96645678cd
__acquire
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lock _____
| \
| __contended
| |
| wait
| _______/
|/
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__acquired
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__release
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unlock
We measure acquisition and contention bouncing.
This is done by recording a cpu stamp in each lock instance.
Contention bouncing requires the cpu stamp to be set on acquisition. Hence we
move __acquired into the generic path.
__acquired is then used to measure acquisition bouncing by comparing the
current cpu with the old stamp before replacing it.
__contended is used to measure contention bouncing (only useful for preemptable
locks)
[akpm@linux-foundation.org: cleanups]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
444 lines
12 KiB
C
444 lines
12 KiB
C
/*
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* Runtime locking correctness validator
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*
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* Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
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* Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
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*
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* see Documentation/lockdep-design.txt for more details.
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*/
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#ifndef __LINUX_LOCKDEP_H
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#define __LINUX_LOCKDEP_H
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struct task_struct;
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struct lockdep_map;
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#ifdef CONFIG_LOCKDEP
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#include <linux/linkage.h>
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#include <linux/list.h>
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#include <linux/debug_locks.h>
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#include <linux/stacktrace.h>
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/*
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* Lock-class usage-state bits:
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*/
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enum lock_usage_bit
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{
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LOCK_USED = 0,
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LOCK_USED_IN_HARDIRQ,
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LOCK_USED_IN_SOFTIRQ,
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LOCK_ENABLED_SOFTIRQS,
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LOCK_ENABLED_HARDIRQS,
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LOCK_USED_IN_HARDIRQ_READ,
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LOCK_USED_IN_SOFTIRQ_READ,
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LOCK_ENABLED_SOFTIRQS_READ,
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LOCK_ENABLED_HARDIRQS_READ,
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LOCK_USAGE_STATES
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};
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/*
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* Usage-state bitmasks:
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*/
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#define LOCKF_USED (1 << LOCK_USED)
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#define LOCKF_USED_IN_HARDIRQ (1 << LOCK_USED_IN_HARDIRQ)
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#define LOCKF_USED_IN_SOFTIRQ (1 << LOCK_USED_IN_SOFTIRQ)
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#define LOCKF_ENABLED_HARDIRQS (1 << LOCK_ENABLED_HARDIRQS)
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#define LOCKF_ENABLED_SOFTIRQS (1 << LOCK_ENABLED_SOFTIRQS)
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#define LOCKF_ENABLED_IRQS (LOCKF_ENABLED_HARDIRQS | LOCKF_ENABLED_SOFTIRQS)
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#define LOCKF_USED_IN_IRQ (LOCKF_USED_IN_HARDIRQ | LOCKF_USED_IN_SOFTIRQ)
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#define LOCKF_USED_IN_HARDIRQ_READ (1 << LOCK_USED_IN_HARDIRQ_READ)
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#define LOCKF_USED_IN_SOFTIRQ_READ (1 << LOCK_USED_IN_SOFTIRQ_READ)
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#define LOCKF_ENABLED_HARDIRQS_READ (1 << LOCK_ENABLED_HARDIRQS_READ)
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#define LOCKF_ENABLED_SOFTIRQS_READ (1 << LOCK_ENABLED_SOFTIRQS_READ)
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#define LOCKF_ENABLED_IRQS_READ \
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(LOCKF_ENABLED_HARDIRQS_READ | LOCKF_ENABLED_SOFTIRQS_READ)
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#define LOCKF_USED_IN_IRQ_READ \
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(LOCKF_USED_IN_HARDIRQ_READ | LOCKF_USED_IN_SOFTIRQ_READ)
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#define MAX_LOCKDEP_SUBCLASSES 8UL
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/*
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* Lock-classes are keyed via unique addresses, by embedding the
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* lockclass-key into the kernel (or module) .data section. (For
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* static locks we use the lock address itself as the key.)
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*/
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struct lockdep_subclass_key {
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char __one_byte;
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} __attribute__ ((__packed__));
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struct lock_class_key {
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struct lockdep_subclass_key subkeys[MAX_LOCKDEP_SUBCLASSES];
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};
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/*
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* The lock-class itself:
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*/
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struct lock_class {
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/*
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* class-hash:
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*/
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struct list_head hash_entry;
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/*
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* global list of all lock-classes:
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*/
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struct list_head lock_entry;
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struct lockdep_subclass_key *key;
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unsigned int subclass;
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/*
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* IRQ/softirq usage tracking bits:
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*/
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unsigned long usage_mask;
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struct stack_trace usage_traces[LOCK_USAGE_STATES];
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/*
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* These fields represent a directed graph of lock dependencies,
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* to every node we attach a list of "forward" and a list of
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* "backward" graph nodes.
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*/
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struct list_head locks_after, locks_before;
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/*
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* Generation counter, when doing certain classes of graph walking,
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* to ensure that we check one node only once:
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*/
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unsigned int version;
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/*
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* Statistics counter:
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*/
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unsigned long ops;
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const char *name;
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int name_version;
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#ifdef CONFIG_LOCK_STAT
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unsigned long contention_point[4];
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#endif
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};
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#ifdef CONFIG_LOCK_STAT
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struct lock_time {
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s64 min;
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s64 max;
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s64 total;
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unsigned long nr;
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};
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enum bounce_type {
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bounce_acquired_write,
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bounce_acquired_read,
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bounce_contended_write,
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bounce_contended_read,
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nr_bounce_types,
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bounce_acquired = bounce_acquired_write,
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bounce_contended = bounce_contended_write,
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};
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struct lock_class_stats {
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unsigned long contention_point[4];
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struct lock_time read_waittime;
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struct lock_time write_waittime;
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struct lock_time read_holdtime;
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struct lock_time write_holdtime;
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unsigned long bounces[nr_bounce_types];
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};
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struct lock_class_stats lock_stats(struct lock_class *class);
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void clear_lock_stats(struct lock_class *class);
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#endif
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/*
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* Map the lock object (the lock instance) to the lock-class object.
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* This is embedded into specific lock instances:
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*/
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struct lockdep_map {
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struct lock_class_key *key;
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struct lock_class *class_cache;
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const char *name;
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#ifdef CONFIG_LOCK_STAT
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int cpu;
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#endif
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};
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/*
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* Every lock has a list of other locks that were taken after it.
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* We only grow the list, never remove from it:
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*/
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struct lock_list {
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struct list_head entry;
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struct lock_class *class;
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struct stack_trace trace;
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int distance;
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};
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/*
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* We record lock dependency chains, so that we can cache them:
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*/
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struct lock_chain {
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struct list_head entry;
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u64 chain_key;
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};
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struct held_lock {
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/*
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* One-way hash of the dependency chain up to this point. We
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* hash the hashes step by step as the dependency chain grows.
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*
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* We use it for dependency-caching and we skip detection
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* passes and dependency-updates if there is a cache-hit, so
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* it is absolutely critical for 100% coverage of the validator
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* to have a unique key value for every unique dependency path
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* that can occur in the system, to make a unique hash value
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* as likely as possible - hence the 64-bit width.
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*
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* The task struct holds the current hash value (initialized
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* with zero), here we store the previous hash value:
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*/
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u64 prev_chain_key;
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struct lock_class *class;
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unsigned long acquire_ip;
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struct lockdep_map *instance;
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#ifdef CONFIG_LOCK_STAT
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u64 waittime_stamp;
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u64 holdtime_stamp;
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#endif
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/*
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* The lock-stack is unified in that the lock chains of interrupt
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* contexts nest ontop of process context chains, but we 'separate'
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* the hashes by starting with 0 if we cross into an interrupt
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* context, and we also keep do not add cross-context lock
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* dependencies - the lock usage graph walking covers that area
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* anyway, and we'd just unnecessarily increase the number of
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* dependencies otherwise. [Note: hardirq and softirq contexts
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* are separated from each other too.]
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*
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* The following field is used to detect when we cross into an
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* interrupt context:
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*/
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int irq_context;
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int trylock;
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int read;
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int check;
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int hardirqs_off;
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};
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/*
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* Initialization, self-test and debugging-output methods:
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*/
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extern void lockdep_init(void);
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extern void lockdep_info(void);
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extern void lockdep_reset(void);
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extern void lockdep_reset_lock(struct lockdep_map *lock);
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extern void lockdep_free_key_range(void *start, unsigned long size);
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extern void lockdep_off(void);
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extern void lockdep_on(void);
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/*
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* These methods are used by specific locking variants (spinlocks,
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* rwlocks, mutexes and rwsems) to pass init/acquire/release events
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* to lockdep:
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*/
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extern void lockdep_init_map(struct lockdep_map *lock, const char *name,
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struct lock_class_key *key, int subclass);
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/*
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* Reinitialize a lock key - for cases where there is special locking or
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* special initialization of locks so that the validator gets the scope
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* of dependencies wrong: they are either too broad (they need a class-split)
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* or they are too narrow (they suffer from a false class-split):
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*/
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#define lockdep_set_class(lock, key) \
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lockdep_init_map(&(lock)->dep_map, #key, key, 0)
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#define lockdep_set_class_and_name(lock, key, name) \
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lockdep_init_map(&(lock)->dep_map, name, key, 0)
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#define lockdep_set_class_and_subclass(lock, key, sub) \
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lockdep_init_map(&(lock)->dep_map, #key, key, sub)
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#define lockdep_set_subclass(lock, sub) \
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lockdep_init_map(&(lock)->dep_map, #lock, \
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(lock)->dep_map.key, sub)
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/*
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* Acquire a lock.
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*
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* Values for "read":
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*
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* 0: exclusive (write) acquire
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* 1: read-acquire (no recursion allowed)
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* 2: read-acquire with same-instance recursion allowed
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*
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* Values for check:
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*
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* 0: disabled
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* 1: simple checks (freeing, held-at-exit-time, etc.)
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* 2: full validation
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*/
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extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
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int trylock, int read, int check, unsigned long ip);
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extern void lock_release(struct lockdep_map *lock, int nested,
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unsigned long ip);
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# define INIT_LOCKDEP .lockdep_recursion = 0,
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#define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0)
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#else /* !LOCKDEP */
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static inline void lockdep_off(void)
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{
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}
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static inline void lockdep_on(void)
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{
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}
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# define lock_acquire(l, s, t, r, c, i) do { } while (0)
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# define lock_release(l, n, i) do { } while (0)
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# define lockdep_init() do { } while (0)
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# define lockdep_info() do { } while (0)
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# define lockdep_init_map(lock, name, key, sub) do { (void)(key); } while (0)
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# define lockdep_set_class(lock, key) do { (void)(key); } while (0)
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# define lockdep_set_class_and_name(lock, key, name) \
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do { (void)(key); } while (0)
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#define lockdep_set_class_and_subclass(lock, key, sub) \
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do { (void)(key); } while (0)
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#define lockdep_set_subclass(lock, sub) do { } while (0)
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# define INIT_LOCKDEP
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# define lockdep_reset() do { debug_locks = 1; } while (0)
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# define lockdep_free_key_range(start, size) do { } while (0)
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/*
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* The class key takes no space if lockdep is disabled:
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*/
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struct lock_class_key { };
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#define lockdep_depth(tsk) (0)
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#endif /* !LOCKDEP */
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#ifdef CONFIG_LOCK_STAT
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extern void lock_contended(struct lockdep_map *lock, unsigned long ip);
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extern void lock_acquired(struct lockdep_map *lock);
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#define LOCK_CONTENDED(_lock, try, lock) \
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do { \
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if (!try(_lock)) { \
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lock_contended(&(_lock)->dep_map, _RET_IP_); \
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lock(_lock); \
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} \
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lock_acquired(&(_lock)->dep_map); \
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} while (0)
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#else /* CONFIG_LOCK_STAT */
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#define lock_contended(lockdep_map, ip) do {} while (0)
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#define lock_acquired(lockdep_map) do {} while (0)
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#define LOCK_CONTENDED(_lock, try, lock) \
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lock(_lock)
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#endif /* CONFIG_LOCK_STAT */
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#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_GENERIC_HARDIRQS)
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extern void early_init_irq_lock_class(void);
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#else
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static inline void early_init_irq_lock_class(void)
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{
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}
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#endif
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#ifdef CONFIG_TRACE_IRQFLAGS
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extern void early_boot_irqs_off(void);
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extern void early_boot_irqs_on(void);
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extern void print_irqtrace_events(struct task_struct *curr);
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#else
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static inline void early_boot_irqs_off(void)
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{
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}
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static inline void early_boot_irqs_on(void)
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{
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}
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static inline void print_irqtrace_events(struct task_struct *curr)
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{
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}
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#endif
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/*
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* For trivial one-depth nesting of a lock-class, the following
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* global define can be used. (Subsystems with multiple levels
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* of nesting should define their own lock-nesting subclasses.)
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*/
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#define SINGLE_DEPTH_NESTING 1
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/*
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* Map the dependency ops to NOP or to real lockdep ops, depending
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* on the per lock-class debug mode:
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*/
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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# ifdef CONFIG_PROVE_LOCKING
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# define spin_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, i)
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# else
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# define spin_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, i)
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# endif
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# define spin_release(l, n, i) lock_release(l, n, i)
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#else
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# define spin_acquire(l, s, t, i) do { } while (0)
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# define spin_release(l, n, i) do { } while (0)
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#endif
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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# ifdef CONFIG_PROVE_LOCKING
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# define rwlock_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, i)
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# define rwlock_acquire_read(l, s, t, i) lock_acquire(l, s, t, 2, 2, i)
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# else
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# define rwlock_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, i)
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# define rwlock_acquire_read(l, s, t, i) lock_acquire(l, s, t, 2, 1, i)
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# endif
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# define rwlock_release(l, n, i) lock_release(l, n, i)
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#else
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# define rwlock_acquire(l, s, t, i) do { } while (0)
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# define rwlock_acquire_read(l, s, t, i) do { } while (0)
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# define rwlock_release(l, n, i) do { } while (0)
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#endif
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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# ifdef CONFIG_PROVE_LOCKING
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# define mutex_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, i)
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# else
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# define mutex_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, i)
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# endif
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# define mutex_release(l, n, i) lock_release(l, n, i)
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#else
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# define mutex_acquire(l, s, t, i) do { } while (0)
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# define mutex_release(l, n, i) do { } while (0)
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#endif
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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# ifdef CONFIG_PROVE_LOCKING
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# define rwsem_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, i)
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# define rwsem_acquire_read(l, s, t, i) lock_acquire(l, s, t, 1, 2, i)
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# else
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# define rwsem_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, i)
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# define rwsem_acquire_read(l, s, t, i) lock_acquire(l, s, t, 1, 1, i)
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# endif
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# define rwsem_release(l, n, i) lock_release(l, n, i)
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#else
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# define rwsem_acquire(l, s, t, i) do { } while (0)
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# define rwsem_acquire_read(l, s, t, i) do { } while (0)
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# define rwsem_release(l, n, i) do { } while (0)
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#endif
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#endif /* __LINUX_LOCKDEP_H */
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