1berry/MariaDB-server
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

MDL_lock encapsulation: MDL_lock::iterate()

Browse Source 
Avoid accessing MDL_lock::m_waiting, MDL_lock::m_granted and
MDL_lock::m_rwlock from mdl_iterate_lock(), use MDL_lock::iterate()
instead.

This is part of broader cleanup, which aims to make large part of
MDL_lock members private. It is needed to simplify further work on
MDEV-19749 - MDL scalability regression after backup locks.
This commit is contained in:
Sergey Vojtovich 2025-04-30 20:58:00 +04:00 committed by Sergei Golubchik
parent 8d0ccd911f
commit 0556a46caa
1 changed files with 30 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

45
sql/mdl.cc
View File

@ -707,6 +707,35 @@ public:
return res;
}
/**
Callback for mdl_iterate()
Another thread may be deleting this MDL_lock concurrently.
Being deleted lock can still be iterated since it must have
valid empty granted/waiting lists.
*/
bool iterate(mdl_iterator_callback callback, void *argument)
{
bool res= true;
mysql_prlock_rdlock(&m_rwlock);
DBUG_ASSERT(m_strategy || is_empty());
for (MDL_ticket &ticket : m_granted)
{
if (callback(&ticket, argument, true))
goto end;
}
for (MDL_ticket &ticket : m_waiting)
{
if (callback(&ticket, argument, false))
goto end;
}
res= false;
end:
mysql_prlock_unlock(&m_rwlock);
return res;
}
const MDL_lock_strategy *m_strategy;
private:
static const MDL_backup_lock m_backup_lock_strategy;
@ -787,21 +816,7 @@ static my_bool mdl_iterate_lock(void *lk, void *a)
{
MDL_lock *lock= static_cast<MDL_lock*>(lk);
mdl_iterate_arg *arg= static_cast<mdl_iterate_arg*>(a);
/*
We can skip check for m_strategy here, becase m_granted
must be empty for such locks anyway.
*/
mysql_prlock_rdlock(&lock->m_rwlock);
bool res= std::any_of(lock->m_granted.begin(), lock->m_granted.end(),
[arg](MDL_ticket &ticket) {
return arg->callback(&ticket, arg->argument, true);
});
res= std::any_of(lock->m_waiting.begin(), lock->m_waiting.end(),
[arg](MDL_ticket &ticket) {
return arg->callback(&ticket, arg->argument, false);
});
mysql_prlock_unlock(&lock->m_rwlock);
return res;
return lock->iterate(arg->callback, arg->argument);
}