1 files changed, 43 insertions, 199 deletions

diff --git a/kernel/locking/qspinlock_stat.h b/kernel/locking/qspinlock_stat.h
index d73f85388d5c..54152670ff24 100644
--- a/kernel/locking/qspinlock_stat.h
+++ b/kernel/locking/qspinlock_stat.h
@@ -9,262 +9,105 @@
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
- * Authors: Waiman Long <waiman.long@hpe.com>
+ * Authors: Waiman Long <longman@redhat.com>
  */
 
-/*
- * When queued spinlock statistical counters are enabled, the following
- * debugfs files will be created for reporting the counter values:
- *
- * <debugfs>/qlockstat/
- *   pv_hash_hops       - average # of hops per hashing operation
- *   pv_kick_unlock     - # of vCPU kicks issued at unlock time
- *   pv_kick_wake       - # of vCPU kicks used for computing pv_latency_wake
- *   pv_latency_kick    - average latency (ns) of vCPU kick operation
- *   pv_latency_wake    - average latency (ns) from vCPU kick to wakeup
- *   pv_lock_stealing   - # of lock stealing operations
- *   pv_spurious_wakeup - # of spurious wakeups in non-head vCPUs
- *   pv_wait_again      - # of wait's after a queue head vCPU kick
- *   pv_wait_early      - # of early vCPU wait's
- *   pv_wait_head       - # of vCPU wait's at the queue head
- *   pv_wait_node       - # of vCPU wait's at a non-head queue node
- *   lock_pending       - # of locking operations via pending code
- *   lock_slowpath      - # of locking operations via MCS lock queue
- *   lock_use_node2     - # of locking operations that use 2nd per-CPU node
- *   lock_use_node3     - # of locking operations that use 3rd per-CPU node
- *   lock_use_node4     - # of locking operations that use 4th per-CPU node
- *   lock_no_node       - # of locking operations without using per-CPU node
- *
- * Subtracting lock_use_node[234] from lock_slowpath will give you
- * lock_use_node1.
- *
- * Writing to the "reset_counters" file will reset all the above counter
- * values.
- *
- * These statistical counters are implemented as per-cpu variables which are
- * summed and computed whenever the corresponding debugfs files are read. This
- * minimizes added overhead making the counters usable even in a production
- * environment.
- *
- * There may be slight difference between pv_kick_wake and pv_kick_unlock.
- */
-enum qlock_stats {
-        qstat_pv_hash_hops,
-        qstat_pv_kick_unlock,
-        qstat_pv_kick_wake,
-        qstat_pv_latency_kick,
-        qstat_pv_latency_wake,
-        qstat_pv_lock_stealing,
-        qstat_pv_spurious_wakeup,
-        qstat_pv_wait_again,
-        qstat_pv_wait_early,
-        qstat_pv_wait_head,
-        qstat_pv_wait_node,
-        qstat_lock_pending,
-        qstat_lock_slowpath,
-        qstat_lock_use_node2,
-        qstat_lock_use_node3,
-        qstat_lock_use_node4,
-        qstat_lock_no_node,
-        qstat_num,      /* Total number of statistical counters */
-        qstat_reset_cnts = qstat_num,
-};
+#include "lock_events.h"
 
-#ifdef CONFIG_QUEUED_LOCK_STAT
+#ifdef CONFIG_LOCK_EVENT_COUNTS
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
 /*
- * Collect pvqspinlock statistics
+ * Collect pvqspinlock locking event counts
  */
-#include <linux/debugfs.h>
 #include <linux/sched.h>
 #include <linux/sched/clock.h>
 #include <linux/fs.h>
 
-static const char * const qstat_names[qstat_num + 1] = {
-        [qstat_pv_hash_hops]       = "pv_hash_hops",
-        [qstat_pv_kick_unlock]     = "pv_kick_unlock",
-        [qstat_pv_kick_wake]       = "pv_kick_wake",
-        [qstat_pv_spurious_wakeup] = "pv_spurious_wakeup",
-        [qstat_pv_latency_kick]    = "pv_latency_kick",
-        [qstat_pv_latency_wake]    = "pv_latency_wake",
-        [qstat_pv_lock_stealing]   = "pv_lock_stealing",
-        [qstat_pv_wait_again]      = "pv_wait_again",
-        [qstat_pv_wait_early]      = "pv_wait_early",
-        [qstat_pv_wait_head]       = "pv_wait_head",
-        [qstat_pv_wait_node]       = "pv_wait_node",
-        [qstat_lock_pending]       = "lock_pending",
-        [qstat_lock_slowpath]      = "lock_slowpath",
-        [qstat_lock_use_node2]     = "lock_use_node2",
-        [qstat_lock_use_node3]     = "lock_use_node3",
-        [qstat_lock_use_node4]     = "lock_use_node4",
-        [qstat_lock_no_node]       = "lock_no_node",
-        [qstat_reset_cnts]         = "reset_counters",
-};
+#define EVENT_COUNT(ev) lockevents[LOCKEVENT_ ## ev]
 
 /*
- * Per-cpu counters
+ * PV specific per-cpu counter
  */
-static DEFINE_PER_CPU(unsigned long, qstats[qstat_num]);
 static DEFINE_PER_CPU(u64, pv_kick_time);
 
 /*
- * Function to read and return the qlock statistical counter values
+ * Function to read and return the PV qspinlock counts.
  *
  * The following counters are handled specially:
- * 1. qstat_pv_latency_kick
+ * 1. pv_latency_kick
  *    Average kick latency (ns) = pv_latency_kick/pv_kick_unlock
- * 2. qstat_pv_latency_wake
+ * 2. pv_latency_wake
  *    Average wake latency (ns) = pv_latency_wake/pv_kick_wake
- * 3. qstat_pv_hash_hops
+ * 3. pv_hash_hops
  *    Average hops/hash = pv_hash_hops/pv_kick_unlock
  */
-static ssize_t qstat_read(struct file *file, char __user *user_buf,
-                          size_t count, loff_t *ppos)
+ssize_t lockevent_read(struct file *file, char __user *user_buf,
+                       size_t count, loff_t *ppos)
 {
         char buf[64];
-        int cpu, counter, len;
-        u64 stat = 0, kicks = 0;
+        int cpu, id, len;
+        u64 sum = 0, kicks = 0;
 
         /*
          * Get the counter ID stored in file->f_inode->i_private
          */
-        counter = (long)file_inode(file)->i_private;
+        id = (long)file_inode(file)->i_private;
 
-        if (counter >= qstat_num)
+        if (id >= lockevent_num)
                 return -EBADF;
 
         for_each_possible_cpu(cpu) {
-                stat += per_cpu(qstats[counter], cpu);
+                sum += per_cpu(lockevents[id], cpu);
                 /*
-                 * Need to sum additional counter for some of them
+                 * Need to sum additional counters for some of them
                  */
-                switch (counter) {
+                switch (id) {
 
-                case qstat_pv_latency_kick:
-                case qstat_pv_hash_hops:
-                        kicks += per_cpu(qstats[qstat_pv_kick_unlock], cpu);
+                case LOCKEVENT_pv_latency_kick:
+                case LOCKEVENT_pv_hash_hops:
+                        kicks += per_cpu(EVENT_COUNT(pv_kick_unlock), cpu);
                         break;
 
-                case qstat_pv_latency_wake:
-                        kicks += per_cpu(qstats[qstat_pv_kick_wake], cpu);
+                case LOCKEVENT_pv_latency_wake:
+                        kicks += per_cpu(EVENT_COUNT(pv_kick_wake), cpu);
                         break;
                 }
         }
 
-        if (counter == qstat_pv_hash_hops) {
+        if (id == LOCKEVENT_pv_hash_hops) {
                 u64 frac = 0;
 
                 if (kicks) {
-                        frac = 100ULL * do_div(stat, kicks);
+                        frac = 100ULL * do_div(sum, kicks);
                         frac = DIV_ROUND_CLOSEST_ULL(frac, kicks);
                 }
 
                 /*
                  * Return a X.XX decimal number
                  */
-                len = snprintf(buf, sizeof(buf) - 1, "%llu.%02llu\n", stat, frac);
+                len = snprintf(buf, sizeof(buf) - 1, "%llu.%02llu\n",
+                               sum, frac);
         } else {
                 /*
                  * Round to the nearest ns
                  */
-                if ((counter == qstat_pv_latency_kick) ||
-                    (counter == qstat_pv_latency_wake)) {
+                if ((id == LOCKEVENT_pv_latency_kick) ||
+                    (id == LOCKEVENT_pv_latency_wake)) {
                         if (kicks)
-                                stat = DIV_ROUND_CLOSEST_ULL(stat, kicks);
+                                sum = DIV_ROUND_CLOSEST_ULL(sum, kicks);
                 }
-                len = snprintf(buf, sizeof(buf) - 1, "%llu\n", stat);
+                len = snprintf(buf, sizeof(buf) - 1, "%llu\n", sum);
         }
 
         return simple_read_from_buffer(user_buf, count, ppos, buf, len);
 }
 
 /*
- * Function to handle write request
- *
- * When counter = reset_cnts, reset all the counter values.
- * Since the counter updates aren't atomic, the resetting is done twice
- * to make sure that the counters are very likely to be all cleared.
- */
-static ssize_t qstat_write(struct file *file, const char __user *user_buf,
-                           size_t count, loff_t *ppos)
-{
-        int cpu;
-
-        /*
-         * Get the counter ID stored in file->f_inode->i_private
-         */
-        if ((long)file_inode(file)->i_private != qstat_reset_cnts)
-                return count;
-
-        for_each_possible_cpu(cpu) {
-                int i;
-                unsigned long *ptr = per_cpu_ptr(qstats, cpu);
-
-                for (i = 0 ; i < qstat_num; i++)
-                        WRITE_ONCE(ptr[i], 0);
-        }
-        return count;
-}
-
-/*
- * Debugfs data structures
- */
-static const struct file_operations fops_qstat = {
-        .read = qstat_read,
-        .write = qstat_write,
-        .llseek = default_llseek,
-};
-
-/*
- * Initialize debugfs for the qspinlock statistical counters
- */
-static int __init init_qspinlock_stat(void)
-{
-        struct dentry *d_qstat = debugfs_create_dir("qlockstat", NULL);
-        int i;
-
-        if (!d_qstat)
-                goto out;
-
-        /*
-         * Create the debugfs files
-         *
-         * As reading from and writing to the stat files can be slow, only
-         * root is allowed to do the read/write to limit impact to system
-         * performance.
-         */
-        for (i = 0; i < qstat_num; i++)
-                if (!debugfs_create_file(qstat_names[i], 0400, d_qstat,
-                                         (void *)(long)i, &fops_qstat))
-                        goto fail_undo;
-
-        if (!debugfs_create_file(qstat_names[qstat_reset_cnts], 0200, d_qstat,
-                                 (void *)(long)qstat_reset_cnts, &fops_qstat))
-                goto fail_undo;
-
-        return 0;
-fail_undo:
-        debugfs_remove_recursive(d_qstat);
-out:
-        pr_warn("Could not create 'qlockstat' debugfs entries\n");
-        return -ENOMEM;
-}
-fs_initcall(init_qspinlock_stat);
-
-/*
- * Increment the PV qspinlock statistical counters
- */
-static inline void qstat_inc(enum qlock_stats stat, bool cond)
-{
-        if (cond)
-                this_cpu_inc(qstats[stat]);
-}
-
-/*
  * PV hash hop count
  */
-static inline void qstat_hop(int hopcnt)
+static inline void lockevent_pv_hop(int hopcnt)
 {
-        this_cpu_add(qstats[qstat_pv_hash_hops], hopcnt);
+        this_cpu_add(EVENT_COUNT(pv_hash_hops), hopcnt);
 }
 
 /*
@@ -276,7 +119,7 @@ static inline void __pv_kick(int cpu)
 
         per_cpu(pv_kick_time, cpu) = start;
         pv_kick(cpu);
-        this_cpu_add(qstats[qstat_pv_latency_kick], sched_clock() - start);
+        this_cpu_add(EVENT_COUNT(pv_latency_kick), sched_clock() - start);
 }
 
 /*
@@ -289,18 +132,19 @@ static inline void __pv_wait(u8 *ptr, u8 val)
         *pkick_time = 0;
         pv_wait(ptr, val);
         if (*pkick_time) {
-                this_cpu_add(qstats[qstat_pv_latency_wake],
+                this_cpu_add(EVENT_COUNT(pv_latency_wake),
                              sched_clock() - *pkick_time);
-                qstat_inc(qstat_pv_kick_wake, true);
+                lockevent_inc(pv_kick_wake);
         }
 }
 
 #define pv_kick(c)      __pv_kick(c)
 #define pv_wait(p, v)   __pv_wait(p, v)
 
-#else /* CONFIG_QUEUED_LOCK_STAT */
+#endif /* CONFIG_PARAVIRT_SPINLOCKS */
+
+#else /* CONFIG_LOCK_EVENT_COUNTS */
 
-static inline void qstat_inc(enum qlock_stats stat, bool cond)  { }
-static inline void qstat_hop(int hopcnt)                        { }
+static inline void lockevent_pv_hop(int hopcnt) { }
 
-#endif /* CONFIG_QUEUED_LOCK_STAT */
+#endif /* CONFIG_LOCK_EVENT_COUNTS */