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Try to implement journal flusher as a FSM

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This commit is contained in:
Vitaliy Filippov
2019-11-12 18:16:38 +03:00
parent ab20aef941
commit 34451b6e44
3 changed files with 154 additions and 64 deletions
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blockstore_stable.cpp
+144 -57
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@@ -123,17 +123,12 @@ void blockstore::handle_stable_event(ring_data_t *data, blockstore_operation *op
if (op->pending_ops == 0)
{
// First step: mark dirty_db entries as stable, acknowledge op completion
// FIXME: oops... we seem to have to copy object id/version pairs...
// No, no, no, copying is bad. We don't want copying.
obj_ver_id* v;
int i;
for (i = 0, v = (obj_ver_id*)op->buf; i < op->len; i++, v++)
{
// Mark all dirty_db entries up to op->version as stable
auto dirty_it = dirty_db.find((obj_ver_id){
.oid = v->oid,
.version = v->version,
});
auto dirty_it = dirty_db.find(*v);
if (dirty_it != dirty_db.end())
{
do
@@ -146,8 +141,13 @@ void blockstore::handle_stable_event(ring_data_t *data, blockstore_operation *op
{
dirty_it->second.state = ST_D_STABLE;
}
else if (IS_STABLE(dirty_it->second.state))
{
break;
}
dirty_it--;
} while (dirty_it != dirty_db.begin() && dirty_it->first.oid == v->oid);
flusher.flush_queue.push_back(*v);
}
}
// Acknowledge op
@@ -161,62 +161,149 @@ struct offset_len
uint64_t offset, len;
};
struct journal_flusher_t
class journal_flusher_t
{
std::deque<obj_ver_id> flush_queue;
blockstore *bs;
int state;
obj_ver_id cur;
std::map<obj_ver_id, dirty_entry>::iterator dirty_it;
std::vector<offset_len> v;
std::vector<offset_len>::iterator it;
uint64_t offset, len;
public:
journal_flusher_t();
std::deque<obj_ver_id> flush_queue;
void stabilize_object_loop();
};
void blockstore::stabilize_object(object_id oid, uint64_t max_ver)
#define F_NEXT_OBJ 0
#define F_NEXT_VER 1
#define F_FIND_POS 2
#define F_SUBMIT_FULL 3
#define F_SUBMIT_PART 4
#define F_CUT_OFFSET 5
#define F_FINISH_VER 6
journal_flusher_t::journal_flusher_t()
{
auto dirty_it = dirty_db.find((obj_ver_id){
.oid = oid,
.version = max_ver,
});
if (dirty_it != dirty_db.end())
{
std::vector<offset_len> v;
do
{
if (dirty_it->second.state == ST_J_STABLE)
{
uint64_t offset = dirty_it->second.offset, len = dirty_it->second.size;
auto it = v.begin();
while (1)
{
for (; it != v.end(); it++)
if (it->offset >= offset)
break;
if (it == v.end() || it->offset >= offset+len)
{
v.insert(it, (offset_len){ .offset = offset, .len = len });
break;
}
else
{
if (it->offset > offset)
v.insert(it, (offset_len){ .offset = offset, .len = it->offset-offset });
if (offset+len > it->offset+it->len)
{
len = offset+len - (it->offset+it->len);
offset = it->offset+it->len;
}
else
break;
}
}
}
else if (dirty_it->second.state == ST_D_STABLE)
{
break;
}
else if (IS_STABLE(dirty_it->second.state))
{
break;
}
} while (dirty_it != dirty_db.begin());
}
state = F_NEXT_OBJ;
}
// It would be prettier as a coroutine (maybe https://github.com/hnes/libaco ?)
// Now it's a state machine
void journal_flusher_t::stabilize_object_loop()
{
begin:
if (state == F_NEXT_OBJ)
{
// Pick next object
if (!flush_queue.size())
return;
while (1)
{
cur = flush_queue.front();
flush_queue.pop_front();
dirty_it = bs->dirty_db.find(cur);
if (dirty_it != bs->dirty_db.end())
{
state = F_NEXT_VER;
v.clear();
break;
}
else if (flush_queue.size() == 0)
return;
}
}
if (state == F_NEXT_VER)
{
if (dirty_it->second.state == ST_J_STABLE)
{
offset = dirty_it->second.offset;
len = dirty_it->second.size;
it = v.begin();
state = F_FIND_POS;
}
else if (dirty_it->second.state == ST_D_STABLE)
{
state = F_NEXT_OBJ;
}
else if (IS_STABLE(dirty_it->second.state))
{
state = F_NEXT_OBJ;
}
else
state = F_FINISH_VER;
}
if (state == F_FIND_POS)
{
for (; it != v.end(); it++)
if (it->offset >= offset)
break;
if (it == v.end() || it->offset >= offset+len)
{
state = F_SUBMIT_FULL;
}
else
{
if (it->offset > offset)
state = F_SUBMIT_PART;
else
state = F_CUT_OFFSET;
}
}
if (state == F_SUBMIT_FULL)
{
struct io_uring_sqe *sqe = get_sqe();
if (!sqe)
return;
struct ring_data_t *data = ((ring_data_t*)sqe->user_data);
data->iov = (struct iovec){ malloc(len), len };
data->op = op; // FIXME OOPS
io_uring_prep_readv(
sqe, journal_fd, &data->iov, 1, journal_offset + dirty_it->second.location + offset
);
op->pending_ops = 1;
v.insert(it, (offset_len){ .offset = offset, .len = len });
state = F_SUBMIT_FULL_WRITE;
return;
}
if (state == F_SUBMIT_FULL_WRITE)
{
struct io_uring_sqe *sqe = get_sqe();
if (!sqe)
return;
struct ring_data_t *data = ((ring_data_t*)sqe->user_data);
}
if (state == F_SUBMIT_PART)
{
if (!can_submit)
{
return;
}
v.insert(it, (offset_len){ .offset = offset, .len = it->offset-offset });
state = F_CUT_OFFSET;
}
if (state == F_CUT_OFFSET)
{
if (offset+len > it->offset+it->len)
{
len = offset+len - (it->offset+it->len);
offset = it->offset+it->len;
state = F_FIND_POS;
}
else
state = F_FINISH_VER;
}
if (state == F_FINISH_VER)
{
dirty_it--;
if (dirty_it == bs->dirty_db.begin() || dirty_it->first.oid != cur.oid)
state = F_NEXT_OBJ;
else
state = F_NEXT_VER;
}
goto begin;
}