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authorUlrich Drepper <drepper@redhat.com>2007-11-06 00:45:40 +0000
committerUlrich Drepper <drepper@redhat.com>2007-11-06 00:45:40 +0000
commitffb1b882828a6fa71fb4e9be1c30cacafb3c70c3 (patch)
tree9819639dc6d59b7cfbd3630b7027b57c0d696f47 /nscd
parent41ff2a4999f64527a0552c6a9c203157e161fa97 (diff)
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* nscd/aicache.c (addhstaiX): Check herrno after IPv4 lookup only
when the lookup call failed. * nscd/nscd.h (struct database_dyn): Rename prunelock to prune_lock. Add prune_cond and wakeup_time. (CACHE_PRUNE_INTERNAL): Define. Update declarations of prune_cache and setup_thread. * nscd/connections.c (dbs): Update initializers. (CACHE_PRUNE_INTERNAL): Moved to nscd.h. (nscd_init): Default number of threads is now 4. (invalidate_cache): Take lock before calling prune_cache. (handle_request): If SELinux forbids the request, say so. (readylist_cond): Use static initializer. (nscd_run_prune): New function. Used only by pruning threads. (nscd_run_worder): Renamed from nscd_run. Remove support for pruning here. (fd_ready): Update nscd_run reference. (start_threads): No need to initialize readylist_cond. Start pruning threads separately. * nscd/nscd_setup_thread.c: Change return value type to int and always return 0. * sysdeps/unix/sysv/linux/nscd_setup_thread.c: Change return value type to int and return nonzero value if we can use the TID address hack. * nscd/cache.c (cache_add): If next wakeup time of cleanup thread for the database is later than the new entry's timeout, update the wakeup time and wake the cleanup thread. (prune_cache): Return seconds the next entry in the database is still valid. Remove locking for pruning here. * nscd/nscd.conf: Document default number of threads.
Diffstat (limited to 'nscd')
-rw-r--r--nscd/aicache.c4
-rw-r--r--nscd/cache.c37
-rw-r--r--nscd/connections.c192
-rw-r--r--nscd/nscd.conf2
-rw-r--r--nscd/nscd.h13
-rw-r--r--nscd/nscd_setup_thread.c3
6 files changed, 145 insertions, 106 deletions
diff --git a/nscd/aicache.c b/nscd/aicache.c
index 68706a4..26968b2 100644
--- a/nscd/aicache.c
+++ b/nscd/aicache.c
@@ -157,7 +157,7 @@ addhstaiX (struct database_dyn *db, int fd, request_header *req,
tmpbuf4 = tmpbuf6;
}
- /* Next collect IPv4 information first. */
+ /* Next collect IPv4 information. */
while (1)
{
rc4 = 0;
@@ -170,7 +170,7 @@ addhstaiX (struct database_dyn *db, int fd, request_header *req,
tmpbuf4 = extend_alloca (tmpbuf4, tmpbuf4len, 2 * tmpbuf4len);
}
- if (rc4 != 0 || herrno == NETDB_INTERNAL)
+ if (rc4 != 0 && herrno == NETDB_INTERNAL)
goto out;
if (status[0] == NSS_STATUS_SUCCESS
diff --git a/nscd/cache.c b/nscd/cache.c
index e5a8499..ea79c38 100644
--- a/nscd/cache.c
+++ b/nscd/cache.c
@@ -197,6 +197,20 @@ cache_add (int type, const void *key, size_t len, struct datahead *packet,
(char *) &table->head->array[hash] - (char *) table->head
+ sizeof (ref_t), MS_ASYNC);
+ /* Perhaps the prune thread for the data is not running in a long
+ time. Wake it if necessary. */
+ time_t next_wakeup = table->wakeup_time;
+ while (next_wakeup + CACHE_PRUNE_INTERVAL > packet->timeout)
+ if (atomic_compare_and_exchange_bool_acq (&table->wakeup_time,
+ packet->timeout,
+ next_wakeup) == 0)
+ {
+ pthread_cond_signal (&table->prune_cond);
+ break;
+ }
+ else
+ next_wakeup = table->wakeup_time;
+
return 0;
}
@@ -212,7 +226,7 @@ cache_add (int type, const void *key, size_t len, struct datahead *packet,
actually remove them. This is complicated by the way we have to
free the data structures since some hash table entries share the same
data. */
-void
+time_t
prune_cache (struct database_dyn *table, time_t now, int fd)
{
size_t cnt = table->head->module;
@@ -226,7 +240,9 @@ prune_cache (struct database_dyn *table, time_t now, int fd)
int32_t resp = 0;
writeall (fd, &resp, sizeof (resp));
}
- return;
+
+ /* No need to do this again anytime soon. */
+ return 24 * 60 * 60;
}
/* If we check for the modification of the underlying file we invalidate
@@ -256,21 +272,6 @@ prune_cache (struct database_dyn *table, time_t now, int fd)
}
}
- /* This function can be called from the cleanup thread but also in
- response to an invalidate command. Make sure only one thread is
- running. When not serving INVALIDATE request, no need for the
- second thread to wait around. */
- if (__builtin_expect (pthread_mutex_trylock (&table->prunelock) != 0, 0))
- {
- /* The work is already being done. */
- if (fd == -1)
- return;
-
- /* We have to wait until the thread is done and then run again
- so that the large NOW value invalidates all entries. */
- pthread_mutex_lock (&table->prunelock);
- }
-
/* We run through the table and find values which are not valid anymore.
Note that for the initial step, finding the entries to be removed,
@@ -473,5 +474,5 @@ prune_cache (struct database_dyn *table, time_t now, int fd)
if (any)
gc (table);
- pthread_mutex_unlock (&table->prunelock);
+ return next_timeout - now;
}
diff --git a/nscd/connections.c b/nscd/connections.c
index 26d75d2..d8244b7 100644
--- a/nscd/connections.c
+++ b/nscd/connections.c
@@ -104,7 +104,7 @@ struct database_dyn dbs[lastdb] =
{
[pwddb] = {
.lock = PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP,
- .prunelock = PTHREAD_MUTEX_INITIALIZER,
+ .prune_lock = PTHREAD_MUTEX_INITIALIZER,
.enabled = 0,
.check_file = 1,
.persistent = 0,
@@ -123,7 +123,7 @@ struct database_dyn dbs[lastdb] =
},
[grpdb] = {
.lock = PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP,
- .prunelock = PTHREAD_MUTEX_INITIALIZER,
+ .prune_lock = PTHREAD_MUTEX_INITIALIZER,
.enabled = 0,
.check_file = 1,
.persistent = 0,
@@ -142,7 +142,7 @@ struct database_dyn dbs[lastdb] =
},
[hstdb] = {
.lock = PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP,
- .prunelock = PTHREAD_MUTEX_INITIALIZER,
+ .prune_lock = PTHREAD_MUTEX_INITIALIZER,
.enabled = 0,
.check_file = 1,
.persistent = 0,
@@ -161,7 +161,7 @@ struct database_dyn dbs[lastdb] =
},
[servdb] = {
.lock = PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP,
- .prunelock = PTHREAD_MUTEX_INITIALIZER,
+ .prune_lock = PTHREAD_MUTEX_INITIALIZER,
.enabled = 0,
.check_file = 1,
.persistent = 0,
@@ -210,10 +210,6 @@ static struct
};
-/* Number of seconds between two cache pruning runs. */
-#define CACHE_PRUNE_INTERVAL 15
-
-
/* Initial number of threads to use. */
int nthreads = -1;
/* Maximum number of threads to use. */
@@ -495,7 +491,7 @@ nscd_init (void)
if (nthreads == -1)
/* No configuration for this value, assume a default. */
- nthreads = 2 * lastdb;
+ nthreads = 4;
for (size_t cnt = 0; cnt < lastdb; ++cnt)
if (dbs[cnt].enabled)
@@ -898,7 +894,11 @@ invalidate_cache (char *key, int fd)
}
if (dbs[number].enabled)
- prune_cache (&dbs[number], LONG_MAX, fd);
+ {
+ pthread_mutex_lock (&dbs[number].prune_lock);
+ prune_cache (&dbs[number], LONG_MAX, fd);
+ pthread_mutex_unlock (&dbs[number].prune_lock);
+ }
else
{
resp = 0;
@@ -970,9 +970,13 @@ cannot handle old request version %d; current version is %d"),
return;
}
- /* Make the SELinux check before we go on to the standard checks. */
+ /* Perform the SELinux check before we go on to the standard checks. */
if (selinux_enabled && nscd_request_avc_has_perm (fd, req->type) != 0)
- return;
+ {
+ if (debug_level > 0)
+ dbg_log (_("request not handled due to missing permission"));
+ return;
+ }
struct database_dyn *db = reqinfo[req->type].db;
@@ -1336,7 +1340,7 @@ static struct fdlist *readylist;
/* Conditional variable and mutex to signal availability of entries in
READYLIST. The condvar is initialized dynamically since we might
use a different clock depending on availability. */
-static pthread_cond_t readylist_cond;
+static pthread_cond_t readylist_cond = PTHREAD_COND_INITIALIZER;
static pthread_mutex_t readylist_lock = PTHREAD_MUTEX_INITIALIZER;
/* The clock to use with the condvar. */
@@ -1346,32 +1350,76 @@ static clockid_t timeout_clock = CLOCK_REALTIME;
static unsigned long int nready;
-/* This is the main loop. It is replicated in different threads but the
- `poll' call makes sure only one thread handles an incoming connection. */
+/* Function for the clean-up threads. */
static void *
__attribute__ ((__noreturn__))
-nscd_run (void *p)
+nscd_run_prune (void *p)
{
const long int my_number = (long int) p;
- const int run_prune = my_number < lastdb && dbs[my_number].enabled;
+ assert (dbs[my_number].enabled);
+
+ int dont_need_update = setup_thread (&dbs[my_number]);
+
+ /* We are running. */
+ dbs[my_number].head->timestamp = time (NULL);
+
struct timespec prune_ts;
- int to = 0;
- char buf[256];
+ if (clock_gettime (timeout_clock, &prune_ts) == -1)
+ /* Should never happen. */
+ abort ();
+
+ /* Compute the initial timeout time. Prevent all the timers to go
+ off at the same time by adding a db-based value. */
+ prune_ts.tv_sec += CACHE_PRUNE_INTERVAL + my_number;
- if (run_prune)
+ pthread_mutex_lock (&dbs[my_number].prune_lock);
+ while (1)
{
- setup_thread (&dbs[my_number]);
+ /* Wait, but not forever. */
+ int e = pthread_cond_timedwait (&dbs[my_number].prune_cond,
+ &dbs[my_number].prune_lock,
+ &prune_ts);
+ assert (e == 0 || e == ETIMEDOUT);
- /* We are running. */
- dbs[my_number].head->timestamp = time (NULL);
+ time_t next_wait;
+ time_t now = time (NULL);
+ if (e == ETIMEDOUT || now >= dbs[my_number].wakeup_time)
+ {
+ next_wait = prune_cache (&dbs[my_number], now, -1);
+ next_wait = MAX (next_wait, CACHE_PRUNE_INTERVAL);
+ /* If clients cannot determine for sure whether nscd is running
+ we need to wake up occasionally to update the timestamp.
+ Wait 90% of the update period. */
+#define UPDATE_MAPPING_TIMEOUT (MAPPING_TIMEOUT * 9 / 10)
+ if (__builtin_expect (! dont_need_update, 0))
+ next_wait = MIN (UPDATE_MAPPING_TIMEOUT, next_wait);
+
+ /* Make it known when we will wake up again. */
+ dbs[my_number].wakeup_time = now + next_wait;
+ }
+ else
+ /* The cache was just pruned. Do not do it again now. Just
+ use the new timeout value. */
+ next_wait = dbs[my_number].wakeup_time - now;
if (clock_gettime (timeout_clock, &prune_ts) == -1)
/* Should never happen. */
abort ();
- /* Compute timeout time. */
- prune_ts.tv_sec += CACHE_PRUNE_INTERVAL;
+ /* Compute next timeout time. */
+ prune_ts.tv_sec += next_wait;
}
+}
+
+
+/* This is the main loop. It is replicated in different threads but
+ the the use of the ready list makes sure only one thread handles an
+ incoming connection. */
+static void *
+__attribute__ ((__noreturn__))
+nscd_run_worker (void *p)
+{
+ char buf[256];
/* Initial locking. */
pthread_mutex_lock (&readylist_lock);
@@ -1382,26 +1430,7 @@ nscd_run (void *p)
while (1)
{
while (readylist == NULL)
- {
- if (run_prune)
- {
- /* Wait, but not forever. */
- to = pthread_cond_timedwait (&readylist_cond, &readylist_lock,
- &prune_ts);
-
- /* If we were woken and there is no work to be done,
- just start pruning. */
- if (readylist == NULL && to == ETIMEDOUT)
- {
- --nready;
- pthread_mutex_unlock (&readylist_lock);
- goto only_prune;
- }
- }
- else
- /* No need to timeout. */
- pthread_cond_wait (&readylist_cond, &readylist_lock);
- }
+ pthread_cond_wait (&readylist_cond, &readylist_lock);
struct fdlist *it = readylist->next;
if (readylist->next == readylist)
@@ -1504,28 +1533,6 @@ handle_request: request received (Version = %d)"), req.version);
/* We are done. */
close (fd);
- /* Check whether we should be pruning the cache. */
- assert (run_prune || to == 0);
- if (to == ETIMEDOUT)
- {
- only_prune:
- /* The pthread_cond_timedwait() call timed out. It is time
- to clean up the cache. */
- assert (my_number < lastdb);
- prune_cache (&dbs[my_number], time (NULL), -1);
-
- if (clock_gettime (timeout_clock, &prune_ts) == -1)
- /* Should never happen. */
- abort ();
-
- /* Compute next timeout time. */
- prune_ts.tv_sec += CACHE_PRUNE_INTERVAL;
-
- /* In case the list is emtpy we do not want to run the prune
- code right away again. */
- to = 0;
- }
-
/* Re-locking. */
pthread_mutex_lock (&readylist_lock);
@@ -1568,7 +1575,7 @@ fd_ready (int fd)
/* Try to start another thread to help out. */
pthread_t th;
if (nthreads < max_nthreads
- && pthread_create (&th, &attr, nscd_run,
+ && pthread_create (&th, &attr, nscd_run_worker,
(void *) (long int) nthreads) == 0)
{
/* We got another thread. */
@@ -1828,10 +1835,6 @@ start_threads (void)
timeout_clock = CLOCK_MONOTONIC;
#endif
- pthread_cond_init (&readylist_cond, &condattr);
- pthread_condattr_destroy (&condattr);
-
-
/* Create the attribute for the threads. They are all created
detached. */
pthread_attr_init (&attr);
@@ -1843,19 +1846,46 @@ start_threads (void)
if (debug_level == 0)
nthreads = MAX (nthreads, lastdb);
- int nfailed = 0;
- for (long int i = 0; i < nthreads; ++i)
+ /* Create the threads which prune the databases. */
+ // XXX Ideally this work would be done by some of the worker threads.
+ // XXX But this is problematic since we would need to be able to wake
+ // XXX them up explicitly as well as part of the group handling the
+ // XXX ready-list. This requires an operation where we can wait on
+ // XXX two conditional variables at the same time. This operation
+ // XXX does not exist (yet).
+ for (long int i = 0; i < lastdb; ++i)
{
+ /* Initialize the conditional variable. */
+ if (pthread_cond_init (&dbs[i].prune_cond, &condattr) != 0)
+ {
+ dbg_log (_("could not initialize conditional variable"));
+ exit (1);
+ }
+
pthread_t th;
- if (pthread_create (&th, &attr, nscd_run, (void *) (i - nfailed)) != 0)
- ++nfailed;
+ if (dbs[i].enabled
+ && pthread_create (&th, &attr, nscd_run_prune, (void *) i) != 0)
+ {
+ dbg_log (_("could not start clean-up thread; terminating"));
+ exit (1);
+ }
}
- if (nthreads - nfailed < lastdb)
+
+ pthread_condattr_destroy (&condattr);
+
+ for (long int i = 0; i < nthreads; ++i)
{
- /* We could not start enough threads. */
- dbg_log (_("could only start %d threads; terminating"),
- nthreads - nfailed);
- exit (1);
+ pthread_t th;
+ if (pthread_create (&th, &attr, nscd_run_worker, NULL) != 0)
+ {
+ if (i == 0)
+ {
+ dbg_log (_("could not start any worker thread; terminating"));
+ exit (1);
+ }
+
+ break;
+ }
}
/* Determine how much room for descriptors we should initially
diff --git a/nscd/nscd.conf b/nscd/nscd.conf
index d0d16ad..84f335e 100644
--- a/nscd/nscd.conf
+++ b/nscd/nscd.conf
@@ -31,7 +31,7 @@
# logfile /var/log/nscd.log
-# threads 6
+# threads 4
# max-threads 128
# server-user nobody
# stat-user somebody
diff --git a/nscd/nscd.h b/nscd/nscd.h
index e8199b8..12b1f85 100644
--- a/nscd/nscd.h
+++ b/nscd/nscd.h
@@ -59,7 +59,9 @@ typedef enum
struct database_dyn
{
pthread_rwlock_t lock;
- pthread_mutex_t prunelock;
+ pthread_cond_t prune_cond;
+ pthread_mutex_t prune_lock;
+ time_t wakeup_time;
int enabled;
int check_file;
@@ -111,6 +113,11 @@ struct database_dyn
#define DEFAULT_DATASIZE_PER_BUCKET 1024
+/* Number of seconds between two cache pruning runs if we do not have
+ better information when it is really needed. */
+#define CACHE_PRUNE_INTERVAL 15
+
+
/* Global variables. */
extern struct database_dyn dbs[lastdb];
extern const char *const dbnames[lastdb];
@@ -189,7 +196,7 @@ extern struct datahead *cache_search (request_type, void *key, size_t len,
extern int cache_add (int type, const void *key, size_t len,
struct datahead *packet, bool first,
struct database_dyn *table, uid_t owner);
-extern void prune_cache (struct database_dyn *table, time_t now, int fd);
+extern time_t prune_cache (struct database_dyn *table, time_t now, int fd);
/* pwdcache.c */
extern void addpwbyname (struct database_dyn *db, int fd, request_header *req,
@@ -258,7 +265,7 @@ extern void gc (struct database_dyn *db);
/* nscd_setup_thread.c */
-extern void setup_thread (struct database_dyn *db);
+extern int setup_thread (struct database_dyn *db);
/* Special version of TEMP_FAILURE_RETRY for functions returning error
diff --git a/nscd/nscd_setup_thread.c b/nscd/nscd_setup_thread.c
index c17fbd5..4b6671e 100644
--- a/nscd/nscd_setup_thread.c
+++ b/nscd/nscd_setup_thread.c
@@ -20,8 +20,9 @@
#include <nscd.h>
-void
+int
setup_thread (struct database_dyn *db)
{
/* Nothing. */
+ return 0;
}