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#define	_DDI_DKI	1
#define	_SYSV4		1

/*
 * STREAMS memory management code.
 *
 * This is layered on top of the fast first-fit heap allocator whose
 * implementation is described in <sys/st_alloc.h>. The particulars of how
 * STREAMS memory is allocated (including synchronisation and watermarks)
 * is kept here so that the generic allocator is just that, generic.
 */

/*
 *-IMPORTS:
 *	<common/ccompat.h>
 *		__USE_PROTO__
 *		__ARGS ()
 *	<common/ccompat.h>
 *		__LOCAL__
 *	<sys/debug.h>
 *		ASSERT ()
 *	<sys/types.h>
 *		_VOID
 *		size_t
 *	<sys/ksynch.h>
 *		lock_t
 *		LOCK_ALLOC ()
 *		LOCK ()
 *		UNLOCK ()
 *	<sys/cmn_err.h>
 *		CE_WARN
 *		cmn_err ()
 */

#include <common/ccompat.h>
#include <kernel/ddi_lock.h>
#include <sys/types.h>
#include <sys/debug.h>
#include <sys/ksynch.h>
#include <sys/cmn_err.h>

#include <sys/kmem.h>
#include <kernel/strmlib.h>
#include <string.h>


/*
 * Number of segments in the streams memory heap.
 *
 * For now, we'll just specify 256 segments, but this should probably be based
 * on the log of the total number of words available.
 */

enum { str_segments = 256 };


/*
 * Here we'll define the actual instance of the streams memory control
 * structure.
 */

struct streams_mem str_mem [1];


/*
 * We need to define information structures for the various locks and
 * synchronization variables used in the above.
 */

__LOCAL__ lkinfo_t _stream_heap_lkinfo = {
	"STREAMS message memory lock", INTERNAL_LOCK
};

__LOCAL__ lkinfo_t _stream_seq_lkinfo = {
	"STREAMS log sequence-number lock", INTERNAL_LOCK
};

__LOCAL__ lkinfo_t _stream_proc_lkinfo = {
	"STREAMS qprocsoff () lock", INTERNAL_LOCK
};

__LOCAL__ lkinfo_t _stream_dir_lkinfo = {
	"STREAM directory read/write lock", INTERNAL_LOCK
};


/*
 *-STATUS:
 *	DDI/DKI
 *
 *-NAME:
 *	kmem_alloc ()	Allocate space from kernel free memory.
 *
 *-SYNOPSIS:
 *	#include <sys/types.h>
 *	#include <sys/kmem.h>
 *
 *	void * kmem_alloc (size_t size, int flag);
 *
 *-ARGUMENTS:
 *	size		Number of bytes to allocate.
 *
 *	flag		Specifies whether the caller is willing to sleep
 *			waiting for memory. If "flag" is set to KM_SLEEP, the
 *			caller will sleep if necessary until the specified
 *			amount of memory is available. If "flag" is set to
 *			KM_NOSLEEP, the caller will not sleep, but
 *			kmem_alloc () will return NULL if the specified amount
 *			of memory is not immediately available.
 *
 *-DESCRIPTION:
 *	kmem_alloc () allocates "size" bytes of kernel memory and returns a
 *	pointer to the allocated memory.
 *
 *-RETURN VALUE:
 *	Upon successful completion, kmem_alloc () returns a pointer to the
 *	allocated memory. If KM_NOSLEEP is specified and sufficient memory is
 *	not immediately available, kmem_alloc () returns a NULL pointer. If
 *	"size" is set to 0, kmem_alloc () always returns NULL regardless of
 *	the value of "flag".
 *
 *-LEVEL:
 *	Base only if "flag" is set to KM_SLEEP. Base or interrupt if "flag" is
 *	set to KM_NOSLEEP.
 *
 *-NOTES:
 *	May sleep if "flag" is set to KM_SLEEP.
 *
 *	Driver-defined basic locks and read/write locks may be held across
 *	calls to this function if "flag" is KM_NOSLEEP but may not be held if
 *	"flag" is KM_SLEEP.
 *
 *	Driver-defined sleep locks may be held across calls to this function
 *	regardless of the value of "flag".
 *
 *	Kernel memory is a limited resource and should be used judiciously.
 *	Memory allocated using kmem_alloc () should be freed as soon as
 *	possible. Drivers should not use local freelists for memory or similar
 *	schemes that cause the memory to be held for longer than necessary.
 *
 *	The address returned by a successful call to kmem_alloc () is word-
 *	aligned.
 *
 *-SEE ALSO:
 *	kmem_free (), kmem_zalloc ()
 */

#if	__USE_PROTO__
_VOID * (kmem_alloc) (size_t size, int flag)
#else
_VOID *
kmem_alloc __ARGS ((size, flag))
size_t		size;
int		flag;
#endif
{
	_VOID	      *	mem;
	pl_t		prev_pl;

	ASSERT (flag == KM_SLEEP || flag == KM_NOSLEEP);

	ASSERT (ATOMIC_FETCH_UCHAR (str_mem->sm_init) ||
		str_mem->sm_other_lock != NULL);

	if (size == 0)
		return NULL;

	for (;;) {
		/*
		 * Lock the basic lock protecting access to the memory pool
		 * and attempt to acquire the memory we desire.
		 */

		if (str_mem->sm_other_lock != NULL)
			prev_pl = LOCK (str_mem->sm_other_lock, str_other_pl);

		if ((mem = st_alloc (str_mem->sm_other_heap, size)) != NULL ||
		    flag == KM_NOSLEEP) {
			OTHER_ALLOCED (size);
			break;
		}

		/*
		 * Since we cannot acquire the memory, but the caller is
		 * willing to wait, we wait on a synchronization variable
		 * for sufficient memory to be available. We record the
		 * minimum amount that will satisfy any outstanding wait so
		 * that kmem_free () need not perform broadcasts in a
		 * totally needless fashion.
		 *
		 * We have arbitrarily chosen a low scheduling priority for
		 * SV_WAIT ().
		 */
		/*
		 * RESEARCH NOTE: This policy is a guess, no more. We need to
		 * do some profiling to find out what effect other policies
		 * might have. In particular, the wakeup heuristic could be
		 * altered to broadcast when we can satisfy the largest
		 * request.
		 */

		if (str_mem->sm_other_needed == 0 ||
		    str_mem->sm_other_needed > size)
			str_mem->sm_other_needed = size;

		SV_WAIT (str_mem->sm_other_sv, prilo, str_mem->sm_other_lock);
	}

	if (str_mem->sm_other_lock != NULL)
		UNLOCK (str_mem->sm_other_lock, prev_pl);

	return mem;
}



/*
 *-STATUS:
 *	DDI/DKI
 *
 *-NAME:
 *	kmem_free ()	Free previously allocated kernel memory.
 *
 *-SYNOPSIS:
 *	#include <sys/types.h>
 *	#include <sys/kmem.h>
 *
 *	void kmem_free (void * addr, size_t size);
 *
 *-ARGUMENTS:
 *	addr		Address of the allocated memory to be returned. "addr"
 *			must specify the same address that was returned by the
 *			corresponding call to kmem_alloc () or kmem_zalloc ()
 *			which allocated the memory.
 *
 *	size		Number of bytes to free. The "size" parameter must
 *			specify the same number of bytes as was allocated by
 *			the corresponding call to kmem_alloc () or\
 *			kmem_zalloc ().
 *
 *-DESCRIPTION:
 *	kmem_free () returns "size" bytes of previously allocated kernel
 *	memory to the free pool. The "addr" and "size" arguments must specify
 *	exactly one complete area of memory that was allocated by a call to
 *	kmem_alloc () or kmem_zalloc () (that is, the memory cannot be freed
 *	piecemeal).
 *
 *-RETURN VALUE:
 *	None.
 *
 *-LEVEL:
 *	Base or Interrupt.
 *
 *-NOTES:
 *	Does not sleep.
 *
 *	Driver-defined basic locks, read/write locks and sleep locks may be
 *	held across calls to this function.
 *
 *-SEE ALSO:
 *	kmem_alloc (), kmem_zalloc ()
 */

#if	__USE_PROTO__
void (kmem_free) (_VOID * addr, size_t size)
#else
void
kmem_free __ARGS ((addr, size))
_VOID	      *	addr;
size_t		size;
#endif
{
	pl_t		prev_pl;
	int		free_ok;

	ASSERT (addr != NULL);
	ASSERT (size > 0);

	ASSERT (ATOMIC_FETCH_UCHAR (str_mem->sm_init) ||
		str_mem->sm_other_lock != NULL);

	/*
	 * Acquire the basic lock protecting access to the memory and free
	 * the caller's area. If there are processes waiting on memory
	 * becoming available, wake them up via a synchronization variable
	 * broadcast.
	 */

	if (str_mem->sm_other_lock != NULL)
		prev_pl = LOCK (str_mem->sm_other_lock, str_other_pl);

	OTHER_FREED (size);

	free_ok = st_free (str_mem->sm_other_heap, addr, size);

	if (str_mem->sm_other_needed > 0 &&
	    str_mem->sm_other_needed <= st_maxavail (str_mem->sm_other_heap)) {
		/*
		 * Wake up *all* the waiting processes and clear the marker
		 * to indicate that there are no waiting processes.
		 */

		SV_BROADCAST (str_mem->sm_other_sv, 0);
		str_mem->sm_other_needed = 0;
	}

	if (str_mem->sm_other_lock != NULL)
		UNLOCK (str_mem->sm_other_lock, prev_pl);

	if (free_ok != 0) {
		/*
		 * The heap manager has a problem with freeing the block that
		 * was passed to it, display a console diagnostic. For
		 * simplicity we display addresses as longs.
		 */

		cmn_err (CE_WARN,
			 "kmem_free : st_free () complained with %d freeing %d bytes at %lx",
			 free_ok, size, (long) addr);
	}
}



/*
 *-STATUS:
 *	DDI/DKI
 *
 *-NAME:
 *	kmem_zalloc ()	Allocate and clear space from kernel free memory.
 *
 *-SYNOPSIS:
 *	#include <sys/types.h>
 *	#include <sys/kmem.h>
 *
 *	void * kmem_zalloc (size_t size, int flag);
 *
 *-ARGUMENTS:
 *	size		Number of bytes to allocate.
 *
 *	flag		Specifies whether the caller is willing to sleep
 *			waiting for memory. If "flag" is set to KM_SLEEP, the
 *			caller will sleep if necessary until the specified
 *			amount of memory is available. If "flag" is set to
 *			KM_NOSLEEP, the caller will not sleep, but
 *			kmem_zalloc () will return NULL if the specified
 *			amount of memory is not immediately available.
 *
 *-DESCRIPTION:
 *	kmem_zalloc () allocates "size" bytes of kernel memory, clears the
 *	memory by filling it with zeros, and returns a pointer to the
 *	allocated memory.
 *
 *-RETURN VALUE:
 *	Upon successful completion, kmem_zalloc () returns a pointer to the
 *	allocated memory. If KM_NOSLEEP is specified and sufficient memory is
 *	not immediately available, kmem_zalloc () returns a NULL pointer. If
 *	"size" is set to 0, kmem_zalloc () always returns NULL regardless of
 *	the value of "flag".
 *
 *-LEVEL:
 *	Base only if "flag" is set to KM_SLEEP. Base or interrupt if "flag" is
 *	set to KM_NOSLEEP.
 *
 *-NOTES:
 *	May sleep if "flag" is set to KM_SLEEP.
 *
 *	Driver-defined basic locks and read/write locks may be held across
 *	calls to this function if "flag" is KM_NOSLEEP but may not be held if
 *	"flag" is KM_SLEEP.
 *
 *	Driver-defined sleep locks may be held across calls to this function
 *	regardless of the value of "flag".
 *
 *	Kernel memory is a limited resource and should be used judiciously.
 *	Memory allocated using kmem_zalloc () should be freed as soon as
 *	possible. Drivers should not use local freelists for memory or similar
 *	schemes that cause the memory to be held for longer than necessary.
 *
 *	The address returned by a successful call to kmem_zalloc () is word-
 *	aligned.
 *
 *-SEE ALSO:
 *	kmem_alloc (), kmem_free ()
 */

#if	__USE_PROTO__
_VOID * (kmem_zalloc) (size_t size, int flag)
#else
_VOID *
kmem_zalloc __ARGS ((size, flag))
size_t		size;
int		flag;
#endif
{
	_VOID	      *	mem;

	if ((mem = kmem_alloc (size, flag)) != NULL)
		memset (mem, 0, size);
	return mem;
}


/*
 *-STATUS:
 *	Initialisation
 *
 *-DESCRIPTION:
 *	This function initializes the memory subsystem given a region of
 *	kernel virtual memory space to manage.
 */

__EXTERN_C__
#if	__USE_PROTO__
int (KMEM_INIT) (_VOID * addr, size_t size)
#else
int
KMEM_INIT __ARGS ((addr, size))
_VOID	      *	addr;
size_t		size;
#endif
{
	int		i;

	/*
	 * We use a test-and-set lock operation on the streams memory
	 * structure so that the initialisation process is multiprocessor-
	 * safe. We don't use a basic lock since we don't know whether basic
	 * locks exist yet.
	 */

	if (ATOMIC_TEST_AND_SET_UCHAR (str_mem->sm_init) != 0) {
		/*
		 * Presumably we are on a separate processor waiting for the
		 * initialization to be completed by someone else. To make
		 * this processor's call to STRMEM_INIT () behave with the
		 * right semantics, we wait for the other instance to complete
		 * the setup process.
		 */

		while (ATOMIC_FETCH_UCHAR (str_mem->sm_init) != 0) {
#ifdef	__UNIPROCESSOR__
			cmn_err (CE_PANIC, "Init startup deadlock???");
#endif
		}
		return 0;
	}

	if (str_mem->sm_other_lock != NULL) {
		/*
		 * The init has already been done, thanks!
		 */

		ATOMIC_CLEAR_UCHAR (str_mem->sm_init);
		return 0;
	}

#ifdef	SPLIT_STREAMS_MEMORY
#endif

	/*
	 * Now initialize the fast-first-fit heap manager.
	 *
	 * For now, we'll just specify 256 segments, but this
	 * should probably be based on the log of the total
	 * number of words available.
	 */

	str_mem->sm_msg_heap = (_ST_HEAP_CONTROL_P) addr;

	addr = (_VOID *) ((char *) addr +
			  _ST_HEAP_CONTROL_SIZE (str_segments));

	size -= _ST_HEAP_CONTROL_SIZE (str_segments);

	st_ctor (str_mem->sm_msg_heap, str_segments,
		 size / sizeof (_ST_WORD_T), (_ST_ADDR_T) addr);

	str_mem->sm_msg_lock =
			LOCK_ALLOC (stream_heap_hierarchy, str_other_pl,
				    & _stream_heap_lkinfo, KM_NOSLEEP);

	str_mem->sm_msg_sv = SV_ALLOC (KM_NOSLEEP);


	/*
	 * If either of the above allocations failed, we have some kind of
	 * major problem, so we exit without unlocking the initialization flag
	 * with an error indication.
	 */

	if (str_mem->sm_msg_lock == NULL || str_mem->sm_msg_sv == NULL) {

init_error:
		cmn_err (CE_PANIC, "Could not initialize STREAMS subsystem");
		return -1;
	}


	/*
	 * Now we can calculate the watermarks... start at the
	 * top and make each lower one some percentage of the
	 * next higher one (say, 15/16 or 93%, so that it's
	 * easy to calculate).
	 */

	for (i = N_PRI_LEVELS ; i -- > 0 ;) {

		str_mem->sm_max [i] = size;
		size -= size >> 4;	/* - 1/16 */
	}


	/*
	 * Do other kinds of initialization for the "str_mem" structure.
	 */

	for (i = N_PRI_LEVELS ; i -- > 0 ; ) {

		if (SELIST_INIT (& str_mem->sm_bcevents [i],
				 KM_SLEEP) == NULL)
			goto init_error;
	}


	str_mem->sm_seq_lock = LOCK_ALLOC (stream_seq_hierarchy, plstr,
					   & _stream_seq_lkinfo, KM_SLEEP);

	str_mem->sm_head_lock = RW_ALLOC (stream_dir_hierarchy, plstr,
					  & _stream_dir_lkinfo, KM_SLEEP);

	str_mem->sm_proc_lock = LOCK_ALLOC (stream_proc_hierarchy, plstr,
					    & _stream_proc_lkinfo, KM_SLEEP);

	str_mem->sm_proc_sv = SV_ALLOC (KM_SLEEP);

	if (SCHED_INIT (str_mem->sm_sched, KM_SLEEP) == NULL ||
	    str_mem->sm_seq_lock == NULL || str_mem->sm_head_lock == NULL ||
	    str_mem->sm_proc_lock == NULL || str_mem->sm_proc_sv == NULL)
		goto init_error;

	/*
	 * All OK, let other CPUs proceed and return success to the caller.
	 */

	ATOMIC_CLEAR_UCHAR (str_mem->sm_init);
	return 0;		/* all OK */
}

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