[tarantool-patches] [PATCH v3 07/14] wal: remove fiber from a journal_entry structure
Georgy Kirichenko
georgy at tarantool.org
Sun Jun 9 23:44:36 MSK 2019
Use a fiber_cond to signal a condition and wake up a waiting fiber.
This relaxes friction between fiber and transaction life cycles.
Prerequisites: #1254
---
src/box/box.cc | 4 +++-
src/box/journal.c | 7 ++++---
src/box/journal.h | 9 +++++++--
src/box/wal.c | 29 +++++++++--------------------
4 files changed, 23 insertions(+), 26 deletions(-)
diff --git a/src/box/box.cc b/src/box/box.cc
index 5e5cd2b08..a88e762c0 100644
--- a/src/box/box.cc
+++ b/src/box/box.cc
@@ -309,9 +309,11 @@ struct recovery_journal {
*/
static int64_t
recovery_journal_write(struct journal *base,
- struct journal_entry * /* entry */)
+ struct journal_entry *entry)
{
struct recovery_journal *journal = (struct recovery_journal *) base;
+ entry->done = true;
+ fiber_cond_broadcast(&entry->done_cond);
return vclock_sum(journal->vclock);
}
diff --git a/src/box/journal.c b/src/box/journal.c
index fe13fb6ee..6406d6f01 100644
--- a/src/box/journal.c
+++ b/src/box/journal.c
@@ -30,7 +30,6 @@
*/
#include "journal.h"
#include <small/region.h>
-#include <fiber.h>
#include <diag.h>
/**
@@ -41,7 +40,8 @@ static int64_t
dummy_journal_write(struct journal *journal, struct journal_entry *entry)
{
(void) journal;
- (void) entry;
+ entry->done = true;
+ fiber_cond_broadcast(&entry->done_cond);
return 0;
}
@@ -69,7 +69,8 @@ journal_entry_new(size_t n_rows, struct region *region)
entry->approx_len = 0;
entry->n_rows = n_rows;
entry->res = -1;
- entry->fiber = fiber();
+ entry->done = false;
+ fiber_cond_create(&entry->done_cond);
return entry;
}
diff --git a/src/box/journal.h b/src/box/journal.h
index 8ac32ee5e..618c68eb2 100644
--- a/src/box/journal.h
+++ b/src/box/journal.h
@@ -33,6 +33,7 @@
#include <stdint.h>
#include <stdbool.h>
#include "salad/stailq.h"
+#include "fiber_cond.h"
#if defined(__cplusplus)
extern "C" {
@@ -55,9 +56,13 @@ struct journal_entry {
*/
int64_t res;
/**
- * The fiber issuing the request.
+ * Turns to true when entry is processed by wal.
*/
- struct fiber *fiber;
+ bool done;
+ /**
+ * Condition to broadcast when processing is done.
+ */
+ struct fiber_cond done_cond;
/**
* Approximate size of this request when encoded.
*/
diff --git a/src/box/wal.c b/src/box/wal.c
index 0ea15a432..5951817d0 100644
--- a/src/box/wal.c
+++ b/src/box/wal.c
@@ -246,22 +246,16 @@ xlog_write_entry(struct xlog *l, struct journal_entry *entry)
}
/**
- * Invoke fibers waiting for their journal_entry's to be
- * completed. The fibers are invoked in strict fifo order:
- * this ensures that, in case of rollback, requests are
- * rolled back in strict reverse order, producing
- * a consistent database state.
+ * Signal done condition.
*/
static void
tx_schedule_queue(struct stailq *queue)
{
- /*
- * fiber_wakeup() is faster than fiber_call() when there
- * are many ready fibers.
- */
struct journal_entry *req;
- stailq_foreach_entry(req, queue, fifo)
- fiber_wakeup(req->fiber);
+ stailq_foreach_entry(req, queue, fifo) {
+ req->done = true;
+ fiber_cond_broadcast(&req->done_cond);
+ }
}
/**
@@ -1172,15 +1166,10 @@ wal_write(struct journal *journal, struct journal_entry *entry)
batch->approx_len += entry->approx_len;
writer->wal_pipe.n_input += entry->n_rows * XROW_IOVMAX;
cpipe_flush_input(&writer->wal_pipe);
- /**
- * It's not safe to spuriously wakeup this fiber
- * since in that case it will ignore a possible
- * error from WAL writer and not roll back the
- * transaction.
- */
- bool cancellable = fiber_set_cancellable(false);
- fiber_yield(); /* Request was inserted. */
- fiber_set_cancellable(cancellable);
+
+ while (!entry->done)
+ fiber_cond_wait(&entry->done_cond);
+
return entry->res;
}
--
2.21.0
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