diff options
| -rw-r--r-- | kernel/locking/lock_events.h | 55 | ||||
| -rw-r--r-- | kernel/locking/lock_events_list.h | 50 | ||||
| -rw-r--r-- | kernel/locking/qspinlock.c | 8 | ||||
| -rw-r--r-- | kernel/locking/qspinlock_paravirt.h | 19 | ||||
| -rw-r--r-- | kernel/locking/qspinlock_stat.h | 163 |
5 files changed, 181 insertions, 114 deletions
diff --git a/kernel/locking/lock_events.h b/kernel/locking/lock_events.h new file mode 100644 index 000000000000..4009e07b474a --- /dev/null +++ b/kernel/locking/lock_events.h @@ -0,0 +1,55 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * Authors: Waiman Long <longman@redhat.com> + */ + +enum lock_events { + +#include "lock_events_list.h" + + lockevent_num, /* Total number of lock event counts */ + LOCKEVENT_reset_cnts = lockevent_num, +}; + +#ifdef CONFIG_QUEUED_LOCK_STAT +/* + * Per-cpu counters + */ +DECLARE_PER_CPU(unsigned long, lockevents[lockevent_num]); + +/* + * Increment the PV qspinlock statistical counters + */ +static inline void __lockevent_inc(enum lock_events event, bool cond) +{ + if (cond) + __this_cpu_inc(lockevents[event]); +} + +#define lockevent_inc(ev) __lockevent_inc(LOCKEVENT_ ##ev, true) +#define lockevent_cond_inc(ev, c) __lockevent_inc(LOCKEVENT_ ##ev, c) + +static inline void __lockevent_add(enum lock_events event, int inc) +{ + __this_cpu_add(lockevents[event], inc); +} + +#define lockevent_add(ev, c) __lockevent_add(LOCKEVENT_ ##ev, c) + +#else /* CONFIG_QUEUED_LOCK_STAT */ + +#define lockevent_inc(ev) +#define lockevent_add(ev, c) +#define lockevent_cond_inc(ev, c) + +#endif /* CONFIG_QUEUED_LOCK_STAT */ diff --git a/kernel/locking/lock_events_list.h b/kernel/locking/lock_events_list.h new file mode 100644 index 000000000000..8b4d2e180475 --- /dev/null +++ b/kernel/locking/lock_events_list.h @@ -0,0 +1,50 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * Authors: Waiman Long <longman@redhat.com> + */ + +#ifndef LOCK_EVENT +#define LOCK_EVENT(name) LOCKEVENT_ ## name, +#endif + +#ifdef CONFIG_QUEUED_SPINLOCKS +#ifdef CONFIG_PARAVIRT_SPINLOCKS +/* + * Locking events for PV qspinlock. + */ +LOCK_EVENT(pv_hash_hops) /* Average # of hops per hashing operation */ +LOCK_EVENT(pv_kick_unlock) /* # of vCPU kicks issued at unlock time */ +LOCK_EVENT(pv_kick_wake) /* # of vCPU kicks for pv_latency_wake */ +LOCK_EVENT(pv_latency_kick) /* Average latency (ns) of vCPU kick */ +LOCK_EVENT(pv_latency_wake) /* Average latency (ns) of kick-to-wakeup */ +LOCK_EVENT(pv_lock_stealing) /* # of lock stealing operations */ +LOCK_EVENT(pv_spurious_wakeup) /* # of spurious wakeups in non-head vCPUs */ +LOCK_EVENT(pv_wait_again) /* # of wait's after queue head vCPU kick */ +LOCK_EVENT(pv_wait_early) /* # of early vCPU wait's */ +LOCK_EVENT(pv_wait_head) /* # of vCPU wait's at the queue head */ +LOCK_EVENT(pv_wait_node) /* # of vCPU wait's at non-head queue node */ +#endif /* CONFIG_PARAVIRT_SPINLOCKS */ + +/* + * Locking events for qspinlock + * + * Subtracting lock_use_node[234] from lock_slowpath will give you + * lock_use_node1. + */ +LOCK_EVENT(lock_pending) /* # of locking ops via pending code */ +LOCK_EVENT(lock_slowpath) /* # of locking ops via MCS lock queue */ +LOCK_EVENT(lock_use_node2) /* # of locking ops that use 2nd percpu node */ +LOCK_EVENT(lock_use_node3) /* # of locking ops that use 3rd percpu node */ +LOCK_EVENT(lock_use_node4) /* # of locking ops that use 4th percpu node */ +LOCK_EVENT(lock_no_node) /* # of locking ops w/o using percpu node */ +#endif /* CONFIG_QUEUED_SPINLOCKS */ diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c index 5e9247dc2515..e14b32c69639 100644 --- a/kernel/locking/qspinlock.c +++ b/kernel/locking/qspinlock.c @@ -395,7 +395,7 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val) * 0,1,0 -> 0,0,1 */ clear_pending_set_locked(lock); - qstat_inc(qstat_lock_pending, true); + lockevent_inc(lock_pending); return; /* @@ -403,7 +403,7 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val) * queuing. */ queue: - qstat_inc(qstat_lock_slowpath, true); + lockevent_inc(lock_slowpath); pv_queue: node = this_cpu_ptr(&qnodes[0].mcs); idx = node->count++; @@ -419,7 +419,7 @@ pv_queue: * simple enough. */ if (unlikely(idx >= MAX_NODES)) { - qstat_inc(qstat_lock_no_node, true); + lockevent_inc(lock_no_node); while (!queued_spin_trylock(lock)) cpu_relax(); goto release; @@ -430,7 +430,7 @@ pv_queue: /* * Keep counts of non-zero index values: */ - qstat_inc(qstat_lock_use_node2 + idx - 1, idx); + lockevent_cond_inc(lock_use_node2 + idx - 1, idx); /* * Ensure that we increment the head node->count before initialising diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h index 8f36c27c1794..89bab079e7a4 100644 --- a/kernel/locking/qspinlock_paravirt.h +++ b/kernel/locking/qspinlock_paravirt.h @@ -89,7 +89,7 @@ static inline bool pv_hybrid_queued_unfair_trylock(struct qspinlock *lock) if (!(val & _Q_LOCKED_PENDING_MASK) && (cmpxchg_acquire(&lock->locked, 0, _Q_LOCKED_VAL) == 0)) { - qstat_inc(qstat_pv_lock_stealing, true); + lockevent_inc(pv_lock_stealing); return true; } if (!(val & _Q_TAIL_MASK) || (val & _Q_PENDING_MASK)) @@ -219,7 +219,7 @@ static struct qspinlock **pv_hash(struct qspinlock *lock, struct pv_node *node) hopcnt++; if (!cmpxchg(&he->lock, NULL, lock)) { WRITE_ONCE(he->node, node); - qstat_hop(hopcnt); + lockevent_pv_hop(hopcnt); return &he->lock; } } @@ -320,8 +320,8 @@ static void pv_wait_node(struct mcs_spinlock *node, struct mcs_spinlock *prev) smp_store_mb(pn->state, vcpu_halted); if (!READ_ONCE(node->locked)) { - qstat_inc(qstat_pv_wait_node, true); - qstat_inc(qstat_pv_wait_early, wait_early); + lockevent_inc(pv_wait_node); + lockevent_cond_inc(pv_wait_early, wait_early); pv_wait(&pn->state, vcpu_halted); } @@ -339,7 +339,8 @@ static void pv_wait_node(struct mcs_spinlock *node, struct mcs_spinlock *prev) * So it is better to spin for a while in the hope that the * MCS lock will be released soon. */ - qstat_inc(qstat_pv_spurious_wakeup, !READ_ONCE(node->locked)); + lockevent_cond_inc(pv_spurious_wakeup, + !READ_ONCE(node->locked)); } /* @@ -416,7 +417,7 @@ pv_wait_head_or_lock(struct qspinlock *lock, struct mcs_spinlock *node) /* * Tracking # of slowpath locking operations */ - qstat_inc(qstat_lock_slowpath, true); + lockevent_inc(lock_slowpath); for (;; waitcnt++) { /* @@ -464,8 +465,8 @@ pv_wait_head_or_lock(struct qspinlock *lock, struct mcs_spinlock *node) } } WRITE_ONCE(pn->state, vcpu_hashed); - qstat_inc(qstat_pv_wait_head, true); - qstat_inc(qstat_pv_wait_again, waitcnt); + lockevent_inc(pv_wait_head); + lockevent_cond_inc(pv_wait_again, waitcnt); pv_wait(&lock->locked, _Q_SLOW_VAL); /* @@ -528,7 +529,7 @@ __pv_queued_spin_unlock_slowpath(struct qspinlock *lock, u8 locked) * vCPU is harmless other than the additional latency in completing * the unlock. */ - qstat_inc(qstat_pv_kick_unlock, true); + lockevent_inc(pv_kick_unlock); pv_kick(node->cpu); } diff --git a/kernel/locking/qspinlock_stat.h b/kernel/locking/qspinlock_stat.h index d73f85388d5c..1db5b375fcf4 100644 --- a/kernel/locking/qspinlock_stat.h +++ b/kernel/locking/qspinlock_stat.h @@ -38,8 +38,8 @@ * 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. + * Writing to the special ".reset_counts" 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 @@ -48,27 +48,7 @@ * * 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 /* @@ -79,99 +59,91 @@ enum qlock_stats { #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] + +#undef LOCK_EVENT +#define LOCK_EVENT(name) [LOCKEVENT_ ## name] = #name, + +static const char * const lockevent_names[lockevent_num + 1] = { + +#include "lock_events_list.h" + + [LOCKEVENT_reset_cnts] = ".reset_counts", }; /* * Per-cpu counters */ -static DEFINE_PER_CPU(unsigned long, qstats[qstat_num]); +DEFINE_PER_CPU(unsigned long, lockevents[lockevent_num]); static DEFINE_PER_CPU(u64, pv_kick_time); /* * Function to read and return the qlock statistical counter values * * 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) +static 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); @@ -180,11 +152,9 @@ static ssize_t qstat_read(struct file *file, char __user *user_buf, /* * 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. + * When id = .reset_cnts, reset all the counter values. */ -static ssize_t qstat_write(struct file *file, const char __user *user_buf, +static ssize_t lockevent_write(struct file *file, const char __user *user_buf, size_t count, loff_t *ppos) { int cpu; @@ -192,14 +162,14 @@ static ssize_t qstat_write(struct file *file, const char __user *user_buf, /* * Get the counter ID stored in file->f_inode->i_private */ - if ((long)file_inode(file)->i_private != qstat_reset_cnts) + if ((long)file_inode(file)->i_private != LOCKEVENT_reset_cnts) return count; for_each_possible_cpu(cpu) { int i; - unsigned long *ptr = per_cpu_ptr(qstats, cpu); + unsigned long *ptr = per_cpu_ptr(lockevents, cpu); - for (i = 0 ; i < qstat_num; i++) + for (i = 0 ; i < lockevent_num; i++) WRITE_ONCE(ptr[i], 0); } return count; @@ -208,9 +178,9 @@ static ssize_t qstat_write(struct file *file, const char __user *user_buf, /* * Debugfs data structures */ -static const struct file_operations fops_qstat = { - .read = qstat_read, - .write = qstat_write, +static const struct file_operations fops_lockevent = { + .read = lockevent_read, + .write = lockevent_write, .llseek = default_llseek, }; @@ -219,10 +189,10 @@ static const struct file_operations fops_qstat = { */ static int __init init_qspinlock_stat(void) { - struct dentry *d_qstat = debugfs_create_dir("qlockstat", NULL); + struct dentry *d_counts = debugfs_create_dir("qlockstat", NULL); int i; - if (!d_qstat) + if (!d_counts) goto out; /* @@ -232,18 +202,19 @@ static int __init init_qspinlock_stat(void) * 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)) + for (i = 0; i < lockevent_num; i++) + if (!debugfs_create_file(lockevent_names[i], 0400, d_counts, + (void *)(long)i, &fops_lockevent)) goto fail_undo; - if (!debugfs_create_file(qstat_names[qstat_reset_cnts], 0200, d_qstat, - (void *)(long)qstat_reset_cnts, &fops_qstat)) + if (!debugfs_create_file(lockevent_names[LOCKEVENT_reset_cnts], 0200, + d_counts, (void *)(long)LOCKEVENT_reset_cnts, + &fops_lockevent)) goto fail_undo; return 0; fail_undo: - debugfs_remove_recursive(d_qstat); + debugfs_remove_recursive(d_counts); out: pr_warn("Could not create 'qlockstat' debugfs entries\n"); return -ENOMEM; @@ -251,20 +222,11 @@ out: 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 +238,7 @@ 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); } /* @@ -289,9 +251,9 @@ 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); } } @@ -300,7 +262,6 @@ static inline void __pv_wait(u8 *ptr, u8 val) #else /* CONFIG_QUEUED_LOCK_STAT */ -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 */ |