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LockWait congestion.

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Add a dlist to track all active lockwait child processes.
Everytime creating a new lockwait handle, check if there is already an
active lockwait process for this database/key and if so,
send the new request straight to the overflow queue.

This means we will only have one active lockwaic child process for a certain key,
even if there were thousands of fetch-lock requests for this key.

When the lockwait processing finishes for the original request, the processing in d_overflow() will automagically process all remaining keys as well.

Add back a --nosetsched argument to make it easier to run under gdb

(This used to be ctdb commit 3e9317a2e1f687b04bf51575d47fcd4faa6e6515)
This commit is contained in:
Ronnie Sahlberg 2011-01-24 11:42:50 +11:00
parent f91f063fe0
commit 0f33605866
3 changed files with 33 additions and 13 deletions
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1
ctdb/include/ctdb_private.h
View File

@ -508,6 +508,7 @@ struct ctdb_db_context {
struct ctdb_vacuum_handle *vacuum_handle;
char *unhealthy_reason;
int pending_requests;
struct lockwait_handle *lockwait_active;
struct lockwait_handle *lockwait_overflow;
};

37
ctdb/server/ctdb_lockwait.c
View File

@ -70,6 +70,15 @@ static void do_overflow(struct ctdb_db_context *ctdb_db,
}
}
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--;
DLIST_REMOVE(h->ctdb_db->lockwait_active, h);
return 0;
}
static void lockwait_handler(struct event_context *ev, struct fd_event *fde,
uint16_t flags, void *private_data)
{
@ -77,7 +86,6 @@ static void lockwait_handler(struct event_context *ev, struct fd_event *fde,
struct lockwait_handle);
void (*callback)(void *) = h->callback;
void *p = h->private_data;
pid_t child = h->child;
TDB_DATA key = h->key;
struct tdb_context *tdb = h->ctdb_db->ltdb->tdb;
TALLOC_CTX *tmp_ctx = talloc_new(ev);
@ -85,9 +93,7 @@ static void lockwait_handler(struct event_context *ev, struct fd_event *fde,
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);
CTDB_DECREMENT_STAT(h->ctdb, pending_lockwait_calls);
/* the handle needs to go away when the context is gone - when
the handle goes away this implicitly closes the pipe, which
@ -107,17 +113,9 @@ static void lockwait_handler(struct event_context *ev, struct fd_event *fde,
}
tdb_chainlock_unmark(tdb, key);
kill(child, SIGKILL);
talloc_free(tmp_ctx);
}
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)
{
@ -141,7 +139,7 @@ struct lockwait_handle *ctdb_lockwait(struct ctdb_db_context *ctdb_db,
void (*callback)(void *private_data),
void *private_data)
{
struct lockwait_handle *result;
struct lockwait_handle *result, *i;
int ret;
pid_t parent = getpid();
@ -159,6 +157,18 @@ struct lockwait_handle *ctdb_lockwait(struct ctdb_db_context *ctdb_db,
result->ctdb_db = ctdb_db;
result->key = key;
/* If we already have a lockwait child for this request, then put this
request on the overflow queue straight away
*/
for (i = ctdb_db->lockwait_active; i; i = i->next) {
if (key.dsize == i->key.dsize
&& memcmp(key.dptr, i->key.dptr, key.dsize) == 0) {
DLIST_ADD_END(ctdb_db->lockwait_overflow, result, NULL);
talloc_set_destructor(result, overflow_lockwait_destructor);
return result;
}
}
/* Don't fire off too many children at once! */
if (ctdb_db->pending_requests > 200) {
DLIST_ADD_END(ctdb_db->lockwait_overflow, result, NULL);
@ -202,6 +212,9 @@ struct lockwait_handle *ctdb_lockwait(struct ctdb_db_context *ctdb_db,
close(result->fd[1]);
set_close_on_exec(result->fd[0]);
/* This is an active lockwait child process */
DLIST_ADD_END(ctdb_db->lockwait_active, result, NULL);
DEBUG(DEBUG_DEBUG, (__location__ " Created PIPE FD:%d to child lockwait process\n", result->fd[0]));
ctdb_db->pending_requests++;

8
ctdb/server/ctdbd.c
View File

@ -43,6 +43,7 @@ static struct {
const char *single_public_ip;
const char *node_ip;
int valgrinding;
int nosetsched;
int use_syslog;
int start_as_disabled;
int start_as_stopped;
@ -133,6 +134,7 @@ int main(int argc, const char *argv[])
{ "dbdir-state", 0, POPT_ARG_STRING, &options.db_dir_state, 0, "directory for internal state tdb files", NULL },
{ "reclock", 0, POPT_ARG_STRING, &options.recovery_lock_file, 0, "location of recovery lock file", "filename" },
{ "valgrinding", 0, POPT_ARG_NONE, &options.valgrinding, 0, "disable setscheduler SCHED_FIFO call, use mmap for tdbs", NULL },
{ "nosetsched", 0, POPT_ARG_NONE, &options.nosetsched, 0, "disable setscheduler SCHED_FIFO call, use mmap for tdbs", NULL },
{ "syslog", 0, POPT_ARG_NONE, &options.use_syslog, 0, "log messages to syslog", NULL },
{ "start-as-disabled", 0, POPT_ARG_NONE, &options.start_as_disabled, 0, "Node starts in disabled state", NULL },
{ "start-as-stopped", 0, POPT_ARG_NONE, &options.start_as_stopped, 0, "Node starts in stopped state", NULL },
@ -315,7 +317,11 @@ int main(int argc, const char *argv[])
}
ctdb->valgrinding = options.valgrinding;
ctdb->do_setsched = !ctdb->valgrinding;
if (options.valgrinding || options.nosetsched) {
ctdb->do_setsched = 0;
} else {
ctdb->do_setsched = 1;
}
if (options.max_persistent_check_errors < 0) {
ctdb->max_persistent_check_errors = 0xFFFFFFFFFFFFFFFFLL;