1
0
mirror of https://github.com/samba-team/samba.git synced 2025-01-24 02:04:21 +03:00

ctdb_lockwait: create overflow queue.

Once we have more than 200 children waiting on a particular db, don't create
any more.  Just put them on an overflow queue, and when a child gets a lock
search that queue to see if others were after the same lock (they probably
were).

(This used to be ctdb commit 5e614e8cfd1e9a4b13035a0e400b7a60a745b510)
This commit is contained in:
Rusty Russell 2011-01-21 21:17:02 +10:30 committed by Ronnie Sahlberg
parent b2d7554b32
commit e57362ecf4
2 changed files with 62 additions and 7 deletions

View File

@ -507,6 +507,8 @@ struct ctdb_db_context {
bool transaction_active;
struct ctdb_vacuum_handle *vacuum_handle;
char *unhealthy_reason;
int pending_requests;
struct lockwait_handle *lockwait_overflow;
};

View File

@ -23,10 +23,12 @@
#include "system/wait.h"
#include "db_wrap.h"
#include "lib/tdb/include/tdb.h"
#include "lib/util/dlinklist.h"
#include "../include/ctdb_private.h"
struct lockwait_handle {
struct lockwait_handle *next, *prev;
struct ctdb_context *ctdb;
struct ctdb_db_context *ctdb_db;
struct fd_event *fde;
@ -38,6 +40,36 @@ struct lockwait_handle {
struct timeval start_time;
};
/* If we managed to obtain a lock, find any overflow records which wanted the
* same one and do all the callbacks at once. */
static void do_overflow(struct ctdb_db_context *ctdb_db,
TDB_DATA key)
{
struct lockwait_handle *i, *next;
TALLOC_CTX *tmp_ctx = talloc_new(ctdb_db);
for (i = ctdb_db->lockwait_overflow; i; i = next) {
/* Careful: destructor removes it from list! */
next = i->next;
if (key.dsize == i->key.dsize
&& memcmp(key.dptr, i->key.dptr, key.dsize) == 0) {
/* Callback might free them, so reparent. */
talloc_steal(tmp_ctx, i);
i->callback(i->private_data);
}
}
/* This will free them if callback didn't. */
talloc_free(tmp_ctx);
/* Remove one from the overflow queue if there is one. */
if (ctdb_db->lockwait_overflow) {
i = ctdb->lockwait_overflow;
ctdb_lockwait(ctdb_db, i->key, i->callback, i->private_data);
talloc_free(i);
}
}
static void lockwait_handler(struct event_context *ev, struct fd_event *fde,
uint16_t flags, void *private_data)
{
@ -51,6 +83,7 @@ static void lockwait_handler(struct event_context *ev, struct fd_event *fde,
TALLOC_CTX *tmp_ctx = talloc_new(ev);
key.dptr = talloc_memdup(tmp_ctx, key.dptr, key.dsize);
h->ctdb_db->pending_requests--;
talloc_set_destructor(h, NULL);
CTDB_UPDATE_LATENCY(h->ctdb, h->ctdb_db, "lockwait", lockwait_latency, h->start_time);
@ -69,6 +102,9 @@ static void lockwait_handler(struct event_context *ev, struct fd_event *fde,
tdb_chainlock_mark(tdb, key);
callback(p);
if (h->ctdb_db->lockwait_overflow) {
do_overflow(h->ctdb_db, key);
}
tdb_chainlock_unmark(tdb, key);
kill(child, SIGKILL);
@ -79,6 +115,14 @@ static int lockwait_destructor(struct lockwait_handle *h)
{
CTDB_DECREMENT_STAT(h->ctdb, pending_lockwait_calls);
kill(h->child, SIGKILL);
h->ctdb_db->pending_requests--;
return 0;
}
static int overflow_lockwait_destructor(struct lockwait_handle *h)
{
CTDB_DECREMENT_STAT(h->ctdb, pending_lockwait_calls);
DLIST_REMOVE(h->ctdb_db->lockwait_overflow, h);
return 0;
}
@ -109,6 +153,21 @@ struct lockwait_handle *ctdb_lockwait(struct ctdb_db_context *ctdb_db,
return NULL;
}
result->callback = callback;
result->private_data = private_data;
result->ctdb = ctdb_db->ctdb;
result->ctdb_db = ctdb_db;
result->key = key;
/* Don't fire off too many children at once! */
if (ctdb_db->pending_requests > 200) {
DLIST_ADD_END(ctdb_db->lockwait_overflow, result, NULL);
talloc_set_destructor(result, overflow_lockwait_destructor);
DEBUG(DEBUG_DEBUG, (__location__ " Created overflow for %s\n",
ctdb_db->db_name));
return result;
}
ret = pipe(result->fd);
if (ret != 0) {
@ -127,12 +186,6 @@ struct lockwait_handle *ctdb_lockwait(struct ctdb_db_context *ctdb_db,
return NULL;
}
result->callback = callback;
result->private_data = private_data;
result->ctdb = ctdb_db->ctdb;
result->ctdb_db = ctdb_db;
result->key = key;
if (result->child == 0) {
char c = 0;
close(result->fd[0]);
@ -151,6 +204,7 @@ struct lockwait_handle *ctdb_lockwait(struct ctdb_db_context *ctdb_db,
DEBUG(DEBUG_DEBUG, (__location__ " Created PIPE FD:%d to child lockwait process\n", result->fd[0]));
ctdb_db->pending_requests++;
talloc_set_destructor(result, lockwait_destructor);
result->fde = event_add_fd(ctdb_db->ctdb->ev, result, result->fd[0],
@ -164,6 +218,5 @@ struct lockwait_handle *ctdb_lockwait(struct ctdb_db_context *ctdb_db,
tevent_fd_set_auto_close(result->fde);
result->start_time = timeval_current();
return result;
}