IB/hfi1: Get rid of divide in pio buffer allocator
The div instruction shows costly in profiles.
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Sebastian Sanchez <sebastian.sanchez@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
diff --git a/drivers/infiniband/hw/hfi1/pio.c b/drivers/infiniband/hw/hfi1/pio.c
index 385e4dc..516fac3 100644
--- a/drivers/infiniband/hw/hfi1/pio.c
+++ b/drivers/infiniband/hw/hfi1/pio.c
@@ -1249,6 +1249,7 @@ int sc_enable(struct send_context *sc)
sc->free = 0;
sc->alloc_free = 0;
sc->fill = 0;
+ sc->fill_wrap = 0;
sc->sr_head = 0;
sc->sr_tail = 0;
sc->flags = 0;
@@ -1392,7 +1393,7 @@ struct pio_buf *sc_buffer_alloc(struct send_context *sc, u32 dw_len,
unsigned long flags;
unsigned long avail;
unsigned long blocks = dwords_to_blocks(dw_len);
- unsigned long start_fill;
+ u32 fill_wrap;
int trycount = 0;
u32 head, next;
@@ -1435,8 +1436,11 @@ struct pio_buf *sc_buffer_alloc(struct send_context *sc, u32 dw_len,
head = sc->sr_head;
/* "allocate" the buffer */
- start_fill = sc->fill;
sc->fill += blocks;
+ fill_wrap = sc->fill_wrap;
+ sc->fill_wrap += blocks;
+ if (sc->fill_wrap >= sc->credits)
+ sc->fill_wrap = sc->fill_wrap - sc->credits;
/*
* Fill the parts that the releaser looks at before moving the head.
@@ -1465,8 +1469,7 @@ struct pio_buf *sc_buffer_alloc(struct send_context *sc, u32 dw_len,
spin_unlock_irqrestore(&sc->alloc_lock, flags);
/* finish filling in the buffer outside the lock */
- pbuf->start = sc->base_addr + ((start_fill % sc->credits)
- * PIO_BLOCK_SIZE);
+ pbuf->start = sc->base_addr + fill_wrap * PIO_BLOCK_SIZE;
pbuf->size = sc->credits * PIO_BLOCK_SIZE;
pbuf->end = sc->base_addr + pbuf->size;
pbuf->block_count = blocks;