshold occupancy value. */static unsigned int rmid_limbo_count; /* * @rmid_entry - The entry in the limbo and free lists. */static struct rmid_entry	*rmid_ptrs; /* * This is the threshold cache occupancy in bytes at which we will consider an * RMID available for re-allocation. */unsigned int resctrl_rmid_realloc_threshold; /* * This is the maximum value for the reallocation threshold, in bytes. */unsigned int resctrl_rmid_realloc_limit; /* * x86 and arm64 differ in their handling of monitoring. * x86's RMID are independent numbers, there is only one source of traffic * with an RMID value of '1'. * arm64's PMG extends the PARTID/CLOSID space, there are multiple sources of * traffic with a PMG value of '1', one for each CLOSID, meaning the RMID * value is no longer unique. * To account for this, resctrl uses an index. On x86 this is just the RMID, * on arm64 it encodes the CLOSID and RMID. This gives a unique number. * * The domain's rmid_busy_llc and rmid_ptrs[] are sized by index. The arch code * must accept an attempt to read every index. */static inline struct rmid_entry *__rmid_entry(u32 idx){	struct rmid_entry *entry;	u32 closid, rmid; 	entry = &rmid_ptrs[idx];	resctrl_arch_rmid_idx_decode(idx, &closid, &rmid); 	WARN_ON_ONCE(entry->closid != closid);	WARN_ON_ONCE(entry->rmid != rmid); 	return entry;} static void limbo_release_entry(struct rmid_entry *entry){	lockdep_assert_held(&rdtgroup_mutex); 	rmid_limbo_count--;	list_add_tail(&entry->list, &rmid_free_lru); 	if (IS_ENABLED(CONFIG_RESCTRL_RMID_DEPENDS_ON_CLOSID))		closid_num_dirty_rmid[entry->closid]--;} /* * Check the RMIDs that are marked as busy for this domain. If the * reported LLC occupancy is below the threshold clear the busy bit and * decrement the count. If the busy count gets to zero on an RMID, we * free the RMID */void __check_limbo(struct rdt_l3_mon_domain *d, bool force_free){	struct rdt_resource *r = resctrl_arch_get_resource(RDT_RESOURCE_L3);	u32 idx_limit = resctrl_arch_system_num_rmid_idx();	struct rmid_entry *entry;	u32 idx, cur_idx = 1;	void *arch_mon_ctx;	void *arch_priv;	bool rmid_dirty;	u64 val = 0; 	arch_priv = mon_event_all[QOS_L3_OCCUP_EVENT_ID].arch_priv;	arch_mon_ctx = resctrl_arch_mon_ctx_alloc(r, QOS_L3_OCCUP_EVENT_ID);	if (IS_ERR(arch_mon_ctx)) {		pr_warn_ratelimited("Failed to allocate monitor context: %ld",				    PTR_ERR(arch_mon_ctx));		return;	} 	/*	 * Skip RMID 0 and start from RMID 1 and check all the RMIDs that	 * are marked as busy for occupancy < threshold. If the occupancy	 * is less than the threshold decrement the busy counter of the	 * RMID and move it to the free list when the counter reaches 0.	 */	for (;;) {		idx = find_next_bit(d->rmid_busy_llc, idx_limit, cur_idx);		if (idx >= idx_limit)			break; 		entry = __rmid_entry(idx);		if (resctrl_arch_rmid_read(r, &d->hdr, entry->closid, entry->rmid,					   QOS_L3_OCCUP_EVENT_ID, arch_priv, &val,					   arch_mon_ctx)) {			rmid_dirty = true;		} else {			rmid_dirty = (val >= resctrl_rmid_realloc_threshold); 			/*			 * x86's CLOSID and RMID are independent numbers, so the entry's			 * CLOSID is an empty CLOSID (X86_RESCTRL_EMPTY_CLOSID). On Arm the			 * RMID (PMG) extends the CLOSID (PARTID) space with bits that aren't			 * used to select the configuration. It is thus necessary to track both			 * CLOSID and RMID because there may be dependencies between them			 * on some architectures.			 */			trace_mon_llc_occupancy_limbo(entry->closid, entry->rmid, d->hdr.id, val);		} 		if (force_free || !rmid_dirty) {			clear_bit(idx, d->rmid_busy_llc);			if (!--entry->busy)				limbo_release_entry(entry);		}		cur_idx = idx + 1;	} 	resctrl_arch_mon_ctx_free(r, QOS_L3_OCCUP_EVENT_ID, arch_mon_ctx);} bool has_busy_rmid(struct rdt_l3_mon_domain *d){	u32 idx_limit = resctrl_arch_system_num_rmid_idx(); 	return find_first_bit(d->rmid_busy_llc, idx_limit) != idx_limit;} static struct rmid_entry *resctrl_find_free_rmid(u32 closid){	struct rmid_entry *itr;	u32 itr_idx, cmp_idx; 	if (list_empty(&rmid_free_lru))		return rmid_limbo_count ? ERR_PTR(-EBUSY) : ERR_PTR(-ENOSPC); 	list_for_each_entry(itr, &rmid_free_lru, list) {		/*		 * Get the index of this free RMID, and the index it would need		 * to be if it were used with this CLOSID.		 * If the CLOSID is irrelevant on this architecture, the two		 * index values are always the same on every entry and thus the		 * very first entry will be returned.		 */		itr_idx = resctrl_arch_rmid_idx_encode(itr->closid, itr->rmid);		cmp_idx = resctrl_arch_rmid_idx_encode(closid, itr->rmid); 		if (itr_idx == cmp_idx)			return itr;	} 	return ERR_PTR(-ENOSPC);} /** * resctrl_find_cleanest_closid() - Find a CLOSID where all the associated *                                  RMID are clean, or the CLOSID that has *                                  the most clean RMID. * * MPAM's equivalent of RMID are per-CLOSID, meaning a freshly allocated CLOSID * may not be able to allocate clean RMID. To avoid this the allocator will * choose the CLOSID with the most clean RMID. * * When the CLOSID and RMID are independent numbers, the first free CLOSID will * be returned. */int resctrl_find_cleanest_closid(void){	u32 cleanest_closid = ~0;	int i = 0; 	lockdep_assert_held(&rdtgroup_mutex); 	if (!IS_ENABLED(CONFIG_RESCTRL_RMID_DEPENDS_ON_CLOSID))		return -EIO; 	for (i = 0; i < closids_supported(); i++) {		int num_dirty; 		if (closid_allocated(i))			continue; 		num_dirty = closid_num_dirty_rmid[i];		if (num_dirty == 0)			return i; 		if (cleanest_closid == ~0)			cleanest_closid = i; 		if (num_dirty < closid_num_dirty_rmid[cleanest_closid])			cleanest_closid = i;	} 	if (cleanest_closid == ~0)		return -ENOSPC; 	return cleanest_closid;} /* * For MPAM the RMID value is not unique, and has to be considered with * the CLOSID. The (CLOSID, RMID) pair is allocated on all domains, which * allows all domains to be managed by a single free list. * Each domain also has a rmid_busy_llc to reduce the work of the limbo handler. */int alloc_rmid(u32 closid){	struct rmid_entry *entry; 	lockdep_assert_held(&rdtgroup_mutex); 	entry = resctrl_find_free_rmid(closid);	if (IS_ERR(entry))		return PTR_ERR(entry); 	list_del(&entry->list);	return entry->rmid;} static void add_rmid_to_limbo(struct rmid_entry *entry){	struct rdt_resource *r = resctrl_arch_get_resource(RDT_RESOURCE_L3);	struct rdt_l3_mon_domain *d;	u32 idx; 	lockdep_assert_held(&rdtgroup_mutex); 	/* Walking r->domains, ensure it can't race with cpuhp */	lockdep_assert_cpus_held(); 	idx = resctrl_arch_rmid_idx_encode(entry->closid, entry->rmid); 	entry->busy = 0;	list_for_each_entry(d, &r->mon_domains, hdr.list) {		/*		 * For the first limbo RMID in the domain,		 * setup up the limbo worker.		 */		if (!has_busy_rmid(d))			cqm_setup_limbo_handler(d, CQM_LIMBOCHECK_INTERVAL,						RESCTRL_PICK_ANY_CPU);		set_bit(idx, d->rmid_busy_llc);		entry->busy++;	} 	rmid_limbo_count++;	if (IS_ENABLED(CONFIG_RESCTRL_RMID_DEPENDS_ON_CLOSID))		closid_num_dirty_rmid[entry->closid]++;} void free_rmid(u32 closid, u32 rmid){	u32 idx = resctrl_arch_rmid_idx_encode(closid, rmid);	struct rmid_entry *entry; 	lockdep_assert_held(&rdtgroup_mutex); 	/*	 * Do not allow the default rmid to be free'd. Comparing by index	 * allows architectures that ignore the closid parameter to avoid an	 * unnecessary check.	 */	if (!resctrl_arch_mon_capable() ||	    idx == resctrl_arch_rmid_idx_encode(RESCTRL_RESERVED_CLOSID,						RESCTRL_RESERVED_RMID))		return; 	entry = __rmid_entry(idx); 	if (resctrl_is_mon_event_enabled(QOS_L3_OCCUP_EVENT_ID))		add_rmid_to_limbo(entry);	else		list_add_tail(&entry->list, &rmid_free_lru);} static struct mbm_state *get_mbm_state(struct rdt_l3_mon_domain *d, u32 closid,				       u32 rmid, enum resctrl_event_id evtid){	u32 idx = resctrl_arch_rmid_idx_encode(closid, rmid);	struct mbm_state *state; 	if (!resctrl_is_mbm_event(evtid))		return NULL; 	state = d->mbm_states[MBM_STATE_IDX(evtid)]; 	return state ? &state[idx] : NULL;} /* * mbm_cntr_get() - Return the counter ID for the matching @evtid and @rdtgrp. * * Return: * Valid counter ID on success, or -ENOENT on failure. */static int mbm_cntr_get(struct rdt_resource *r, struct rdt_l3_mon_domain *d,			struct rdtgroup *rdtgrp, enum resctrl_event_id evtid){	int cntr_id; 	if (!r->mon.mbm_cntr_assignable)		return -ENOENT; 	if (!resctrl_is_mbm_event(evtid))		return -ENOENT; 	for (cntr_id = 0; cntr_id < r->mon.num_mbm_cntrs; cntr_id++) {		if (d->cntr_cfg[cntr_id].rdtgrp == rdtgrp &&		    d->cntr_cfg[cntr_id].evtid == evtid)			return cntr_id;	} 	return -ENOENT;} /* * mbm_cntr_alloc() - Initialize and return a new counter ID in the domain @d. * Caller must ensure that the specified event is not assigned already. * * Return: * Valid counter ID on success, or -ENOSPC on failure. */static int mbm_cntr_alloc(struct rdt_resource *r, struct rdt_l3_mon_domain *d,			  struct rdtgroup *rdtgrp, enum resctrl_event_id evtid){	int cntr_id; 	for (cntr_id = 0; cntr_id < r->mon.num_mbm_cntrs; cntr_id++) {		if (!d->cntr_cfg[cntr_id].rdtgrp) {			d->cntr_cfg[cntr_id].rdtgrp = rdtgrp;			d->cntr_cfg[cntr_id].evtid = evtid;			return cntr_id;		}	} 	return -ENOSPC;} /* * mbm_cntr_free() - Clear the counter ID configuration details in the domain @d. */static void mbm_cntr_free(struct rdt_l3_mon_domain *d, int cntr_id){	memset(&d->cntr_cfg[cntr_id], 0, sizeof(*d->cntr_cfg));} static int __l3_mon_event_count(struct rdtgroup *rdtgrp, struct rmid_read *rr){	int cpu = smp_processor_id();	u32 closid = rdtgrp->closid;	u32 rmid = rdtgrp->mon.rmid;	struct rdt_l3_mon_domain *d;	int cntr_id = -ENOENT;	struct mbm_state *m;	u64 tval = 0; 	if (!domain_header_is_valid(rr->hdr, RESCTRL_MON_DOMAIN, RDT_RESOURCE_L3)) {		rr->err = -EIO;		return -EINVAL;	}	d = container_of(rr->hdr, struct rdt_l3_mon_domain, hdr); 	if (rr->is_mbm_cntr) {		cntr_id = mbm_cntr_get(rr->r, d, rdtgrp, rr->evt->evtid);		if (cntr_id < 0) {			rr->err = -ENOENT;			return -EINVAL;		}	} 	if (rr->first) {		if (rr->is_mbm_cntr)			resctrl_arch_reset_cntr(rr->r, d, closid, rmid, cntr_id, rr->evt->evtid);		else			resctrl_arch_reset_rmid(rr->r, d, closid, rmid, rr->evt->evtid);		m = get_mbm_state(d, closid, rmid, rr->evt->evtid);		if (m)			memset(m, 0, sizeof(struct mbm_state));		return 0;	} 	/* Reading a single domain, must be on a CPU in that domain. */	if (!cpumask_test_cpu(cpu, &d->hdr.cpu_mask))		return -EINVAL;	if (rr->is_mbm_cntr)		rr->err = resctrl_arch_cntr_read(rr->r, d, closid, rmid, cntr_id,						 rr->evt->evtid, &tval);	else		rr->err = resctrl_arch_rmid_read(rr->r, rr->hdr, closid, rmid,						 rr->evt->evtid, rr->evt->arch_priv,						 &tval, rr->arch_mon_ctx);	if (rr->err)		return rr->err; 	rr->val += tval; 	return 0;} static int __l3_mon_event_count_sum(struct rdtgroup *rdtgrp, struct rmid_read *rr){	int cpu = smp_processor_id();	u32 closid = rdtgrp->closid;	u32 rmid = rdtgrp->mon.rmid;	struct rdt_l3_mon_domain *d;	u64 tval = 0;	int err, ret; 	/*	 * Summing across domains is only done for systems that implement	 * Sub-NUMA Cluster. There is no overlap with systems that support	 * assignable counters.	 */	if (rr->is_mbm_cntr) {		pr_warn_once("Summing domains using assignable counters is not supported\n");		rr->err = -EINVAL;		return -EINVAL;	} 	/* Summing domains that share a cache, must be on a CPU for that cache. */	if (!cpumask_test_cpu(cpu, &rr->ci->shared_cpu_map))		return -EINVAL; 	/*	 * Legacy files must report the sum of an event across all	 * domains that share the same L3 cache instance.	 * Report success if a read from any domain succeeds, -EINVAL	 * (translated to "Unavailable" for user space) if reading from	 * all domains fail for any reason.

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