[PATCH iwl-next] libeth, idpf: use GFP_KERNEL for the initial Rx ring fill

[PATCH iwl-next] libeth, idpf: use GFP_KERNEL for the initial Rx ring fill

[Luigi Rizzo]

libeth_rx_alloc() always allocates with GFP_ATOMIC, including when idpf
fills its Rx rings at open or on queue reconfiguration. That fill runs
in process context, right after page_pool_create() and before the
queues' NAPI is enabled, so it may sleep, and GFP_ATOMIC is needlessly
restrictive there: it can neither reclaim nor compact, while the initial
fill can allocate tens of thousands of buffers across all queues.

Add libeth_rx_alloc_gfp(), which takes the allocation flags, and make
libeth_rx_alloc() its GFP_ATOMIC wrapper. Use GFP_KERNEL for the initial
fill in idpf.

Signed-off-by: Luigi Rizzo <lrizzo@google.com>
---
 .../ethernet/intel/idpf/idpf_singleq_txrx.c   |  7 +++---
 drivers/net/ethernet/intel/idpf/idpf_txrx.c   |  9 +++++---
 drivers/net/ethernet/intel/idpf/idpf_txrx.h   |  2 +-
 include/net/libeth/rx.h                       | 23 +++++++++++++++----
 4 files changed, 30 insertions(+), 11 deletions(-)

diff --git a/drivers/net/ethernet/intel/idpf/idpf_singleq_txrx.c b/drivers/net/ethernet/intel/idpf/idpf_singleq_txrx.c
index e3ddf18dcbf51..d623e4ab8511f 100644
--- a/drivers/net/ethernet/intel/idpf/idpf_singleq_txrx.c
+++ b/drivers/net/ethernet/intel/idpf/idpf_singleq_txrx.c
@@ -885,11 +885,12 @@ static void idpf_rx_buf_hw_update(struct idpf_rx_queue *rxq, u32 val)
  * idpf_rx_singleq_buf_hw_alloc_all - Replace used receive buffers
  * @rx_q: queue for which the hw buffers are allocated
  * @cleaned_count: number of buffers to replace
+ * @gfp: GFP_KERNEL for the initial fill, GFP_ATOMIC from NAPI
  *
  * Returns false if all allocations were successful, true if any fail
  */
 bool idpf_rx_singleq_buf_hw_alloc_all(struct idpf_rx_queue *rx_q,
-				      u16 cleaned_count)
+				      u16 cleaned_count, gfp_t gfp)
 {
 	struct virtchnl2_singleq_rx_buf_desc *desc;
 	const struct libeth_fq_fp fq = {
@@ -908,7 +909,7 @@ bool idpf_rx_singleq_buf_hw_alloc_all(struct idpf_rx_queue *rx_q,
 	do {
 		dma_addr_t addr;
 
-		addr = libeth_rx_alloc(&fq, nta);
+		addr = libeth_rx_alloc_gfp(&fq, nta, gfp);
 		if (addr == DMA_MAPPING_ERROR)
 			break;
 
@@ -1095,7 +1096,7 @@ static int idpf_rx_singleq_clean(struct idpf_rx_queue *rx_q, int budget)
 
 	page_pool_nid_changed(rx_q->pp, numa_mem_id());
 	if (cleaned_count)
-		idpf_rx_singleq_buf_hw_alloc_all(rx_q, cleaned_count);
+		idpf_rx_singleq_buf_hw_alloc_all(rx_q, cleaned_count, GFP_ATOMIC);
 
 	u64_stats_update_begin(&rx_q->stats_sync);
 	u64_stats_add(&rx_q->q_stats.packets, rs.packets);
diff --git a/drivers/net/ethernet/intel/idpf/idpf_txrx.c b/drivers/net/ethernet/intel/idpf/idpf_txrx.c
index 4311ffa30bb18..b1127ab48ef3f 100644
--- a/drivers/net/ethernet/intel/idpf/idpf_txrx.c
+++ b/drivers/net/ethernet/intel/idpf/idpf_txrx.c
@@ -600,6 +600,9 @@ static void idpf_post_buf_refill(struct idpf_sw_queue *refillq, u16 buf_id)
  * @bufq: buffer queue to post to
  * @buf_id: buffer id to post
  *
+ * Only used for the initial fill, from process context, so it allocates
+ * with GFP_KERNEL.
+ *
  * Return: %false if buffer could not be allocated, %true otherwise.
  */
 static bool idpf_rx_post_buf_desc(struct idpf_buf_queue *bufq, u16 buf_id)
@@ -618,7 +621,7 @@ static bool idpf_rx_post_buf_desc(struct idpf_buf_queue *bufq, u16 buf_id)
 		fq.fqes = bufq->hdr_buf;
 		fq.truesize = bufq->hdr_truesize;
 
-		addr = libeth_rx_alloc(&fq, buf_id);
+		addr = libeth_rx_alloc_gfp(&fq, buf_id, GFP_KERNEL);
 		if (addr == DMA_MAPPING_ERROR)
 			return false;
 
@@ -629,7 +632,7 @@ static bool idpf_rx_post_buf_desc(struct idpf_buf_queue *bufq, u16 buf_id)
 	fq.fqes = bufq->buf;
 	fq.truesize = bufq->truesize;
 
-	addr = libeth_rx_alloc(&fq, buf_id);
+	addr = libeth_rx_alloc_gfp(&fq, buf_id, GFP_KERNEL);
 	if (addr == DMA_MAPPING_ERROR)
 		return false;
 
@@ -675,7 +678,7 @@ static bool idpf_rx_post_init_bufs(struct idpf_buf_queue *bufq,
  */
 static int idpf_rx_buf_alloc_singleq(struct idpf_rx_queue *rxq)
 {
-	if (idpf_rx_singleq_buf_hw_alloc_all(rxq, rxq->desc_count - 1))
+	if (idpf_rx_singleq_buf_hw_alloc_all(rxq, rxq->desc_count - 1, GFP_KERNEL))
 		goto err;
 
 	return 0;
diff --git a/drivers/net/ethernet/intel/idpf/idpf_txrx.h b/drivers/net/ethernet/intel/idpf/idpf_txrx.h
index 93547597efd2a..e27438c78ec79 100644
--- a/drivers/net/ethernet/intel/idpf/idpf_txrx.h
+++ b/drivers/net/ethernet/intel/idpf/idpf_txrx.h
@@ -1123,7 +1123,7 @@ netdev_tx_t idpf_tx_singleq_frame(struct sk_buff *skb,
 				  struct idpf_tx_queue *tx_q);
 netdev_tx_t idpf_tx_start(struct sk_buff *skb, struct net_device *netdev);
 bool idpf_rx_singleq_buf_hw_alloc_all(struct idpf_rx_queue *rxq,
-				      u16 cleaned_count);
+				      u16 cleaned_count, gfp_t gfp);
 bool idpf_rx_process_skb_fields(struct sk_buff *skb,
 				const struct libeth_xdp_buff *xdp,
 				struct libeth_rq_napi_stats *rs);
diff --git a/include/net/libeth/rx.h b/include/net/libeth/rx.h
index 0e736846c5e8a..14a528ea8a075 100644
--- a/include/net/libeth/rx.h
+++ b/include/net/libeth/rx.h
@@ -96,20 +96,23 @@ int libeth_rx_fq_create(struct libeth_fq *fq, void *napi_dev);
 void libeth_rx_fq_destroy(struct libeth_fq *fq);
 
 /**
- * libeth_rx_alloc - allocate a new Rx buffer
+ * libeth_rx_alloc_gfp - allocate a new Rx buffer
  * @fq: fill queue to allocate for
  * @i: index of the buffer within the queue
+ * @gfp: allocation flags: GFP_KERNEL where the caller may sleep (e.g. the
+ *	 initial fill of the ring), GFP_ATOMIC from NAPI
  *
  * Return: DMA address to be passed to HW for Rx on successful allocation,
  * ```DMA_MAPPING_ERROR``` otherwise.
  */
-static inline dma_addr_t libeth_rx_alloc(const struct libeth_fq_fp *fq, u32 i)
+static inline dma_addr_t libeth_rx_alloc_gfp(const struct libeth_fq_fp *fq,
+					     u32 i, gfp_t gfp)
 {
 	struct libeth_fqe *buf = &fq->fqes[i];
 
 	buf->truesize = fq->truesize;
-	buf->netmem = page_pool_dev_alloc_netmem(fq->pp, &buf->offset,
-						 &buf->truesize);
+	buf->netmem = page_pool_alloc_netmem(fq->pp, &buf->offset,
+					     &buf->truesize, gfp | __GFP_NOWARN);
 	if (unlikely(!buf->netmem))
 		return DMA_MAPPING_ERROR;
 
@@ -117,6 +120,18 @@ static inline dma_addr_t libeth_rx_alloc(const struct libeth_fq_fp *fq, u32 i)
 	       fq->pp->p.offset;
 }
 
+/**
+ * libeth_rx_alloc - allocate a new Rx buffer from NAPI context
+ * @fq: fill queue to allocate for
+ * @i: index of the buffer within the queue
+ *
+ * Return: as libeth_rx_alloc_gfp().
+ */
+static inline dma_addr_t libeth_rx_alloc(const struct libeth_fq_fp *fq, u32 i)
+{
+	return libeth_rx_alloc_gfp(fq, i, GFP_ATOMIC);
+}
+
 void libeth_rx_recycle_slow(netmem_ref netmem);
 
 /**
-- 
2.56.0.176.g3575e65682-goog