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Subject[tip:x86/cache] x86/perf/cqm: Wipe out perf based cqm
Commit-ID:  c39a0e2c8850f08249383f2425dbd8dbe4baad69
Gitweb: http://git.kernel.org/tip/c39a0e2c8850f08249383f2425dbd8dbe4baad69
Author: Vikas Shivappa <vikas.shivappa@linux.intel.com>
AuthorDate: Tue, 25 Jul 2017 14:14:20 -0700
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Tue, 1 Aug 2017 22:41:18 +0200

x86/perf/cqm: Wipe out perf based cqm

'perf cqm' never worked due to the incompatibility between perf
infrastructure and cqm hardware support. The hardware uses RMIDs to
track the llc occupancy of tasks and these RMIDs are per package. This
makes monitoring a hierarchy like cgroup along with monitoring of tasks
separately difficult and several patches sent to lkml to fix them were
NACKed. Further more, the following issues in the current perf cqm make
it almost unusable:

1. No support to monitor the same group of tasks for which we do
allocation using resctrl.

2. It gives random and inaccurate data (mostly 0s) once we run out
of RMIDs due to issues in Recycling.

3. Recycling results in inaccuracy of data because we cannot
guarantee that the RMID was stolen from a task when it was not
pulling data into cache or even when it pulled the least data. Also
for monitoring llc_occupancy, if we stop using an RMID_x and then
start using an RMID_y after we reclaim an RMID from an other event,
we miss accounting all the occupancy that was tagged to RMID_x at a
later perf_count.

2. Recycling code makes the monitoring code complex including
scheduling because the event can lose RMID any time. Since MBM
counters count bandwidth for a period of time by taking snap shot of
total bytes at two different times, recycling complicates the way we
count MBM in a hierarchy. Also we need a spin lock while we do the
processing to account for MBM counter overflow. We also currently
use a spin lock in scheduling to prevent the RMID from being taken
away.

4. Lack of support when we run different kind of event like task,
system-wide and cgroup events together. Data mostly prints 0s. This
is also because we can have only one RMID tied to a cpu as defined
by the cqm hardware but a perf can at the same time tie multiple
events during one sched_in.

5. No support of monitoring a group of tasks. There is partial support
for cgroup but it does not work once there is a hierarchy of cgroups
or if we want to monitor a task in a cgroup and the cgroup itself.

6. No support for monitoring tasks for the lifetime without perf
overhead.

7. It reported the aggregate cache occupancy or memory bandwidth over
all sockets. But most cloud and VMM based use cases want to know the
individual per-socket usage.

Signed-off-by: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: vikas.shivappa@intel.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Cc: reinette.chatre@intel.com
Link: http://lkml.kernel.org/r/1501017287-28083-2-git-send-email-vikas.shivappa@linux.intel.com

---
arch/x86/events/intel/Makefile | 2 +-
arch/x86/events/intel/cqm.c | 1766 -------------------------------
arch/x86/include/asm/intel_rdt_common.h | 2 -
arch/x86/kernel/cpu/intel_rdt.c | 8 +
include/linux/perf_event.h | 18 -
kernel/events/core.c | 14 +-
6 files changed, 10 insertions(+), 1800 deletions(-)

diff --git a/arch/x86/events/intel/Makefile b/arch/x86/events/intel/Makefile
index 06c2baa..e9d8520 100644
--- a/arch/x86/events/intel/Makefile
+++ b/arch/x86/events/intel/Makefile
@@ -1,4 +1,4 @@
-obj-$(CONFIG_CPU_SUP_INTEL) += core.o bts.o cqm.o
+obj-$(CONFIG_CPU_SUP_INTEL) += core.o bts.o
obj-$(CONFIG_CPU_SUP_INTEL) += ds.o knc.o
obj-$(CONFIG_CPU_SUP_INTEL) += lbr.o p4.o p6.o pt.o
obj-$(CONFIG_PERF_EVENTS_INTEL_RAPL) += intel-rapl-perf.o
diff --git a/arch/x86/events/intel/cqm.c b/arch/x86/events/intel/cqm.c
deleted file mode 100644
index 2521f77..0000000
--- a/arch/x86/events/intel/cqm.c
+++ /dev/null
@@ -1,1766 +0,0 @@
-/*
- * Intel Cache Quality-of-Service Monitoring (CQM) support.
- *
- * Based very, very heavily on work by Peter Zijlstra.
- */
-
-#include <linux/perf_event.h>
-#include <linux/slab.h>
-#include <asm/cpu_device_id.h>
-#include <asm/intel_rdt_common.h>
-#include "../perf_event.h"
-
-#define MSR_IA32_QM_CTR 0x0c8e
-#define MSR_IA32_QM_EVTSEL 0x0c8d
-
-#define MBM_CNTR_WIDTH 24
-/*
- * Guaranteed time in ms as per SDM where MBM counters will not overflow.
- */
-#define MBM_CTR_OVERFLOW_TIME 1000
-
-static u32 cqm_max_rmid = -1;
-static unsigned int cqm_l3_scale; /* supposedly cacheline size */
-static bool cqm_enabled, mbm_enabled;
-unsigned int mbm_socket_max;
-
-/*
- * The cached intel_pqr_state is strictly per CPU and can never be
- * updated from a remote CPU. Both functions which modify the state
- * (intel_cqm_event_start and intel_cqm_event_stop) are called with
- * interrupts disabled, which is sufficient for the protection.
- */
-DEFINE_PER_CPU(struct intel_pqr_state, pqr_state);
-static struct hrtimer *mbm_timers;
-/**
- * struct sample - mbm event's (local or total) data
- * @total_bytes #bytes since we began monitoring
- * @prev_msr previous value of MSR
- */
-struct sample {
- u64 total_bytes;
- u64 prev_msr;
-};
-
-/*
- * samples profiled for total memory bandwidth type events
- */
-static struct sample *mbm_total;
-/*
- * samples profiled for local memory bandwidth type events
- */
-static struct sample *mbm_local;
-
-#define pkg_id topology_physical_package_id(smp_processor_id())
-/*
- * rmid_2_index returns the index for the rmid in mbm_local/mbm_total array.
- * mbm_total[] and mbm_local[] are linearly indexed by socket# * max number of
- * rmids per socket, an example is given below
- * RMID1 of Socket0: vrmid = 1
- * RMID1 of Socket1: vrmid = 1 * (cqm_max_rmid + 1) + 1
- * RMID1 of Socket2: vrmid = 2 * (cqm_max_rmid + 1) + 1
- */
-#define rmid_2_index(rmid) ((pkg_id * (cqm_max_rmid + 1)) + rmid)
-/*
- * Protects cache_cgroups and cqm_rmid_free_lru and cqm_rmid_limbo_lru.
- * Also protects event->hw.cqm_rmid
- *
- * Hold either for stability, both for modification of ->hw.cqm_rmid.
- */
-static DEFINE_MUTEX(cache_mutex);
-static DEFINE_RAW_SPINLOCK(cache_lock);
-
-/*
- * Groups of events that have the same target(s), one RMID per group.
- */
-static LIST_HEAD(cache_groups);
-
-/*
- * Mask of CPUs for reading CQM values. We only need one per-socket.
- */
-static cpumask_t cqm_cpumask;
-
-#define RMID_VAL_ERROR (1ULL << 63)
-#define RMID_VAL_UNAVAIL (1ULL << 62)
-
-/*
- * Event IDs are used to program IA32_QM_EVTSEL before reading event
- * counter from IA32_QM_CTR
- */
-#define QOS_L3_OCCUP_EVENT_ID 0x01
-#define QOS_MBM_TOTAL_EVENT_ID 0x02
-#define QOS_MBM_LOCAL_EVENT_ID 0x03
-
-/*
- * This is central to the rotation algorithm in __intel_cqm_rmid_rotate().
- *
- * This rmid is always free and is guaranteed to have an associated
- * near-zero occupancy value, i.e. no cachelines are tagged with this
- * RMID, once __intel_cqm_rmid_rotate() returns.
- */
-static u32 intel_cqm_rotation_rmid;
-
-#define INVALID_RMID (-1)
-
-/*
- * Is @rmid valid for programming the hardware?
- *
- * rmid 0 is reserved by the hardware for all non-monitored tasks, which
- * means that we should never come across an rmid with that value.
- * Likewise, an rmid value of -1 is used to indicate "no rmid currently
- * assigned" and is used as part of the rotation code.
- */
-static inline bool __rmid_valid(u32 rmid)
-{
- if (!rmid || rmid == INVALID_RMID)
- return false;
-
- return true;
-}
-
-static u64 __rmid_read(u32 rmid)
-{
- u64 val;
-
- /*
- * Ignore the SDM, this thing is _NOTHING_ like a regular perfcnt,
- * it just says that to increase confusion.
- */
- wrmsr(MSR_IA32_QM_EVTSEL, QOS_L3_OCCUP_EVENT_ID, rmid);
- rdmsrl(MSR_IA32_QM_CTR, val);
-
- /*
- * Aside from the ERROR and UNAVAIL bits, assume this thing returns
- * the number of cachelines tagged with @rmid.
- */
- return val;
-}
-
-enum rmid_recycle_state {
- RMID_YOUNG = 0,
- RMID_AVAILABLE,
- RMID_DIRTY,
-};
-
-struct cqm_rmid_entry {
- u32 rmid;
- enum rmid_recycle_state state;
- struct list_head list;
- unsigned long queue_time;
-};
-
-/*
- * cqm_rmid_free_lru - A least recently used list of RMIDs.
- *
- * Oldest entry at the head, newest (most recently used) entry at the
- * tail. This list is never traversed, it's only used to keep track of
- * the lru order. That is, we only pick entries of the head or insert
- * them on the tail.
- *
- * All entries on the list are 'free', and their RMIDs are not currently
- * in use. To mark an RMID as in use, remove its entry from the lru
- * list.
- *
- *
- * cqm_rmid_limbo_lru - list of currently unused but (potentially) dirty RMIDs.
- *
- * This list is contains RMIDs that no one is currently using but that
- * may have a non-zero occupancy value associated with them. The
- * rotation worker moves RMIDs from the limbo list to the free list once
- * the occupancy value drops below __intel_cqm_threshold.
- *
- * Both lists are protected by cache_mutex.
- */
-static LIST_HEAD(cqm_rmid_free_lru);
-static LIST_HEAD(cqm_rmid_limbo_lru);
-
-/*
- * We use a simple array of pointers so that we can lookup a struct
- * cqm_rmid_entry in O(1). This alleviates the callers of __get_rmid()
- * and __put_rmid() from having to worry about dealing with struct
- * cqm_rmid_entry - they just deal with rmids, i.e. integers.
- *
- * Once this array is initialized it is read-only. No locks are required
- * to access it.
- *
- * All entries for all RMIDs can be looked up in the this array at all
- * times.
- */
-static struct cqm_rmid_entry **cqm_rmid_ptrs;
-
-static inline struct cqm_rmid_entry *__rmid_entry(u32 rmid)
-{
- struct cqm_rmid_entry *entry;
-
- entry = cqm_rmid_ptrs[rmid];
- WARN_ON(entry->rmid != rmid);
-
- return entry;
-}
-
-/*
- * Returns < 0 on fail.
- *
- * We expect to be called with cache_mutex held.
- */
-static u32 __get_rmid(void)
-{
- struct cqm_rmid_entry *entry;
-
- lockdep_assert_held(&cache_mutex);
-
- if (list_empty(&cqm_rmid_free_lru))
- return INVALID_RMID;
-
- entry = list_first_entry(&cqm_rmid_free_lru, struct cqm_rmid_entry, list);
- list_del(&entry->list);
-
- return entry->rmid;
-}
-
-static void __put_rmid(u32 rmid)
-{
- struct cqm_rmid_entry *entry;
-
- lockdep_assert_held(&cache_mutex);
-
- WARN_ON(!__rmid_valid(rmid));
- entry = __rmid_entry(rmid);
-
- entry->queue_time = jiffies;
- entry->state = RMID_YOUNG;
-
- list_add_tail(&entry->list, &cqm_rmid_limbo_lru);
-}
-
-static void cqm_cleanup(void)
-{
- int i;
-
- if (!cqm_rmid_ptrs)
- return;
-
- for (i = 0; i < cqm_max_rmid; i++)
- kfree(cqm_rmid_ptrs[i]);
-
- kfree(cqm_rmid_ptrs);
- cqm_rmid_ptrs = NULL;
- cqm_enabled = false;
-}
-
-static int intel_cqm_setup_rmid_cache(void)
-{
- struct cqm_rmid_entry *entry;
- unsigned int nr_rmids;
- int r = 0;
-
- nr_rmids = cqm_max_rmid + 1;
- cqm_rmid_ptrs = kzalloc(sizeof(struct cqm_rmid_entry *) *
- nr_rmids, GFP_KERNEL);
- if (!cqm_rmid_ptrs)
- return -ENOMEM;
-
- for (; r <= cqm_max_rmid; r++) {
- struct cqm_rmid_entry *entry;
-
- entry = kmalloc(sizeof(*entry), GFP_KERNEL);
- if (!entry)
- goto fail;
-
- INIT_LIST_HEAD(&entry->list);
- entry->rmid = r;
- cqm_rmid_ptrs[r] = entry;
-
- list_add_tail(&entry->list, &cqm_rmid_free_lru);
- }
-
- /*
- * RMID 0 is special and is always allocated. It's used for all
- * tasks that are not monitored.
- */
- entry = __rmid_entry(0);
- list_del(&entry->list);
-
- mutex_lock(&cache_mutex);
- intel_cqm_rotation_rmid = __get_rmid();
- mutex_unlock(&cache_mutex);
-
- return 0;
-
-fail:
- cqm_cleanup();
- return -ENOMEM;
-}
-
-/*
- * Determine if @a and @b measure the same set of tasks.
- *
- * If @a and @b measure the same set of tasks then we want to share a
- * single RMID.
- */
-static bool __match_event(struct perf_event *a, struct perf_event *b)
-{
- /* Per-cpu and task events don't mix */
- if ((a->attach_state & PERF_ATTACH_TASK) !=
- (b->attach_state & PERF_ATTACH_TASK))
- return false;
-
-#ifdef CONFIG_CGROUP_PERF
- if (a->cgrp != b->cgrp)
- return false;
-#endif
-
- /* If not task event, we're machine wide */
- if (!(b->attach_state & PERF_ATTACH_TASK))
- return true;
-
- /*
- * Events that target same task are placed into the same cache group.
- * Mark it as a multi event group, so that we update ->count
- * for every event rather than just the group leader later.
- */
- if (a->hw.target == b->hw.target) {
- b->hw.is_group_event = true;
- return true;
- }
-
- /*
- * Are we an inherited event?
- */
- if (b->parent == a)
- return true;
-
- return false;
-}
-
-#ifdef CONFIG_CGROUP_PERF
-static inline struct perf_cgroup *event_to_cgroup(struct perf_event *event)
-{
- if (event->attach_state & PERF_ATTACH_TASK)
- return perf_cgroup_from_task(event->hw.target, event->ctx);
-
- return event->cgrp;
-}
-#endif
-
-/*
- * Determine if @a's tasks intersect with @b's tasks
- *
- * There are combinations of events that we explicitly prohibit,
- *
- * PROHIBITS
- * system-wide -> cgroup and task
- * cgroup -> system-wide
- * -> task in cgroup
- * task -> system-wide
- * -> task in cgroup
- *
- * Call this function before allocating an RMID.
- */
-static bool __conflict_event(struct perf_event *a, struct perf_event *b)
-{
-#ifdef CONFIG_CGROUP_PERF
- /*
- * We can have any number of cgroups but only one system-wide
- * event at a time.
- */
- if (a->cgrp && b->cgrp) {
- struct perf_cgroup *ac = a->cgrp;
- struct perf_cgroup *bc = b->cgrp;
-
- /*
- * This condition should have been caught in
- * __match_event() and we should be sharing an RMID.
- */
- WARN_ON_ONCE(ac == bc);
-
- if (cgroup_is_descendant(ac->css.cgroup, bc->css.cgroup) ||
- cgroup_is_descendant(bc->css.cgroup, ac->css.cgroup))
- return true;
-
- return false;
- }
-
- if (a->cgrp || b->cgrp) {
- struct perf_cgroup *ac, *bc;
-
- /*
- * cgroup and system-wide events are mutually exclusive
- */
- if ((a->cgrp && !(b->attach_state & PERF_ATTACH_TASK)) ||
- (b->cgrp && !(a->attach_state & PERF_ATTACH_TASK)))
- return true;
-
- /*
- * Ensure neither event is part of the other's cgroup
- */
- ac = event_to_cgroup(a);
- bc = event_to_cgroup(b);
- if (ac == bc)
- return true;
-
- /*
- * Must have cgroup and non-intersecting task events.
- */
- if (!ac || !bc)
- return false;
-
- /*
- * We have cgroup and task events, and the task belongs
- * to a cgroup. Check for for overlap.
- */
- if (cgroup_is_descendant(ac->css.cgroup, bc->css.cgroup) ||
- cgroup_is_descendant(bc->css.cgroup, ac->css.cgroup))
- return true;
-
- return false;
- }
-#endif
- /*
- * If one of them is not a task, same story as above with cgroups.
- */
- if (!(a->attach_state & PERF_ATTACH_TASK) ||
- !(b->attach_state & PERF_ATTACH_TASK))
- return true;
-
- /*
- * Must be non-overlapping.
- */
- return false;
-}
-
-struct rmid_read {
- u32 rmid;
- u32 evt_type;
- atomic64_t value;
-};
-
-static void __intel_cqm_event_count(void *info);
-static void init_mbm_sample(u32 rmid, u32 evt_type);
-static void __intel_mbm_event_count(void *info);
-
-static bool is_cqm_event(int e)
-{
- return (e == QOS_L3_OCCUP_EVENT_ID);
-}
-
-static bool is_mbm_event(int e)
-{
- return (e >= QOS_MBM_TOTAL_EVENT_ID && e <= QOS_MBM_LOCAL_EVENT_ID);
-}
-
-static void cqm_mask_call(struct rmid_read *rr)
-{
- if (is_mbm_event(rr->evt_type))
- on_each_cpu_mask(&cqm_cpumask, __intel_mbm_event_count, rr, 1);
- else
- on_each_cpu_mask(&cqm_cpumask, __intel_cqm_event_count, rr, 1);
-}
-
-/*
- * Exchange the RMID of a group of events.
- */
-static u32 intel_cqm_xchg_rmid(struct perf_event *group, u32 rmid)
-{
- struct perf_event *event;
- struct list_head *head = &group->hw.cqm_group_entry;
- u32 old_rmid = group->hw.cqm_rmid;
-
- lockdep_assert_held(&cache_mutex);
-
- /*
- * If our RMID is being deallocated, perform a read now.
- */
- if (__rmid_valid(old_rmid) && !__rmid_valid(rmid)) {
- struct rmid_read rr = {
- .rmid = old_rmid,
- .evt_type = group->attr.config,
- .value = ATOMIC64_INIT(0),
- };
-
- cqm_mask_call(&rr);
- local64_set(&group->count, atomic64_read(&rr.value));
- }
-
- raw_spin_lock_irq(&cache_lock);
-
- group->hw.cqm_rmid = rmid;
- list_for_each_entry(event, head, hw.cqm_group_entry)
- event->hw.cqm_rmid = rmid;
-
- raw_spin_unlock_irq(&cache_lock);
-
- /*
- * If the allocation is for mbm, init the mbm stats.
- * Need to check if each event in the group is mbm event
- * because there could be multiple type of events in the same group.
- */
- if (__rmid_valid(rmid)) {
- event = group;
- if (is_mbm_event(event->attr.config))
- init_mbm_sample(rmid, event->attr.config);
-
- list_for_each_entry(event, head, hw.cqm_group_entry) {
- if (is_mbm_event(event->attr.config))
- init_mbm_sample(rmid, event->attr.config);
- }
- }
-
- return old_rmid;
-}
-
-/*
- * If we fail to assign a new RMID for intel_cqm_rotation_rmid because
- * cachelines are still tagged with RMIDs in limbo, we progressively
- * increment the threshold until we find an RMID in limbo with <=
- * __intel_cqm_threshold lines tagged. This is designed to mitigate the
- * problem where cachelines tagged with an RMID are not steadily being
- * evicted.
- *
- * On successful rotations we decrease the threshold back towards zero.
- *
- * __intel_cqm_max_threshold provides an upper bound on the threshold,
- * and is measured in bytes because it's exposed to userland.
- */
-static unsigned int __intel_cqm_threshold;
-static unsigned int __intel_cqm_max_threshold;
-
-/*
- * Test whether an RMID has a zero occupancy value on this cpu.
- */
-static void intel_cqm_stable(void *arg)
-{
- struct cqm_rmid_entry *entry;
-
- list_for_each_entry(entry, &cqm_rmid_limbo_lru, list) {
- if (entry->state != RMID_AVAILABLE)
- break;
-
- if (__rmid_read(entry->rmid) > __intel_cqm_threshold)
- entry->state = RMID_DIRTY;
- }
-}
-
-/*
- * If we have group events waiting for an RMID that don't conflict with
- * events already running, assign @rmid.
- */
-static bool intel_cqm_sched_in_event(u32 rmid)
-{
- struct perf_event *leader, *event;
-
- lockdep_assert_held(&cache_mutex);
-
- leader = list_first_entry(&cache_groups, struct perf_event,
- hw.cqm_groups_entry);
- event = leader;
-
- list_for_each_entry_continue(event, &cache_groups,
- hw.cqm_groups_entry) {
- if (__rmid_valid(event->hw.cqm_rmid))
- continue;
-
- if (__conflict_event(event, leader))
- continue;
-
- intel_cqm_xchg_rmid(event, rmid);
- return true;
- }
-
- return false;
-}
-
-/*
- * Initially use this constant for both the limbo queue time and the
- * rotation timer interval, pmu::hrtimer_interval_ms.
- *
- * They don't need to be the same, but the two are related since if you
- * rotate faster than you recycle RMIDs, you may run out of available
- * RMIDs.
- */
-#define RMID_DEFAULT_QUEUE_TIME 250 /* ms */
-
-static unsigned int __rmid_queue_time_ms = RMID_DEFAULT_QUEUE_TIME;
-
-/*
- * intel_cqm_rmid_stabilize - move RMIDs from limbo to free list
- * @nr_available: number of freeable RMIDs on the limbo list
- *
- * Quiescent state; wait for all 'freed' RMIDs to become unused, i.e. no
- * cachelines are tagged with those RMIDs. After this we can reuse them
- * and know that the current set of active RMIDs is stable.
- *
- * Return %true or %false depending on whether stabilization needs to be
- * reattempted.
- *
- * If we return %true then @nr_available is updated to indicate the
- * number of RMIDs on the limbo list that have been queued for the
- * minimum queue time (RMID_AVAILABLE), but whose data occupancy values
- * are above __intel_cqm_threshold.
- */
-static bool intel_cqm_rmid_stabilize(unsigned int *available)
-{
- struct cqm_rmid_entry *entry, *tmp;
-
- lockdep_assert_held(&cache_mutex);
-
- *available = 0;
- list_for_each_entry(entry, &cqm_rmid_limbo_lru, list) {
- unsigned long min_queue_time;
- unsigned long now = jiffies;
-
- /*
- * We hold RMIDs placed into limbo for a minimum queue
- * time. Before the minimum queue time has elapsed we do
- * not recycle RMIDs.
- *
- * The reasoning is that until a sufficient time has
- * passed since we stopped using an RMID, any RMID
- * placed onto the limbo list will likely still have
- * data tagged in the cache, which means we'll probably
- * fail to recycle it anyway.
- *
- * We can save ourselves an expensive IPI by skipping
- * any RMIDs that have not been queued for the minimum
- * time.
- */
- min_queue_time = entry->queue_time +
- msecs_to_jiffies(__rmid_queue_time_ms);
-
- if (time_after(min_queue_time, now))
- break;
-
- entry->state = RMID_AVAILABLE;
- (*available)++;
- }
-
- /*
- * Fast return if none of the RMIDs on the limbo list have been
- * sitting on the queue for the minimum queue time.
- */
- if (!*available)
- return false;
-
- /*
- * Test whether an RMID is free for each package.
- */
- on_each_cpu_mask(&cqm_cpumask, intel_cqm_stable, NULL, true);
-
- list_for_each_entry_safe(entry, tmp, &cqm_rmid_limbo_lru, list) {
- /*
- * Exhausted all RMIDs that have waited min queue time.
- */
- if (entry->state == RMID_YOUNG)
- break;
-
- if (entry->state == RMID_DIRTY)
- continue;
-
- list_del(&entry->list); /* remove from limbo */
-
- /*
- * The rotation RMID gets priority if it's
- * currently invalid. In which case, skip adding
- * the RMID to the the free lru.
- */
- if (!__rmid_valid(intel_cqm_rotation_rmid)) {
- intel_cqm_rotation_rmid = entry->rmid;
- continue;
- }
-
- /*
- * If we have groups waiting for RMIDs, hand
- * them one now provided they don't conflict.
- */
- if (intel_cqm_sched_in_event(entry->rmid))
- continue;
-
- /*
- * Otherwise place it onto the free list.
- */
- list_add_tail(&entry->list, &cqm_rmid_free_lru);
- }
-
-
- return __rmid_valid(intel_cqm_rotation_rmid);
-}
-
-/*
- * Pick a victim group and move it to the tail of the group list.
- * @next: The first group without an RMID
- */
-static void __intel_cqm_pick_and_rotate(struct perf_event *next)
-{
- struct perf_event *rotor;
- u32 rmid;
-
- lockdep_assert_held(&cache_mutex);
-
- rotor = list_first_entry(&cache_groups, struct perf_event,
- hw.cqm_groups_entry);
-
- /*
- * The group at the front of the list should always have a valid
- * RMID. If it doesn't then no groups have RMIDs assigned and we
- * don't need to rotate the list.
- */
- if (next == rotor)
- return;
-
- rmid = intel_cqm_xchg_rmid(rotor, INVALID_RMID);
- __put_rmid(rmid);
-
- list_rotate_left(&cache_groups);
-}
-
-/*
- * Deallocate the RMIDs from any events that conflict with @event, and
- * place them on the back of the group list.
- */
-static void intel_cqm_sched_out_conflicting_events(struct perf_event *event)
-{
- struct perf_event *group, *g;
- u32 rmid;
-
- lockdep_assert_held(&cache_mutex);
-
- list_for_each_entry_safe(group, g, &cache_groups, hw.cqm_groups_entry) {
- if (group == event)
- continue;
-
- rmid = group->hw.cqm_rmid;
-
- /*
- * Skip events that don't have a valid RMID.
- */
- if (!__rmid_valid(rmid))
- continue;
-
- /*
- * No conflict? No problem! Leave the event alone.
- */
- if (!__conflict_event(group, event))
- continue;
-
- intel_cqm_xchg_rmid(group, INVALID_RMID);
- __put_rmid(rmid);
- }
-}
-
-/*
- * Attempt to rotate the groups and assign new RMIDs.
- *
- * We rotate for two reasons,
- * 1. To handle the scheduling of conflicting events
- * 2. To recycle RMIDs
- *
- * Rotating RMIDs is complicated because the hardware doesn't give us
- * any clues.
- *
- * There's problems with the hardware interface; when you change the
- * task:RMID map cachelines retain their 'old' tags, giving a skewed
- * picture. In order to work around this, we must always keep one free
- * RMID - intel_cqm_rotation_rmid.
- *
- * Rotation works by taking away an RMID from a group (the old RMID),
- * and assigning the free RMID to another group (the new RMID). We must
- * then wait for the old RMID to not be used (no cachelines tagged).
- * This ensure that all cachelines are tagged with 'active' RMIDs. At
- * this point we can start reading values for the new RMID and treat the
- * old RMID as the free RMID for the next rotation.
- *
- * Return %true or %false depending on whether we did any rotating.
- */
-static bool __intel_cqm_rmid_rotate(void)
-{
- struct perf_event *group, *start = NULL;
- unsigned int threshold_limit;
- unsigned int nr_needed = 0;
- unsigned int nr_available;
- bool rotated = false;
-
- mutex_lock(&cache_mutex);
-
-again:
- /*
- * Fast path through this function if there are no groups and no
- * RMIDs that need cleaning.
- */
- if (list_empty(&cache_groups) && list_empty(&cqm_rmid_limbo_lru))
- goto out;
-
- list_for_each_entry(group, &cache_groups, hw.cqm_groups_entry) {
- if (!__rmid_valid(group->hw.cqm_rmid)) {
- if (!start)
- start = group;
- nr_needed++;
- }
- }
-
- /*
- * We have some event groups, but they all have RMIDs assigned
- * and no RMIDs need cleaning.
- */
- if (!nr_needed && list_empty(&cqm_rmid_limbo_lru))
- goto out;
-
- if (!nr_needed)
- goto stabilize;
-
- /*
- * We have more event groups without RMIDs than available RMIDs,
- * or we have event groups that conflict with the ones currently
- * scheduled.
- *
- * We force deallocate the rmid of the group at the head of
- * cache_groups. The first event group without an RMID then gets
- * assigned intel_cqm_rotation_rmid. This ensures we always make
- * forward progress.
- *
- * Rotate the cache_groups list so the previous head is now the
- * tail.
- */
- __intel_cqm_pick_and_rotate(start);
-
- /*
- * If the rotation is going to succeed, reduce the threshold so
- * that we don't needlessly reuse dirty RMIDs.
- */
- if (__rmid_valid(intel_cqm_rotation_rmid)) {
- intel_cqm_xchg_rmid(start, intel_cqm_rotation_rmid);
- intel_cqm_rotation_rmid = __get_rmid();
-
- intel_cqm_sched_out_conflicting_events(start);
-
- if (__intel_cqm_threshold)
- __intel_cqm_threshold--;
- }
-
- rotated = true;
-
-stabilize:
- /*
- * We now need to stablize the RMID we freed above (if any) to
- * ensure that the next time we rotate we have an RMID with zero
- * occupancy value.
- *
- * Alternatively, if we didn't need to perform any rotation,
- * we'll have a bunch of RMIDs in limbo that need stabilizing.
- */
- threshold_limit = __intel_cqm_max_threshold / cqm_l3_scale;
-
- while (intel_cqm_rmid_stabilize(&nr_available) &&
- __intel_cqm_threshold < threshold_limit) {
- unsigned int steal_limit;
-
- /*
- * Don't spin if nobody is actively waiting for an RMID,
- * the rotation worker will be kicked as soon as an
- * event needs an RMID anyway.
- */
- if (!nr_needed)
- break;
-
- /* Allow max 25% of RMIDs to be in limbo. */
- steal_limit = (cqm_max_rmid + 1) / 4;
-
- /*
- * We failed to stabilize any RMIDs so our rotation
- * logic is now stuck. In order to make forward progress
- * we have a few options:
- *
- * 1. rotate ("steal") another RMID
- * 2. increase the threshold
- * 3. do nothing
- *
- * We do both of 1. and 2. until we hit the steal limit.
- *
- * The steal limit prevents all RMIDs ending up on the
- * limbo list. This can happen if every RMID has a
- * non-zero occupancy above threshold_limit, and the
- * occupancy values aren't dropping fast enough.
- *
- * Note that there is prioritisation at work here - we'd
- * rather increase the number of RMIDs on the limbo list
- * than increase the threshold, because increasing the
- * threshold skews the event data (because we reuse
- * dirty RMIDs) - threshold bumps are a last resort.
- */
- if (nr_available < steal_limit)
- goto again;
-
- __intel_cqm_threshold++;
- }
-
-out:
- mutex_unlock(&cache_mutex);
- return rotated;
-}
-
-static void intel_cqm_rmid_rotate(struct work_struct *work);
-
-static DECLARE_DELAYED_WORK(intel_cqm_rmid_work, intel_cqm_rmid_rotate);
-
-static struct pmu intel_cqm_pmu;
-
-static void intel_cqm_rmid_rotate(struct work_struct *work)
-{
- unsigned long delay;
-
- __intel_cqm_rmid_rotate();
-
- delay = msecs_to_jiffies(intel_cqm_pmu.hrtimer_interval_ms);
- schedule_delayed_work(&intel_cqm_rmid_work, delay);
-}
-
-static u64 update_sample(unsigned int rmid, u32 evt_type, int first)
-{
- struct sample *mbm_current;
- u32 vrmid = rmid_2_index(rmid);
- u64 val, bytes, shift;
- u32 eventid;
-
- if (evt_type == QOS_MBM_LOCAL_EVENT_ID) {
- mbm_current = &mbm_local[vrmid];
- eventid = QOS_MBM_LOCAL_EVENT_ID;
- } else {
- mbm_current = &mbm_total[vrmid];
- eventid = QOS_MBM_TOTAL_EVENT_ID;
- }
-
- wrmsr(MSR_IA32_QM_EVTSEL, eventid, rmid);
- rdmsrl(MSR_IA32_QM_CTR, val);
- if (val & (RMID_VAL_ERROR | RMID_VAL_UNAVAIL))
- return mbm_current->total_bytes;
-
- if (first) {
- mbm_current->prev_msr = val;
- mbm_current->total_bytes = 0;
- return mbm_current->total_bytes;
- }
-
- /*
- * The h/w guarantees that counters will not overflow
- * so long as we poll them at least once per second.
- */
- shift = 64 - MBM_CNTR_WIDTH;
- bytes = (val << shift) - (mbm_current->prev_msr << shift);
- bytes >>= shift;
-
- bytes *= cqm_l3_scale;
-
- mbm_current->total_bytes += bytes;
- mbm_current->prev_msr = val;
-
- return mbm_current->total_bytes;
-}
-
-static u64 rmid_read_mbm(unsigned int rmid, u32 evt_type)
-{
- return update_sample(rmid, evt_type, 0);
-}
-
-static void __intel_mbm_event_init(void *info)
-{
- struct rmid_read *rr = info;
-
- update_sample(rr->rmid, rr->evt_type, 1);
-}
-
-static void init_mbm_sample(u32 rmid, u32 evt_type)
-{
- struct rmid_read rr = {
- .rmid = rmid,
- .evt_type = evt_type,
- .value = ATOMIC64_INIT(0),
- };
-
- /* on each socket, init sample */
- on_each_cpu_mask(&cqm_cpumask, __intel_mbm_event_init, &rr, 1);
-}
-
-/*
- * Find a group and setup RMID.
- *
- * If we're part of a group, we use the group's RMID.
- */
-static void intel_cqm_setup_event(struct perf_event *event,
- struct perf_event **group)
-{
- struct perf_event *iter;
- bool conflict = false;
- u32 rmid;
-
- event->hw.is_group_event = false;
- list_for_each_entry(iter, &cache_groups, hw.cqm_groups_entry) {
- rmid = iter->hw.cqm_rmid;
-
- if (__match_event(iter, event)) {
- /* All tasks in a group share an RMID */
- event->hw.cqm_rmid = rmid;
- *group = iter;
- if (is_mbm_event(event->attr.config) && __rmid_valid(rmid))
- init_mbm_sample(rmid, event->attr.config);
- return;
- }
-
- /*
- * We only care about conflicts for events that are
- * actually scheduled in (and hence have a valid RMID).
- */
- if (__conflict_event(iter, event) && __rmid_valid(rmid))
- conflict = true;
- }
-
- if (conflict)
- rmid = INVALID_RMID;
- else
- rmid = __get_rmid();
-
- if (is_mbm_event(event->attr.config) && __rmid_valid(rmid))
- init_mbm_sample(rmid, event->attr.config);
-
- event->hw.cqm_rmid = rmid;
-}
-
-static void intel_cqm_event_read(struct perf_event *event)
-{
- unsigned long flags;
- u32 rmid;
- u64 val;
-
- /*
- * Task events are handled by intel_cqm_event_count().
- */
- if (event->cpu == -1)
- return;
-
- raw_spin_lock_irqsave(&cache_lock, flags);
- rmid = event->hw.cqm_rmid;
-
- if (!__rmid_valid(rmid))
- goto out;
-
- if (is_mbm_event(event->attr.config))
- val = rmid_read_mbm(rmid, event->attr.config);
- else
- val = __rmid_read(rmid);
-
- /*
- * Ignore this reading on error states and do not update the value.
- */
- if (val & (RMID_VAL_ERROR | RMID_VAL_UNAVAIL))
- goto out;
-
- local64_set(&event->count, val);
-out:
- raw_spin_unlock_irqrestore(&cache_lock, flags);
-}
-
-static void __intel_cqm_event_count(void *info)
-{
- struct rmid_read *rr = info;
- u64 val;
-
- val = __rmid_read(rr->rmid);
-
- if (val & (RMID_VAL_ERROR | RMID_VAL_UNAVAIL))
- return;
-
- atomic64_add(val, &rr->value);
-}
-
-static inline bool cqm_group_leader(struct perf_event *event)
-{
- return !list_empty(&event->hw.cqm_groups_entry);
-}
-
-static void __intel_mbm_event_count(void *info)
-{
- struct rmid_read *rr = info;
- u64 val;
-
- val = rmid_read_mbm(rr->rmid, rr->evt_type);
- if (val & (RMID_VAL_ERROR | RMID_VAL_UNAVAIL))
- return;
- atomic64_add(val, &rr->value);
-}
-
-static enum hrtimer_restart mbm_hrtimer_handle(struct hrtimer *hrtimer)
-{
- struct perf_event *iter, *iter1;
- int ret = HRTIMER_RESTART;
- struct list_head *head;
- unsigned long flags;
- u32 grp_rmid;
-
- /*
- * Need to cache_lock as the timer Event Select MSR reads
- * can race with the mbm/cqm count() and mbm_init() reads.
- */
- raw_spin_lock_irqsave(&cache_lock, flags);
-
- if (list_empty(&cache_groups)) {
- ret = HRTIMER_NORESTART;
- goto out;
- }
-
- list_for_each_entry(iter, &cache_groups, hw.cqm_groups_entry) {
- grp_rmid = iter->hw.cqm_rmid;
- if (!__rmid_valid(grp_rmid))
- continue;
- if (is_mbm_event(iter->attr.config))
- update_sample(grp_rmid, iter->attr.config, 0);
-
- head = &iter->hw.cqm_group_entry;
- if (list_empty(head))
- continue;
- list_for_each_entry(iter1, head, hw.cqm_group_entry) {
- if (!iter1->hw.is_group_event)
- break;
- if (is_mbm_event(iter1->attr.config))
- update_sample(iter1->hw.cqm_rmid,
- iter1->attr.config, 0);
- }
- }
-
- hrtimer_forward_now(hrtimer, ms_to_ktime(MBM_CTR_OVERFLOW_TIME));
-out:
- raw_spin_unlock_irqrestore(&cache_lock, flags);
-
- return ret;
-}
-
-static void __mbm_start_timer(void *info)
-{
- hrtimer_start(&mbm_timers[pkg_id], ms_to_ktime(MBM_CTR_OVERFLOW_TIME),
- HRTIMER_MODE_REL_PINNED);
-}
-
-static void __mbm_stop_timer(void *info)
-{
- hrtimer_cancel(&mbm_timers[pkg_id]);
-}
-
-static void mbm_start_timers(void)
-{
- on_each_cpu_mask(&cqm_cpumask, __mbm_start_timer, NULL, 1);
-}
-
-static void mbm_stop_timers(void)
-{
- on_each_cpu_mask(&cqm_cpumask, __mbm_stop_timer, NULL, 1);
-}
-
-static void mbm_hrtimer_init(void)
-{
- struct hrtimer *hr;
- int i;
-
- for (i = 0; i < mbm_socket_max; i++) {
- hr = &mbm_timers[i];
- hrtimer_init(hr, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
- hr->function = mbm_hrtimer_handle;
- }
-}
-
-static u64 intel_cqm_event_count(struct perf_event *event)
-{
- unsigned long flags;
- struct rmid_read rr = {
- .evt_type = event->attr.config,
- .value = ATOMIC64_INIT(0),
- };
-
- /*
- * We only need to worry about task events. System-wide events
- * are handled like usual, i.e. entirely with
- * intel_cqm_event_read().
- */
- if (event->cpu != -1)
- return __perf_event_count(event);
-
- /*
- * Only the group leader gets to report values except in case of
- * multiple events in the same group, we still need to read the
- * other events.This stops us
- * reporting duplicate values to userspace, and gives us a clear
- * rule for which task gets to report the values.
- *
- * Note that it is impossible to attribute these values to
- * specific packages - we forfeit that ability when we create
- * task events.
- */
- if (!cqm_group_leader(event) && !event->hw.is_group_event)
- return 0;
-
- /*
- * Getting up-to-date values requires an SMP IPI which is not
- * possible if we're being called in interrupt context. Return
- * the cached values instead.
- */
- if (unlikely(in_interrupt()))
- goto out;
-
- /*
- * Notice that we don't perform the reading of an RMID
- * atomically, because we can't hold a spin lock across the
- * IPIs.
- *
- * Speculatively perform the read, since @event might be
- * assigned a different (possibly invalid) RMID while we're
- * busying performing the IPI calls. It's therefore necessary to
- * check @event's RMID afterwards, and if it has changed,
- * discard the result of the read.
- */
- rr.rmid = ACCESS_ONCE(event->hw.cqm_rmid);
-
- if (!__rmid_valid(rr.rmid))
- goto out;
-
- cqm_mask_call(&rr);
-
- raw_spin_lock_irqsave(&cache_lock, flags);
- if (event->hw.cqm_rmid == rr.rmid)
- local64_set(&event->count, atomic64_read(&rr.value));
- raw_spin_unlock_irqrestore(&cache_lock, flags);
-out:
- return __perf_event_count(event);
-}
-
-static void intel_cqm_event_start(struct perf_event *event, int mode)
-{
- struct intel_pqr_state *state = this_cpu_ptr(&pqr_state);
- u32 rmid = event->hw.cqm_rmid;
-
- if (!(event->hw.cqm_state & PERF_HES_STOPPED))
- return;
-
- event->hw.cqm_state &= ~PERF_HES_STOPPED;
-
- if (state->rmid_usecnt++) {
- if (!WARN_ON_ONCE(state->rmid != rmid))
- return;
- } else {
- WARN_ON_ONCE(state->rmid);
- }
-
- state->rmid = rmid;
- wrmsr(MSR_IA32_PQR_ASSOC, rmid, state->closid);
-}
-
-static void intel_cqm_event_stop(struct perf_event *event, int mode)
-{
- struct intel_pqr_state *state = this_cpu_ptr(&pqr_state);
-
- if (event->hw.cqm_state & PERF_HES_STOPPED)
- return;
-
- event->hw.cqm_state |= PERF_HES_STOPPED;
-
- intel_cqm_event_read(event);
-
- if (!--state->rmid_usecnt) {
- state->rmid = 0;
- wrmsr(MSR_IA32_PQR_ASSOC, 0, state->closid);
- } else {
- WARN_ON_ONCE(!state->rmid);
- }
-}
-
-static int intel_cqm_event_add(struct perf_event *event, int mode)
-{
- unsigned long flags;
- u32 rmid;
-
- raw_spin_lock_irqsave(&cache_lock, flags);
-
- event->hw.cqm_state = PERF_HES_STOPPED;
- rmid = event->hw.cqm_rmid;
-
- if (__rmid_valid(rmid) && (mode & PERF_EF_START))
- intel_cqm_event_start(event, mode);
-
- raw_spin_unlock_irqrestore(&cache_lock, flags);
-
- return 0;
-}
-
-static void intel_cqm_event_destroy(struct perf_event *event)
-{
- struct perf_event *group_other = NULL;
- unsigned long flags;
-
- mutex_lock(&cache_mutex);
- /*
- * Hold the cache_lock as mbm timer handlers could be
- * scanning the list of events.
- */
- raw_spin_lock_irqsave(&cache_lock, flags);
-
- /*
- * If there's another event in this group...
- */
- if (!list_empty(&event->hw.cqm_group_entry)) {
- group_other = list_first_entry(&event->hw.cqm_group_entry,
- struct perf_event,
- hw.cqm_group_entry);
- list_del(&event->hw.cqm_group_entry);
- }
-
- /*
- * And we're the group leader..
- */
- if (cqm_group_leader(event)) {
- /*
- * If there was a group_other, make that leader, otherwise
- * destroy the group and return the RMID.
- */
- if (group_other) {
- list_replace(&event->hw.cqm_groups_entry,
- &group_other->hw.cqm_groups_entry);
- } else {
- u32 rmid = event->hw.cqm_rmid;
-
- if (__rmid_valid(rmid))
- __put_rmid(rmid);
- list_del(&event->hw.cqm_groups_entry);
- }
- }
-
- raw_spin_unlock_irqrestore(&cache_lock, flags);
-
- /*
- * Stop the mbm overflow timers when the last event is destroyed.
- */
- if (mbm_enabled && list_empty(&cache_groups))
- mbm_stop_timers();
-
- mutex_unlock(&cache_mutex);
-}
-
-static int intel_cqm_event_init(struct perf_event *event)
-{
- struct perf_event *group = NULL;
- bool rotate = false;
- unsigned long flags;
-
- if (event->attr.type != intel_cqm_pmu.type)
- return -ENOENT;
-
- if ((event->attr.config < QOS_L3_OCCUP_EVENT_ID) ||
- (event->attr.config > QOS_MBM_LOCAL_EVENT_ID))
- return -EINVAL;
-
- if ((is_cqm_event(event->attr.config) && !cqm_enabled) ||
- (is_mbm_event(event->attr.config) && !mbm_enabled))
- return -EINVAL;
-
- /* unsupported modes and filters */
- if (event->attr.exclude_user ||
- event->attr.exclude_kernel ||
- event->attr.exclude_hv ||
- event->attr.exclude_idle ||
- event->attr.exclude_host ||
- event->attr.exclude_guest ||
- event->attr.sample_period) /* no sampling */
- return -EINVAL;
-
- INIT_LIST_HEAD(&event->hw.cqm_group_entry);
- INIT_LIST_HEAD(&event->hw.cqm_groups_entry);
-
- event->destroy = intel_cqm_event_destroy;
-
- mutex_lock(&cache_mutex);
-
- /*
- * Start the mbm overflow timers when the first event is created.
- */
- if (mbm_enabled && list_empty(&cache_groups))
- mbm_start_timers();
-
- /* Will also set rmid */
- intel_cqm_setup_event(event, &group);
-
- /*
- * Hold the cache_lock as mbm timer handlers be
- * scanning the list of events.
- */
- raw_spin_lock_irqsave(&cache_lock, flags);
-
- if (group) {
- list_add_tail(&event->hw.cqm_group_entry,
- &group->hw.cqm_group_entry);
- } else {
- list_add_tail(&event->hw.cqm_groups_entry,
- &cache_groups);
-
- /*
- * All RMIDs are either in use or have recently been
- * used. Kick the rotation worker to clean/free some.
- *
- * We only do this for the group leader, rather than for
- * every event in a group to save on needless work.
- */
- if (!__rmid_valid(event->hw.cqm_rmid))
- rotate = true;
- }
-
- raw_spin_unlock_irqrestore(&cache_lock, flags);
- mutex_unlock(&cache_mutex);
-
- if (rotate)
- schedule_delayed_work(&intel_cqm_rmid_work, 0);
-
- return 0;
-}
-
-EVENT_ATTR_STR(llc_occupancy, intel_cqm_llc, "event=0x01");
-EVENT_ATTR_STR(llc_occupancy.per-pkg, intel_cqm_llc_pkg, "1");
-EVENT_ATTR_STR(llc_occupancy.unit, intel_cqm_llc_unit, "Bytes");
-EVENT_ATTR_STR(llc_occupancy.scale, intel_cqm_llc_scale, NULL);
-EVENT_ATTR_STR(llc_occupancy.snapshot, intel_cqm_llc_snapshot, "1");
-
-EVENT_ATTR_STR(total_bytes, intel_cqm_total_bytes, "event=0x02");
-EVENT_ATTR_STR(total_bytes.per-pkg, intel_cqm_total_bytes_pkg, "1");
-EVENT_ATTR_STR(total_bytes.unit, intel_cqm_total_bytes_unit, "MB");
-EVENT_ATTR_STR(total_bytes.scale, intel_cqm_total_bytes_scale, "1e-6");
-
-EVENT_ATTR_STR(local_bytes, intel_cqm_local_bytes, "event=0x03");
-EVENT_ATTR_STR(local_bytes.per-pkg, intel_cqm_local_bytes_pkg, "1");
-EVENT_ATTR_STR(local_bytes.unit, intel_cqm_local_bytes_unit, "MB");
-EVENT_ATTR_STR(local_bytes.scale, intel_cqm_local_bytes_scale, "1e-6");
-
-static struct attribute *intel_cqm_events_attr[] = {
- EVENT_PTR(intel_cqm_llc),
- EVENT_PTR(intel_cqm_llc_pkg),
- EVENT_PTR(intel_cqm_llc_unit),
- EVENT_PTR(intel_cqm_llc_scale),
- EVENT_PTR(intel_cqm_llc_snapshot),
- NULL,
-};
-
-static struct attribute *intel_mbm_events_attr[] = {
- EVENT_PTR(intel_cqm_total_bytes),
- EVENT_PTR(intel_cqm_local_bytes),
- EVENT_PTR(intel_cqm_total_bytes_pkg),
- EVENT_PTR(intel_cqm_local_bytes_pkg),
- EVENT_PTR(intel_cqm_total_bytes_unit),
- EVENT_PTR(intel_cqm_local_bytes_unit),
- EVENT_PTR(intel_cqm_total_bytes_scale),
- EVENT_PTR(intel_cqm_local_bytes_scale),
- NULL,
-};
-
-static struct attribute *intel_cmt_mbm_events_attr[] = {
- EVENT_PTR(intel_cqm_llc),
- EVENT_PTR(intel_cqm_total_bytes),
- EVENT_PTR(intel_cqm_local_bytes),
- EVENT_PTR(intel_cqm_llc_pkg),
- EVENT_PTR(intel_cqm_total_bytes_pkg),
- EVENT_PTR(intel_cqm_local_bytes_pkg),
- EVENT_PTR(intel_cqm_llc_unit),
- EVENT_PTR(intel_cqm_total_bytes_unit),
- EVENT_PTR(intel_cqm_local_bytes_unit),
- EVENT_PTR(intel_cqm_llc_scale),
- EVENT_PTR(intel_cqm_total_bytes_scale),
- EVENT_PTR(intel_cqm_local_bytes_scale),
- EVENT_PTR(intel_cqm_llc_snapshot),
- NULL,
-};
-
-static struct attribute_group intel_cqm_events_group = {
- .name = "events",
- .attrs = NULL,
-};
-
-PMU_FORMAT_ATTR(event, "config:0-7");
-static struct attribute *intel_cqm_formats_attr[] = {
- &format_attr_event.attr,
- NULL,
-};
-
-static struct attribute_group intel_cqm_format_group = {
- .name = "format",
- .attrs = intel_cqm_formats_attr,
-};
-
-static ssize_t
-max_recycle_threshold_show(struct device *dev, struct device_attribute *attr,
- char *page)
-{
- ssize_t rv;
-
- mutex_lock(&cache_mutex);
- rv = snprintf(page, PAGE_SIZE-1, "%u\n", __intel_cqm_max_threshold);
- mutex_unlock(&cache_mutex);
-
- return rv;
-}
-
-static ssize_t
-max_recycle_threshold_store(struct device *dev,
- struct device_attribute *attr,
- const char *buf, size_t count)
-{
- unsigned int bytes, cachelines;
- int ret;
-
- ret = kstrtouint(buf, 0, &bytes);
- if (ret)
- return ret;
-
- mutex_lock(&cache_mutex);
-
- __intel_cqm_max_threshold = bytes;
- cachelines = bytes / cqm_l3_scale;
-
- /*
- * The new maximum takes effect immediately.
- */
- if (__intel_cqm_threshold > cachelines)
- __intel_cqm_threshold = cachelines;
-
- mutex_unlock(&cache_mutex);
-
- return count;
-}
-
-static DEVICE_ATTR_RW(max_recycle_threshold);
-
-static struct attribute *intel_cqm_attrs[] = {
- &dev_attr_max_recycle_threshold.attr,
- NULL,
-};
-
-static const struct attribute_group intel_cqm_group = {
- .attrs = intel_cqm_attrs,
-};
-
-static const struct attribute_group *intel_cqm_attr_groups[] = {
- &intel_cqm_events_group,
- &intel_cqm_format_group,
- &intel_cqm_group,
- NULL,
-};
-
-static struct pmu intel_cqm_pmu = {
- .hrtimer_interval_ms = RMID_DEFAULT_QUEUE_TIME,
- .attr_groups = intel_cqm_attr_groups,
- .task_ctx_nr = perf_sw_context,
- .event_init = intel_cqm_event_init,
- .add = intel_cqm_event_add,
- .del = intel_cqm_event_stop,
- .start = intel_cqm_event_start,
- .stop = intel_cqm_event_stop,
- .read = intel_cqm_event_read,
- .count = intel_cqm_event_count,
-};
-
-static inline void cqm_pick_event_reader(int cpu)
-{
- int reader;
-
- /* First online cpu in package becomes the reader */
- reader = cpumask_any_and(&cqm_cpumask, topology_core_cpumask(cpu));
- if (reader >= nr_cpu_ids)
- cpumask_set_cpu(cpu, &cqm_cpumask);
-}
-
-static int intel_cqm_cpu_starting(unsigned int cpu)
-{
- struct intel_pqr_state *state = &per_cpu(pqr_state, cpu);
- struct cpuinfo_x86 *c = &cpu_data(cpu);
-
- state->rmid = 0;
- state->closid = 0;
- state->rmid_usecnt = 0;
-
- WARN_ON(c->x86_cache_max_rmid != cqm_max_rmid);
- WARN_ON(c->x86_cache_occ_scale != cqm_l3_scale);
-
- cqm_pick_event_reader(cpu);
- return 0;
-}
-
-static int intel_cqm_cpu_exit(unsigned int cpu)
-{
- int target;
-
- /* Is @cpu the current cqm reader for this package ? */
- if (!cpumask_test_and_clear_cpu(cpu, &cqm_cpumask))
- return 0;
-
- /* Find another online reader in this package */
- target = cpumask_any_but(topology_core_cpumask(cpu), cpu);
-
- if (target < nr_cpu_ids)
- cpumask_set_cpu(target, &cqm_cpumask);
-
- return 0;
-}
-
-static const struct x86_cpu_id intel_cqm_match[] = {
- { .vendor = X86_VENDOR_INTEL, .feature = X86_FEATURE_CQM_OCCUP_LLC },
- {}
-};
-
-static void mbm_cleanup(void)
-{
- if (!mbm_enabled)
- return;
-
- kfree(mbm_local);
- kfree(mbm_total);
- mbm_enabled = false;
-}
-
-static const struct x86_cpu_id intel_mbm_local_match[] = {
- { .vendor = X86_VENDOR_INTEL, .feature = X86_FEATURE_CQM_MBM_LOCAL },
- {}
-};
-
-static const struct x86_cpu_id intel_mbm_total_match[] = {
- { .vendor = X86_VENDOR_INTEL, .feature = X86_FEATURE_CQM_MBM_TOTAL },
- {}
-};
-
-static int intel_mbm_init(void)
-{
- int ret = 0, array_size, maxid = cqm_max_rmid + 1;
-
- mbm_socket_max = topology_max_packages();
- array_size = sizeof(struct sample) * maxid * mbm_socket_max;
- mbm_local = kmalloc(array_size, GFP_KERNEL);
- if (!mbm_local)
- return -ENOMEM;
-
- mbm_total = kmalloc(array_size, GFP_KERNEL);
- if (!mbm_total) {
- ret = -ENOMEM;
- goto out;
- }
-
- array_size = sizeof(struct hrtimer) * mbm_socket_max;
- mbm_timers = kmalloc(array_size, GFP_KERNEL);
- if (!mbm_timers) {
- ret = -ENOMEM;
- goto out;
- }
- mbm_hrtimer_init();
-
-out:
- if (ret)
- mbm_cleanup();
-
- return ret;
-}
-
-static int __init intel_cqm_init(void)
-{
- char *str = NULL, scale[20];
- int cpu, ret;
-
- if (x86_match_cpu(intel_cqm_match))
- cqm_enabled = true;
-
- if (x86_match_cpu(intel_mbm_local_match) &&
- x86_match_cpu(intel_mbm_total_match))
- mbm_enabled = true;
-
- if (!cqm_enabled && !mbm_enabled)
- return -ENODEV;
-
- cqm_l3_scale = boot_cpu_data.x86_cache_occ_scale;
-
- /*
- * It's possible that not all resources support the same number
- * of RMIDs. Instead of making scheduling much more complicated
- * (where we have to match a task's RMID to a cpu that supports
- * that many RMIDs) just find the minimum RMIDs supported across
- * all cpus.
- *
- * Also, check that the scales match on all cpus.
- */
- cpus_read_lock();
- for_each_online_cpu(cpu) {
- struct cpuinfo_x86 *c = &cpu_data(cpu);
-
- if (c->x86_cache_max_rmid < cqm_max_rmid)
- cqm_max_rmid = c->x86_cache_max_rmid;
-
- if (c->x86_cache_occ_scale != cqm_l3_scale) {
- pr_err("Multiple LLC scale values, disabling\n");
- ret = -EINVAL;
- goto out;
- }
- }
-
- /*
- * A reasonable upper limit on the max threshold is the number
- * of lines tagged per RMID if all RMIDs have the same number of
- * lines tagged in the LLC.
- *
- * For a 35MB LLC and 56 RMIDs, this is ~1.8% of the LLC.
- */
- __intel_cqm_max_threshold =
- boot_cpu_data.x86_cache_size * 1024 / (cqm_max_rmid + 1);
-
- snprintf(scale, sizeof(scale), "%u", cqm_l3_scale);
- str = kstrdup(scale, GFP_KERNEL);
- if (!str) {
- ret = -ENOMEM;
- goto out;
- }
-
- event_attr_intel_cqm_llc_scale.event_str = str;
-
- ret = intel_cqm_setup_rmid_cache();
- if (ret)
- goto out;
-
- if (mbm_enabled)
- ret = intel_mbm_init();
- if (ret && !cqm_enabled)
- goto out;
-
- if (cqm_enabled && mbm_enabled)
- intel_cqm_events_group.attrs = intel_cmt_mbm_events_attr;
- else if (!cqm_enabled && mbm_enabled)
- intel_cqm_events_group.attrs = intel_mbm_events_attr;
- else if (cqm_enabled && !mbm_enabled)
- intel_cqm_events_group.attrs = intel_cqm_events_attr;
-
- ret = perf_pmu_register(&intel_cqm_pmu, "intel_cqm", -1);
- if (ret) {
- pr_err("Intel CQM perf registration failed: %d\n", ret);
- goto out;
- }
-
- if (cqm_enabled)
- pr_info("Intel CQM monitoring enabled\n");
- if (mbm_enabled)
- pr_info("Intel MBM enabled\n");
-
- /*
- * Setup the hot cpu notifier once we are sure cqm
- * is enabled to avoid notifier leak.
- */
- cpuhp_setup_state_cpuslocked(CPUHP_AP_PERF_X86_CQM_STARTING,
- "perf/x86/cqm:starting",
- intel_cqm_cpu_starting, NULL);
- cpuhp_setup_state_cpuslocked(CPUHP_AP_PERF_X86_CQM_ONLINE,
- "perf/x86/cqm:online",
- NULL, intel_cqm_cpu_exit);
-out:
- cpus_read_unlock();
-
- if (ret) {
- kfree(str);
- cqm_cleanup();
- mbm_cleanup();
- }
-
- return ret;
-}
-device_initcall(intel_cqm_init);
diff --git a/arch/x86/include/asm/intel_rdt_common.h b/arch/x86/include/asm/intel_rdt_common.h
index b31081b..c953218 100644
--- a/arch/x86/include/asm/intel_rdt_common.h
+++ b/arch/x86/include/asm/intel_rdt_common.h
@@ -7,7 +7,6 @@
* struct intel_pqr_state - State cache for the PQR MSR
* @rmid: The cached Resource Monitoring ID
* @closid: The cached Class Of Service ID
- * @rmid_usecnt: The usage counter for rmid
*
* The upper 32 bits of MSR_IA32_PQR_ASSOC contain closid and the
* lower 10 bits rmid. The update to MSR_IA32_PQR_ASSOC always
@@ -19,7 +18,6 @@
struct intel_pqr_state {
u32 rmid;
u32 closid;
- int rmid_usecnt;
};

DECLARE_PER_CPU(struct intel_pqr_state, pqr_state);
diff --git a/arch/x86/kernel/cpu/intel_rdt.c b/arch/x86/kernel/cpu/intel_rdt.c
index 5b36646..989a997 100644
--- a/arch/x86/kernel/cpu/intel_rdt.c
+++ b/arch/x86/kernel/cpu/intel_rdt.c
@@ -41,6 +41,14 @@ DEFINE_MUTEX(rdtgroup_mutex);
DEFINE_PER_CPU_READ_MOSTLY(int, cpu_closid);

/*
+ * The cached intel_pqr_state is strictly per CPU and can never be
+ * updated from a remote CPU. Functions which modify the state
+ * are called with interrupts disabled and no preemption, which
+ * is sufficient for the protection.
+ */
+DEFINE_PER_CPU(struct intel_pqr_state, pqr_state);
+
+/*
* Used to store the max resource name width and max resource data width
* to display the schemata in a tabular format
*/
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index a3b873f..4572dba 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -139,14 +139,6 @@ struct hw_perf_event {
/* for tp_event->class */
struct list_head tp_list;
};
- struct { /* intel_cqm */
- int cqm_state;
- u32 cqm_rmid;
- int is_group_event;
- struct list_head cqm_events_entry;
- struct list_head cqm_groups_entry;
- struct list_head cqm_group_entry;
- };
struct { /* itrace */
int itrace_started;
};
@@ -417,11 +409,6 @@ struct pmu {


/*
- * Return the count value for a counter.
- */
- u64 (*count) (struct perf_event *event); /*optional*/
-
- /*
* Set up pmu-private data structures for an AUX area
*/
void *(*setup_aux) (int cpu, void **pages,
@@ -1111,11 +1098,6 @@ static inline void perf_event_task_sched_out(struct task_struct *prev,
__perf_event_task_sched_out(prev, next);
}

-static inline u64 __perf_event_count(struct perf_event *event)
-{
- return local64_read(&event->count) + atomic64_read(&event->child_count);
-}
-
extern void perf_event_mmap(struct vm_area_struct *vma);
extern struct perf_guest_info_callbacks *perf_guest_cbs;
extern int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *callbacks);
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 426c2ff..6e17154 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3625,10 +3625,7 @@ unlock:

static inline u64 perf_event_count(struct perf_event *event)
{
- if (event->pmu->count)
- return event->pmu->count(event);
-
- return __perf_event_count(event);
+ return local64_read(&event->count) + atomic64_read(&event->child_count);
}

/*
@@ -3659,15 +3656,6 @@ int perf_event_read_local(struct perf_event *event, u64 *value)
goto out;
}

- /*
- * It must not have a pmu::count method, those are not
- * NMI safe.
- */
- if (event->pmu->count) {
- ret = -EOPNOTSUPP;
- goto out;
- }
-
/* If this is a per-task event, it must be for current */
if ((event->attach_state & PERF_ATTACH_TASK) &&
event->hw.target != current) {
\
 
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  Last update: 2017-08-01 22:48    [W:0.228 / U:1.284 seconds]
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