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Revision 22e1170310ec6afa41e0dc7ac9dfac735d82dcab authored by Stephen Hemminger on 12 July 2006, 22:23:48 UTC, committed by Jeff Garzik on 12 July 2006, 22:39:22 UTC 
[PATCH] sky2: optimize receive restart
 
When the driver handles multiple packets per NAPI poll, it is
better to reload the receive ring, then tell the hardware. Otherwise,
under packet storm with flow control, the driver/hardware will degrade
down to one packet getting through per pause-exchange.

Likewise on transmit, don't wakeup until a little more than minimum
ring space is available.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
1 parent afa195d
Raw File
atomic.h 
/* $Id: atomic.h,v 1.3 2001/07/25 16:15:19 bjornw Exp $ */

#ifndef __ASM_CRIS_ATOMIC__
#define __ASM_CRIS_ATOMIC__

#include <asm/system.h>
#include <asm/arch/atomic.h>

/*
 * Atomic operations that C can't guarantee us.  Useful for
 * resource counting etc..
 */

typedef struct { volatile int counter; } atomic_t;

#define ATOMIC_INIT(i)  { (i) }

#define atomic_read(v) ((v)->counter)
#define atomic_set(v,i) (((v)->counter) = (i))

/* These should be written in asm but we do it in C for now. */

static inline void atomic_add(int i, volatile atomic_t *v)
{
	unsigned long flags;
	cris_atomic_save(v, flags);
	v->counter += i;
	cris_atomic_restore(v, flags);
}

static inline void atomic_sub(int i, volatile atomic_t *v)
{
	unsigned long flags;
	cris_atomic_save(v, flags);
	v->counter -= i;
	cris_atomic_restore(v, flags);
}

static inline int atomic_add_return(int i, volatile atomic_t *v)
{
	unsigned long flags;
	int retval;
	cris_atomic_save(v, flags);
	retval = (v->counter += i);
	cris_atomic_restore(v, flags);
	return retval;
}

#define atomic_add_negative(a, v)	(atomic_add_return((a), (v)) < 0)

static inline int atomic_sub_return(int i, volatile atomic_t *v)
{
	unsigned long flags;
	int retval;
	cris_atomic_save(v, flags);
	retval = (v->counter -= i);
	cris_atomic_restore(v, flags);
	return retval;
}

static inline int atomic_sub_and_test(int i, volatile atomic_t *v)
{
	int retval;
	unsigned long flags;
	cris_atomic_save(v, flags);
	retval = (v->counter -= i) == 0;
	cris_atomic_restore(v, flags);
	return retval;
}

static inline void atomic_inc(volatile atomic_t *v)
{
	unsigned long flags;
	cris_atomic_save(v, flags);
	(v->counter)++;
	cris_atomic_restore(v, flags);
}

static inline void atomic_dec(volatile atomic_t *v)
{
	unsigned long flags;
	cris_atomic_save(v, flags);
	(v->counter)--;
	cris_atomic_restore(v, flags);
}

static inline int atomic_inc_return(volatile atomic_t *v)
{
	unsigned long flags;
	int retval;
	cris_atomic_save(v, flags);
	retval = (v->counter)++;
	cris_atomic_restore(v, flags);
	return retval;
}

static inline int atomic_dec_return(volatile atomic_t *v)
{
	unsigned long flags;
	int retval;
	cris_atomic_save(v, flags);
	retval = (v->counter)--;
	cris_atomic_restore(v, flags);
	return retval;
}
static inline int atomic_dec_and_test(volatile atomic_t *v)
{
	int retval;
	unsigned long flags;
	cris_atomic_save(v, flags);
	retval = --(v->counter) == 0;
	cris_atomic_restore(v, flags);
	return retval;
}

static inline int atomic_inc_and_test(volatile atomic_t *v)
{
	int retval;
	unsigned long flags;
	cris_atomic_save(v, flags);
	retval = ++(v->counter) == 0;
	cris_atomic_restore(v, flags);
	return retval;
}

static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
{
	int ret;
	unsigned long flags;

	cris_atomic_save(v, flags);
	ret = v->counter;
	if (likely(ret == old))
		v->counter = new;
	cris_atomic_restore(v, flags);
	return ret;
}

#define atomic_xchg(v, new) (xchg(&((v)->counter), new))

static inline int atomic_add_unless(atomic_t *v, int a, int u)
{
	int ret;
	unsigned long flags;

	cris_atomic_save(v, flags);
	ret = v->counter;
	if (ret != u)
		v->counter += a;
	cris_atomic_restore(v, flags);
	return ret != u;
}
#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)

/* Atomic operations are already serializing */
#define smp_mb__before_atomic_dec()    barrier()
#define smp_mb__after_atomic_dec()     barrier()
#define smp_mb__before_atomic_inc()    barrier()
#define smp_mb__after_atomic_inc()     barrier()

#include <asm-generic/atomic.h>
#endif
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