Hi! When you proposed to put wait queues into task_struct, you were probably looking for less coding and more analysis?
Anyway, there's starter patch below... It compiles, but is otherwise completely untested. Signed-off-by: Pavel Machek <[email protected]> Pavel diff --git a/fs/eventpoll.c b/fs/eventpoll.c index af90312..6dde102 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -1591,7 +1591,7 @@ static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events, int res = 0, eavail, timed_out = 0; unsigned long flags; long slack = 0; - wait_queue_t wait; + wait_queue_t *wait; ktime_t expires, *to = NULL; if (timeout > 0) { @@ -1614,13 +1614,14 @@ fetch_events: spin_lock_irqsave(&ep->lock, flags); if (!ep_events_available(ep)) { + wait = alloc_waitqueue(GFP_KERNEL); /* * We don't have any available event to return to the caller. * We need to sleep here, and we will be wake up by * ep_poll_callback() when events will become available. */ - init_waitqueue_entry(&wait, current); - __add_wait_queue_exclusive(&ep->wq, &wait); + init_waitqueue_entry(wait, current); + __add_wait_queue_exclusive(&ep->wq, wait); for (;;) { /* @@ -1642,7 +1643,8 @@ fetch_events: spin_lock_irqsave(&ep->lock, flags); } - __remove_wait_queue(&ep->wq, &wait); + __remove_wait_queue(&ep->wq, wait); + free_waitqueue(wait); set_current_state(TASK_RUNNING); } diff --git a/include/linux/sched.h b/include/linux/sched.h index 25f54c7..0b2be71 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -26,6 +26,7 @@ struct sched_param { #include <linux/nodemask.h> #include <linux/mm_types.h> #include <linux/preempt_mask.h> +#include <linux/slab.h> #include <asm/page.h> #include <asm/ptrace.h> @@ -1607,6 +1608,8 @@ struct task_struct { unsigned int sequential_io; unsigned int sequential_io_avg; #endif + + wait_queue_t wait_queues[NUM_TASK_WAIT_QUEUES]; }; /* Future-safe accessor for struct task_struct's cpus_allowed. */ @@ -2991,4 +2994,26 @@ static inline unsigned long rlimit_max(unsigned int limit) return task_rlimit_max(current, limit); } +static inline wait_queue_t *alloc_waitqueue(int gfp) +{ + int i; + for (i=0; i<NUM_TASK_WAIT_QUEUES; i++) { + if (current->wait_queues[i].flags & WQ_FLAG_FREE) { + current->wait_queues[i].flags &= ~WQ_FLAG_FREE; + return ¤t->wait_queues[i]; + } + } + return kmalloc(sizeof(wait_queue_t), gfp); +} + +static inline void free_waitqueue(wait_queue_t *q) +{ + if (q->flags & WQ_FLAG_HARDCODED) { + q->flags |= WQ_FLAG_FREE; + return; + } + kfree(q); +} + + #endif diff --git a/include/linux/wait.h b/include/linux/wait.h index bd68819..6c0dd83 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -16,11 +16,15 @@ int default_wake_function(wait_queue_t *wait, unsigned mode, int flags, void *ke struct __wait_queue { unsigned int flags; #define WQ_FLAG_EXCLUSIVE 0x01 +#define WQ_FLAG_FREE 0x02 +#define WQ_FLAG_HARDCODED 0x04 void *private; wait_queue_func_t func; struct list_head task_list; }; +#define NUM_TASK_WAIT_QUEUES 2 + struct wait_bit_key { void *flags; int bit_nr; @@ -83,6 +87,7 @@ extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name) #endif + static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p) { q->flags = 0; diff --git a/kernel/fork.c b/kernel/fork.c index 54a8d26..c339e18 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1315,6 +1315,13 @@ static struct task_struct *copy_process(unsigned long clone_flags, p->sequential_io = 0; p->sequential_io_avg = 0; #endif + { + int i; + for (i=0; i<NUM_TASK_WAIT_QUEUES; i++) { + init_waitqueue_entry(&p->wait_queues[i], p); + p->wait_queues[i].flags = WQ_FLAG_FREE | WQ_FLAG_HARDCODED; + } + } /* Perform scheduler related setup. Assign this task to a CPU. */ retval = sched_fork(clone_flags, p); -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
