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Changed the utility thread sleep function to use a custom sleep based on pipe/select

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so they can be terminated quickly when the driver shuts down.
This commit is contained in:
Jon Meredith 2009-02-11 11:22:44 -07:00
parent 5ccd73c2ea
commit 09081f000b
1 changed files with 95 additions and 32 deletions
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127
c_src/bdberl_drv.c
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@ -11,6 +11,10 @@
#include <stdint.h>
#include <time.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <sys/time.h>
#include <sys/select.h>
#include "hive_hash.h"
#include "bdberl_drv.h"
@ -19,7 +23,7 @@
/**
* Function prototypes
*/
static int open_database(const char* name, DBTYPE type, unsigned flags, PortData* data, int* errno);
static int open_database(const char* name, DBTYPE type, unsigned int flags, PortData* data, int* dbref_res);
static int close_database(int dbref, unsigned flags, PortData* data);
static int delete_database(const char* name);
@ -106,6 +110,12 @@ static ErlDrvTid G_CHECKPOINT_THREAD = 0;
static unsigned int G_CHECKPOINT_ACTIVE = 1;
static unsigned int G_CHECKPOINT_INTERVAL = 60 * 60; /* Seconds between checkpoints */
/**
* Pipe to used to wake up the various monitors. Instead of just sleeping
* they wait for an exceptional condition on the read fd of the pipe. When it is time to
* shutdown, the driver closes the write fd and waits for the threads to be joined.
*/
static int G_BDBERL_PIPE[2] = {-1, -1};
/**
*
@ -188,6 +198,9 @@ DRIVER_INIT(bdberl_drv)
if (G_DB_ENV_ERROR == 0)
{
// Pipe for signalling the utility threads all is over.
assert(0 == pipe(G_BDBERL_PIPE));
// Use the BDBERL_MAX_DBS environment value to determine the max # of
// databases to permit the VM to open at once. Defaults to 1024.
G_DATABASES_SIZE = 1024;
@ -336,6 +349,10 @@ static void bdberl_drv_finish()
bdberl_tpool_stop(G_TPOOL_GENERAL);
bdberl_tpool_stop(G_TPOOL_TXNS);
// Close the writer fd on the pipe to signal finish to the utility threads
close(G_BDBERL_PIPE[1]);
G_BDBERL_PIPE[1] = -1;
// Signal the trickle write thread to shutdown
G_TRICKLE_ACTIVE = 0;
erl_drv_thread_join(G_TRICKLE_THREAD, 0);
@ -348,6 +365,10 @@ static void bdberl_drv_finish()
G_CHECKPOINT_ACTIVE = 0;
erl_drv_thread_join(G_CHECKPOINT_THREAD, 0);
// Close the reader fd on the pipe now utility threads are closed
close(G_BDBERL_PIPE[0]);
G_BDBERL_PIPE[0] = -1;
// Cleanup and shut down the BDB environment. Note that we assume
// all ports have been released and thuse all databases/txns/etc are also gone.
G_DB_ENV->close(G_DB_ENV, 0);
@ -1101,6 +1122,8 @@ static void do_async_cursor_get(void* arg)
// the transaction
if (rc && rc != DB_NOTFOUND)
{
DBG("cursor flags=%d rc=%d\n", flags, rc);
d->cursor->close(d->cursor);
d->cursor = 0;
if (d->txn)
@ -1349,6 +1372,70 @@ static int alloc_dbref()
}
/**
* Utility thread sleep - returns true if being signalled to exit
* otherwise false if timeout exceeded.
*/
int util_thread_usleep(unsigned int usecs)
{
fd_set fds;
struct timeval sleep_until;
struct timeval sleep_for;
struct timeval now;
struct timeval tv;
int done;
int nfds = (G_BDBERL_PIPE[0] > G_BDBERL_PIPE[1] ? G_BDBERL_PIPE[0] : G_BDBERL_PIPE[1]) + 1;
memset(&sleep_for, 0, sizeof(sleep_for));
sleep_for.tv_sec = usecs / 1000000;
sleep_for.tv_usec = usecs % 1000000;
gettimeofday(&now, NULL);
timeradd(&now, &sleep_for, &sleep_until);
do
{
FD_ZERO(&fds);
FD_SET(G_BDBERL_PIPE[0], &fds); // read fd of pipe
// Check if we have slept long enough
gettimeofday(&now, NULL);
if (timercmp(&now, &sleep_until, >))
{
done = 1;
}
else // take a nap
{
// work out the remaining time to sleep on the fd for - make sure that this time
// is less than or equal to the original sleep time requested, just in
// case the system time is being adjusted. If the adjustment would result
// in a longer wait then cap it at the sleep_for time.
timersub(&sleep_until, &now, &tv);
if (timercmp(&tv, &sleep_for, >))
{
memcpy(&tv, &sleep_for, sizeof(tv));
}
done = 1;
if (-1 == select(nfds, &fds, NULL, NULL, &tv))
{
if (EINTR == errno) // a signal woke up select, back to sleep for us
{
done = 0;
}
// any other signals can return to the caller to fail safe as it
// doesn't matter if the util threads get woken up more often
}
else if (FD_ISSET(G_BDBERL_PIPE[0], &fds))
{
done = 1;
}
}
} while (!done);
return FD_ISSET(G_BDBERL_PIPE[0], &fds);
}
/**
* Thread function that runs the deadlock checker periodically
*/
@ -1364,8 +1451,7 @@ static void* deadlock_check(void* arg)
DBG("Rejected deadlocks: %d\r\n", count);
}
// TODO: Use nanosleep
usleep(G_DEADLOCK_CHECK_INTERVAL * 1000);
util_thread_usleep(G_DEADLOCK_CHECK_INTERVAL * 1000);
}
DBG("Deadlock checker exiting.\r\n");
@ -1377,25 +1463,14 @@ static void* deadlock_check(void* arg)
*/
static void* trickle_write(void* arg)
{
int elapsed_secs = 0;
while(G_TRICKLE_ACTIVE)
{
if (elapsed_secs == G_TRICKLE_INTERVAL)
{
// Enough time has passed -- time to run the trickle operation again
int pages_wrote = 0;
G_DB_ENV->memp_trickle(G_DB_ENV, G_TRICKLE_PERCENTAGE, &pages_wrote);
DBG("Wrote %d pages to achieve %d trickle\r\n", pages_wrote, G_TRICKLE_PERCENTAGE);
// Enough time has passed -- time to run the trickle operation again
int pages_wrote = 0;
G_DB_ENV->memp_trickle(G_DB_ENV, G_TRICKLE_PERCENTAGE, &pages_wrote);
DBG("Wrote %d pages to achieve %d trickle\r\n", pages_wrote, G_TRICKLE_PERCENTAGE);
// Reset the counter
elapsed_secs = 0;
}
else
{
// TODO: Use nanosleep
usleep(1000 * 1000); /* Sleep for 1 second */
elapsed_secs++;
}
util_thread_usleep(G_TRICKLE_INTERVAL * 1000000);
}
DBG("Trickle writer exiting.\r\n");
@ -1409,11 +1484,8 @@ static void* txn_checkpoint(void* arg)
{
DBG("Checkpoint interval: %d seconds\r\n", G_CHECKPOINT_INTERVAL);
int elapsed_secs = 0;
while (G_CHECKPOINT_ACTIVE)
{
if (elapsed_secs == G_CHECKPOINT_INTERVAL)
{
G_DB_ENV->txn_checkpoint(G_DB_ENV, 0, 0, 0);
G_DB_ENV->log_archive(G_DB_ENV, NULL, DB_ARCH_REMOVE);
@ -1421,16 +1493,7 @@ static void* txn_checkpoint(void* arg)
time_t tm = time(NULL);
printf("Transaction checkpoint complete at %s\r\n", ctime(&tm));
#endif
// Reset the counter
elapsed_secs = 0;
}
else
{
// TODO: Use nanosleep
usleep(1000 * 1000); /* Sleep for 1 second */
elapsed_secs++;
}
util_thread_usleep(G_CHECKPOINT_INTERVAL * 1000000);
}
DBG("Checkpointer exiting.\r\n");