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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 changes in this cycle are:

   - RCU flavor consolidation cleanups and optmizations

   - Documentation updates

   - Miscellaneous fixes

   - SRCU updates

   - RCU-sync flavor consolidation

   - Torture-test updates

   - Linux-kernel memory-consistency-model updates, most notably the
     addition of plain C-language accesses"

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (61 commits)
  tools/memory-model: Improve data-race detection
  tools/memory-model: Change definition of rcu-fence
  tools/memory-model: Expand definition of barrier
  tools/memory-model: Do not use "herd" to refer to "herd7"
  tools/memory-model: Fix comment in MP+poonceonces.litmus
  Documentation: atomic_t.txt: Explain ordering provided by smp_mb__{before,after}_atomic()
  rcu: Don't return a value from rcu_assign_pointer()
  rcu: Force inlining of rcu_read_lock()
  rcu: Fix irritating whitespace error in rcu_assign_pointer()
  rcu: Upgrade sync_exp_work_done() to smp_mb()
  rcutorture: Upper case solves the case of the vanishing NULL pointer
  torture: Suppress propagating trace_printk() warning
  rcutorture: Dump trace buffer for callback pipe drain failures
  torture: Add --trust-make to suppress "make clean"
  torture: Make --cpus override idleness calculations
  torture: Run kernel build in source directory
  torture: Add function graph-tracing cheat sheet
  torture: Capture qemu output
  rcutorture: Tweak kvm options
  rcutorture: Add trivial RCU implementation
  ...
This commit is contained in:
Linus Torvalds 2019-07-08 15:45:14 -07:00
commit 46f1ec23a4
61 changed files with 861 additions and 482 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
Documentation/RCU/rcuref.txt
View File

@ -12,6 +12,7 @@ please read on.
Reference counting on elements of lists which are protected by traditional
reader/writer spinlocks or semaphores are straightforward:
CODE LISTING A:
1. 2.
add() search_and_reference()
{ {
@ -28,7 +29,8 @@ add() search_and_reference()
release_referenced() delete()
{ {
... write_lock(&list_lock);
atomic_dec(&el->rc, relfunc) ...
if(atomic_dec_and_test(&el->rc)) ...
kfree(el);
... remove_element
} write_unlock(&list_lock);
...
@ -44,6 +46,7 @@ search_and_reference() could potentially hold reference to an element which
has already been deleted from the list/array. Use atomic_inc_not_zero()
in this scenario as follows:
CODE LISTING B:
1. 2.
add() search_and_reference()
{ {
@ -79,6 +82,7 @@ search_and_reference() code path. In such cases, the
atomic_dec_and_test() may be moved from delete() to el_free()
as follows:
CODE LISTING C:
1. 2.
add() search_and_reference()
{ {
@ -114,6 +118,17 @@ element can therefore safely be freed. This in turn guarantees that if
any reader finds the element, that reader may safely acquire a reference
without checking the value of the reference counter.
A clear advantage of the RCU-based pattern in listing C over the one
in listing B is that any call to search_and_reference() that locates
a given object will succeed in obtaining a reference to that object,
even given a concurrent invocation of delete() for that same object.
Similarly, a clear advantage of both listings B and C over listing A is
that a call to delete() is not delayed even if there are an arbitrarily
large number of calls to search_and_reference() searching for the same
object that delete() was invoked on. Instead, all that is delayed is
the eventual invocation of kfree(), which is usually not a problem on
modern computer systems, even the small ones.
In cases where delete() can sleep, synchronize_rcu() can be called from
delete(), so that el_free() can be subsumed into delete as follows:
@ -130,3 +145,7 @@ delete()
kfree(el);
...
}
As additional examples in the kernel, the pattern in listing C is used by
reference counting of struct pid, while the pattern in listing B is used by
struct posix_acl.

2
Documentation/RCU/stallwarn.txt
View File

@ -153,7 +153,7 @@ rcupdate.rcu_task_stall_timeout
This boot/sysfs parameter controls the RCU-tasks stall warning
interval. A value of zero or less suppresses RCU-tasks stall
warnings. A positive value sets the stall-warning interval
in jiffies. An RCU-tasks stall warning starts with the line:
in seconds. An RCU-tasks stall warning starts with the line:
INFO: rcu_tasks detected stalls on tasks:

8
Documentation/RCU/whatisRCU.txt
View File

@ -212,7 +212,7 @@ synchronize_rcu()
rcu_assign_pointer()
typeof(p) rcu_assign_pointer(p, typeof(p) v);
void rcu_assign_pointer(p, typeof(p) v);
Yes, rcu_assign_pointer() -is- implemented as a macro, though it
would be cool to be able to declare a function in this manner.
@ -220,9 +220,9 @@ rcu_assign_pointer()
The updater uses this function to assign a new value to an
RCU-protected pointer, in order to safely communicate the change
in value from the updater to the reader. This function returns
the new value, and also executes any memory-barrier instructions
required for a given CPU architecture.
in value from the updater to the reader. This macro does not
evaluate to an rvalue, but it does execute any memory-barrier
instructions required for a given CPU architecture.
Perhaps just as important, it serves to document (1) which
pointers are protected by RCU and (2) the point at which a

6
Documentation/admin-guide/kernel-parameters.txt
View File

@ -3752,6 +3752,12 @@
the propagation of recent CPU-hotplug changes up
the rcu_node combining tree.
rcutree.use_softirq= [KNL]
If set to zero, move all RCU_SOFTIRQ processing to
per-CPU rcuc kthreads. Defaults to a non-zero
value, meaning that RCU_SOFTIRQ is used by default.
Specify rcutree.use_softirq=0 to use rcuc kthreads.
rcutree.rcu_fanout_exact= [KNL]
Disable autobalancing of the rcu_node combining
tree. This is used by rcutorture, and might

17
Documentation/atomic_t.txt
View File

@ -187,8 +187,14 @@ The barriers:
smp_mb__{before,after}_atomic()
only apply to the RMW ops and can be used to augment/upgrade the ordering
inherent to the used atomic op. These barriers provide a full smp_mb().
only apply to the RMW atomic ops and can be used to augment/upgrade the
ordering inherent to the op. These barriers act almost like a full smp_mb():
smp_mb__before_atomic() orders all earlier accesses against the RMW op
itself and all accesses following it, and smp_mb__after_atomic() orders all
later accesses against the RMW op and all accesses preceding it. However,
accesses between the smp_mb__{before,after}_atomic() and the RMW op are not
ordered, so it is advisable to place the barrier right next to the RMW atomic
op whenever possible.
These helper barriers exist because architectures have varying implicit
ordering on their SMP atomic primitives. For example our TSO architectures
@ -212,7 +218,9 @@ Further, while something like:
atomic_dec(&X);
is a 'typical' RELEASE pattern, the barrier is strictly stronger than
a RELEASE. Similarly for something like:
a RELEASE because it orders preceding instructions against both the read
and write parts of the atomic_dec(), and against all following instructions
as well. Similarly, something like:
atomic_inc(&X);
smp_mb__after_atomic();
@ -244,7 +252,8 @@ strictly stronger than ACQUIRE. As illustrated:
This should not happen; but a hypothetical atomic_inc_acquire() --
(void)atomic_fetch_inc_acquire() for instance -- would allow the outcome,
since then:
because it would not order the W part of the RMW against the following
WRITE_ONCE. Thus:
P1 P2

2
Documentation/core-api/circular-buffers.rst
View File

@ -3,7 +3,7 @@ Circular Buffers
================
:Author: David Howells <dhowells@redhat.com>
:Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
:Author: Paul E. McKenney <paulmck@linux.ibm.com>
Linux provides a number of features that can be used to implement circular

2
Documentation/memory-barriers.txt
View File

@ -3,7 +3,7 @@
============================
By: David Howells <dhowells@redhat.com>
Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney <paulmck@linux.ibm.com>
Will Deacon <will.deacon@arm.com>
Peter Zijlstra <peterz@infradead.org>

2
Documentation/translations/ko_KR/memory-barriers.txt
View File

@ -24,7 +24,7 @@ Documentation/memory-barriers.txt
=========================
저자: David Howells <dhowells@redhat.com>
Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney <paulmck@linux.ibm.com>
Will Deacon <will.deacon@arm.com>
Peter Zijlstra <peterz@infradead.org>

7
include/linux/lockdep.h
View File

@ -632,11 +632,18 @@ do { \
"IRQs not disabled as expected\n"); \
} while (0)
#define lockdep_assert_in_irq() do { \
WARN_ONCE(debug_locks && !current->lockdep_recursion && \
!current->hardirq_context, \
"Not in hardirq as expected\n"); \
} while (0)
#else
# define might_lock(lock) do { } while (0)
# define might_lock_read(lock) do { } while (0)
# define lockdep_assert_irqs_enabled() do { } while (0)
# define lockdep_assert_irqs_disabled() do { } while (0)
# define lockdep_assert_in_irq() do { } while (0)
#endif
#ifdef CONFIG_LOCKDEP

5
include/linux/module.h
View File

@ -21,6 +21,7 @@
#include <linux/rbtree_latch.h>
#include <linux/error-injection.h>
#include <linux/tracepoint-defs.h>
#include <linux/srcu.h>
#include <linux/percpu.h>
#include <asm/module.h>
@ -450,6 +451,10 @@ struct module {
unsigned int num_tracepoints;
tracepoint_ptr_t *tracepoints_ptrs;
#endif
#ifdef CONFIG_TREE_SRCU
unsigned int num_srcu_structs;
struct srcu_struct **srcu_struct_ptrs;
#endif
#ifdef CONFIG_BPF_EVENTS
unsigned int num_bpf_raw_events;
struct bpf_raw_event_map *bpf_raw_events;

10
include/linux/percpu-rwsem.h
View File

@ -17,14 +17,18 @@ struct percpu_rw_semaphore {
int readers_block;
};
#define DEFINE_STATIC_PERCPU_RWSEM(name) \
#define __DEFINE_PERCPU_RWSEM(name, is_static) \
static DEFINE_PER_CPU(unsigned int, __percpu_rwsem_rc_##name); \
static struct percpu_rw_semaphore name = { \
.rss = __RCU_SYNC_INITIALIZER(name.rss, RCU_SCHED_SYNC), \
is_static struct percpu_rw_semaphore name = { \
.rss = __RCU_SYNC_INITIALIZER(name.rss), \
.read_count = &__percpu_rwsem_rc_##name, \
.rw_sem = __RWSEM_INITIALIZER(name.rw_sem), \
.writer = __RCUWAIT_INITIALIZER(name.writer), \
}
#define DEFINE_PERCPU_RWSEM(name) \
__DEFINE_PERCPU_RWSEM(name, /* not static */)
#define DEFINE_STATIC_PERCPU_RWSEM(name) \
__DEFINE_PERCPU_RWSEM(name, static)
extern int __percpu_down_read(struct percpu_rw_semaphore *, int);
extern void __percpu_up_read(struct percpu_rw_semaphore *);

40
include/linux/rcu_sync.h
View File

@ -13,62 +13,44 @@
#include <linux/wait.h>
#include <linux/rcupdate.h>
enum rcu_sync_type { RCU_SYNC, RCU_SCHED_SYNC, RCU_BH_SYNC };
/* Structure to mediate between updaters and fastpath-using readers. */
struct rcu_sync {
int gp_state;
int gp_count;
wait_queue_head_t gp_wait;
int cb_state;
struct rcu_head cb_head;
enum rcu_sync_type gp_type;
};
extern void rcu_sync_lockdep_assert(struct rcu_sync *);
/**
* rcu_sync_is_idle() - Are readers permitted to use their fastpaths?
* @rsp: Pointer to rcu_sync structure to use for synchronization
*
* Returns true if readers are permitted to use their fastpaths.
* Must be invoked within an RCU read-side critical section whose
* flavor matches that of the rcu_sync struture.
* Returns true if readers are permitted to use their fastpaths. Must be
* invoked within some flavor of RCU read-side critical section.
*/
static inline bool rcu_sync_is_idle(struct rcu_sync *rsp)
{
#ifdef CONFIG_PROVE_RCU
rcu_sync_lockdep_assert(rsp);
#endif
return !rsp->gp_state; /* GP_IDLE */
RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&
!rcu_read_lock_bh_held() &&
!rcu_read_lock_sched_held(),
"suspicious rcu_sync_is_idle() usage");
return !READ_ONCE(rsp->gp_state); /* GP_IDLE */
}
extern void rcu_sync_init(struct rcu_sync *, enum rcu_sync_type);
extern void rcu_sync_init(struct rcu_sync *);
extern void rcu_sync_enter_start(struct rcu_sync *);
extern void rcu_sync_enter(struct rcu_sync *);
extern void rcu_sync_exit(struct rcu_sync *);
extern void rcu_sync_dtor(struct rcu_sync *);
#define __RCU_SYNC_INITIALIZER(name, type) { \
#define __RCU_SYNC_INITIALIZER(name) { \
.gp_state = 0, \
.gp_count = 0, \
.gp_wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.gp_wait), \
.cb_state = 0, \
.gp_type = type, \
}
#define __DEFINE_RCU_SYNC(name, type) \
struct rcu_sync_struct name = __RCU_SYNC_INITIALIZER(name, type)
#define DEFINE_RCU_SYNC(name) \
__DEFINE_RCU_SYNC(name, RCU_SYNC)
#define DEFINE_RCU_SCHED_SYNC(name) \
__DEFINE_RCU_SYNC(name, RCU_SCHED_SYNC)
#define DEFINE_RCU_BH_SYNC(name) \
__DEFINE_RCU_SYNC(name, RCU_BH_SYNC)
#define DEFINE_RCU_SYNC(name) \
struct rcu_sync name = __RCU_SYNC_INITIALIZER(name)
#endif /* _LINUX_RCU_SYNC_H_ */

21
include/linux/rcupdate.h
View File

@ -365,16 +365,15 @@ static inline void rcu_preempt_sleep_check(void) { }
* other macros that it invokes.
*/
#define rcu_assign_pointer(p, v) \
({ \
do { \
uintptr_t _r_a_p__v = (uintptr_t)(v); \
rcu_check_sparse(p, __rcu); \
rcu_check_sparse(p, __rcu); \
\
if (__builtin_constant_p(v) && (_r_a_p__v) == (uintptr_t)NULL) \
WRITE_ONCE((p), (typeof(p))(_r_a_p__v)); \
else \
smp_store_release(&p, RCU_INITIALIZER((typeof(p))_r_a_p__v)); \
_r_a_p__v; \
})
} while (0)
/**
* rcu_swap_protected() - swap an RCU and a regular pointer
@ -586,7 +585,7 @@ static inline void rcu_preempt_sleep_check(void) { }
* read-side critical sections may be preempted and they may also block, but
* only when acquiring spinlocks that are subject to priority inheritance.
*/
static inline void rcu_read_lock(void)
static __always_inline void rcu_read_lock(void)
{
__rcu_read_lock();
__acquire(RCU);
@ -803,7 +802,7 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
/**
* kfree_rcu() - kfree an object after a grace period.
* @ptr: pointer to kfree
* @rcu_head: the name of the struct rcu_head within the type of @ptr.
* @rhf: the name of the struct rcu_head within the type of @ptr.
*
* Many rcu callbacks functions just call kfree() on the base structure.
* These functions are trivial, but their size adds up, and furthermore
@ -826,9 +825,13 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
* The BUILD_BUG_ON check must not involve any function calls, hence the
* checks are done in macros here.
*/
#define kfree_rcu(ptr, rcu_head) \
__kfree_rcu(&((ptr)->rcu_head), offsetof(typeof(*(ptr)), rcu_head))
#define kfree_rcu(ptr, rhf) \
do { \
typeof (ptr) ___p = (ptr); \
\
if (___p) \
__kfree_rcu(&((___p)->rhf), offsetof(typeof(*(ptr)), rhf)); \
} while (0)
/*
* Place this after a lock-acquisition primitive to guarantee that

2
include/linux/sched.h
View File

@ -565,7 +565,7 @@ union rcu_special {
u8 blocked;
u8 need_qs;
u8 exp_hint; /* Hint for performance. */
u8 pad; /* No garbage from compiler! */
u8 deferred_qs;
} b; /* Bits. */
u32 s; /* Set of bits. */
};

14
include/linux/srcutree.h
View File

@ -120,9 +120,17 @@ struct srcu_struct {
*
* See include/linux/percpu-defs.h for the rules on per-CPU variables.
*/
#define __DEFINE_SRCU(name, is_static) \
static DEFINE_PER_CPU(struct srcu_data, name##_srcu_data);\
is_static struct srcu_struct name = __SRCU_STRUCT_INIT(name, name##_srcu_data)
#ifdef MODULE
# define __DEFINE_SRCU(name, is_static) \
is_static struct srcu_struct name; \
struct srcu_struct * const __srcu_struct_##name \
__section("___srcu_struct_ptrs") = &name
#else
# define __DEFINE_SRCU(name, is_static) \
static DEFINE_PER_CPU(struct srcu_data, name##_srcu_data); \
is_static struct srcu_struct name = \
__SRCU_STRUCT_INIT(name, name##_srcu_data)
#endif
#define DEFINE_SRCU(name) __DEFINE_SRCU(name, /* not static */)
#define DEFINE_STATIC_SRCU(name) __DEFINE_SRCU(name, static)

2
include/linux/torture.h
View File

@ -66,7 +66,7 @@ int torture_shutdown_init(int ssecs, void (*cleanup)(void));
/* Task stuttering, which forces load/no-load transitions. */
bool stutter_wait(const char *title);
int torture_stutter_init(int s);
int torture_stutter_init(int s, int sgap);
/* Initialization and cleanup. */
bool torture_init_begin(char *ttype, int v);

3
kernel/cgroup/cgroup.c
View File

@ -101,7 +101,7 @@ static DEFINE_SPINLOCK(cgroup_idr_lock);
*/
static DEFINE_SPINLOCK(cgroup_file_kn_lock);
struct percpu_rw_semaphore cgroup_threadgroup_rwsem;
DEFINE_PERCPU_RWSEM(cgroup_threadgroup_rwsem);
#define cgroup_assert_mutex_or_rcu_locked() \
RCU_LOCKDEP_WARN(!rcu_read_lock_held() && \
@ -5666,7 +5666,6 @@ int __init cgroup_init(void)
int ssid;
BUILD_BUG_ON(CGROUP_SUBSYS_COUNT > 16);
BUG_ON(percpu_init_rwsem(&cgroup_threadgroup_rwsem));
BUG_ON(cgroup_init_cftypes(NULL, cgroup_base_files));
BUG_ON(cgroup_init_cftypes(NULL, cgroup1_base_files));

4
kernel/events/uprobes.c
View File

@ -46,7 +46,7 @@ static DEFINE_SPINLOCK(uprobes_treelock); /* serialize rbtree access */
static struct mutex uprobes_mmap_mutex[UPROBES_HASH_SZ];
#define uprobes_mmap_hash(v) (&uprobes_mmap_mutex[((unsigned long)(v)) % UPROBES_HASH_SZ])
static struct percpu_rw_semaphore dup_mmap_sem;
DEFINE_STATIC_PERCPU_RWSEM(dup_mmap_sem);
/* Have a copy of original instruction */
#define UPROBE_COPY_INSN 0
@ -2302,7 +2302,5 @@ void __init uprobes_init(void)
for (i = 0; i < UPROBES_HASH_SZ; i++)
mutex_init(&uprobes_mmap_mutex[i]);
BUG_ON(percpu_init_rwsem(&dup_mmap_sem));
BUG_ON(register_die_notifier(&uprobe_exception_nb));
}

2
kernel/locking/locktorture.c
View File

@ -975,7 +975,7 @@ static int __init lock_torture_init(void)
goto unwind;
}
if (stutter > 0) {
firsterr = torture_stutter_init(stutter);
firsterr = torture_stutter_init(stutter, stutter);
if (firsterr)
goto unwind;
}

2
kernel/locking/percpu-rwsem.c
View File

@ -18,7 +18,7 @@ int __percpu_init_rwsem(struct percpu_rw_semaphore *sem,
return -ENOMEM;
/* ->rw_sem represents the whole percpu_rw_semaphore for lockdep */
rcu_sync_init(&sem->rss, RCU_SCHED_SYNC);
rcu_sync_init(&sem->rss);
__init_rwsem(&sem->rw_sem, name, rwsem_key);
rcuwait_init(&sem->writer);
sem->readers_block = 0;

5
kernel/module.c
View File

@ -3083,6 +3083,11 @@ static int find_module_sections(struct module *mod, struct load_info *info)
sizeof(*mod->tracepoints_ptrs),
&mod->num_tracepoints);
#endif
#ifdef CONFIG_TREE_SRCU
mod->srcu_struct_ptrs = section_objs(info, "___srcu_struct_ptrs",
sizeof(*mod->srcu_struct_ptrs),
&mod->num_srcu_structs);
#endif
#ifdef CONFIG_BPF_EVENTS
mod->bpf_raw_events = section_objs(info, "__bpf_raw_tp_map",
sizeof(*mod->bpf_raw_events),

5
kernel/rcu/rcu.h
View File

@ -446,6 +446,7 @@ void rcu_request_urgent_qs_task(struct task_struct *t);
enum rcutorture_type {
RCU_FLAVOR,
RCU_TASKS_FLAVOR,
RCU_TRIVIAL_FLAVOR,
SRCU_FLAVOR,
INVALID_RCU_FLAVOR
};
@ -479,6 +480,10 @@ void do_trace_rcu_torture_read(const char *rcutorturename,
#endif
#endif
#if IS_ENABLED(CONFIG_RCU_TORTURE_TEST) || IS_MODULE(CONFIG_RCU_TORTURE_TEST)
long rcutorture_sched_setaffinity(pid_t pid, const struct cpumask *in_mask);
#endif
#ifdef CONFIG_TINY_SRCU
static inline void srcutorture_get_gp_data(enum rcutorture_type test_type,

96
kernel/rcu/rcutorture.c
View File

@ -299,6 +299,7 @@ struct rcu_torture_ops {
int irq_capable;
int can_boost;
int extendables;
int slow_gps;
const char *name;
};
@ -667,9 +668,51 @@ static struct rcu_torture_ops tasks_ops = {
.fqs = NULL,
.stats = NULL,
.irq_capable = 1,
.slow_gps = 1,
.name = "tasks"
};
/*
* Definitions for trivial CONFIG_PREEMPT=n-only torture testing.
* This implementation does not necessarily work well with CPU hotplug.
*/
static void synchronize_rcu_trivial(void)
{
int cpu;
for_each_online_cpu(cpu) {
rcutorture_sched_setaffinity(current->pid, cpumask_of(cpu));
WARN_ON_ONCE(raw_smp_processor_id() != cpu);
}
}
static int rcu_torture_read_lock_trivial(void) __acquires(RCU)
{
preempt_disable();
return 0;
}
static void rcu_torture_read_unlock_trivial(int idx) __releases(RCU)
{
preempt_enable();
}
static struct rcu_torture_ops trivial_ops = {
.ttype = RCU_TRIVIAL_FLAVOR,
.init = rcu_sync_torture_init,
.readlock = rcu_torture_read_lock_trivial,
.read_delay = rcu_read_delay, /* just reuse rcu's version. */
.readunlock = rcu_torture_read_unlock_trivial,
.get_gp_seq = rcu_no_completed,
.sync = synchronize_rcu_trivial,
.exp_sync = synchronize_rcu_trivial,
.fqs = NULL,
.stats = NULL,
.irq_capable = 1,
.name = "trivial"
};
static unsigned long rcutorture_seq_diff(unsigned long new, unsigned long old)
{
if (!cur_ops->gp_diff)
@ -1010,10 +1053,17 @@ rcu_torture_writer(void *arg)
!rcu_gp_is_normal();
}
rcu_torture_writer_state = RTWS_STUTTER;
if (stutter_wait("rcu_torture_writer"))
if (stutter_wait("rcu_torture_writer") &&
!READ_ONCE(rcu_fwd_cb_nodelay) &&
!cur_ops->slow_gps &&
!torture_must_stop())
for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++)
if (list_empty(&rcu_tortures[i].rtort_free))
WARN_ON_ONCE(1);
if (list_empty(&rcu_tortures[i].rtort_free) &&
rcu_access_pointer(rcu_torture_current) !=
&rcu_tortures[i]) {
rcu_ftrace_dump(DUMP_ALL);
WARN(1, "%s: rtort_pipe_count: %d\n", __func__, rcu_tortures[i].rtort_pipe_count);
}
} while (!torture_must_stop());
/* Reset expediting back to unexpedited. */
if (expediting > 0)
@ -1358,8 +1408,9 @@ rcu_torture_stats_print(void)
}
pr_alert("%s%s ", torture_type, TORTURE_FLAG);
pr_cont("rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
pr_cont("rtc: %p %s: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
rcu_torture_current,
rcu_torture_current ? "ver" : "VER",
rcu_torture_current_version,
list_empty(&rcu_torture_freelist),
atomic_read(&n_rcu_torture_alloc),
@ -1661,6 +1712,17 @@ static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp)
spin_unlock_irqrestore(&rcu_fwd_lock, flags);
}
// Give the scheduler a chance, even on nohz_full CPUs.
static void rcu_torture_fwd_prog_cond_resched(void)
{
if (IS_ENABLED(CONFIG_PREEMPT) && IS_ENABLED(CONFIG_NO_HZ_FULL)) {
if (need_resched())
schedule();
} else {
cond_resched();
}
}
/*
* Free all callbacks on the rcu_fwd_cb_head list, either because the
* test is over or because we hit an OOM event.
@ -1674,16 +1736,18 @@ static unsigned long rcu_torture_fwd_prog_cbfree(void)
for (;;) {
spin_lock_irqsave(&rcu_fwd_lock, flags);
rfcp = rcu_fwd_cb_head;
if (!rfcp)
if (!rfcp) {
spin_unlock_irqrestore(&rcu_fwd_lock, flags);
break;
}
rcu_fwd_cb_head = rfcp->rfc_next;
if (!rcu_fwd_cb_head)
rcu_fwd_cb_tail = &rcu_fwd_cb_head;
spin_unlock_irqrestore(&rcu_fwd_lock, flags);
kfree(rfcp);
freed++;
rcu_torture_fwd_prog_cond_resched();
}
spin_unlock_irqrestore(&rcu_fwd_lock, flags);
return freed;
}
@ -1707,6 +1771,8 @@ static void rcu_torture_fwd_prog_nr(int *tested, int *tested_tries)
}
/* Tight loop containing cond_resched(). */
WRITE_ONCE(rcu_fwd_cb_nodelay, true);
cur_ops->sync(); /* Later readers see above write. */
if (selfpropcb) {
WRITE_ONCE(fcs.stop, 0);
cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb);
@ -1724,7 +1790,7 @@ static void rcu_torture_fwd_prog_nr(int *tested, int *tested_tries)
udelay(10);
cur_ops->readunlock(idx);
if (!fwd_progress_need_resched || need_resched())
cond_resched();
rcu_torture_fwd_prog_cond_resched();
}
(*tested_tries)++;
if (!time_before(jiffies, stopat) &&
@ -1745,6 +1811,8 @@ static void rcu_torture_fwd_prog_nr(int *tested, int *tested_tries)
WARN_ON(READ_ONCE(fcs.stop) != 2);
destroy_rcu_head_on_stack(&fcs.rh);
}
schedule_timeout_uninterruptible(HZ / 10); /* Let kthreads recover. */
WRITE_ONCE(rcu_fwd_cb_nodelay, false);
}
/* Carry out call_rcu() forward-progress testing. */
@ -1765,6 +1833,8 @@ static void rcu_torture_fwd_prog_cr(void)
if (READ_ONCE(rcu_fwd_emergency_stop))
return; /* Get out of the way quickly, no GP wait! */
if (!cur_ops->call)
return; /* Can't do call_rcu() fwd prog without ->call. */
/* Loop continuously posting RCU callbacks. */
WRITE_ONCE(rcu_fwd_cb_nodelay, true);
@ -1805,7 +1875,7 @@ static void rcu_torture_fwd_prog_cr(void)
rfcp->rfc_gps = 0;
}
cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr);
cond_resched();
rcu_torture_fwd_prog_cond_resched();
}
stoppedat = jiffies;
n_launders_cb_snap = READ_ONCE(n_launders_cb);
@ -1814,7 +1884,6 @@ static void rcu_torture_fwd_prog_cr(void)
cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */
(void)rcu_torture_fwd_prog_cbfree();
WRITE_ONCE(rcu_fwd_cb_nodelay, false);
if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop)) {
WARN_ON(n_max_gps < MIN_FWD_CBS_LAUNDERED);
pr_alert("%s Duration %lu barrier: %lu pending %ld n_launders: %ld n_launders_sa: %ld n_max_gps: %ld n_max_cbs: %ld cver %ld gps %ld\n",
@ -1825,6 +1894,8 @@ static void rcu_torture_fwd_prog_cr(void)
n_max_gps, n_max_cbs, cver, gps);
rcu_torture_fwd_cb_hist();
}
schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */
WRITE_ONCE(rcu_fwd_cb_nodelay, false);
}
@ -2240,7 +2311,7 @@ rcu_torture_init(void)
int firsterr = 0;
static struct rcu_torture_ops *torture_ops[] = {
&rcu_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops,
&busted_srcud_ops, &tasks_ops,
&busted_srcud_ops, &tasks_ops, &trivial_ops,
};
if (!torture_init_begin(torture_type, verbose))
@ -2363,7 +2434,10 @@ rcu_torture_init(void)
if (stutter < 0)
stutter = 0;
if (stutter) {
firsterr = torture_stutter_init(stutter * HZ);
int t;
t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ;
firsterr = torture_stutter_init(stutter * HZ, t);
if (firsterr)
goto unwind;
}

69
kernel/rcu/srcutree.c
View File

@ -831,8 +831,8 @@ static void srcu_leak_callback(struct rcu_head *rhp)
* srcu_read_lock(), and srcu_read_unlock() that are all passed the same
* srcu_struct structure.
*/
void __call_srcu(struct srcu_struct *ssp, struct rcu_head *rhp,
rcu_callback_t func, bool do_norm)
static void __call_srcu(struct srcu_struct *ssp, struct rcu_head *rhp,
rcu_callback_t func, bool do_norm)
{
unsigned long flags;
int idx;
@ -1310,3 +1310,68 @@ void __init srcu_init(void)
queue_work(rcu_gp_wq, &ssp->work.work);
}
}
#ifdef CONFIG_MODULES
/* Initialize any global-scope srcu_struct structures used by this module. */
static int srcu_module_coming(struct module *mod)
{
int i;
struct srcu_struct **sspp = mod->srcu_struct_ptrs;
int ret;
for (i = 0; i < mod->num_srcu_structs; i++) {
ret = init_srcu_struct(*(sspp++));
if (WARN_ON_ONCE(ret))
return ret;
}
return 0;
}
/* Clean up any global-scope srcu_struct structures used by this module. */
static void srcu_module_going(struct module *mod)
{
int i;
struct srcu_struct **sspp = mod->srcu_struct_ptrs;
for (i = 0; i < mod->num_srcu_structs; i++)
cleanup_srcu_struct(*(sspp++));
}
/* Handle one module, either coming or going. */
static int srcu_module_notify(struct notifier_block *self,
unsigned long val, void *data)
{
struct module *mod = data;
int ret = 0;
switch (val) {
case MODULE_STATE_COMING:
ret = srcu_module_coming(mod);
break;
case MODULE_STATE_GOING:
srcu_module_going(mod);
break;
default:
break;
}
return ret;
}
static struct notifier_block srcu_module_nb = {
.notifier_call = srcu_module_notify,
.priority = 0,
};
static __init int init_srcu_module_notifier(void)
{
int ret;
ret = register_module_notifier(&srcu_module_nb);
if (ret)
pr_warn("Failed to register srcu module notifier\n");
return ret;
}
late_initcall(init_srcu_module_notifier);
#endif /* #ifdef CONFIG_MODULES */

240
kernel/rcu/sync.c
View File

@ -10,65 +10,18 @@
#include <linux/rcu_sync.h>
#include <linux/sched.h>
#ifdef CONFIG_PROVE_RCU
#define __INIT_HELD(func) .held = func,
#else
#define __INIT_HELD(func)
#endif
static const struct {
void (*sync)(void);
void (*call)(struct rcu_head *, void (*)(struct rcu_head *));
void (*wait)(void);
#ifdef CONFIG_PROVE_RCU
int (*held)(void);
#endif
} gp_ops[] = {
[RCU_SYNC] = {
.sync = synchronize_rcu,
.call = call_rcu,
.wait = rcu_barrier,
__INIT_HELD(rcu_read_lock_held)
},
[RCU_SCHED_SYNC] = {
.sync = synchronize_rcu,
.call = call_rcu,
.wait = rcu_barrier,
__INIT_HELD(rcu_read_lock_sched_held)
},
[RCU_BH_SYNC] = {
.sync = synchronize_rcu,
.call = call_rcu,
.wait = rcu_barrier,
__INIT_HELD(rcu_read_lock_bh_held)
},
};
enum { GP_IDLE = 0, GP_PENDING, GP_PASSED };
enum { CB_IDLE = 0, CB_PENDING, CB_REPLAY };
enum { GP_IDLE = 0, GP_ENTER, GP_PASSED, GP_EXIT, GP_REPLAY };
#define rss_lock gp_wait.lock
#ifdef CONFIG_PROVE_RCU
void rcu_sync_lockdep_assert(struct rcu_sync *rsp)
{
RCU_LOCKDEP_WARN(!gp_ops[rsp->gp_type].held(),
"suspicious rcu_sync_is_idle() usage");
}
EXPORT_SYMBOL_GPL(rcu_sync_lockdep_assert);
#endif
/**
* rcu_sync_init() - Initialize an rcu_sync structure
* @rsp: Pointer to rcu_sync structure to be initialized
* @type: Flavor of RCU with which to synchronize rcu_sync structure
*/
void rcu_sync_init(struct rcu_sync *rsp, enum rcu_sync_type type)
void rcu_sync_init(struct rcu_sync *rsp)
{
memset(rsp, 0, sizeof(*rsp));
init_waitqueue_head(&rsp->gp_wait);
rsp->gp_type = type;
}
/**
@ -86,6 +39,70 @@ void rcu_sync_enter_start(struct rcu_sync *rsp)
rsp->gp_state = GP_PASSED;
}
static void rcu_sync_func(struct rcu_head *rhp);
static void rcu_sync_call(struct rcu_sync *rsp)
{
call_rcu(&rsp->cb_head, rcu_sync_func);
}
/**
* rcu_sync_func() - Callback function managing reader access to fastpath
* @rhp: Pointer to rcu_head in rcu_sync structure to use for synchronization
*
* This function is passed to call_rcu() function by rcu_sync_enter() and
* rcu_sync_exit(), so that it is invoked after a grace period following the
* that invocation of enter/exit.
*
* If it is called by rcu_sync_enter() it signals that all the readers were
* switched onto slow path.
*
* If it is called by rcu_sync_exit() it takes action based on events that
* have taken place in the meantime, so that closely spaced rcu_sync_enter()
* and rcu_sync_exit() pairs need not wait for a grace period.
*
* If another rcu_sync_enter() is invoked before the grace period
* ended, reset state to allow the next rcu_sync_exit() to let the
* readers back onto their fastpaths (after a grace period). If both
* another rcu_sync_enter() and its matching rcu_sync_exit() are invoked
* before the grace period ended, re-invoke call_rcu() on behalf of that
* rcu_sync_exit(). Otherwise, set all state back to idle so that readers
* can again use their fastpaths.
*/
static void rcu_sync_func(struct rcu_head *rhp)
{
struct rcu_sync *rsp = container_of(rhp, struct rcu_sync, cb_head);
unsigned long flags;
WARN_ON_ONCE(READ_ONCE(rsp->gp_state) == GP_IDLE);
WARN_ON_ONCE(READ_ONCE(rsp->gp_state) == GP_PASSED);
spin_lock_irqsave(&rsp->rss_lock, flags);
if (rsp->gp_count) {
/*
* We're at least a GP after the GP_IDLE->GP_ENTER transition.
*/
WRITE_ONCE(rsp->gp_state, GP_PASSED);
wake_up_locked(&rsp->gp_wait);
} else if (rsp->gp_state == GP_REPLAY) {
/*
* A new rcu_sync_exit() has happened; requeue the callback to
* catch a later GP.
*/
WRITE_ONCE(rsp->gp_state, GP_EXIT);
rcu_sync_call(rsp);
} else {
/*
* We're at least a GP after the last rcu_sync_exit(); eveybody
* will now have observed the write side critical section.
* Let 'em rip!.
*/
WRITE_ONCE(rsp->gp_state, GP_IDLE);
}
spin_unlock_irqrestore(&rsp->rss_lock, flags);
}
/**
* rcu_sync_enter() - Force readers onto slowpath
* @rsp: Pointer to rcu_sync structure to use for synchronization
@ -103,84 +120,43 @@ void rcu_sync_enter_start(struct rcu_sync *rsp)
*/
void rcu_sync_enter(struct rcu_sync *rsp)
{
bool need_wait, need_sync;
int gp_state;
spin_lock_irq(&rsp->rss_lock);
need_wait = rsp->gp_count++;
need_sync = rsp->gp_state == GP_IDLE;
if (need_sync)
rsp->gp_state = GP_PENDING;
gp_state = rsp->gp_state;
if (gp_state == GP_IDLE) {
WRITE_ONCE(rsp->gp_state, GP_ENTER);
WARN_ON_ONCE(rsp->gp_count);
/*
* Note that we could simply do rcu_sync_call(rsp) here and
* avoid the "if (gp_state == GP_IDLE)" block below.
*
* However, synchronize_rcu() can be faster if rcu_expedited
* or rcu_blocking_is_gp() is true.
*
* Another reason is that we can't wait for rcu callback if
* we are called at early boot time but this shouldn't happen.
*/
}
rsp->gp_count++;
spin_unlock_irq(&rsp->rss_lock);
WARN_ON_ONCE(need_wait && need_sync);
if (need_sync) {
gp_ops[rsp->gp_type].sync();
rsp->gp_state = GP_PASSED;
wake_up_all(&rsp->gp_wait);
} else if (need_wait) {
wait_event(rsp->gp_wait, rsp->gp_state == GP_PASSED);
} else {
if (gp_state == GP_IDLE) {
/*
* Possible when there's a pending CB from a rcu_sync_exit().
* Nobody has yet been allowed the 'fast' path and thus we can
* avoid doing any sync(). The callback will get 'dropped'.
* See the comment above, this simply does the "synchronous"
* call_rcu(rcu_sync_func) which does GP_ENTER -> GP_PASSED.
*/
WARN_ON_ONCE(rsp->gp_state != GP_PASSED);
synchronize_rcu();
rcu_sync_func(&rsp->cb_head);
/* Not really needed, wait_event() would see GP_PASSED. */
return;
}
wait_event(rsp->gp_wait, READ_ONCE(rsp->gp_state) >= GP_PASSED);
}
/**
* rcu_sync_func() - Callback function managing reader access to fastpath
* @rhp: Pointer to rcu_head in rcu_sync structure to use for synchronization
*
* This function is passed to one of the call_rcu() functions by
* rcu_sync_exit(), so that it is invoked after a grace period following the
* that invocation of rcu_sync_exit(). It takes action based on events that
* have taken place in the meantime, so that closely spaced rcu_sync_enter()
* and rcu_sync_exit() pairs need not wait for a grace period.
*
* If another rcu_sync_enter() is invoked before the grace period
* ended, reset state to allow the next rcu_sync_exit() to let the
* readers back onto their fastpaths (after a grace period). If both
* another rcu_sync_enter() and its matching rcu_sync_exit() are invoked
* before the grace period ended, re-invoke call_rcu() on behalf of that
* rcu_sync_exit(). Otherwise, set all state back to idle so that readers
* can again use their fastpaths.
*/
static void rcu_sync_func(struct rcu_head *rhp)
{
struct rcu_sync *rsp = container_of(rhp, struct rcu_sync, cb_head);
unsigned long flags;
WARN_ON_ONCE(rsp->gp_state != GP_PASSED);
WARN_ON_ONCE(rsp->cb_state == CB_IDLE);
spin_lock_irqsave(&rsp->rss_lock, flags);
if (rsp->gp_count) {
/*
* A new rcu_sync_begin() has happened; drop the callback.
*/
rsp->cb_state = CB_IDLE;
} else if (rsp->cb_state == CB_REPLAY) {
/*
* A new rcu_sync_exit() has happened; requeue the callback
* to catch a later GP.
*/
rsp->cb_state = CB_PENDING;
gp_ops[rsp->gp_type].call(&rsp->cb_head, rcu_sync_func);
} else {
/*
* We're at least a GP after rcu_sync_exit(); eveybody will now
* have observed the write side critical section. Let 'em rip!.
*/
rsp->cb_state = CB_IDLE;
rsp->gp_state = GP_IDLE;
}
spin_unlock_irqrestore(&rsp->rss_lock, flags);
}
/**
* rcu_sync_exit() - Allow readers back onto fast patch after grace period
* rcu_sync_exit() - Allow readers back onto fast path after grace period
* @rsp: Pointer to rcu_sync structure to use for synchronization
*
* This function is used by updaters who have completed, and can therefore
@ -191,13 +167,16 @@ static void rcu_sync_func(struct rcu_head *rhp)
*/
void rcu_sync_exit(struct rcu_sync *rsp)
{
WARN_ON_ONCE(READ_ONCE(rsp->gp_state) == GP_IDLE);
WARN_ON_ONCE(READ_ONCE(rsp->gp_count) == 0);
spin_lock_irq(&rsp->rss_lock);
if (!--rsp->gp_count) {
if (rsp->cb_state == CB_IDLE) {
rsp->cb_state = CB_PENDING;
gp_ops[rsp->gp_type].call(&rsp->cb_head, rcu_sync_func);
} else if (rsp->cb_state == CB_PENDING) {
rsp->cb_state = CB_REPLAY;
if (rsp->gp_state == GP_PASSED) {
WRITE_ONCE(rsp->gp_state, GP_EXIT);
rcu_sync_call(rsp);
} else if (rsp->gp_state == GP_EXIT) {
WRITE_ONCE(rsp->gp_state, GP_REPLAY);
}
}
spin_unlock_irq(&rsp->rss_lock);
@ -209,18 +188,19 @@ void rcu_sync_exit(struct rcu_sync *rsp)
*/
void rcu_sync_dtor(struct rcu_sync *rsp)
{
int cb_state;
int gp_state;
WARN_ON_ONCE(rsp->gp_count);
WARN_ON_ONCE(READ_ONCE(rsp->gp_count));
WARN_ON_ONCE(READ_ONCE(rsp->gp_state) == GP_PASSED);
spin_lock_irq(&rsp->rss_lock);
if (rsp->cb_state == CB_REPLAY)
rsp->cb_state = CB_PENDING;
cb_state = rsp->cb_state;
if (rsp->gp_state == GP_REPLAY)
WRITE_ONCE(rsp->gp_state, GP_EXIT);
gp_state = rsp->gp_state;
spin_unlock_irq(&rsp->rss_lock);
if (cb_state != CB_IDLE) {
gp_ops[rsp->gp_type].wait();
WARN_ON_ONCE(rsp->cb_state != CB_IDLE);
if (gp_state != GP_IDLE) {
rcu_barrier();
WARN_ON_ONCE(rsp->gp_state != GP_IDLE);
}
}

168
kernel/rcu/tree.c
View File

@ -51,6 +51,12 @@
#include <linux/tick.h>
#include <linux/sysrq.h>
#include <linux/kprobes.h>
#include <linux/gfp.h>
#include <linux/oom.h>
#include <linux/smpboot.h>
#include <linux/jiffies.h>
#include <linux/sched/isolation.h>
#include "../time/tick-internal.h"
#include "tree.h"
#include "rcu.h"
@ -92,6 +98,9 @@ struct rcu_state rcu_state = {
/* Dump rcu_node combining tree at boot to verify correct setup. */
static bool dump_tree;
module_param(dump_tree, bool, 0444);
/* By default, use RCU_SOFTIRQ instead of rcuc kthreads. */
static bool use_softirq = 1;
module_param(use_softirq, bool, 0444);
/* Control rcu_node-tree auto-balancing at boot time. */
static bool rcu_fanout_exact;
module_param(rcu_fanout_exact, bool, 0444);
@ -138,7 +147,6 @@ static void rcu_init_new_rnp(struct rcu_node *rnp_leaf);
static void rcu_cleanup_dead_rnp(struct rcu_node *rnp_leaf);
static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu);
static void invoke_rcu_core(void);
static void invoke_rcu_callbacks(struct rcu_data *rdp);
static void rcu_report_exp_rdp(struct rcu_data *rdp);
static void sync_sched_exp_online_cleanup(int cpu);
@ -368,19 +376,33 @@ static void __maybe_unused rcu_momentary_dyntick_idle(void)
}
/**
* rcu_is_cpu_rrupt_from_idle - see if idle or immediately interrupted from idle
* rcu_is_cpu_rrupt_from_idle - see if interrupted from idle
*
* If the current CPU is idle or running at a first-level (not nested)
* If the current CPU is idle and running at a first-level (not nested)
* interrupt from idle, return true. The caller must have at least
* disabled preemption.
*/
static int rcu_is_cpu_rrupt_from_idle(void)
{
return __this_cpu_read(rcu_data.dynticks_nesting) <= 0 &&
__this_cpu_read(rcu_data.dynticks_nmi_nesting) <= 1;
/* Called only from within the scheduling-clock interrupt */
lockdep_assert_in_irq();
/* Check for counter underflows */
RCU_LOCKDEP_WARN(__this_cpu_read(rcu_data.dynticks_nesting) < 0,
"RCU dynticks_nesting counter underflow!");
RCU_LOCKDEP_WARN(__this_cpu_read(rcu_data.dynticks_nmi_nesting) <= 0,
"RCU dynticks_nmi_nesting counter underflow/zero!");
/* Are we at first interrupt nesting level? */
if (__this_cpu_read(rcu_data.dynticks_nmi_nesting) != 1)
return false;
/* Does CPU appear to be idle from an RCU standpoint? */
return __this_cpu_read(rcu_data.dynticks_nesting) == 0;
}
#define DEFAULT_RCU_BLIMIT 10 /* Maximum callbacks per rcu_do_batch. */
#define DEFAULT_RCU_BLIMIT 10 /* Maximum callbacks per rcu_do_batch ... */
#define DEFAULT_MAX_RCU_BLIMIT 10000 /* ... even during callback flood. */
static long blimit = DEFAULT_RCU_BLIMIT;
#define DEFAULT_RCU_QHIMARK 10000 /* If this many pending, ignore blimit. */
static long qhimark = DEFAULT_RCU_QHIMARK;
@ -2113,7 +2135,7 @@ static void rcu_do_batch(struct rcu_data *rdp)
/* Reinstate batch limit if we have worked down the excess. */
count = rcu_segcblist_n_cbs(&rdp->cblist);
if (rdp->blimit == LONG_MAX && count <= qlowmark)
if (rdp->blimit >= DEFAULT_MAX_RCU_BLIMIT && count <= qlowmark)
rdp->blimit = blimit;
/* Reset ->qlen_last_fqs_check trigger if enough CBs have drained. */
@ -2253,7 +2275,7 @@ void rcu_force_quiescent_state(void)
EXPORT_SYMBOL_GPL(rcu_force_quiescent_state);
/* Perform RCU core processing work for the current CPU. */
static __latent_entropy void rcu_core(struct softirq_action *unused)
static __latent_entropy void rcu_core(void)
{
unsigned long flags;
struct rcu_data *rdp = raw_cpu_ptr(&rcu_data);
@ -2287,38 +2309,127 @@ static __latent_entropy void rcu_core(struct softirq_action *unused)
rcu_check_gp_start_stall(rnp, rdp, rcu_jiffies_till_stall_check());
/* If there are callbacks ready, invoke them. */
if (rcu_segcblist_ready_cbs(&rdp->cblist))
invoke_rcu_callbacks(rdp);
if (rcu_segcblist_ready_cbs(&rdp->cblist) &&
likely(READ_ONCE(rcu_scheduler_fully_active)))
rcu_do_batch(rdp);
/* Do any needed deferred wakeups of rcuo kthreads. */
do_nocb_deferred_wakeup(rdp);
trace_rcu_utilization(TPS("End RCU core"));
}
/*
* Schedule RCU callback invocation. If the running implementation of RCU
* does not support RCU priority boosting, just do a direct call, otherwise
* wake up the per-CPU kernel kthread. Note that because we are running
* on the current CPU with softirqs disabled, the rcu_cpu_kthread_task
* cannot disappear out from under us.
*/
static void invoke_rcu_callbacks(struct rcu_data *rdp)
static void rcu_core_si(struct softirq_action *h)
{
if (unlikely(!READ_ONCE(rcu_scheduler_fully_active)))
return;
if (likely(!rcu_state.boost)) {
rcu_do_batch(rdp);
return;
}
invoke_rcu_callbacks_kthread();
rcu_core();
}
static void rcu_wake_cond(struct task_struct *t, int status)
{
/*
* If the thread is yielding, only wake it when this
* is invoked from idle
*/
if (t && (status != RCU_KTHREAD_YIELDING || is_idle_task(current)))
wake_up_process(t);
}
static void invoke_rcu_core_kthread(void)
{
struct task_struct *t;
unsigned long flags;
local_irq_save(flags);
__this_cpu_write(rcu_data.rcu_cpu_has_work, 1);
t = __this_cpu_read(rcu_data.rcu_cpu_kthread_task);
if (t != NULL && t != current)
rcu_wake_cond(t, __this_cpu_read(rcu_data.rcu_cpu_kthread_status));
local_irq_restore(flags);
}
/*
* Wake up this CPU's rcuc kthread to do RCU core processing.
*/
static void invoke_rcu_core(void)
{
if (cpu_online(smp_processor_id()))
if (!cpu_online(smp_processor_id()))
return;
if (use_softirq)
raise_softirq(RCU_SOFTIRQ);
else
invoke_rcu_core_kthread();
}
static void rcu_cpu_kthread_park(unsigned int cpu)
{
per_cpu(rcu_data.rcu_cpu_kthread_status, cpu) = RCU_KTHREAD_OFFCPU;
}
static int rcu_cpu_kthread_should_run(unsigned int cpu)
{
return __this_cpu_read(rcu_data.rcu_cpu_has_work);
}
/*
* Per-CPU kernel thread that invokes RCU callbacks. This replaces
* the RCU softirq used in configurations of RCU that do not support RCU
* priority boosting.
*/
static void rcu_cpu_kthread(unsigned int cpu)
{
unsigned int *statusp = this_cpu_ptr(&rcu_data.rcu_cpu_kthread_status);
char work, *workp = this_cpu_ptr(&rcu_data.rcu_cpu_has_work);
int spincnt;
for (spincnt = 0; spincnt < 10; spincnt++) {
trace_rcu_utilization(TPS("Start CPU kthread@rcu_wait"));
local_bh_disable();
*statusp = RCU_KTHREAD_RUNNING;
local_irq_disable();
work = *workp;
*workp = 0;
local_irq_enable();
if (work)
rcu_core();
local_bh_enable();
if (*workp == 0) {
trace_rcu_utilization(TPS("End CPU kthread@rcu_wait"));
*statusp = RCU_KTHREAD_WAITING;
return;
}
}
*statusp = RCU_KTHREAD_YIELDING;
trace_rcu_utilization(TPS("Start CPU kthread@rcu_yield"));
schedule_timeout_interruptible(2);
trace_rcu_utilization(TPS("End CPU kthread@rcu_yield"));
*statusp = RCU_KTHREAD_WAITING;
}
static struct smp_hotplug_thread rcu_cpu_thread_spec = {
.store = &rcu_data.rcu_cpu_kthread_task,
.thread_should_run = rcu_cpu_kthread_should_run,
.thread_fn = rcu_cpu_kthread,
.thread_comm = "rcuc/%u",
.setup = rcu_cpu_kthread_setup,
.park = rcu_cpu_kthread_park,
};
/*
* Spawn per-CPU RCU core processing kthreads.
*/
static int __init rcu_spawn_core_kthreads(void)
{
int cpu;
for_each_possible_cpu(cpu)
per_cpu(rcu_data.rcu_cpu_has_work, cpu) = 0;
if (!IS_ENABLED(CONFIG_RCU_BOOST) && use_softirq)
return 0;
WARN_ONCE(smpboot_register_percpu_thread(&rcu_cpu_thread_spec),
"%s: Could not start rcuc kthread, OOM is now expected behavior\n", __func__);
return 0;
}
early_initcall(rcu_spawn_core_kthreads);
/*
* Handle any core-RCU processing required by a call_rcu() invocation.
*/
@ -2354,7 +2465,7 @@ static void __call_rcu_core(struct rcu_data *rdp, struct rcu_head *head,
rcu_accelerate_cbs_unlocked(rdp->mynode, rdp);
} else {
/* Give the grace period a kick. */
rdp->blimit = LONG_MAX;
rdp->blimit = DEFAULT_MAX_RCU_BLIMIT;
if (rcu_state.n_force_qs == rdp->n_force_qs_snap &&
rcu_segcblist_first_pend_cb(&rdp->cblist) != head)
rcu_force_quiescent_state();
@ -3355,7 +3466,8 @@ void __init rcu_init(void)
rcu_init_one();
if (dump_tree)
rcu_dump_rcu_node_tree();
open_softirq(RCU_SOFTIRQ, rcu_core);
if (use_softirq)
open_softirq(RCU_SOFTIRQ, rcu_core_si);
/*
* We don't need protection against CPU-hotplug here because

6
kernel/rcu/tree.h
View File

@ -154,13 +154,15 @@ struct rcu_data {
bool core_needs_qs; /* Core waits for quiesc state. */
bool beenonline; /* CPU online at least once. */
bool gpwrap; /* Possible ->gp_seq wrap. */
bool deferred_qs; /* This CPU awaiting a deferred QS? */
bool exp_deferred_qs; /* This CPU awaiting a deferred QS? */
struct rcu_node *mynode; /* This CPU's leaf of hierarchy */
unsigned long grpmask; /* Mask to apply to leaf qsmask. */
unsigned long ticks_this_gp; /* The number of scheduling-clock */
/* ticks this CPU has handled */
/* during and after the last grace */
/* period it is aware of. */
struct irq_work defer_qs_iw; /* Obtain later scheduler attention. */
bool defer_qs_iw_pending; /* Scheduler attention pending? */
/* 2) batch handling */
struct rcu_segcblist cblist; /* Segmented callback list, with */
@ -407,8 +409,8 @@ void call_rcu(struct rcu_head *head, rcu_callback_t func);
static void dump_blkd_tasks(struct rcu_node *rnp, int ncheck);
static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags);
static void rcu_preempt_boost_start_gp(struct rcu_node *rnp);
static void invoke_rcu_callbacks_kthread(void);
static bool rcu_is_callbacks_kthread(void);
static void rcu_cpu_kthread_setup(unsigned int cpu);
static void __init rcu_spawn_boost_kthreads(void);
static void rcu_prepare_kthreads(int cpu);
static void rcu_cleanup_after_idle(void);

53
kernel/rcu/tree_exp.h
View File

@ -250,7 +250,7 @@ static void rcu_report_exp_cpu_mult(struct rcu_node *rnp,
*/
static void rcu_report_exp_rdp(struct rcu_data *rdp)
{
WRITE_ONCE(rdp->deferred_qs, false);
WRITE_ONCE(rdp->exp_deferred_qs, false);
rcu_report_exp_cpu_mult(rdp->mynode, rdp->grpmask, true);
}
@ -259,8 +259,7 @@ static bool sync_exp_work_done(unsigned long s)
{
if (rcu_exp_gp_seq_done(s)) {
trace_rcu_exp_grace_period(rcu_state.name, s, TPS("done"));
/* Ensure test happens before caller kfree(). */
smp_mb__before_atomic(); /* ^^^ */
smp_mb(); /* Ensure test happens before caller kfree(). */
return true;
}
return false;
@ -384,7 +383,12 @@ retry_ipi:
mask_ofl_test |= mask;
continue;
}
if (get_cpu() == cpu) {
put_cpu();
continue;
}
ret = smp_call_function_single(cpu, rcu_exp_handler, NULL, 0);
put_cpu();
if (!ret) {
mask_ofl_ipi &= ~mask;
continue;
@ -611,7 +615,7 @@ static void rcu_exp_handler(void *unused)
rcu_dynticks_curr_cpu_in_eqs()) {
rcu_report_exp_rdp(rdp);
} else {
rdp->deferred_qs = true;
rdp->exp_deferred_qs = true;
set_tsk_need_resched(t);
set_preempt_need_resched();
}
@ -633,7 +637,7 @@ static void rcu_exp_handler(void *unused)
if (t->rcu_read_lock_nesting > 0) {
raw_spin_lock_irqsave_rcu_node(rnp, flags);
if (rnp->expmask & rdp->grpmask) {
rdp->deferred_qs = true;
rdp->exp_deferred_qs = true;
t->rcu_read_unlock_special.b.exp_hint = true;
}
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
@ -656,7 +660,7 @@ static void rcu_exp_handler(void *unused)
*
* Otherwise, force a context switch after the CPU enables everything.
*/
rdp->deferred_qs = true;
rdp->exp_deferred_qs = true;
if (!(preempt_count() & (PREEMPT_MASK | SOFTIRQ_MASK)) ||
WARN_ON_ONCE(rcu_dynticks_curr_cpu_in_eqs())) {
rcu_preempt_deferred_qs(t);
@ -694,6 +698,16 @@ static int rcu_print_task_exp_stall(struct rcu_node *rnp)
#else /* #ifdef CONFIG_PREEMPT_RCU */
/* Request an expedited quiescent state. */
static void rcu_exp_need_qs(void)
{
__this_cpu_write(rcu_data.cpu_no_qs.b.exp, true);
/* Store .exp before .rcu_urgent_qs. */
smp_store_release(this_cpu_ptr(&rcu_data.rcu_urgent_qs), true);
set_tsk_need_resched(current);
set_preempt_need_resched();
}
/* Invoked on each online non-idle CPU for expedited quiescent state. */
static void rcu_exp_handler(void *unused)
{
@ -709,25 +723,38 @@ static void rcu_exp_handler(void *unused)
rcu_report_exp_rdp(this_cpu_ptr(&rcu_data));
return;
}
__this_cpu_write(rcu_data.cpu_no_qs.b.exp, true);
/* Store .exp before .rcu_urgent_qs. */
smp_store_release(this_cpu_ptr(&rcu_data.rcu_urgent_qs), true);
set_tsk_need_resched(current);
set_preempt_need_resched();
rcu_exp_need_qs();
}
/* Send IPI for expedited cleanup if needed at end of CPU-hotplug operation. */
static void sync_sched_exp_online_cleanup(int cpu)
{
unsigned long flags;
int my_cpu;
struct rcu_data *rdp;
int ret;
struct rcu_node *rnp;
rdp = per_cpu_ptr(&rcu_data, cpu);
rnp = rdp->mynode;
if (!(READ_ONCE(rnp->expmask) & rdp->grpmask))
my_cpu = get_cpu();
/* Quiescent state either not needed or already requested, leave. */
if (!(READ_ONCE(rnp->expmask) & rdp->grpmask) ||
__this_cpu_read(rcu_data.cpu_no_qs.b.exp)) {
put_cpu();
return;
}
/* Quiescent state needed on current CPU, so set it up locally. */
if (my_cpu == cpu) {
local_irq_save(flags);
rcu_exp_need_qs();
local_irq_restore(flags);
put_cpu();
return;
}
/* Quiescent state needed on some other CPU, send IPI. */
ret = smp_call_function_single(cpu, rcu_exp_handler, NULL, 0);
put_cpu();
WARN_ON_ONCE(ret);
}
@ -765,7 +792,6 @@ static int rcu_print_task_exp_stall(struct rcu_node *rnp)
*/
void synchronize_rcu_expedited(void)
{
struct rcu_data *rdp;
struct rcu_exp_work rew;
struct rcu_node *rnp;
unsigned long s;
@ -802,7 +828,6 @@ void synchronize_rcu_expedited(void)
}
/* Wait for expedited grace period to complete. */
rdp = per_cpu_ptr(&rcu_data, raw_smp_processor_id());
rnp = rcu_get_root();
wait_event(rnp->exp_wq[rcu_seq_ctr(s) & 0x3],
sync_exp_work_done(s));

197
kernel/rcu/tree_plugin.h
View File

@ -11,29 +11,7 @@
* Paul E. McKenney <paulmck@linux.ibm.com>
*/
#include <linux/delay.h>
#include <linux/gfp.h>
#include <linux/oom.h>
#include <linux/sched/debug.h>
#include <linux/smpboot.h>
#include <linux/sched/isolation.h>
#include <uapi/linux/sched/types.h>
#include "../time/tick-internal.h"
#ifdef CONFIG_RCU_BOOST
#include "../locking/rtmutex_common.h"
#else /* #ifdef CONFIG_RCU_BOOST */
/*
* Some architectures do not define rt_mutexes, but if !CONFIG_RCU_BOOST,
* all uses are in dead code. Provide a definition to keep the compiler
* happy, but add WARN_ON_ONCE() to complain if used in the wrong place.
* This probably needs to be excluded from -rt builds.
*/
#define rt_mutex_owner(a) ({ WARN_ON_ONCE(1); NULL; })
#define rt_mutex_futex_unlock(x) WARN_ON_ONCE(1)
#endif /* #else #ifdef CONFIG_RCU_BOOST */
#ifdef CONFIG_RCU_NOCB_CPU
static cpumask_var_t rcu_nocb_mask; /* CPUs to have callbacks offloaded. */
@ -94,6 +72,8 @@ static void __init rcu_bootup_announce_oddness(void)
pr_info("\tRCU debug GP init slowdown %d jiffies.\n", gp_init_delay);
if (gp_cleanup_delay)
pr_info("\tRCU debug GP init slowdown %d jiffies.\n", gp_cleanup_delay);
if (!use_softirq)
pr_info("\tRCU_SOFTIRQ processing moved to rcuc kthreads.\n");
if (IS_ENABLED(CONFIG_RCU_EQS_DEBUG))
pr_info("\tRCU debug extended QS entry/exit.\n");
rcupdate_announce_bootup_oddness();
@ -257,10 +237,10 @@ static void rcu_preempt_ctxt_queue(struct rcu_node *rnp, struct rcu_data *rdp)
* no need to check for a subsequent expedited GP. (Though we are
* still in a quiescent state in any case.)
*/
if (blkd_state & RCU_EXP_BLKD && rdp->deferred_qs)
if (blkd_state & RCU_EXP_BLKD && rdp->exp_deferred_qs)
rcu_report_exp_rdp(rdp);
else
WARN_ON_ONCE(rdp->deferred_qs);
WARN_ON_ONCE(rdp->exp_deferred_qs);
}
/*
@ -357,7 +337,7 @@ void rcu_note_context_switch(bool preempt)
* means that we continue to block the current grace period.
*/
rcu_qs();
if (rdp->deferred_qs)
if (rdp->exp_deferred_qs)
rcu_report_exp_rdp(rdp);
trace_rcu_utilization(TPS("End context switch"));
barrier(); /* Avoid RCU read-side critical sections leaking up. */
@ -471,14 +451,15 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags)
*/
special = t->rcu_read_unlock_special;
rdp = this_cpu_ptr(&rcu_data);
if (!special.s && !rdp->deferred_qs) {
if (!special.s && !rdp->exp_deferred_qs) {
local_irq_restore(flags);
return;
}
t->rcu_read_unlock_special.b.deferred_qs = false;
if (special.b.need_qs) {
rcu_qs();
t->rcu_read_unlock_special.b.need_qs = false;
if (!t->rcu_read_unlock_special.s && !rdp->deferred_qs) {
if (!t->rcu_read_unlock_special.s && !rdp->exp_deferred_qs) {
local_irq_restore(flags);
return;
}
@ -490,7 +471,7 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags)
* tasks are handled when removing the task from the
* blocked-tasks list below.
*/
if (rdp->deferred_qs) {
if (rdp->exp_deferred_qs) {
rcu_report_exp_rdp(rdp);
if (!t->rcu_read_unlock_special.s) {
local_irq_restore(flags);
@ -579,7 +560,7 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags)
*/
static bool rcu_preempt_need_deferred_qs(struct task_struct *t)
{
return (__this_cpu_read(rcu_data.deferred_qs) ||
return (__this_cpu_read(rcu_data.exp_deferred_qs) ||
READ_ONCE(t->rcu_read_unlock_special.s)) &&
t->rcu_read_lock_nesting <= 0;
}
@ -606,6 +587,17 @@ static void rcu_preempt_deferred_qs(struct task_struct *t)
t->rcu_read_lock_nesting += RCU_NEST_BIAS;
}
/*
* Minimal handler to give the scheduler a chance to re-evaluate.
*/
static void rcu_preempt_deferred_qs_handler(struct irq_work *iwp)
{
struct rcu_data *rdp;
rdp = container_of(iwp, struct rcu_data, defer_qs_iw);
rdp->defer_qs_iw_pending = false;
}
/*
* Handle special cases during rcu_read_unlock(), such as needing to
* notify RCU core processing or task having blocked during the RCU
@ -625,16 +617,41 @@ static void rcu_read_unlock_special(struct task_struct *t)
local_irq_save(flags);
irqs_were_disabled = irqs_disabled_flags(flags);
if (preempt_bh_were_disabled || irqs_were_disabled) {
WRITE_ONCE(t->rcu_read_unlock_special.b.exp_hint, false);
/* Need to defer quiescent state until everything is enabled. */
if (irqs_were_disabled) {
/* Enabling irqs does not reschedule, so... */
bool exp;
struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
struct rcu_node *rnp = rdp->mynode;
t->rcu_read_unlock_special.b.exp_hint = false;
exp = (t->rcu_blocked_node && t->rcu_blocked_node->exp_tasks) ||
(rdp->grpmask & rnp->expmask) ||
tick_nohz_full_cpu(rdp->cpu);
// Need to defer quiescent state until everything is enabled.
if ((exp || in_irq()) && irqs_were_disabled && use_softirq &&
(in_irq() || !t->rcu_read_unlock_special.b.deferred_qs)) {
// Using softirq, safe to awaken, and we get
// no help from enabling irqs, unlike bh/preempt.
raise_softirq_irqoff(RCU_SOFTIRQ);
} else if (exp && irqs_were_disabled && !use_softirq &&
!t->rcu_read_unlock_special.b.deferred_qs) {
// Safe to awaken and we get no help from enabling
// irqs, unlike bh/preempt.
invoke_rcu_core();
} else {
/* Enabling BH or preempt does reschedule, so... */
// Enabling BH or preempt does reschedule, so...
// Also if no expediting or NO_HZ_FULL, slow is OK.
set_tsk_need_resched(current);
set_preempt_need_resched();
if (IS_ENABLED(CONFIG_IRQ_WORK) &&
!rdp->defer_qs_iw_pending && exp) {
// Get scheduler to re-evaluate and call hooks.
// If !IRQ_WORK, FQS scan will eventually IPI.
init_irq_work(&rdp->defer_qs_iw,
rcu_preempt_deferred_qs_handler);
rdp->defer_qs_iw_pending = true;
irq_work_queue_on(&rdp->defer_qs_iw, rdp->cpu);
}
}
t->rcu_read_unlock_special.b.deferred_qs = true;
local_irq_restore(flags);
return;
}
@ -760,7 +777,7 @@ dump_blkd_tasks(struct rcu_node *rnp, int ncheck)
i = 0;
list_for_each(lhp, &rnp->blkd_tasks) {
pr_cont(" %p", lhp);
if (++i >= 10)
if (++i >= ncheck)
break;
}
pr_cont("\n");
@ -944,18 +961,21 @@ dump_blkd_tasks(struct rcu_node *rnp, int ncheck)
#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
#ifdef CONFIG_RCU_BOOST
static void rcu_wake_cond(struct task_struct *t, int status)
/*
* If boosting, set rcuc kthreads to realtime priority.
*/
static void rcu_cpu_kthread_setup(unsigned int cpu)
{
/*
* If the thread is yielding, only wake it when this
* is invoked from idle
*/
if (status != RCU_KTHREAD_YIELDING || is_idle_task(current))
wake_up_process(t);
#ifdef CONFIG_RCU_BOOST
struct sched_param sp;
sp.sched_priority = kthread_prio;
sched_setscheduler_nocheck(current, SCHED_FIFO, &sp);
#endif /* #ifdef CONFIG_RCU_BOOST */
}
#ifdef CONFIG_RCU_BOOST
/*
* Carry out RCU priority boosting on the task indicated by ->exp_tasks
* or ->boost_tasks, advancing the pointer to the next task in the
@ -1090,23 +1110,6 @@ static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags)
}
}
/*
* Wake up the per-CPU kthread to invoke RCU callbacks.
*/
static void invoke_rcu_callbacks_kthread(void)
{
unsigned long flags;
local_irq_save(flags);
__this_cpu_write(rcu_data.rcu_cpu_has_work, 1);
if (__this_cpu_read(rcu_data.rcu_cpu_kthread_task) != NULL &&
current != __this_cpu_read(rcu_data.rcu_cpu_kthread_task)) {
rcu_wake_cond(__this_cpu_read(rcu_data.rcu_cpu_kthread_task),
__this_cpu_read(rcu_data.rcu_cpu_kthread_status));
}
local_irq_restore(flags);
}
/*
* Is the current CPU running the RCU-callbacks kthread?
* Caller must have preemption disabled.
@ -1160,59 +1163,6 @@ static int rcu_spawn_one_boost_kthread(struct rcu_node *rnp)
return 0;
}
static void rcu_cpu_kthread_setup(unsigned int cpu)
{
struct sched_param sp;
sp.sched_priority = kthread_prio;
sched_setscheduler_nocheck(current, SCHED_FIFO, &sp);
}
static void rcu_cpu_kthread_park(unsigned int cpu)
{
per_cpu(rcu_data.rcu_cpu_kthread_status, cpu) = RCU_KTHREAD_OFFCPU;
}
static int rcu_cpu_kthread_should_run(unsigned int cpu)
{
return __this_cpu_read(rcu_data.rcu_cpu_has_work);
}
/*
* Per-CPU kernel thread that invokes RCU callbacks. This replaces
* the RCU softirq used in configurations of RCU that do not support RCU
* priority boosting.
*/
static void rcu_cpu_kthread(unsigned int cpu)
{
unsigned int *statusp = this_cpu_ptr(&rcu_data.rcu_cpu_kthread_status);
char work, *workp = this_cpu_ptr(&rcu_data.rcu_cpu_has_work);
int spincnt;
for (spincnt = 0; spincnt < 10; spincnt++) {
trace_rcu_utilization(TPS("Start CPU kthread@rcu_wait"));
local_bh_disable();
*statusp = RCU_KTHREAD_RUNNING;
local_irq_disable();
work = *workp;
*workp = 0;
local_irq_enable();
if (work)
rcu_do_batch(this_cpu_ptr(&rcu_data));
local_bh_enable();
if (*workp == 0) {
trace_rcu_utilization(TPS("End CPU kthread@rcu_wait"));
*statusp = RCU_KTHREAD_WAITING;
return;
}
}
*statusp = RCU_KTHREAD_YIELDING;
trace_rcu_utilization(TPS("Start CPU kthread@rcu_yield"));
schedule_timeout_interruptible(2);
trace_rcu_utilization(TPS("End CPU kthread@rcu_yield"));
*statusp = RCU_KTHREAD_WAITING;
}
/*
* Set the per-rcu_node kthread's affinity to cover all CPUs that are
* served by the rcu_node in question. The CPU hotplug lock is still
@ -1243,27 +1193,13 @@ static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu)
free_cpumask_var(cm);
}
static struct smp_hotplug_thread rcu_cpu_thread_spec = {
.store = &rcu_data.rcu_cpu_kthread_task,
.thread_should_run = rcu_cpu_kthread_should_run,
.thread_fn = rcu_cpu_kthread,
.thread_comm = "rcuc/%u",
.setup = rcu_cpu_kthread_setup,
.park = rcu_cpu_kthread_park,
};
/*
* Spawn boost kthreads -- called as soon as the scheduler is running.
*/
static void __init rcu_spawn_boost_kthreads(void)
{
struct rcu_node *rnp;
int cpu;
for_each_possible_cpu(cpu)
per_cpu(rcu_data.rcu_cpu_has_work, cpu) = 0;
if (WARN_ONCE(smpboot_register_percpu_thread(&rcu_cpu_thread_spec), "%s: Could not start rcub kthread, OOM is now expected behavior\n", __func__))
return;
rcu_for_each_leaf_node(rnp)
(void)rcu_spawn_one_boost_kthread(rnp);
}
@ -1286,11 +1222,6 @@ static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags)
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
static void invoke_rcu_callbacks_kthread(void)
{
WARN_ON_ONCE(1);
}
static bool rcu_is_callbacks_kthread(void)
{
return false;

4
kernel/rcu/tree_stall.h
View File

@ -630,7 +630,9 @@ static void rcu_check_gp_start_stall(struct rcu_node *rnp, struct rcu_data *rdp,
time_before(j, rcu_state.gp_req_activity + gpssdelay) ||
time_before(j, rcu_state.gp_activity + gpssdelay) ||
atomic_xchg(&warned, 1)) {
raw_spin_unlock_rcu_node(rnp_root); /* irqs remain disabled. */
if (rnp_root != rnp)
/* irqs remain disabled. */
raw_spin_unlock_rcu_node(rnp_root);
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
return;
}

13
kernel/rcu/update.c
View File

@ -423,6 +423,19 @@ EXPORT_SYMBOL_GPL(do_trace_rcu_torture_read);
do { } while (0)
#endif
#if IS_ENABLED(CONFIG_RCU_TORTURE_TEST) || IS_MODULE(CONFIG_RCU_TORTURE_TEST)
/* Get rcutorture access to sched_setaffinity(). */
long rcutorture_sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
{
int ret;
ret = sched_setaffinity(pid, in_mask);
WARN_ONCE(ret, "%s: sched_setaffinity() returned %d\n", __func__, ret);
return ret;
}
EXPORT_SYMBOL_GPL(rcutorture_sched_setaffinity);
#endif
#ifdef CONFIG_RCU_STALL_COMMON
int rcu_cpu_stall_suppress __read_mostly; /* 1 = suppress stall warnings. */
EXPORT_SYMBOL_GPL(rcu_cpu_stall_suppress);

23
kernel/torture.c
View File

@ -570,6 +570,7 @@ static void torture_shutdown_cleanup(void)
static struct task_struct *stutter_task;
static int stutter_pause_test;
static int stutter;
static int stutter_gap;
/*
* Block until the stutter interval ends. This must be called periodically
@ -578,10 +579,12 @@ static int stutter;
bool stutter_wait(const char *title)
{
int spt;
bool ret = false;
cond_resched_tasks_rcu_qs();
spt = READ_ONCE(stutter_pause_test);
for (; spt; spt = READ_ONCE(stutter_pause_test)) {
ret = true;
if (spt == 1) {
schedule_timeout_interruptible(1);
} else if (spt == 2) {
@ -592,7 +595,7 @@ bool stutter_wait(const char *title)
}
torture_shutdown_absorb(title);
}
return !!spt;
return ret;
}
EXPORT_SYMBOL_GPL(stutter_wait);
@ -602,17 +605,24 @@ EXPORT_SYMBOL_GPL(stutter_wait);
*/
static int torture_stutter(void *arg)
{
int wtime;
VERBOSE_TOROUT_STRING("torture_stutter task started");
do {
if (!torture_must_stop() && stutter > 1) {
WRITE_ONCE(stutter_pause_test, 1);
schedule_timeout_interruptible(stutter - 1);
wtime = stutter;
if (stutter > HZ + 1) {
WRITE_ONCE(stutter_pause_test, 1);
wtime = stutter - HZ - 1;
schedule_timeout_interruptible(wtime);
wtime = HZ + 1;
}
WRITE_ONCE(stutter_pause_test, 2);
schedule_timeout_interruptible(1);
schedule_timeout_interruptible(wtime);
}
WRITE_ONCE(stutter_pause_test, 0);
if (!torture_must_stop())
schedule_timeout_interruptible(stutter);
schedule_timeout_interruptible(stutter_gap);
torture_shutdown_absorb("torture_stutter");
} while (!torture_must_stop());
torture_kthread_stopping("torture_stutter");
@ -622,9 +632,10 @@ static int torture_stutter(void *arg)
/*
* Initialize and kick off the torture_stutter kthread.
*/
int torture_stutter_init(const int s)
int torture_stutter_init(const int s, const int sgap)
{
stutter = s;
stutter_gap = sgap;
return torture_create_kthread(torture_stutter, NULL, stutter_task);
}
EXPORT_SYMBOL_GPL(torture_stutter_init);

4
tools/include/linux/rcu.h
View File

@ -19,7 +19,7 @@ static inline bool rcu_is_watching(void)
return false;
}
#define rcu_assign_pointer(p, v) ((p) = (v))
#define RCU_INIT_POINTER(p, v) p=(v)
#define rcu_assign_pointer(p, v) do { (p) = (v); } while (0)
#define RCU_INIT_POINTER(p, v) do { (p) = (v); } while (0)
#endif

6
tools/memory-model/linux-kernel.bell
View File

@ -24,6 +24,7 @@ instructions RMW[{'once,'acquire,'release}]
enum Barriers = 'wmb (*smp_wmb*) ||
'rmb (*smp_rmb*) ||
'mb (*smp_mb*) ||
'barrier (*barrier*) ||
'rcu-lock (*rcu_read_lock*) ||
'rcu-unlock (*rcu_read_unlock*) ||
'sync-rcu (*synchronize_rcu*) ||
@ -76,3 +77,8 @@ flag ~empty rcu-rscs & (po ; [Sync-srcu] ; po) as invalid-sleep
(* Validate SRCU dynamic match *)
flag ~empty different-values(srcu-rscs) as srcu-bad-nesting
(* Compute marked and plain memory accesses *)
let Marked = (~M) | IW | Once | Release | Acquire | domain(rmw) | range(rmw) |
LKR | LKW | UL | LF | RL | RU
let Plain = M \ Marked

102
tools/memory-model/linux-kernel.cat
View File

@ -24,8 +24,14 @@ include "lock.cat"
(* Basic relations *)
(*******************)
(* Release Acquire *)
let acq-po = [Acquire] ; po ; [M]
let po-rel = [M] ; po ; [Release]
let po-unlock-rf-lock-po = po ; [UL] ; rf ; [LKR] ; po
(* Fences *)
let rmb = [R \ Noreturn] ; fencerel(Rmb) ; [R \ Noreturn]
let R4rmb = R \ Noreturn (* Reads for which rmb works *)
let rmb = [R4rmb] ; fencerel(Rmb) ; [R4rmb]
let wmb = [W] ; fencerel(Wmb) ; [W]
let mb = ([M] ; fencerel(Mb) ; [M]) |
([M] ; fencerel(Before-atomic) ; [RMW] ; po? ; [M]) |
@ -34,13 +40,14 @@ let mb = ([M] ; fencerel(Mb) ; [M]) |
([M] ; po ; [UL] ; (co | po) ; [LKW] ;
fencerel(After-unlock-lock) ; [M])
let gp = po ; [Sync-rcu | Sync-srcu] ; po?
let strong-fence = mb | gp
(* Release Acquire *)
let acq-po = [Acquire] ; po ; [M]
let po-rel = [M] ; po ; [Release]
let po-unlock-rf-lock-po = po ; [UL] ; rf ; [LKR] ; po
let nonrw-fence = strong-fence | po-rel | acq-po
let fence = nonrw-fence | wmb | rmb
let barrier = fencerel(Barrier | Rmb | Wmb | Mb | Sync-rcu | Sync-srcu |
Before-atomic | After-atomic | Acquire | Release |
Rcu-lock | Rcu-unlock | Srcu-lock | Srcu-unlock) |
(po ; [Release]) | ([Acquire] ; po)
(**********************************)
(* Fundamental coherence ordering *)
@ -61,21 +68,22 @@ empty rmw & (fre ; coe) as atomic
let dep = addr | data
let rwdep = (dep | ctrl) ; [W]
let overwrite = co | fr
let to-w = rwdep | (overwrite & int)
let to-r = addr | (dep ; rfi)
let fence = strong-fence | wmb | po-rel | rmb | acq-po
let to-w = rwdep | (overwrite & int) | (addr ; [Plain] ; wmb)
let to-r = addr | (dep ; [Marked] ; rfi)
let ppo = to-r | to-w | fence | (po-unlock-rf-lock-po & int)
(* Propagation: Ordering from release operations and strong fences. *)
let A-cumul(r) = rfe? ; r
let cumul-fence = A-cumul(strong-fence | po-rel) | wmb | po-unlock-rf-lock-po
let prop = (overwrite & ext)? ; cumul-fence* ; rfe?
let A-cumul(r) = (rfe ; [Marked])? ; r
let cumul-fence = [Marked] ; (A-cumul(strong-fence | po-rel) | wmb |
po-unlock-rf-lock-po) ; [Marked]
let prop = [Marked] ; (overwrite & ext)? ; cumul-fence* ;
[Marked] ; rfe? ; [Marked]
(*
* Happens Before: Ordering from the passage of time.
* No fences needed here for prop because relation confined to one process.
*)
let hb = ppo | rfe | ((prop \ id) & int)
let hb = [Marked] ; (ppo | rfe | ((prop \ id) & int)) ; [Marked]
acyclic hb as happens-before
(****************************************)
@ -83,7 +91,7 @@ acyclic hb as happens-before
(****************************************)
(* Propagation: Each non-rf link needs a strong fence. *)
let pb = prop ; strong-fence ; hb*
let pb = prop ; strong-fence ; hb* ; [Marked]
acyclic pb as propagation
(*******)
@ -114,24 +122,28 @@ let rcu-link = po? ; hb* ; pb* ; prop ; po
(*
* Any sequence containing at least as many grace periods as RCU read-side
* critical sections (joined by rcu-link) acts as a generalized strong fence.
* critical sections (joined by rcu-link) induces order like a generalized
* inter-CPU strong fence.
* Likewise for SRCU grace periods and read-side critical sections, provided
* the synchronize_srcu() and srcu_read_[un]lock() calls refer to the same
* struct srcu_struct location.
*)
let rec rcu-fence = rcu-gp | srcu-gp |
let rec rcu-order = rcu-gp | srcu-gp |
(rcu-gp ; rcu-link ; rcu-rscsi) |
((srcu-gp ; rcu-link ; srcu-rscsi) & loc) |
(rcu-rscsi ; rcu-link ; rcu-gp) |
((srcu-rscsi ; rcu-link ; srcu-gp) & loc) |
(rcu-gp ; rcu-link ; rcu-fence ; rcu-link ; rcu-rscsi) |
((srcu-gp ; rcu-link ; rcu-fence ; rcu-link ; srcu-rscsi) & loc) |
(rcu-rscsi ; rcu-link ; rcu-fence ; rcu-link ; rcu-gp) |
((srcu-rscsi ; rcu-link ; rcu-fence ; rcu-link ; srcu-gp) & loc) |
(rcu-fence ; rcu-link ; rcu-fence)
(rcu-gp ; rcu-link ; rcu-order ; rcu-link ; rcu-rscsi) |
((srcu-gp ; rcu-link ; rcu-order ; rcu-link ; srcu-rscsi) & loc) |
(rcu-rscsi ; rcu-link ; rcu-order ; rcu-link ; rcu-gp) |
((srcu-rscsi ; rcu-link ; rcu-order ; rcu-link ; srcu-gp) & loc) |
(rcu-order ; rcu-link ; rcu-order)
let rcu-fence = po ; rcu-order ; po?
let fence = fence | rcu-fence
let strong-fence = strong-fence | rcu-fence
(* rb orders instructions just as pb does *)
let rb = prop ; po ; rcu-fence ; po? ; hb* ; pb*
let rb = prop ; rcu-fence ; hb* ; pb* ; [Marked]
irreflexive rb as rcu
@ -143,3 +155,49 @@ irreflexive rb as rcu
* let xb = hb | pb | rb
* acyclic xb as executes-before
*)
(*********************************)
(* Plain accesses and data races *)
(*********************************)
(* Warn about plain writes and marked accesses in the same region *)
let mixed-accesses = ([Plain & W] ; (po-loc \ barrier) ; [Marked]) |
([Marked] ; (po-loc \ barrier) ; [Plain & W])
flag ~empty mixed-accesses as mixed-accesses
(* Executes-before and visibility *)
let xbstar = (hb | pb | rb)*
let vis = cumul-fence* ; rfe? ; [Marked] ;
((strong-fence ; [Marked] ; xbstar) | (xbstar & int))
(* Boundaries for lifetimes of plain accesses *)
let w-pre-bounded = [Marked] ; (addr | fence)?
let r-pre-bounded = [Marked] ; (addr | nonrw-fence |
([R4rmb] ; fencerel(Rmb) ; [~Noreturn]))?
let w-post-bounded = fence? ; [Marked]
let r-post-bounded = (nonrw-fence | ([~Noreturn] ; fencerel(Rmb) ; [R4rmb]))? ;
[Marked]
(* Visibility and executes-before for plain accesses *)
let ww-vis = fence | (strong-fence ; xbstar ; w-pre-bounded) |
(w-post-bounded ; vis ; w-pre-bounded)
let wr-vis = fence | (strong-fence ; xbstar ; r-pre-bounded) |
(w-post-bounded ; vis ; r-pre-bounded)
let rw-xbstar = fence | (r-post-bounded ; xbstar ; w-pre-bounded)
(* Potential races *)
let pre-race = ext & ((Plain * M) | ((M \ IW) * Plain))
(* Coherence requirements for plain accesses *)
let wr-incoh = pre-race & rf & rw-xbstar^-1
let rw-incoh = pre-race & fr & wr-vis^-1
let ww-incoh = pre-race & co & ww-vis^-1
empty (wr-incoh | rw-incoh | ww-incoh) as plain-coherence
(* Actual races *)
let ww-nonrace = ww-vis & ((Marked * W) | rw-xbstar) & ((W * Marked) | wr-vis)
let ww-race = (pre-race & co) \ ww-nonrace
let wr-race = (pre-race & (co? ; rf)) \ wr-vis
let rw-race = (pre-race & fr) \ rw-xbstar
flag ~empty (ww-race | wr-race | rw-race) as data-race

1
tools/memory-model/linux-kernel.def
View File

@ -24,6 +24,7 @@ smp_mb__before_atomic() { __fence{before-atomic}; }
smp_mb__after_atomic() { __fence{after-atomic}; }
smp_mb__after_spinlock() { __fence{after-spinlock}; }
smp_mb__after_unlock_lock() { __fence{after-unlock-lock}; }
barrier() { __fence{barrier}; }
// Exchange
xchg(X,V) __xchg{mb}(X,V)

2
tools/memory-model/litmus-tests/MP+poonceonces.litmus
View File

@ -1,7 +1,7 @@
C MP+poonceonces
(*
* Result: Maybe
* Result: Sometimes
*
* Can the counter-intuitive message-passing outcome be prevented with
* no ordering at all?

2
tools/memory-model/litmus-tests/README
View File

@ -244,7 +244,7 @@ produce the name:
Adding the ".litmus" suffix: SB+rfionceonce-poonceonces.litmus
The descriptors that describe connections between consecutive accesses
within the cycle through a given litmus test can be provided by the herd
within the cycle through a given litmus test can be provided by the herd7
tool (Rfi, Po, Fre, and so on) or by the linux-kernel.bell file (Once,
Release, Acquire, and so on).

2
tools/memory-model/lock.cat
View File

@ -11,7 +11,7 @@
include "cross.cat"
(*
* The lock-related events generated by herd are as follows:
* The lock-related events generated by herd7 are as follows:
*
* LKR Lock-Read: the read part of a spin_lock() or successful
* spin_trylock() read-modify-write event pair

4
tools/memory-model/scripts/README
View File

@ -22,7 +22,7 @@ checklitmushist.sh
Run all litmus tests having .litmus.out files from previous
initlitmushist.sh or newlitmushist.sh runs, comparing the
herd output to that of the original runs.
herd7 output to that of the original runs.
checklitmus.sh
@ -43,7 +43,7 @@ initlitmushist.sh
judgelitmus.sh
Given a .litmus file and its .litmus.out herd output, check the
Given a .litmus file and its .litmus.out herd7 output, check the
.litmus.out file against the .litmus file's "Result:" comment to
judge whether the test ran correctly. Not normally run manually,
provided instead for use by other scripts.

2
tools/memory-model/scripts/checkalllitmus.sh
View File

@ -1,7 +1,7 @@
#!/bin/sh
# SPDX-License-Identifier: GPL-2.0+
#
# Run herd tests on all .litmus files in the litmus-tests directory
# Run herd7 tests on all .litmus files in the litmus-tests directory
# and check each file's result against a "Result:" comment within that
# litmus test. If the verification result does not match that specified
# in the litmus test, this script prints an error message prefixed with

2
tools/memory-model/scripts/checklitmus.sh
View File

@ -1,7 +1,7 @@
#!/bin/sh
# SPDX-License-Identifier: GPL-2.0+
#
# Run a herd test and invokes judgelitmus.sh to check the result against
# Run a herd7 test and invokes judgelitmus.sh to check the result against
# a "Result:" comment within the litmus test. It also outputs verification
# results to a file whose name is that of the specified litmus test, but
# with ".out" appended.

2
tools/memory-model/scripts/parseargs.sh
View File

@ -91,7 +91,7 @@ do
shift
;;
--herdopts|--herdopt)
checkarg --destdir "(herd options)" "$#" "$2" '.*' '^--'
checkarg --destdir "(herd7 options)" "$#" "$2" '.*' '^--'
LKMM_HERD_OPTIONS="$2"
shift
;;

2
tools/memory-model/scripts/runlitmushist.sh
View File

@ -79,7 +79,7 @@ then
echo ' ---' Summary: 1>&2
grep '!!!' $T/*.sh.out 1>&2
nfail="`grep '!!!' $T/*.sh.out | wc -l`"
echo 'Number of failed herd runs (e.g., timeout): ' $nfail 1>&2
echo 'Number of failed herd7 runs (e.g., timeout): ' $nfail 1>&2
exit 1
else
echo All runs completed successfully. 1>&2

2
tools/testing/radix-tree/linux/rcupdate.h
View File

@ -7,6 +7,6 @@
#define rcu_dereference_raw(p) rcu_dereference(p)
#define rcu_dereference_protected(p, cond) rcu_dereference(p)
#define rcu_dereference_check(p, cond) rcu_dereference(p)
#define RCU_INIT_POINTER(p, v) (p) = (v)
#define RCU_INIT_POINTER(p, v) do { (p) = (v); } while (0)
#endif

3
tools/testing/selftests/rcutorture/Makefile Normal file
View File

@ -0,0 +1,3 @@
# SPDX-License-Identifier: GPL-2.0+
all:
( cd ../../../..; tools/testing/selftests/rcutorture/bin/kvm.sh --duration 10 --configs TREE01 )

39
tools/testing/selftests/rcutorture/bin/configinit.sh
View File

@ -1,7 +1,7 @@
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0+
#
# Usage: configinit.sh config-spec-file build-output-dir results-dir
# Usage: configinit.sh config-spec-file results-dir
#
# Create a .config file from the spec file. Run from the kernel source tree.
# Exits with 0 if all went well, with 1 if all went well but the config
@ -11,10 +11,6 @@
# desired settings, for example, "CONFIG_NO_HZ=y". For best results,
# this should be a full pathname.
#
# The second argument is a optional path to a build output directory,
# for example, "O=/tmp/foo". If this argument is omitted, the .config
# file will be generated directly in the current directory.
#
# Copyright (C) IBM Corporation, 2013
#
# Authors: Paul E. McKenney <paulmck@linux.ibm.com>
@ -26,34 +22,23 @@ mkdir $T
# Capture config spec file.
c=$1
buildloc=$2
resdir=$3
builddir=
if echo $buildloc | grep -q '^O='
then
builddir=`echo $buildloc | sed -e 's/^O=//'`
if test ! -d $builddir
then
mkdir $builddir
fi
else
echo Bad build directory: \"$buildloc\"
exit 2
fi
resdir=$2
sed -e 's/^\(CONFIG[0-9A-Z_]*\)=.*$/grep -v "^# \1" |/' < $c > $T/u.sh
sed -e 's/^\(CONFIG[0-9A-Z_]*=\).*$/grep -v \1 |/' < $c >> $T/u.sh
grep '^grep' < $T/u.sh > $T/upd.sh
echo "cat - $c" >> $T/upd.sh
make mrproper
make $buildloc distclean > $resdir/Make.distclean 2>&1
make $buildloc $TORTURE_DEFCONFIG > $resdir/Make.defconfig.out 2>&1
mv $builddir/.config $builddir/.config.sav
sh $T/upd.sh < $builddir/.config.sav > $builddir/.config
cp $builddir/.config $builddir/.config.new
yes '' | make $buildloc oldconfig > $resdir/Make.oldconfig.out 2> $resdir/Make.oldconfig.err
if test -z "$TORTURE_TRUST_MAKE"
then
make clean > $resdir/Make.clean 2>&1
fi
make $TORTURE_DEFCONFIG > $resdir/Make.defconfig.out 2>&1
mv .config .config.sav
sh $T/upd.sh < .config.sav > .config
cp .config .config.new
yes '' | make oldconfig > $resdir/Make.oldconfig.out 2> $resdir/Make.oldconfig.err
# verify new config matches specification.
configcheck.sh $builddir/.config $c
configcheck.sh .config $c
exit 0

5
tools/testing/selftests/rcutorture/bin/cpus2use.sh
View File

@ -9,6 +9,11 @@
#
# Authors: Paul E. McKenney <paulmck@linux.ibm.com>
if test -n "$TORTURE_ALLOTED_CPUS"
then
echo $TORTURE_ALLOTED_CPUS
exit 0
fi
ncpus=`grep '^processor' /proc/cpuinfo | wc -l`
idlecpus=`mpstat | tail -1 | \
awk -v ncpus=$ncpus '{ print ncpus * ($7 + $NF) / 100 }'`

13
tools/testing/selftests/rcutorture/bin/functions.sh
View File

@ -172,7 +172,7 @@ identify_qemu_append () {
local console=ttyS0
case "$1" in
qemu-system-x86_64|qemu-system-i386)
echo noapic selinux=0 initcall_debug debug
echo selinux=0 initcall_debug debug
;;
qemu-system-aarch64)
console=ttyAMA0
@ -191,8 +191,19 @@ identify_qemu_append () {
# Output arguments for qemu arguments based on the TORTURE_QEMU_MAC
# and TORTURE_QEMU_INTERACTIVE environment variables.
identify_qemu_args () {
local KVM_CPU=""
case "$1" in
qemu-system-x86_64)
KVM_CPU=kvm64
;;
qemu-system-i386)
KVM_CPU=kvm32
;;
esac
case "$1" in
qemu-system-x86_64|qemu-system-i386)
echo -machine q35,accel=kvm
echo -cpu ${KVM_CPU}
;;
qemu-system-aarch64)
echo -machine virt,gic-version=host -cpu host

13
tools/testing/selftests/rcutorture/bin/jitter.sh
View File

@ -34,10 +34,15 @@ do
exit 0;
fi
# Set affinity to randomly selected CPU
cpus=`ls /sys/devices/system/cpu/*/online |
sed -e 's,/[^/]*$,,' -e 's/^[^0-9]*//' |
grep -v '^0*$'`
# Set affinity to randomly selected online CPU
cpus=`grep 1 /sys/devices/system/cpu/*/online |
sed -e 's,/[^/]*$,,' -e 's/^[^0-9]*//'`
# Do not leave out poor old cpu0 which may not be hot-pluggable
if [ ! -f "/sys/devices/system/cpu/cpu0/online" ]; then
cpus="0 $cpus"
fi
cpumask=`awk -v cpus="$cpus" -v me=$me -v n=$n 'BEGIN {
srand(n + me + systime());
ncpus = split(cpus, ca);

9
tools/testing/selftests/rcutorture/bin/kvm-build.sh
View File

@ -3,7 +3,7 @@
#
# Build a kvm-ready Linux kernel from the tree in the current directory.
#
# Usage: kvm-build.sh config-template build-dir resdir
# Usage: kvm-build.sh config-template resdir
#
# Copyright (C) IBM Corporation, 2011
#
@ -15,8 +15,7 @@ then
echo "kvm-build.sh :$config_template: Not a readable file"
exit 1
fi
builddir=${2}
resdir=${3}
resdir=${2}
T=${TMPDIR-/tmp}/test-linux.sh.$$
trap 'rm -rf $T' 0
@ -29,14 +28,14 @@ CONFIG_VIRTIO_PCI=y
CONFIG_VIRTIO_CONSOLE=y
___EOF___
configinit.sh $T/config O=$builddir $resdir
configinit.sh $T/config $resdir
retval=$?
if test $retval -gt 1
then
exit 2
fi
ncpus=`cpus2use.sh`
make O=$builddir -j$ncpus $TORTURE_KMAKE_ARG > $resdir/Make.out 2>&1
make -j$ncpus $TORTURE_KMAKE_ARG > $resdir/Make.out 2>&1
retval=$?
if test $retval -ne 0 || grep "rcu[^/]*": < $resdir/Make.out | egrep -q "Stop|Error|error:|warning:" || egrep -q "Stop|Error|error:" < $resdir/Make.out
then

3
tools/testing/selftests/rcutorture/bin/kvm-find-errors.sh
View File

@ -11,6 +11,7 @@
#
# The "directory" above should end with the date/time directory, for example,
# "tools/testing/selftests/rcutorture/res/2018.02.25-14:27:27".
# Returns error status reflecting the success (or not) of the specified run.
#
# Copyright (C) IBM Corporation, 2018
#
@ -56,6 +57,8 @@ done
if test -n "$files"
then
$editor $files
exit 1
else
echo No errors in console logs.
exit 0
fi

13
tools/testing/selftests/rcutorture/bin/kvm-recheck.sh
View File

@ -7,6 +7,8 @@
#
# Usage: kvm-recheck.sh resdir ...
#
# Returns status reflecting the success or not of the last run specified.
#
# Copyright (C) IBM Corporation, 2011
#
# Authors: Paul E. McKenney <paulmck@linux.ibm.com>
@ -28,8 +30,16 @@ do
TORTURE_SUITE="`cat $i/../TORTURE_SUITE`"
rm -f $i/console.log.*.diags
kvm-recheck-${TORTURE_SUITE}.sh $i
if test -f "$i/console.log"
if test -f "$i/qemu-retval" && test "`cat $i/qemu-retval`" -ne 0 && test "`cat $i/qemu-retval`" -ne 137
then
echo QEMU error, output:
cat $i/qemu-output
elif test -f "$i/console.log"
then
if test -f "$i/qemu-retval" && test "`cat $i/qemu-retval`" -eq 137
then
echo QEMU killed
fi
configcheck.sh $i/.config $i/ConfigFragment
if test -r $i/Make.oldconfig.err
then
@ -58,3 +68,4 @@ do
fi
done
done
EDITOR=echo kvm-find-errors.sh "${@: -1}" > /dev/null 2>&1

23
tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh
View File

@ -36,11 +36,6 @@ config_template=${1}
config_dir=`echo $config_template | sed -e 's,/[^/]*$,,'`
title=`echo $config_template | sed -e 's/^.*\///'`
builddir=${2}
if test -z "$builddir" -o ! -d "$builddir" -o ! -w "$builddir"
then
echo "kvm-test-1-run.sh :$builddir: Not a writable directory, cannot build into it"
exit 1
fi
resdir=${3}
if test -z "$resdir" -o ! -d "$resdir" -o ! -w "$resdir"
then
@ -85,18 +80,18 @@ then
ln -s $base_resdir/.config $resdir # for kvm-recheck.sh
# Arch-independent indicator
touch $resdir/builtkernel
elif kvm-build.sh $T/Kc2 $builddir $resdir
elif kvm-build.sh $T/Kc2 $resdir
then
# Had to build a kernel for this test.
QEMU="`identify_qemu $builddir/vmlinux`"
QEMU="`identify_qemu vmlinux`"
BOOT_IMAGE="`identify_boot_image $QEMU`"
cp $builddir/vmlinux $resdir
cp $builddir/.config $resdir
cp $builddir/Module.symvers $resdir > /dev/null || :
cp $builddir/System.map $resdir > /dev/null || :
cp vmlinux $resdir
cp .config $resdir
cp Module.symvers $resdir > /dev/null || :
cp System.map $resdir > /dev/null || :
if test -n "$BOOT_IMAGE"
then
cp $builddir/$BOOT_IMAGE $resdir
cp $BOOT_IMAGE $resdir
KERNEL=$resdir/${BOOT_IMAGE##*/}
# Arch-independent indicator
touch $resdir/builtkernel
@ -107,7 +102,7 @@ then
parse-build.sh $resdir/Make.out $title
else
# Build failed.
cp $builddir/.config $resdir || :
cp .config $resdir || :
echo Build failed, not running KVM, see $resdir.
if test -f $builddir.wait
then
@ -165,7 +160,7 @@ then
fi
echo "NOTE: $QEMU either did not run or was interactive" > $resdir/console.log
echo $QEMU $qemu_args -m $TORTURE_QEMU_MEM -kernel $KERNEL -append \"$qemu_append $boot_args\" > $resdir/qemu-cmd
( $QEMU $qemu_args -m $TORTURE_QEMU_MEM -kernel $KERNEL -append "$qemu_append $boot_args"& echo $! > $resdir/qemu_pid; wait `cat $resdir/qemu_pid`; echo $? > $resdir/qemu-retval ) &
( $QEMU $qemu_args -m $TORTURE_QEMU_MEM -kernel $KERNEL -append "$qemu_append $boot_args" > $resdir/qemu-output 2>&1 & echo $! > $resdir/qemu_pid; wait `cat $resdir/qemu_pid`; echo $? > $resdir/qemu-retval ) &
commandcompleted=0
sleep 10 # Give qemu's pid a chance to reach the file
if test -s "$resdir/qemu_pid"

14
tools/testing/selftests/rcutorture/bin/kvm.sh
View File

@ -24,6 +24,7 @@ dur=$((30*60))
dryrun=""
KVM="`pwd`/tools/testing/selftests/rcutorture"; export KVM
PATH=${KVM}/bin:$PATH; export PATH
TORTURE_ALLOTED_CPUS=""
TORTURE_DEFCONFIG=defconfig
TORTURE_BOOT_IMAGE=""
TORTURE_INITRD="$KVM/initrd"; export TORTURE_INITRD
@ -32,6 +33,7 @@ TORTURE_KMAKE_ARG=""
TORTURE_QEMU_MEM=512
TORTURE_SHUTDOWN_GRACE=180
TORTURE_SUITE=rcu
TORTURE_TRUST_MAKE=""
resdir=""
configs=""
cpus=0
@ -62,6 +64,7 @@ usage () {
echo " --qemu-cmd qemu-system-..."
echo " --results absolute-pathname"
echo " --torture rcu"
echo " --trust-make"
exit 1
}
@ -89,6 +92,7 @@ do
--cpus)
checkarg --cpus "(number)" "$#" "$2" '^[0-9]*$' '^--'
cpus=$2
TORTURE_ALLOTED_CPUS="$2"
shift
;;
--datestamp)
@ -173,6 +177,9 @@ do
jitter=0
fi
;;
--trust-make)
TORTURE_TRUST_MAKE="y"
;;
*)
echo Unknown argument $1
usage
@ -285,6 +292,7 @@ cat << ___EOF___ > $T/script
CONFIGFRAG="$CONFIGFRAG"; export CONFIGFRAG
KVM="$KVM"; export KVM
PATH="$PATH"; export PATH
TORTURE_ALLOTED_CPUS="$TORTURE_ALLOTED_CPUS"; export TORTURE_ALLOTED_CPUS
TORTURE_BOOT_IMAGE="$TORTURE_BOOT_IMAGE"; export TORTURE_BOOT_IMAGE
TORTURE_BUILDONLY="$TORTURE_BUILDONLY"; export TORTURE_BUILDONLY
TORTURE_DEFCONFIG="$TORTURE_DEFCONFIG"; export TORTURE_DEFCONFIG
@ -297,6 +305,7 @@ TORTURE_QEMU_MAC="$TORTURE_QEMU_MAC"; export TORTURE_QEMU_MAC
TORTURE_QEMU_MEM="$TORTURE_QEMU_MEM"; export TORTURE_QEMU_MEM
TORTURE_SHUTDOWN_GRACE="$TORTURE_SHUTDOWN_GRACE"; export TORTURE_SHUTDOWN_GRACE
TORTURE_SUITE="$TORTURE_SUITE"; export TORTURE_SUITE
TORTURE_TRUST_MAKE="$TORTURE_TRUST_MAKE"; export TORTURE_TRUST_MAKE
if ! test -e $resdir
then
mkdir -p "$resdir" || :
@ -342,7 +351,7 @@ function dump(first, pastlast, batchnum)
print "needqemurun="
jn=1
for (j = first; j < pastlast; j++) {
builddir=KVM "/b1"
builddir=KVM "/b" j - first + 1
cpusr[jn] = cpus[j];
if (cfrep[cf[j]] == "") {
cfr[jn] = cf[j];
@ -358,7 +367,6 @@ function dump(first, pastlast, batchnum)
print "echo ", cfr[jn], cpusr[jn] ovf ": Starting build. `date` | tee -a " rd "log";
print "rm -f " builddir ".*";
print "touch " builddir ".wait";
print "mkdir " builddir " > /dev/null 2>&1 || :";
print "mkdir " rd cfr[jn] " || :";
print "kvm-test-1-run.sh " CONFIGDIR cf[j], builddir, rd cfr[jn], dur " \"" TORTURE_QEMU_ARG "\" \"" TORTURE_BOOTARGS "\" > " rd cfr[jn] "/kvm-test-1-run.sh.out 2>&1 &"
print "echo ", cfr[jn], cpusr[jn] ovf ": Waiting for build to complete. `date` | tee -a " rd "log";
@ -464,3 +472,5 @@ else
fi
# Tracing: trace_event=rcu:rcu_grace_period,rcu:rcu_future_grace_period,rcu:rcu_grace_period_init,rcu:rcu_nocb_wake,rcu:rcu_preempt_task,rcu:rcu_unlock_preempted_task,rcu:rcu_quiescent_state_report,rcu:rcu_fqs,rcu:rcu_callback,rcu:rcu_kfree_callback,rcu:rcu_batch_start,rcu:rcu_invoke_callback,rcu:rcu_invoke_kfree_callback,rcu:rcu_batch_end,rcu:rcu_torture_read,rcu:rcu_barrier
# Function-graph tracing: ftrace=function_graph ftrace_graph_filter=sched_setaffinity,migration_cpu_stop
# Also --kconfig "CONFIG_FUNCTION_TRACER=y CONFIG_FUNCTION_GRAPH_TRACER=y"

2
tools/testing/selftests/rcutorture/bin/parse-build.sh
View File

@ -21,7 +21,7 @@ mkdir $T
. functions.sh
if grep -q CC < $F
if grep -q CC < $F || test -n "$TORTURE_TRUST_MAKE"
then
:
else

1
tools/testing/selftests/rcutorture/bin/parse-console.sh
View File

@ -106,6 +106,7 @@ fi | tee -a $file.diags
egrep 'Badness|WARNING:|Warn|BUG|===========|Call Trace:|Oops:|detected stalls on CPUs/tasks:|self-detected stall on CPU|Stall ended before state dump start|\?\?\? Writer stall state|rcu_.*kthread starved for' < $file |
grep -v 'ODEBUG: ' |
grep -v 'This means that this is a DEBUG kernel and it is' |
grep -v 'Warning: unable to open an initial console' > $T.diags
if test -s $T.diags
then

3
tools/testing/selftests/rcutorture/configs/rcu/CFcommon
View File

@ -1,2 +1,5 @@
CONFIG_RCU_TORTURE_TEST=y
CONFIG_PRINTK_TIME=y
CONFIG_HYPERVISOR_GUEST=y
CONFIG_PARAVIRT=y
CONFIG_KVM_GUEST=y

1
tools/testing/selftests/rcutorture/configs/rcu/TREE01.boot
View File

@ -3,3 +3,4 @@ rcutree.gp_preinit_delay=3
rcutree.gp_init_delay=3
rcutree.gp_cleanup_delay=3
rcu_nocbs=0
rcutorture.fwd_progress=0

14
tools/testing/selftests/rcutorture/configs/rcu/TRIVIAL Normal file
View File

@ -0,0 +1,14 @@
CONFIG_SMP=y
CONFIG_NR_CPUS=8
CONFIG_PREEMPT_NONE=y
CONFIG_PREEMPT_VOLUNTARY=n
CONFIG_PREEMPT=n
CONFIG_HZ_PERIODIC=n
CONFIG_NO_HZ_IDLE=y
CONFIG_NO_HZ_FULL=n
CONFIG_HOTPLUG_CPU=n
CONFIG_SUSPEND=n
CONFIG_HIBERNATION=n
CONFIG_DEBUG_LOCK_ALLOC=n
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
CONFIG_RCU_EXPERT=y

3
tools/testing/selftests/rcutorture/configs/rcu/TRIVIAL.boot Normal file
View File

@ -0,0 +1,3 @@
rcutorture.torture_type=trivial
rcutorture.onoff_interval=0
rcutorture.shuffle_interval=0