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authorMichael S. Tsirkin <mst@redhat.com>2017-03-06 22:21:35 +0200
committerMichael S. Tsirkin <mst@redhat.com>2017-05-09 16:43:21 +0300
commite377fcc8486d40867c6c217077ad0fa40977e060 (patch)
treeaa80472501bb1f180165f6571559ec0a693dca44 /drivers/net/virtio_net.c
parent680557cf79f82623e2c4fd42733077d60a843513 (diff)
virtio_net: reduce alignment for buffers
We don't need to align length to any particular value anymore. Aligning to L1 cache size probably sill makes sense to reduce false sharing. Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'drivers/net/virtio_net.c')
-rw-r--r--drivers/net/virtio_net.c13
1 files changed, 1 insertions, 12 deletions
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 2170a5caf68d..6e47e653a05d 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -53,17 +53,6 @@ module_param(gso, bool, 0444);
*/
DECLARE_EWMA(pkt_len, 0, 64)
-/* With mergeable buffers we align buffer address and use the low bits to
- * encode its true size. Buffer size is up to 1 page so we need to align to
- * square root of page size to ensure we reserve enough bits to encode the true
- * size.
- */
-#define MERGEABLE_BUFFER_MIN_ALIGN_SHIFT ((PAGE_SHIFT + 1) / 2)
-
-/* Minimum alignment for mergeable packet buffers. */
-#define MERGEABLE_BUFFER_ALIGN max(L1_CACHE_BYTES, \
- 1 << MERGEABLE_BUFFER_MIN_ALIGN_SHIFT)
-
#define VIRTNET_DRIVER_VERSION "1.0.0"
struct virtnet_stats {
@@ -849,7 +838,7 @@ static unsigned int get_mergeable_buf_len(struct ewma_pkt_len *avg_pkt_len)
len = hdr_len + clamp_t(unsigned int, ewma_pkt_len_read(avg_pkt_len),
GOOD_PACKET_LEN, PAGE_SIZE - hdr_len);
- return ALIGN(len, MERGEABLE_BUFFER_ALIGN);
+ return ALIGN(len, L1_CACHE_BYTES);
}
static int add_recvbuf_mergeable(struct virtnet_info *vi,