[PATCH 1/2] net: thunderx: Set recevie buffer page usage count in bulk

From: sunil . kovvuri
Date: Mon Mar 07 2016 - 02:33:05 EST


From: Sunil Goutham <sgoutham@xxxxxxxxxx>

Instead of calling get_page() for every receive buffer carved out
of page, set page's usage count at the end, to reduce no of atomic
calls.

Signed-off-by: Sunil Goutham <sgoutham@xxxxxxxxxx>
---
drivers/net/ethernet/cavium/thunder/nic.h | 1 +
drivers/net/ethernet/cavium/thunder/nicvf_queues.c | 31 ++++++++++++++-----
2 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/cavium/thunder/nic.h b/drivers/net/ethernet/cavium/thunder/nic.h
index 00cc915..5628aea 100644
--- a/drivers/net/ethernet/cavium/thunder/nic.h
+++ b/drivers/net/ethernet/cavium/thunder/nic.h
@@ -285,6 +285,7 @@ struct nicvf {
u32 speed;
struct page *rb_page;
u32 rb_page_offset;
+ u16 rb_pageref;
bool rb_alloc_fail;
bool rb_work_scheduled;
struct delayed_work rbdr_work;
diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_queues.c b/drivers/net/ethernet/cavium/thunder/nicvf_queues.c
index 0dd1abf..fa05e34 100644
--- a/drivers/net/ethernet/cavium/thunder/nicvf_queues.c
+++ b/drivers/net/ethernet/cavium/thunder/nicvf_queues.c
@@ -18,6 +18,15 @@
#include "q_struct.h"
#include "nicvf_queues.h"

+static void nicvf_get_page(struct nicvf *nic)
+{
+ if (!nic->rb_pageref || !nic->rb_page)
+ return;
+
+ atomic_add(nic->rb_pageref, &nic->rb_page->_count);
+ nic->rb_pageref = 0;
+}
+
/* Poll a register for a specific value */
static int nicvf_poll_reg(struct nicvf *nic, int qidx,
u64 reg, int bit_pos, int bits, int val)
@@ -81,16 +90,15 @@ static inline int nicvf_alloc_rcv_buffer(struct nicvf *nic, gfp_t gfp,
int order = (PAGE_SIZE <= 4096) ? PAGE_ALLOC_COSTLY_ORDER : 0;

/* Check if request can be accomodated in previous allocated page */
- if (nic->rb_page) {
- if ((nic->rb_page_offset + buf_len + buf_len) >
- (PAGE_SIZE << order)) {
- nic->rb_page = NULL;
- } else {
- nic->rb_page_offset += buf_len;
- get_page(nic->rb_page);
- }
+ if (nic->rb_page &&
+ ((nic->rb_page_offset + buf_len) < (PAGE_SIZE << order))) {
+ nic->rb_pageref++;
+ goto ret;
}

+ nicvf_get_page(nic);
+ nic->rb_page = NULL;
+
/* Allocate a new page */
if (!nic->rb_page) {
nic->rb_page = alloc_pages(gfp | __GFP_COMP | __GFP_NOWARN,
@@ -102,7 +110,9 @@ static inline int nicvf_alloc_rcv_buffer(struct nicvf *nic, gfp_t gfp,
nic->rb_page_offset = 0;
}

+ret:
*rbuf = (u64 *)((u64)page_address(nic->rb_page) + nic->rb_page_offset);
+ nic->rb_page_offset += buf_len;

return 0;
}
@@ -158,6 +168,9 @@ static int nicvf_init_rbdr(struct nicvf *nic, struct rbdr *rbdr,
desc = GET_RBDR_DESC(rbdr, idx);
desc->buf_addr = virt_to_phys(rbuf) >> NICVF_RCV_BUF_ALIGN;
}
+
+ nicvf_get_page(nic);
+
return 0;
}

@@ -241,6 +254,8 @@ refill:
new_rb++;
}

+ nicvf_get_page(nic);
+
/* make sure all memory stores are done before ringing doorbell */
smp_wmb();

--
1.7.1