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ck_epoch: introduce synchronize_wait that allows blocking synchronize operation.

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ck_pring
Samy Al Bahra 8 years ago
parent a25e073a2b
commit 8580ccc580
9 changed files with 107 additions and 43 deletions
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41
include/ck_epoch.h
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@ -93,7 +93,7 @@ struct ck_epoch_record {
unsigned int n_pending;
unsigned int n_peak;
unsigned int n_dispatch;
unsigned int unused;
void *ct;
ck_stack_t pending[CK_EPOCH_LENGTH];
ck_stack_entry_t record_next;
} CK_CC_CACHELINE;
@ -113,6 +113,13 @@ typedef struct ck_epoch ck_epoch_t;
void _ck_epoch_addref(ck_epoch_record_t *, ck_epoch_section_t *);
void _ck_epoch_delref(ck_epoch_record_t *, ck_epoch_section_t *);
CK_CC_FORCE_INLINE static void *
ck_epoch_record_ct(const ck_epoch_record_t *record)
{
return ck_pr_load_ptr(&record->ct);
}
/*
* Marks the beginning of an epoch-protected section.
*/
@ -185,7 +192,6 @@ ck_epoch_end(ck_epoch_record_t *record, ck_epoch_section_t *section)
* of the epoch counter. Worst case, this will result in some delays
* before object destruction.
*/
/*
CK_CC_FORCE_INLINE static void
ck_epoch_call(ck_epoch_record_t *record,
ck_epoch_entry_t *entry,
@ -200,13 +206,12 @@ ck_epoch_call(ck_epoch_record_t *record,
ck_stack_push_spnc(&record->pending[offset], &entry->stack_entry);
return;
}
*/
/*
* Same as ck_epoch_call, but allows for records to be shared and is reentrant.
*/
CK_CC_FORCE_INLINE static void
ck_epoch_call(ck_epoch_record_t *record,
ck_epoch_call_strict(ck_epoch_record_t *record,
ck_epoch_entry_t *entry,
ck_epoch_cb_t *function)
{
@ -222,12 +227,36 @@ ck_epoch_call(ck_epoch_record_t *record,
return;
}
/*
* This callback is used for synchronize_wait to allow for custom blocking
* behavior.
*/
typedef void ck_epoch_wait_cb_t(ck_epoch_t *, ck_epoch_record_t *,
void *);
void ck_epoch_init(ck_epoch_t *);
ck_epoch_record_t *ck_epoch_recycle(ck_epoch_t *);
void ck_epoch_register(ck_epoch_t *, ck_epoch_record_t *);
/*
* Attempts to recycle an unused epoch record. If one is successfully
* allocated, the record context pointer is also updated.
*/
ck_epoch_record_t *ck_epoch_recycle(ck_epoch_t *, void *);
/*
* Registers an epoch record. An optional context pointer may be passed that
* is retrievable with ck_epoch_record_ct.
*/
void ck_epoch_register(ck_epoch_t *, ck_epoch_record_t *, void *);
/*
* Marks a record as available for re-use by a subsequent recycle operation.
* Note that the record cannot be physically destroyed.
*/
void ck_epoch_unregister(ck_epoch_record_t *);
bool ck_epoch_poll(ck_epoch_record_t *);
void ck_epoch_synchronize(ck_epoch_record_t *);
void ck_epoch_synchronize_wait(ck_epoch_t *, ck_epoch_wait_cb_t *, void *);
void ck_epoch_barrier(ck_epoch_record_t *);
void ck_epoch_reclaim(ck_epoch_record_t *);

4
regressions/ck_epoch/validate/ck_epoch_call.c
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@ -51,8 +51,8 @@ main(void)
{
ck_epoch_entry_t entry;
ck_epoch_register(&epoch, &record[0]);
ck_epoch_register(&epoch, &record[1]);
ck_epoch_register(&epoch, &record[0], NULL);
ck_epoch_register(&epoch, &record[1], NULL);
ck_epoch_call(&record[1], &entry, cb);
ck_epoch_barrier(&record[1]);

4
regressions/ck_epoch/validate/ck_epoch_poll.c
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@ -89,7 +89,7 @@ read_thread(void *unused CK_CC_UNUSED)
ck_epoch_record_t record CK_CC_CACHELINE;
ck_stack_entry_t *cursor, *n;
ck_epoch_register(&stack_epoch, &record);
ck_epoch_register(&stack_epoch, &record, NULL);
if (aff_iterate(&a)) {
perror("ERROR: failed to affine thread");
@ -141,7 +141,7 @@ write_thread(void *unused CK_CC_UNUSED)
ck_epoch_record_t record;
ck_stack_entry_t *s;
ck_epoch_register(&stack_epoch, &record);
ck_epoch_register(&stack_epoch, &record, NULL);
if (aff_iterate(&a)) {
perror("ERROR: failed to affine thread");

6
regressions/ck_epoch/validate/ck_epoch_section.c
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@ -46,8 +46,8 @@ setup_test(void)
{
ck_epoch_init(&epc);
ck_epoch_register(&epc, &record);
ck_epoch_register(&epc, &record2);
ck_epoch_register(&epc, &record, NULL);
ck_epoch_register(&epc, &record2, NULL);
cleanup_calls = 0;
return;
@ -157,7 +157,7 @@ reader_work(void *arg)
ck_epoch_section_t section;
struct obj *o;
ck_epoch_register(&epc, &local_record);
ck_epoch_register(&epc, &local_record, NULL);
o = (struct obj *)arg;

4
regressions/ck_epoch/validate/ck_epoch_section_2.c
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@ -64,7 +64,7 @@ read_thread(void *unused CK_CC_UNUSED)
record = malloc(sizeof *record);
assert(record != NULL);
ck_epoch_register(&epoch, record);
ck_epoch_register(&epoch, record, NULL);
if (aff_iterate(&a)) {
perror("ERROR: failed to affine thread");
@ -133,7 +133,7 @@ write_thread(void *unused CK_CC_UNUSED)
ck_epoch_record_t record;
unsigned long iterations = 0;
ck_epoch_register(&epoch, &record);
ck_epoch_register(&epoch, &record, NULL);
if (aff_iterate(&a)) {
perror("ERROR: failed to affine thread");

4
regressions/ck_epoch/validate/ck_epoch_synchronize.c
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@ -91,7 +91,7 @@ read_thread(void *unused CK_CC_UNUSED)
ck_stack_entry_t *n;
unsigned int i;
ck_epoch_register(&stack_epoch, &record);
ck_epoch_register(&stack_epoch, &record, NULL);
if (aff_iterate(&a)) {
perror("ERROR: failed to affine thread");
@ -148,7 +148,7 @@ write_thread(void *unused CK_CC_UNUSED)
ck_epoch_record_t record;
ck_stack_entry_t *s;
ck_epoch_register(&stack_epoch, &record);
ck_epoch_register(&stack_epoch, &record, NULL);
if (aff_iterate(&a)) {
perror("ERROR: failed to affine thread");

2
regressions/ck_epoch/validate/ck_stack.c
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@ -81,7 +81,7 @@ thread(void *unused CK_CC_UNUSED)
unsigned long smr = 0;
unsigned int i;
ck_epoch_register(&stack_epoch, &record);
ck_epoch_register(&stack_epoch, &record, NULL);
if (aff_iterate(&a)) {
perror("ERROR: failed to affine thread");

4
regressions/ck_epoch/validate/torture.c
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@ -119,7 +119,7 @@ read_thread(void *unused CK_CC_UNUSED)
record = malloc(sizeof *record);
assert(record != NULL);
ck_epoch_register(&epoch, record);
ck_epoch_register(&epoch, record, NULL);
if (aff_iterate(&a)) {
perror("ERROR: failed to affine thread");
@ -151,7 +151,7 @@ write_thread(void *unused CK_CC_UNUSED)
record = malloc(sizeof *record);
assert(record != NULL);
ck_epoch_register(&epoch, record);
ck_epoch_register(&epoch, record, NULL);
if (aff_iterate(&a)) {
perror("ERROR: failed to affine thread");

81
src/ck_epoch.c
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@ -230,7 +230,7 @@ ck_epoch_init(struct ck_epoch *global)
}
struct ck_epoch_record *
ck_epoch_recycle(struct ck_epoch *global)
ck_epoch_recycle(struct ck_epoch *global, void *ct)
{
struct ck_epoch_record *record;
ck_stack_entry_t *cursor;
@ -249,6 +249,12 @@ ck_epoch_recycle(struct ck_epoch *global)
CK_EPOCH_STATE_USED);
if (state == CK_EPOCH_STATE_FREE) {
ck_pr_dec_uint(&global->n_free);
ck_pr_store_ptr(&record->ct, ct);
/*
* The context pointer is ordered by a
* subsequent protected section.
*/
return record;
}
}
@ -258,7 +264,8 @@ ck_epoch_recycle(struct ck_epoch *global)
}
void
ck_epoch_register(struct ck_epoch *global, struct ck_epoch_record *record)
ck_epoch_register(struct ck_epoch *global, struct ck_epoch_record *record,
void *ct)
{
size_t i;
@ -269,6 +276,7 @@ ck_epoch_register(struct ck_epoch *global, struct ck_epoch_record *record)
record->n_dispatch = 0;
record->n_peak = 0;
record->n_pending = 0;
record->ct = ct;
memset(&record->local, 0, sizeof record->local);
for (i = 0; i < CK_EPOCH_LENGTH; i++)
@ -295,6 +303,7 @@ ck_epoch_unregister(struct ck_epoch_record *record)
for (i = 0; i < CK_EPOCH_LENGTH; i++)
ck_stack_init(&record->pending[i]);
ck_pr_store_ptr(&record->ct, NULL);
ck_pr_fence_store();
ck_pr_store_uint(&record->state, CK_EPOCH_STATE_FREE);
ck_pr_inc_uint(&global->n_free);
@ -365,8 +374,11 @@ ck_epoch_dispatch(struct ck_epoch_record *record, unsigned int e)
if (n_pending > n_peak)
ck_pr_store_uint(&record->n_peak, n_peak);
ck_pr_add_uint(&record->n_dispatch, i);
ck_pr_sub_uint(&record->n_pending, i);
if (i > 0) {
ck_pr_add_uint(&record->n_dispatch, i);
ck_pr_sub_uint(&record->n_pending, i);
}
return;
}
@ -384,13 +396,24 @@ ck_epoch_reclaim(struct ck_epoch_record *record)
return;
}
CK_CC_FORCE_INLINE static void
epoch_block(struct ck_epoch *global, struct ck_epoch_record *cr,
ck_epoch_wait_cb_t *cb, void *ct)
{
if (cb != NULL)
cb(global, cr, ct);
return;
}
/*
* This function must not be called with-in read section.
*/
void
ck_epoch_synchronize(struct ck_epoch_record *record)
ck_epoch_synchronize_wait(struct ck_epoch *global,
ck_epoch_wait_cb_t *cb, void *ct)
{
struct ck_epoch *global = record->global;
struct ck_epoch_record *cr;
unsigned int delta, epoch, goal, i;
bool active;
@ -427,10 +450,27 @@ ck_epoch_synchronize(struct ck_epoch_record *record)
* period.
*/
e_d = ck_pr_load_uint(&global->epoch);
if (e_d != delta) {
delta = e_d;
goto reload;
if (e_d == delta) {
epoch_block(global, cr, cb, ct);
continue;
}
/*
* If the epoch has been updated, we may have already
* met our goal.
*/
delta = e_d;
if ((goal > epoch) & (delta >= goal))
goto leave;
epoch_block(global, cr, cb, ct);
/*
* If the epoch has been updated, then a grace period
* requires that all threads are observed idle at the
* same epoch.
*/
cr = NULL;
}
/*
@ -462,20 +502,6 @@ ck_epoch_synchronize(struct ck_epoch_record *record)
* Otherwise, we have just acquired latest snapshot.
*/
delta = delta + r;
continue;
reload:
if ((goal > epoch) & (delta >= goal)) {
/*
* Right now, epoch overflow is handled as an edge
* case. If we have already observed an epoch
* generation, then we can be sure no hazardous
* references exist to objects from this generation. We
* can actually avoid an addtional scan step at this
* point.
*/
break;
}
}
/*
@ -483,10 +509,19 @@ reload:
* However, if non-temporal instructions are used, full barrier
* semantics are necessary.
*/
leave:
ck_pr_fence_memory();
return;
}
void
ck_epoch_synchronize(struct ck_epoch_record *record)
{
ck_epoch_synchronize_wait(record->global, NULL, NULL);
return;
}
void
ck_epoch_barrier(struct ck_epoch_record *record)
{

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