[PATCH v2 1/2] net: thunderx: Set recevie buffer page usage count in bulk

[sunil . kovvuri]

From: Sunil Goutham <sgout...@cavium.com>

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 <sgout...@cavium.com>
---
 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 092f097..872b22d 100644
--- a/drivers/net/ethernet/cavium/thunder/nic.h
+++ b/drivers/net/ethernet/cavium/thunder/nic.h
@@ -294,6 +294,7 @@ 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