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-rw-r--r--include/linux/posix-timers.h1
-rw-r--r--include/linux/sched.h3
-rw-r--r--kernel/posix-timers.c106
3 files changed, 72 insertions, 38 deletions
diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h
index 042058f..60bac69 100644
--- a/include/linux/posix-timers.h
+++ b/include/linux/posix-timers.h
@@ -55,6 +55,7 @@ struct cpu_timer_list {
/* POSIX.1b interval timer structure. */
struct k_itimer {
struct list_head list; /* free/ allocate list */
+ struct hlist_node t_hash;
spinlock_t it_lock;
clockid_t it_clock; /* which timer type */
timer_t it_id; /* timer id */
diff --git a/include/linux/sched.h b/include/linux/sched.h
index d35d2b6..d13341b 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -526,7 +526,8 @@ struct signal_struct {
unsigned int has_child_subreaper:1;
/* POSIX.1b Interval Timers */
- struct list_head posix_timers;
+ int posix_timer_id;
+ struct list_head posix_timers;
/* ITIMER_REAL timer for the process */
struct hrtimer real_timer;
diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c
index 2a2e173..34d7592 100644
--- a/kernel/posix-timers.c
+++ b/kernel/posix-timers.c
@@ -40,38 +40,31 @@
#include <linux/list.h>
#include <linux/init.h>
#include <linux/compiler.h>
-#include <linux/idr.h>
+#include <linux/hash.h>
#include <linux/posix-clock.h>
#include <linux/posix-timers.h>
#include <linux/syscalls.h>
#include <linux/wait.h>
#include <linux/workqueue.h>
#include <linux/export.h>
+#include <linux/hashtable.h>
/*
- * Management arrays for POSIX timers. Timers are kept in slab memory
- * Timer ids are allocated by an external routine that keeps track of the
- * id and the timer. The external interface is:
- *
- * void *idr_find(struct idr *idp, int id); to find timer_id <id>
- * int idr_get_new(struct idr *idp, void *ptr); to get a new id and
- * related it to <ptr>
- * void idr_remove(struct idr *idp, int id); to release <id>
- * void idr_init(struct idr *idp); to initialize <idp>
- * which we supply.
- * The idr_get_new *may* call slab for more memory so it must not be
- * called under a spin lock. Likewise idr_remore may release memory
- * (but it may be ok to do this under a lock...).
- * idr_find is just a memory look up and is quite fast. A -1 return
- * indicates that the requested id does not exist.
+ * Management arrays for POSIX timers. Timers are now kept in static hash table
+ * with 512 entries.
+ * Timer ids are allocated by local routine, which selects proper hash head by
+ * key, constructed from current->signal address and per signal struct counter.
+ * This keeps timer ids unique per process, but now they can intersect between
+ * processes.
*/
/*
* Lets keep our timers in a slab cache :-)
*/
static struct kmem_cache *posix_timers_cache;
-static struct idr posix_timers_id;
-static DEFINE_SPINLOCK(idr_lock);
+
+static DEFINE_HASHTABLE(posix_timers_hashtable, 9);
+static DEFINE_SPINLOCK(hash_lock);
/*
* we assume that the new SIGEV_THREAD_ID shares no bits with the other
@@ -152,6 +145,57 @@ static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags);
__timr; \
})
+static int hash(struct signal_struct *sig, unsigned int nr)
+{
+ return hash_32(hash32_ptr(sig) ^ nr, HASH_BITS(posix_timers_hashtable));
+}
+
+static struct k_itimer *__posix_timers_find(struct hlist_head *head,
+ struct signal_struct *sig,
+ timer_t id)
+{
+ struct hlist_node *node;
+ struct k_itimer *timer;
+
+ hlist_for_each_entry_rcu(timer, head, t_hash) {
+ if ((timer->it_signal == sig) && (timer->it_id == id))
+ return timer;
+ }
+ return NULL;
+}
+
+static struct k_itimer *posix_timer_by_id(timer_t id)
+{
+ struct signal_struct *sig = current->signal;
+ struct hlist_head *head = &posix_timers_hashtable[hash(sig, id)];
+
+ return __posix_timers_find(head, sig, id);
+}
+
+static int posix_timer_add(struct k_itimer *timer)
+{
+ struct signal_struct *sig = current->signal;
+ int first_free_id = sig->posix_timer_id;
+ struct hlist_head *head;
+ int ret = -ENOENT;
+
+ do {
+ spin_lock(&hash_lock);
+ head = &posix_timers_hashtable[hash(sig, sig->posix_timer_id)];
+ if (!__posix_timers_find(head, sig, sig->posix_timer_id)) {
+ hlist_add_head_rcu(&timer->t_hash, head);
+ ret = sig->posix_timer_id;
+ }
+ if (++sig->posix_timer_id < 0)
+ sig->posix_timer_id = 0;
+ if ((sig->posix_timer_id == first_free_id) && (ret == -ENOENT))
+ /* Loop over all possible ids completed */
+ ret = -EAGAIN;
+ spin_unlock(&hash_lock);
+ } while (ret == -ENOENT);
+ return ret;
+}
+
static inline void unlock_timer(struct k_itimer *timr, unsigned long flags)
{
spin_unlock_irqrestore(&timr->it_lock, flags);
@@ -298,7 +342,6 @@ static __init int init_posix_timers(void)
posix_timers_cache = kmem_cache_create("posix_timers_cache",
sizeof (struct k_itimer), 0, SLAB_PANIC,
NULL);
- idr_init(&posix_timers_id);
return 0;
}
@@ -520,9 +563,9 @@ static void release_posix_timer(struct k_itimer *tmr, int it_id_set)
{
if (it_id_set) {
unsigned long flags;
- spin_lock_irqsave(&idr_lock, flags);
- idr_remove(&posix_timers_id, tmr->it_id);
- spin_unlock_irqrestore(&idr_lock, flags);
+ spin_lock_irqsave(&hash_lock, flags);
+ hlist_del_rcu(&tmr->t_hash);
+ spin_unlock_irqrestore(&hash_lock, flags);
}
put_pid(tmr->it_pid);
sigqueue_free(tmr->sigq);
@@ -568,22 +611,11 @@ SYSCALL_DEFINE3(timer_create, const clockid_t, which_clock,
return -EAGAIN;
spin_lock_init(&new_timer->it_lock);
-
- idr_preload(GFP_KERNEL);
- spin_lock_irq(&idr_lock);
- error = idr_alloc(&posix_timers_id, new_timer, 0, 0, GFP_NOWAIT);
- spin_unlock_irq(&idr_lock);
- idr_preload_end();
- if (error < 0) {
- /*
- * Weird looking, but we return EAGAIN if the IDR is
- * full (proper POSIX return value for this)
- */
- if (error == -ENOSPC)
- error = -EAGAIN;
+ new_timer_id = posix_timer_add(new_timer);
+ if (new_timer_id < 0) {
+ error = new_timer_id;
goto out;
}
- new_timer_id = error;
it_id_set = IT_ID_SET;
new_timer->it_id = (timer_t) new_timer_id;
@@ -661,7 +693,7 @@ static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags)
return NULL;
rcu_read_lock();
- timr = idr_find(&posix_timers_id, (int)timer_id);
+ timr = posix_timer_by_id(timer_id);
if (timr) {
spin_lock_irqsave(&timr->it_lock, *flags);
if (timr->it_signal == current->signal) {