MEDIUM: threads/stick-tables: handle multithreads on stick tables
The stick table API was slightly reworked:
A global spin lock on stick table was added to perform lookup and
insert in a thread safe way. The handling of refcount on entries
is now handled directly by stick tables functions under protection
of this lock and was removed from the code of callers.
The "stktable_store" function is no more externalized and users should
now use "stktable_set_entry" in any case of insertion. This last one performs
a lookup followed by a store if not found. So the code using "stktable_store"
was re-worked.
Lookup, and set_entry functions automatically increase the refcount
of the returned/stored entry.
The function "sticktable_touch" was renamed "sticktable_touch_local"
and is now able to decrease the refcount if last arg is set to true. It
is allowing to release the entry without taking the lock twice.
A new function "sticktable_touch_remote" is now used to insert
entries coming from remote peers at the right place in the update tree.
The code of peer update was re-worked to use this new function.
This function is also able to decrease the refcount if wanted.
The function "stksess_kill" also handle a parameter to decrease
the refcount on the entry.
A read/write lock is added on each entry to protect the data content
updates of the entry.
diff --git a/include/types/stick_table.h b/include/types/stick_table.h
index 77eeccd..4f5de99 100644
--- a/include/types/stick_table.h
+++ b/include/types/stick_table.h
@@ -129,6 +129,9 @@
struct stksess {
unsigned int expire; /* session expiration date */
unsigned int ref_cnt; /* reference count, can only purge when zero */
+#ifdef USE_THREAD
+ HA_RWLOCK_T lock; /* lock related to the table entry */
+#endif
struct eb32_node exp; /* ebtree node used to hold the session in expiration tree */
struct eb32_node upd; /* ebtree node used to hold the update sequence tree */
struct ebmb_node key; /* ebtree node used to hold the session in table */
@@ -143,6 +146,9 @@
struct eb_root exps; /* head of sticky session expiration tree */
struct eb_root updates; /* head of sticky updates sequence tree */
struct pool_head *pool; /* pool used to allocate sticky sessions */
+#ifdef USE_THREAD
+ HA_SPINLOCK_T lock; /* spin lock related to the table */
+#endif
struct task *exp_task; /* expiration task */
struct task *sync_task; /* sync task */
unsigned int update;