thebestvibedev/tromcho.net
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

First implementation of journal trimming

Browse Source 
In theory it's possible to start testing blockstore at this point!
This commit is contained in:
Vitaliy Filippov
2019-11-15 16:12:55 +03:00
parent c7d9dc027b
commit a4aaa3c7c7
6 changed files with 94 additions and 19 deletions
Download Patch File Download Diff File Expand all files Collapse all files
blockstore_flush.cpp
+65 -7
View File
@@ -4,10 +4,13 @@ journal_flusher_t::journal_flusher_t(int flusher_count, blockstore *bs)
{
this->bs = bs;
this->flusher_count = flusher_count;
this->active_flushers = 0;
this->active_until_sync = 0;
this->sync_required = true;
this->sync_threshold = flusher_count == 1 ? 1 : flusher_count/2;
active_flushers = 0;
active_until_sync = 0;
sync_required = true;
sync_threshold = flusher_count == 1 ? 1 : flusher_count/2;
journal_trim_interval = sync_threshold;
journal_trim_counter = 0;
journal_superblock = (uint8_t*)memalign(512, 512);
co = new journal_flusher_co[flusher_count];
for (int i = 0; i < flusher_count; i++)
{
@@ -31,6 +34,7 @@ journal_flusher_co::journal_flusher_co()
journal_flusher_t::~journal_flusher_t()
{
free(journal_superblock);
delete[] co;
}
@@ -110,6 +114,10 @@ void journal_flusher_co::loop()
goto resume_10;
else if (wait_state == 11)
goto resume_11;
else if (wait_state == 12)
goto resume_12;
else if (wait_state == 13)
goto resume_13;
resume_0:
if (!flusher->flush_queue.size())
return;
@@ -276,8 +284,8 @@ resume_0:
.oid = cur.oid,
.version = cur.version,
};
// I consider unordered writes to data & metadata safe here, because
// "dirty" entries always override "clean" entries in our case
// I consider unordered writes to data & metadata safe here
// BUT it requires that journal entries even older than clean_db should be replayed after restart
await_sqe(6);
data->iov = (struct iovec){ meta_it->second.buf, 512 };
data->callback = simple_callback;
@@ -373,7 +381,57 @@ resume_0:
if (dirty_it->first.oid != cur.oid)
dirty_it++;
bs->dirty_db.erase(dirty_it, std::next(dirty_end));
// FIXME: ...and clear unused part of the journal (with some interval, not for every flushed op)
// Clear unused part of the journal every <journal_trim_interval> flushes
if (!((++flusher->journal_trim_counter) % flusher->journal_trim_interval))
{
flusher->journal_trim_counter = 0;
journal_used_it = bs->journal.used_sectors.lower_bound(bs->journal.used_start);
if (journal_used_it == bs->journal.used_sectors.end())
{
// Journal is cleared to its end, restart from the beginning
journal_used_it = bs->journal.used_sectors.begin();
if (journal_used_it == bs->journal.used_sectors.end())
{
// Journal is empty
bs->journal.used_start = bs->journal.next_free;
}
else
{
bs->journal.used_start = journal_used_it->first;
}
}
else if (journal_used_it->first > bs->journal.used_start)
{
// Journal is cleared up to <journal_used_it>
bs->journal.used_start = journal_used_it->first;
}
else
{
// Can't trim journal
goto do_not_trim;
}
// Update journal "superblock"
await_sqe(12);
data->callback = simple_callback;
*((journal_entry_start*)flusher->journal_superblock) = {
.crc32 = 0,
.magic = JOURNAL_MAGIC,
.type = JE_START,
.size = sizeof(journal_entry_start),
.reserved = 0,
.journal_start = bs->journal.used_start,
};
((journal_entry_start*)flusher->journal_superblock)->crc32 = je_crc32((journal_entry*)flusher->journal_superblock);
data->iov = (struct iovec){ flusher->journal_superblock, 512 };
io_uring_prep_writev(sqe, bs->journal.fd, &data->iov, 1, bs->journal.offset);
wait_count++;
wait_state = 13;
resume_13:
if (wait_count > 0)
return;
}
do_not_trim:
// All done
wait_state = 0;
flusher->active_flushers--;
repeat_it = flusher->sync_to_repeat.find(cur.oid);