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Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Browse source 
Pull RCU updates from Ingo Molnar:
 "The biggest RCU changes in this cycle were:

   - Convert RCU's BUG_ON() and similar calls to WARN_ON() and similar.

   - Replace calls of RCU-bh and RCU-sched update-side functions to
     their vanilla RCU counterparts. This series is a step towards
     complete removal of the RCU-bh and RCU-sched update-side functions.

     ( Note that some of these conversions are going upstream via their
       respective maintainers. )

   - Documentation updates, including a number of flavor-consolidation
     updates from Joel Fernandes.

   - Miscellaneous fixes.

   - Automate generation of the initrd filesystem used for rcutorture
     testing.

   - Convert spin_is_locked() assertions to instead use lockdep.

     ( Note that some of these conversions are going upstream via their
       respective maintainers. )

   - SRCU updates, especially including a fix from Dennis Krein for a
     bag-on-head-class bug.

   - RCU torture-test updates"

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (112 commits)
  rcutorture: Don't do busted forward-progress testing
  rcutorture: Use 100ms buckets for forward-progress callback histograms
  rcutorture: Recover from OOM during forward-progress tests
  rcutorture: Print forward-progress test age upon failure
  rcutorture: Print time since GP end upon forward-progress failure
  rcutorture: Print histogram of CB invocation at OOM time
  rcutorture: Print GP age upon forward-progress failure
  rcu: Print per-CPU callback counts for forward-progress failures
  rcu: Account for nocb-CPU callback counts in RCU CPU stall warnings
  rcutorture: Dump grace-period diagnostics upon forward-progress OOM
  rcutorture: Prepare for asynchronous access to rcu_fwd_startat
  torture: Remove unnecessary "ret" variables
  rcutorture: Affinity forward-progress test to avoid housekeeping CPUs
  rcutorture: Break up too-long rcu_torture_fwd_prog() function
  rcutorture: Remove cbflood facility
  torture: Bring any extra CPUs online during kernel startup
  rcutorture: Add call_rcu() flooding forward-progress tests
  rcutorture/formal: Replace synchronize_sched() with synchronize_rcu()
  tools/kernel.h: Replace synchronize_sched() with synchronize_rcu()
  net/decnet: Replace rcu_barrier_bh() with rcu_barrier()
  ...
This commit is contained in:
Linus Torvalds 2018-12-26 13:07:19 -08:00
commit 792bf4d871
88 changed files with 4282 additions and 4109 deletions
Download patch file Download diff file Expand all files Collapse all files

2
include/linux/percpu-rwsem.h
View file

@ -41,7 +41,7 @@ static inline void percpu_down_read_preempt_disable(struct percpu_rw_semaphore *
* cannot both change sem->state from readers_fast and start checking
* counters while we are here. So if we see !sem->state, we know that
* the writer won't be checking until we're past the preempt_enable()
* and that one the synchronize_sched() is done, the writer will see
* and that once the synchronize_rcu() is done, the writer will see
* anything we did within this RCU-sched read-size critical section.
*/
__this_cpu_inc(*sem->read_count);

17
include/linux/rcupdate_wait.h
View file

@ -31,21 +31,4 @@ do { \
#define wait_rcu_gp(...) _wait_rcu_gp(false, __VA_ARGS__)
/**
* synchronize_rcu_mult - Wait concurrently for multiple grace periods
* @...: List of call_rcu() functions for different grace periods to wait on
*
* This macro waits concurrently for multiple types of RCU grace periods.
* For example, synchronize_rcu_mult(call_rcu, call_rcu_tasks) would wait
* on concurrent RCU and RCU-tasks grace periods. Waiting on a give SRCU
* domain requires you to write a wrapper function for that SRCU domain's
* call_srcu() function, supplying the corresponding srcu_struct.
*
* If Tiny RCU, tell _wait_rcu_gp() does not bother waiting for RCU,
* given that anywhere synchronize_rcu_mult() can be called is automatically
* a grace period.
*/
#define synchronize_rcu_mult(...) \
_wait_rcu_gp(IS_ENABLED(CONFIG_TINY_RCU), __VA_ARGS__)
#endif /* _LINUX_SCHED_RCUPDATE_WAIT_H */

4
include/linux/sched.h
View file

@ -572,8 +572,10 @@ union rcu_special {
struct {
u8 blocked;
u8 need_qs;
u8 exp_hint; /* Hint for performance. */
u8 pad; /* No garbage from compiler! */
} b; /* Bits. */
u16 s; /* Set of bits. */
u32 s; /* Set of bits. */
};
enum perf_event_task_context {

79
include/linux/srcu.h
View file

@ -38,20 +38,20 @@ struct srcu_struct;
#ifdef CONFIG_DEBUG_LOCK_ALLOC
int __init_srcu_struct(struct srcu_struct *sp, const char *name,
int __init_srcu_struct(struct srcu_struct *ssp, const char *name,
struct lock_class_key *key);
#define init_srcu_struct(sp) \
#define init_srcu_struct(ssp) \
({ \
static struct lock_class_key __srcu_key; \
\
__init_srcu_struct((sp), #sp, &__srcu_key); \
__init_srcu_struct((ssp), #ssp, &__srcu_key); \
})
#define __SRCU_DEP_MAP_INIT(srcu_name) .dep_map = { .name = #srcu_name },
#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
int init_srcu_struct(struct srcu_struct *sp);
int init_srcu_struct(struct srcu_struct *ssp);
#define __SRCU_DEP_MAP_INIT(srcu_name)
#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
@ -67,28 +67,28 @@ int init_srcu_struct(struct srcu_struct *sp);
struct srcu_struct { };
#endif
void call_srcu(struct srcu_struct *sp, struct rcu_head *head,
void call_srcu(struct srcu_struct *ssp, struct rcu_head *head,
void (*func)(struct rcu_head *head));
void _cleanup_srcu_struct(struct srcu_struct *sp, bool quiesced);
int __srcu_read_lock(struct srcu_struct *sp) __acquires(sp);
void __srcu_read_unlock(struct srcu_struct *sp, int idx) __releases(sp);
void synchronize_srcu(struct srcu_struct *sp);
void _cleanup_srcu_struct(struct srcu_struct *ssp, bool quiesced);
int __srcu_read_lock(struct srcu_struct *ssp) __acquires(ssp);
void __srcu_read_unlock(struct srcu_struct *ssp, int idx) __releases(ssp);
void synchronize_srcu(struct srcu_struct *ssp);
/**
* cleanup_srcu_struct - deconstruct a sleep-RCU structure
* @sp: structure to clean up.
* @ssp: structure to clean up.
*
* Must invoke this after you are finished using a given srcu_struct that
* was initialized via init_srcu_struct(), else you leak memory.
*/
static inline void cleanup_srcu_struct(struct srcu_struct *sp)
static inline void cleanup_srcu_struct(struct srcu_struct *ssp)
{
_cleanup_srcu_struct(sp, false);
_cleanup_srcu_struct(ssp, false);
}
/**
* cleanup_srcu_struct_quiesced - deconstruct a quiesced sleep-RCU structure
* @sp: structure to clean up.
* @ssp: structure to clean up.
*
* Must invoke this after you are finished using a given srcu_struct that
* was initialized via init_srcu_struct(), else you leak memory. Also,
@ -103,16 +103,16 @@ static inline void cleanup_srcu_struct(struct srcu_struct *sp)
* (with high probability, anyway), and will also cause the srcu_struct
* to be leaked.
*/
static inline void cleanup_srcu_struct_quiesced(struct srcu_struct *sp)
static inline void cleanup_srcu_struct_quiesced(struct srcu_struct *ssp)
{
_cleanup_srcu_struct(sp, true);
_cleanup_srcu_struct(ssp, true);
}
#ifdef CONFIG_DEBUG_LOCK_ALLOC
/**
* srcu_read_lock_held - might we be in SRCU read-side critical section?
* @sp: The srcu_struct structure to check
* @ssp: The srcu_struct structure to check
*
* If CONFIG_DEBUG_LOCK_ALLOC is selected, returns nonzero iff in an SRCU
* read-side critical section. In absence of CONFIG_DEBUG_LOCK_ALLOC,
@ -126,16 +126,16 @@ static inline void cleanup_srcu_struct_quiesced(struct srcu_struct *sp)
* relies on normal RCU, it can be called from the CPU which
* is in the idle loop from an RCU point of view or offline.
*/
static inline int srcu_read_lock_held(const struct srcu_struct *sp)
static inline int srcu_read_lock_held(const struct srcu_struct *ssp)
{
if (!debug_lockdep_rcu_enabled())
return 1;
return lock_is_held(&sp->dep_map);
return lock_is_held(&ssp->dep_map);
}
#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
static inline int srcu_read_lock_held(const struct srcu_struct *sp)
static inline int srcu_read_lock_held(const struct srcu_struct *ssp)
{
return 1;
}
@ -145,7 +145,7 @@ static inline int srcu_read_lock_held(const struct srcu_struct *sp)
/**
* srcu_dereference_check - fetch SRCU-protected pointer for later dereferencing
* @p: the pointer to fetch and protect for later dereferencing
* @sp: pointer to the srcu_struct, which is used to check that we
* @ssp: pointer to the srcu_struct, which is used to check that we
* really are in an SRCU read-side critical section.
* @c: condition to check for update-side use
*
@ -154,29 +154,32 @@ static inline int srcu_read_lock_held(const struct srcu_struct *sp)
* to 1. The @c argument will normally be a logical expression containing
* lockdep_is_held() calls.
*/
#define srcu_dereference_check(p, sp, c) \
__rcu_dereference_check((p), (c) || srcu_read_lock_held(sp), __rcu)
#define srcu_dereference_check(p, ssp, c) \
__rcu_dereference_check((p), (c) || srcu_read_lock_held(ssp), __rcu)
/**
* srcu_dereference - fetch SRCU-protected pointer for later dereferencing
* @p: the pointer to fetch and protect for later dereferencing
* @sp: pointer to the srcu_struct, which is used to check that we
* @ssp: pointer to the srcu_struct, which is used to check that we
* really are in an SRCU read-side critical section.
*
* Makes rcu_dereference_check() do the dirty work. If PROVE_RCU
* is enabled, invoking this outside of an RCU read-side critical
* section will result in an RCU-lockdep splat.
*/
#define srcu_dereference(p, sp) srcu_dereference_check((p), (sp), 0)
#define srcu_dereference(p, ssp) srcu_dereference_check((p), (ssp), 0)
/**
* srcu_dereference_notrace - no tracing and no lockdep calls from here
* @p: the pointer to fetch and protect for later dereferencing
* @ssp: pointer to the srcu_struct, which is used to check that we
* really are in an SRCU read-side critical section.
*/
#define srcu_dereference_notrace(p, sp) srcu_dereference_check((p), (sp), 1)
#define srcu_dereference_notrace(p, ssp) srcu_dereference_check((p), (ssp), 1)
/**
* srcu_read_lock - register a new reader for an SRCU-protected structure.
* @sp: srcu_struct in which to register the new reader.
* @ssp: srcu_struct in which to register the new reader.
*
* Enter an SRCU read-side critical section. Note that SRCU read-side
* critical sections may be nested. However, it is illegal to
@ -191,44 +194,44 @@ static inline int srcu_read_lock_held(const struct srcu_struct *sp)
* srcu_read_unlock() in an irq handler if the matching srcu_read_lock()
* was invoked in process context.
*/
static inline int srcu_read_lock(struct srcu_struct *sp) __acquires(sp)
static inline int srcu_read_lock(struct srcu_struct *ssp) __acquires(ssp)
{
int retval;
retval = __srcu_read_lock(sp);
rcu_lock_acquire(&(sp)->dep_map);
retval = __srcu_read_lock(ssp);
rcu_lock_acquire(&(ssp)->dep_map);
return retval;
}
/* Used by tracing, cannot be traced and cannot invoke lockdep. */
static inline notrace int
srcu_read_lock_notrace(struct srcu_struct *sp) __acquires(sp)
srcu_read_lock_notrace(struct srcu_struct *ssp) __acquires(ssp)
{
int retval;
retval = __srcu_read_lock(sp);
retval = __srcu_read_lock(ssp);
return retval;
}
/**
* srcu_read_unlock - unregister a old reader from an SRCU-protected structure.
* @sp: srcu_struct in which to unregister the old reader.
* @ssp: srcu_struct in which to unregister the old reader.
* @idx: return value from corresponding srcu_read_lock().
*
* Exit an SRCU read-side critical section.
*/
static inline void srcu_read_unlock(struct srcu_struct *sp, int idx)
__releases(sp)
static inline void srcu_read_unlock(struct srcu_struct *ssp, int idx)
__releases(ssp)
{
rcu_lock_release(&(sp)->dep_map);
__srcu_read_unlock(sp, idx);
rcu_lock_release(&(ssp)->dep_map);
__srcu_read_unlock(ssp, idx);
}
/* Used by tracing, cannot be traced and cannot call lockdep. */
static inline notrace void
srcu_read_unlock_notrace(struct srcu_struct *sp, int idx) __releases(sp)
srcu_read_unlock_notrace(struct srcu_struct *ssp, int idx) __releases(ssp)
{
__srcu_read_unlock(sp, idx);
__srcu_read_unlock(ssp, idx);
}
/**

24
include/linux/srcutiny.h
View file

@ -60,7 +60,7 @@ void srcu_drive_gp(struct work_struct *wp);
#define DEFINE_STATIC_SRCU(name) \
static struct srcu_struct name = __SRCU_STRUCT_INIT(name, name)
void synchronize_srcu(struct srcu_struct *sp);
void synchronize_srcu(struct srcu_struct *ssp);
/*
* Counts the new reader in the appropriate per-CPU element of the
@ -68,36 +68,36 @@ void synchronize_srcu(struct srcu_struct *sp);
* __srcu_read_unlock() must be in the same handler instance. Returns an
* index that must be passed to the matching srcu_read_unlock().
*/
static inline int __srcu_read_lock(struct srcu_struct *sp)
static inline int __srcu_read_lock(struct srcu_struct *ssp)
{
int idx;
idx = READ_ONCE(sp->srcu_idx);
WRITE_ONCE(sp->srcu_lock_nesting[idx], sp->srcu_lock_nesting[idx] + 1);
idx = READ_ONCE(ssp->srcu_idx);
WRITE_ONCE(ssp->srcu_lock_nesting[idx], ssp->srcu_lock_nesting[idx] + 1);
return idx;
}
static inline void synchronize_srcu_expedited(struct srcu_struct *sp)
static inline void synchronize_srcu_expedited(struct srcu_struct *ssp)
{
synchronize_srcu(sp);
synchronize_srcu(ssp);
}
static inline void srcu_barrier(struct srcu_struct *sp)
static inline void srcu_barrier(struct srcu_struct *ssp)
{
synchronize_srcu(sp);
synchronize_srcu(ssp);
}
/* Defined here to avoid size increase for non-torture kernels. */
static inline void srcu_torture_stats_print(struct srcu_struct *sp,
static inline void srcu_torture_stats_print(struct srcu_struct *ssp,
char *tt, char *tf)
{
int idx;
idx = READ_ONCE(sp->srcu_idx) & 0x1;
idx = READ_ONCE(ssp->srcu_idx) & 0x1;
pr_alert("%s%s Tiny SRCU per-CPU(idx=%d): (%hd,%hd)\n",
tt, tf, idx,
READ_ONCE(sp->srcu_lock_nesting[!idx]),
READ_ONCE(sp->srcu_lock_nesting[idx]));
READ_ONCE(ssp->srcu_lock_nesting[!idx]),
READ_ONCE(ssp->srcu_lock_nesting[idx]));
}
#endif

8
include/linux/srcutree.h
View file

@ -51,7 +51,7 @@ struct srcu_data {
unsigned long grpmask; /* Mask for leaf srcu_node */
/* ->srcu_data_have_cbs[]. */
int cpu;
struct srcu_struct *sp;
struct srcu_struct *ssp;
};
/*
@ -138,8 +138,8 @@ struct srcu_struct {
#define DEFINE_SRCU(name) __DEFINE_SRCU(name, /* not static */)
#define DEFINE_STATIC_SRCU(name) __DEFINE_SRCU(name, static)
void synchronize_srcu_expedited(struct srcu_struct *sp);
void srcu_barrier(struct srcu_struct *sp);
void srcu_torture_stats_print(struct srcu_struct *sp, char *tt, char *tf);
void synchronize_srcu_expedited(struct srcu_struct *ssp);
void srcu_barrier(struct srcu_struct *ssp);
void srcu_torture_stats_print(struct srcu_struct *ssp, char *tt, char *tf);
#endif

2
include/linux/tracepoint.h
View file

@ -82,7 +82,7 @@ int unregister_tracepoint_module_notifier(struct notifier_block *nb)
static inline void tracepoint_synchronize_unregister(void)
{
synchronize_srcu(&tracepoint_srcu);
synchronize_sched();
synchronize_rcu();
}
#else
static inline void tracepoint_synchronize_unregister(void)

4
include/linux/types.h
View file

@ -212,8 +212,8 @@ struct ustat {
* weird ABI and we need to ask it explicitly.
*
* The alignment is required to guarantee that bit 0 of @next will be
* clear under normal conditions -- as long as we use call_rcu(),
* call_rcu_bh(), call_rcu_sched(), or call_srcu() to queue callback.
* clear under normal conditions -- as long as we use call_rcu() or
* call_srcu() to queue the callback.
*
* This guarantee is important for few reasons:
* - future call_rcu_lazy() will make use of lower bits in the pointer;