diff --git a/drivers/net/ethernet/google/gve/gve.h b/drivers/net/ethernet/google/gve/gve.h index f6e43cf96a46..84fb3deca21f 100644 --- a/drivers/net/ethernet/google/gve/gve.h +++ b/drivers/net/ethernet/google/gve/gve.h @@ -10,6 +10,7 @@ #include #include #include +#include #include #include @@ -36,6 +37,7 @@ /* Interval to schedule a stats report update, 20000ms. */ #define GVE_STATS_REPORT_TIMER_PERIOD 20000 +#define GVE_RX_NAPI_RESCHED_MS 20 /* msecs */ /* Numbers of NIC tx/rx stats in stats report. */ #define NIC_TX_STATS_REPORT_NUM 0 @@ -281,6 +283,7 @@ struct gve_rx_ring { struct xdp_rxq_info xsk_rxq; struct xsk_buff_pool *xsk_pool; struct page_frag_cache page_cache; /* Page cache to allocate XDP frames */ + struct timer_list starvation_timer; /* for queue starvation recovery */ }; /* A TX desc ring entry */ diff --git a/drivers/net/ethernet/google/gve/gve_main.c b/drivers/net/ethernet/google/gve/gve_main.c index 08f444ee10c7..9a287a376479 100644 --- a/drivers/net/ethernet/google/gve/gve_main.c +++ b/drivers/net/ethernet/google/gve/gve_main.c @@ -583,6 +583,9 @@ static void gve_remove_napi(struct gve_priv *priv, int ntfy_idx) { struct gve_notify_block *block = &priv->ntfy_blocks[ntfy_idx]; + if (block->rx && !gve_is_gqi(priv)) + timer_shutdown_sync(&block->rx->starvation_timer); + netif_napi_del(&block->napi); disable_irq(block->irq); } diff --git a/drivers/net/ethernet/google/gve/gve_rx_dqo.c b/drivers/net/ethernet/google/gve/gve_rx_dqo.c index 3d60ea25711f..12520c9813ac 100644 --- a/drivers/net/ethernet/google/gve/gve_rx_dqo.c +++ b/drivers/net/ethernet/google/gve/gve_rx_dqo.c @@ -16,6 +16,16 @@ #include #include +static void gve_rx_starvation_timer(struct timer_list *t) +{ + struct gve_rx_ring *rx = from_timer(rx, t, starvation_timer); + struct gve_priv *priv = rx->gve; + struct gve_notify_block *block; + + block = &priv->ntfy_blocks[rx->ntfy_id]; + napi_schedule(&block->napi); +} + static int gve_buf_ref_cnt(struct gve_rx_buf_state_dqo *bs) { return page_count(bs->page_info.page) - bs->page_info.pagecnt_bias; @@ -211,6 +221,7 @@ static void gve_rx_free_ring_dqo(struct gve_priv *priv, int idx) completion_queue_slots = rx->dqo.complq.mask + 1; buffer_queue_slots = rx->dqo.bufq.mask + 1; + timer_shutdown_sync(&rx->starvation_timer); gve_rx_remove_from_block(priv, idx); if (rx->q_resources) { @@ -268,6 +279,7 @@ static int gve_rx_alloc_ring_dqo(struct gve_priv *priv, int idx) memset(rx, 0, sizeof(*rx)); rx->gve = priv; rx->q_num = idx; + timer_setup(&rx->starvation_timer, gve_rx_starvation_timer, 0); rx->dqo.bufq.mask = buffer_queue_slots - 1; rx->dqo.complq.num_free_slots = completion_queue_slots; rx->dqo.complq.mask = completion_queue_slots - 1; @@ -374,6 +386,7 @@ void gve_rx_post_buffers_dqo(struct gve_rx_ring *rx) struct gve_rx_compl_queue_dqo *complq = &rx->dqo.complq; struct gve_rx_buf_queue_dqo *bufq = &rx->dqo.bufq; struct gve_priv *priv = rx->gve; + u32 num_bufs_avail_to_hw; u32 num_avail_slots; u32 num_full_slots; u32 num_posted = 0; @@ -414,6 +427,26 @@ void gve_rx_post_buffers_dqo(struct gve_rx_ring *rx) } rx->fill_cnt += num_posted; + + /* If the queue has fewer than GVE_RX_BUF_THRESH_DQO descriptors + * visible to the hardware, the hardware is in danger of starving + * and cannot trigger interrupts. + * + * We use a threshold of 32 because a single maximum-sized RSC + * packet can consume up to 19 descriptors in the Rx path. Lower + * thresholds (e.g., 8 or 16) would be unsafe as they could cause + * the device to drop/stall on a maximum-sized RSC packet. + * + * Start the timer to periodically reschedule NAPI and recover. + */ + num_bufs_avail_to_hw = + ((bufq->tail & ~(GVE_RX_BUF_THRESH_DQO - 1)) - + bufq->head) & bufq->mask; + + if (num_bufs_avail_to_hw < GVE_RX_BUF_THRESH_DQO) { + mod_timer(&rx->starvation_timer, + jiffies + msecs_to_jiffies(GVE_RX_NAPI_RESCHED_MS)); + } } static void gve_try_recycle_buf(struct gve_priv *priv, struct gve_rx_ring *rx,