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Subject[PATCH v2 17/17] staging: qlge: Refill empty buffer queues from wq
Date
When operating at mtu 9000, qlge does order-1 allocations for rx buffers in
atomic context. This is especially unreliable when free memory is low or
fragmented. Add an approach similar to commit 3161e453e496 ("virtio: net
refill on out-of-memory") to qlge so that the device doesn't lock up if
there are allocation failures.

Signed-off-by: Benjamin Poirier <bpoirier@suse.com>
---
drivers/staging/qlge/TODO | 3 --
drivers/staging/qlge/qlge.h | 8 ++++
drivers/staging/qlge/qlge_main.c | 80 +++++++++++++++++++++++++-------
3 files changed, 72 insertions(+), 19 deletions(-)

diff --git a/drivers/staging/qlge/TODO b/drivers/staging/qlge/TODO
index 51c509084e80..f93f7428f5d5 100644
--- a/drivers/staging/qlge/TODO
+++ b/drivers/staging/qlge/TODO
@@ -1,6 +1,3 @@
-* reception stalls permanently (until admin intervention) if the rx buffer
- queues become empty because of allocation failures (ex. under memory
- pressure)
* commit 7c734359d350 ("qlge: Size RX buffers based on MTU.", v2.6.33-rc1)
introduced dead code in the receive routines, which should be rewritten
anyways by the admission of the author himself, see the comment above
diff --git a/drivers/staging/qlge/qlge.h b/drivers/staging/qlge/qlge.h
index e5a352df8228..6ec7e3ce3863 100644
--- a/drivers/staging/qlge/qlge.h
+++ b/drivers/staging/qlge/qlge.h
@@ -1452,6 +1452,13 @@ struct qlge_bq {

#define QLGE_BQ_WRAP(index) ((index) & (QLGE_BQ_LEN - 1))

+#define QLGE_BQ_HW_OWNED(bq) \
+({ \
+ typeof(bq) _bq = bq; \
+ QLGE_BQ_WRAP(QLGE_BQ_ALIGN((_bq)->next_to_use) - \
+ (_bq)->next_to_clean); \
+})
+
struct rx_ring {
struct cqicb cqicb; /* The chip's completion queue init control block. */

@@ -1479,6 +1486,7 @@ struct rx_ring {
/* Misc. handler elements. */
u32 irq; /* Which vector this ring is assigned. */
u32 cpu; /* Which CPU this should run on. */
+ struct delayed_work refill_work;
char name[IFNAMSIZ + 5];
struct napi_struct napi;
u8 reserved;
diff --git a/drivers/staging/qlge/qlge_main.c b/drivers/staging/qlge/qlge_main.c
index 02ad0cdf4856..0c381d91faa6 100644
--- a/drivers/staging/qlge/qlge_main.c
+++ b/drivers/staging/qlge/qlge_main.c
@@ -1029,7 +1029,7 @@ static const char * const bq_type_name[] = {

/* return 0 or negative error */
static int qlge_refill_sb(struct rx_ring *rx_ring,
- struct qlge_bq_desc *sbq_desc)
+ struct qlge_bq_desc *sbq_desc, gfp_t gfp)
{
struct ql_adapter *qdev = rx_ring->qdev;
struct sk_buff *skb;
@@ -1041,7 +1041,7 @@ static int qlge_refill_sb(struct rx_ring *rx_ring,
"ring %u sbq: getting new skb for index %d.\n",
rx_ring->cq_id, sbq_desc->index);

- skb = netdev_alloc_skb(qdev->ndev, SMALL_BUFFER_SIZE);
+ skb = __netdev_alloc_skb(qdev->ndev, SMALL_BUFFER_SIZE, gfp);
if (!skb)
return -ENOMEM;
skb_reserve(skb, QLGE_SB_PAD);
@@ -1062,7 +1062,7 @@ static int qlge_refill_sb(struct rx_ring *rx_ring,

/* return 0 or negative error */
static int qlge_refill_lb(struct rx_ring *rx_ring,
- struct qlge_bq_desc *lbq_desc)
+ struct qlge_bq_desc *lbq_desc, gfp_t gfp)
{
struct ql_adapter *qdev = rx_ring->qdev;
struct qlge_page_chunk *master_chunk = &rx_ring->master_chunk;
@@ -1071,8 +1071,7 @@ static int qlge_refill_lb(struct rx_ring *rx_ring,
struct page *page;
dma_addr_t dma_addr;

- page = alloc_pages(__GFP_COMP | GFP_ATOMIC,
- qdev->lbq_buf_order);
+ page = alloc_pages(gfp | __GFP_COMP, qdev->lbq_buf_order);
if (unlikely(!page))
return -ENOMEM;
dma_addr = pci_map_page(qdev->pdev, page, 0,
@@ -1109,33 +1108,33 @@ static int qlge_refill_lb(struct rx_ring *rx_ring,
return 0;
}

-static void qlge_refill_bq(struct qlge_bq *bq)
+/* return 0 or negative error */
+static int qlge_refill_bq(struct qlge_bq *bq, gfp_t gfp)
{
struct rx_ring *rx_ring = QLGE_BQ_CONTAINER(bq);
struct ql_adapter *qdev = rx_ring->qdev;
struct qlge_bq_desc *bq_desc;
int refill_count;
+ int retval;
int i;

refill_count = QLGE_BQ_WRAP(QLGE_BQ_ALIGN(bq->next_to_clean - 1) -
bq->next_to_use);
if (!refill_count)
- return;
+ return 0;

i = bq->next_to_use;
bq_desc = &bq->queue[i];
i -= QLGE_BQ_LEN;
do {
- int retval;
-
netif_printk(qdev, rx_status, KERN_DEBUG, qdev->ndev,
"ring %u %s: try cleaning idx %d\n",
rx_ring->cq_id, bq_type_name[bq->type], i);

if (bq->type == QLGE_SB)
- retval = qlge_refill_sb(rx_ring, bq_desc);
+ retval = qlge_refill_sb(rx_ring, bq_desc, gfp);
else
- retval = qlge_refill_lb(rx_ring, bq_desc);
+ retval = qlge_refill_lb(rx_ring, bq_desc, gfp);
if (retval < 0) {
netif_err(qdev, ifup, qdev->ndev,
"ring %u %s: Could not get a page chunk, idx %d\n",
@@ -1163,12 +1162,52 @@ static void qlge_refill_bq(struct qlge_bq *bq)
}
bq->next_to_use = i;
}
+
+ return retval;
+}
+
+static void ql_update_buffer_queues(struct rx_ring *rx_ring, gfp_t gfp,
+ unsigned long delay)
+{
+ bool sbq_fail, lbq_fail;
+
+ sbq_fail = !!qlge_refill_bq(&rx_ring->sbq, gfp);
+ lbq_fail = !!qlge_refill_bq(&rx_ring->lbq, gfp);
+
+ /* Minimum number of buffers needed to be able to receive at least one
+ * frame of any format:
+ * sbq: 1 for header + 1 for data
+ * lbq: mtu 9000 / lb size
+ * Below this, the queue might stall.
+ */
+ if ((sbq_fail && QLGE_BQ_HW_OWNED(&rx_ring->sbq) < 2) ||
+ (lbq_fail && QLGE_BQ_HW_OWNED(&rx_ring->lbq) <
+ DIV_ROUND_UP(9000, LARGE_BUFFER_MAX_SIZE)))
+ /* Allocations can take a long time in certain cases (ex.
+ * reclaim). Therefore, use a workqueue for long-running
+ * work items.
+ */
+ queue_delayed_work_on(smp_processor_id(), system_long_wq,
+ &rx_ring->refill_work, delay);
}

-static void ql_update_buffer_queues(struct rx_ring *rx_ring)
+static void qlge_slow_refill(struct work_struct *work)
{
- qlge_refill_bq(&rx_ring->sbq);
- qlge_refill_bq(&rx_ring->lbq);
+ struct rx_ring *rx_ring = container_of(work, struct rx_ring,
+ refill_work.work);
+ struct napi_struct *napi = &rx_ring->napi;
+
+ napi_disable(napi);
+ ql_update_buffer_queues(rx_ring, GFP_KERNEL, HZ / 2);
+ napi_enable(napi);
+
+ local_bh_disable();
+ /* napi_disable() might have prevented incomplete napi work from being
+ * rescheduled.
+ */
+ napi_schedule(napi);
+ /* trigger softirq processing */
+ local_bh_enable();
}

/* Unmaps tx buffers. Can be called from send() if a pci mapping
@@ -2168,7 +2207,7 @@ static int ql_clean_inbound_rx_ring(struct rx_ring *rx_ring, int budget)
if (count == budget)
break;
}
- ql_update_buffer_queues(rx_ring);
+ ql_update_buffer_queues(rx_ring, GFP_ATOMIC, 0);
ql_write_cq_idx(rx_ring);
return count;
}
@@ -2778,7 +2817,8 @@ static void ql_alloc_rx_buffers(struct ql_adapter *qdev)
int i;

for (i = 0; i < qdev->rss_ring_count; i++)
- ql_update_buffer_queues(&qdev->rx_ring[i]);
+ ql_update_buffer_queues(&qdev->rx_ring[i], GFP_KERNEL,
+ HZ / 2);
}

static int qlge_init_bq(struct qlge_bq *bq)
@@ -3883,6 +3923,7 @@ static int ql_get_adapter_resources(struct ql_adapter *qdev)
static int qlge_close(struct net_device *ndev)
{
struct ql_adapter *qdev = netdev_priv(ndev);
+ int i;

/* If we hit pci_channel_io_perm_failure
* failure condition, then we already
@@ -3900,6 +3941,11 @@ static int qlge_close(struct net_device *ndev)
*/
while (!test_bit(QL_ADAPTER_UP, &qdev->flags))
msleep(1);
+
+ /* Make sure refill_work doesn't re-enable napi */
+ for (i = 0; i < qdev->rss_ring_count; i++)
+ cancel_delayed_work_sync(&qdev->rx_ring[i].refill_work);
+
ql_adapter_down(qdev);
ql_release_adapter_resources(qdev);
return 0;
@@ -3966,6 +4012,8 @@ static int ql_configure_rings(struct ql_adapter *qdev)
rx_ring->cq_len * sizeof(struct ql_net_rsp_iocb);
rx_ring->lbq.type = QLGE_LB;
rx_ring->sbq.type = QLGE_SB;
+ INIT_DELAYED_WORK(&rx_ring->refill_work,
+ &qlge_slow_refill);
} else {
/*
* Outbound queue handles outbound completions only.
--
2.23.0
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