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ctdb-locking: Add per database queues for pending and active lock requests

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This avoids traversing a single pending queue which is quite expensive
when there are lots of pending lock requests.  This seems to happen
quite a lot on a loaded cluster for notify_index.tdb.

Adding per database queues avoids the need to traverse pending queue
for that database if there are already the maximum number of active
lock requests.

Signed-off-by: Amitay Isaacs <amitay@gmail.com>
Reviewed-by: Volker Lendecke <vl@samba.org>

Autobuild-User(master): Volker Lendecke <vl@samba.org>
Autobuild-Date(master): Mon Aug  4 20:23:45 CEST 2014 on sn-devel-104
This commit is contained in:
Amitay Isaacs 2014-07-24 15:56:41 +10:00 committed by Volker Lendecke
parent f73adff737
commit 88f6a6c188
2 changed files with 82 additions and 32 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
ctdb/include/ctdb_private.h
View File

@ -597,6 +597,8 @@ struct ctdb_db_context {
struct ctdb_db_statistics statistics;
struct lock_context *lock_current;
struct lock_context *lock_pending;
int lock_num_current;
};

112
ctdb/server/ctdb_lock.c
View File

@ -274,7 +274,11 @@ static int ctdb_lock_context_destructor(struct lock_context *lock_ctx)
{
if (lock_ctx->child > 0) {
ctdb_kill(lock_ctx->ctdb, lock_ctx->child, SIGKILL);
DLIST_REMOVE(lock_ctx->ctdb->lock_current, lock_ctx);
if (lock_ctx->type == LOCK_RECORD) {
DLIST_REMOVE(lock_ctx->ctdb_db->lock_current, lock_ctx);
} else {
DLIST_REMOVE(lock_ctx->ctdb->lock_current, lock_ctx);
}
if (lock_ctx->ctdb_db) {
lock_ctx->ctdb_db->lock_num_current--;
}
@ -283,7 +287,11 @@ static int ctdb_lock_context_destructor(struct lock_context *lock_ctx)
CTDB_DECREMENT_DB_STAT(lock_ctx->ctdb_db, locks.num_current);
}
} else {
DLIST_REMOVE(lock_ctx->ctdb->lock_pending, lock_ctx);
if (lock_ctx->type == LOCK_RECORD) {
DLIST_REMOVE(lock_ctx->ctdb_db->lock_pending, lock_ctx);
} else {
DLIST_REMOVE(lock_ctx->ctdb->lock_pending, lock_ctx);
}
CTDB_DECREMENT_STAT(lock_ctx->ctdb, locks.num_pending);
if (lock_ctx->ctdb_db) {
CTDB_DECREMENT_DB_STAT(lock_ctx->ctdb_db, locks.num_pending);
@ -649,6 +657,65 @@ static char **lock_helper_args(TALLOC_CTX *mem_ctx, struct lock_context *lock_ct
return args;
}
/*
* Find a lock request that can be scheduled
*/
struct lock_context *ctdb_find_lock_context(struct ctdb_context *ctdb)
{
struct lock_context *lock_ctx, *next_ctx;
struct ctdb_db_context *ctdb_db;
/* First check if there are database lock requests */
lock_ctx = ctdb->lock_pending;
while (lock_ctx != NULL) {
next_ctx = lock_ctx->next;
if (! lock_ctx->request) {
DEBUG(DEBUG_INFO, ("Removing lock context without lock request\n"));
DLIST_REMOVE(ctdb->lock_pending, lock_ctx);
CTDB_DECREMENT_STAT(ctdb, locks.num_pending);
if (lock_ctx->ctdb_db) {
CTDB_DECREMENT_DB_STAT(lock_ctx->ctdb_db, locks.num_pending);
}
talloc_free(lock_ctx);
} else {
/* Found a lock context with lock requests */
break;
}
lock_ctx = next_ctx;
}
if (lock_ctx) {
return lock_ctx;
}
/* Next check database queues */
for (ctdb_db = ctdb->db_list; ctdb_db; ctdb_db = ctdb_db->next) {
if (ctdb_db->lock_num_current == ctdb->tunable.lock_processes_per_db) {
continue;
}
lock_ctx = ctdb_db->lock_pending;
while (lock_ctx != NULL) {
next_ctx = lock_ctx->next;
if (! lock_ctx->request) {
DEBUG(DEBUG_INFO, ("Removing lock context without lock request\n"));
DLIST_REMOVE(ctdb_db->lock_pending, lock_ctx);
CTDB_DECREMENT_STAT(ctdb, locks.num_pending);
CTDB_DECREMENT_DB_STAT(ctdb_db, locks.num_pending);
talloc_free(lock_ctx);
} else {
break;
}
lock_ctx = next_ctx;
}
if (lock_ctx) {
return lock_ctx;
}
}
return NULL;
}
/*
* Schedule a new lock child process
@ -656,7 +723,7 @@ static char **lock_helper_args(TALLOC_CTX *mem_ctx, struct lock_context *lock_ct
*/
static void ctdb_lock_schedule(struct ctdb_context *ctdb)
{
struct lock_context *lock_ctx, *next_ctx;
struct lock_context *lock_ctx;
int ret;
TALLOC_CTX *tmp_ctx;
const char *helper = BINDIR "/ctdb_lock_helper";
@ -675,32 +742,8 @@ static void ctdb_lock_schedule(struct ctdb_context *ctdb)
CTDB_NO_MEMORY_VOID(ctdb, prog);
}
if (ctdb->lock_pending == NULL) {
return;
}
/* Find a lock context with requests */
lock_ctx = ctdb->lock_pending;
while (lock_ctx != NULL) {
next_ctx = lock_ctx->next;
if (! lock_ctx->request) {
DEBUG(DEBUG_INFO, ("Removing lock context without lock request\n"));
DLIST_REMOVE(ctdb->lock_pending, lock_ctx);
CTDB_DECREMENT_STAT(ctdb, locks.num_pending);
if (lock_ctx->ctdb_db) {
CTDB_DECREMENT_DB_STAT(lock_ctx->ctdb_db, locks.num_pending);
}
talloc_free(lock_ctx);
} else {
if (lock_ctx->ctdb_db == NULL ||
lock_ctx->ctdb_db->lock_num_current < ctdb->tunable.lock_processes_per_db) {
/* Found a lock context with lock requests */
break;
}
}
lock_ctx = next_ctx;
}
lock_ctx = ctdb_find_lock_context(ctdb);
if (lock_ctx == NULL) {
return;
}
@ -794,8 +837,13 @@ static void ctdb_lock_schedule(struct ctdb_context *ctdb)
tevent_fd_set_auto_close(lock_ctx->tfd);
/* Move the context from pending to current */
DLIST_REMOVE(ctdb->lock_pending, lock_ctx);
DLIST_ADD_END(ctdb->lock_current, lock_ctx, NULL);
if (lock_ctx->type == LOCK_RECORD) {
DLIST_REMOVE(lock_ctx->ctdb_db->lock_pending, lock_ctx);
DLIST_ADD_END(lock_ctx->ctdb_db->lock_current, lock_ctx, NULL);
} else {
DLIST_REMOVE(ctdb->lock_pending, lock_ctx);
DLIST_ADD_END(ctdb->lock_current, lock_ctx, NULL);
}
CTDB_DECREMENT_STAT(lock_ctx->ctdb, locks.num_pending);
CTDB_INCREMENT_STAT(lock_ctx->ctdb, locks.num_current);
if (lock_ctx->ctdb_db) {
@ -862,9 +910,9 @@ static struct lock_request *ctdb_lock_internal(struct ctdb_context *ctdb,
* immediately, so keep them at the head of the pending queue.
*/
if (lock_ctx->type == LOCK_RECORD) {
DLIST_ADD_END(ctdb->lock_pending, lock_ctx, NULL);
DLIST_ADD_END(ctdb_db->lock_pending, lock_ctx, NULL);
} else {
DLIST_ADD(ctdb->lock_pending, lock_ctx);
DLIST_ADD_END(ctdb->lock_pending, lock_ctx, NULL);
}
CTDB_INCREMENT_STAT(ctdb, locks.num_pending);
if (ctdb_db) {