[PATCH] ath10k: Fix Tx DMA alloc failure during continuous wifi down/up

Adrian Chadd adrian at freebsd.org
Wed Nov 30 10:27:25 PST 2016


Heh, I had to do something like this for freebsd too for my ath10k
port. So thanks. :)

Suggestion - take a look at where tasklets, completions, locks, etc
are all re-allocated multiple times, once upon initial VAP bringup. I
had to also undo this in FreeBSD, as we don't allow re-init of tasks,
completions, callouts and locks without first freeing/zero'ing them
appropriately. :)



-adrian


On 30 November 2016 at 01:50, Mohammed Shafi Shajakhan
<mohammed at qti.qualcomm.com> wrote:
> From: Mohammed Shafi Shajakhan <mohammed at qti.qualcomm.com>
>
> With maximum number of vap's configured in a two radio supported
> systems of ~256 Mb RAM, doing a continuous wifi down/up and
> intermittent traffic streaming from the connected stations results
> in failure to allocate contiguous memory for tx buffers. This results
> in the disappearance of all VAP's and a manual reboot is needed as
> this is not a crash (or) OOM(for OOM killer to be invoked). To address
> this allocate contiguous memory for tx buffers one time and re-use them
> until the modules are unloaded but this results in a slight increase in
> memory footprint of ath10k when the wifi is down, but the modules are
> still loaded. Also as of now we use a separate bool 'tx_mem_allocated'
> to keep track of the one time memory allocation, as we cannot come up
> with something like 'ath10k_tx_{register,unregister}' before
> 'ath10k_probe_fw' is called as 'ath10k_htt_tx_alloc_cont_frag_desc'
> memory allocation is dependent on the hw_param 'continuous_frag_desc'
>
> a) memory footprint of ath10k without the change
>
> lsmod | grep ath10k
> ath10k_core           414498  1 ath10k_pci
> ath10k_pci             38236  0
>
> b) memory footprint of ath10k with the change
>
> ath10k_core           414980  1 ath10k_pci
> ath10k_pci             38236  0
>
> Memory Failure Call trace:
>
> hostapd: page allocation failure: order:6, mode:0xd0
>  [<c021f150>] (__dma_alloc_buffer.isra.23) from
> [<c021f23c>] (__alloc_remap_buffer.isra.26+0x14/0xb8)
> [<c021f23c>] (__alloc_remap_buffer.isra.26) from
> [<c021f664>] (__dma_alloc+0x224/0x2b8)
> [<c021f664>] (__dma_alloc) from [<c021f810>]
> (arm_dma_alloc+0x84/0x90)
> [<c021f810>] (arm_dma_alloc) from [<bf954764>]
> (ath10k_htt_tx_alloc+0xe0/0x2e4 [ath10k_core])
> [<bf954764>] (ath10k_htt_tx_alloc [ath10k_core]) from
> [<bf94e6ac>] (ath10k_core_start+0x538/0xcf8 [ath10k_core])
> [<bf94e6ac>] (ath10k_core_start [ath10k_core]) from
> [<bf947eec>] (ath10k_start+0xbc/0x56c [ath10k_core])
> [<bf947eec>] (ath10k_start [ath10k_core]) from
> [<bf8a7a04>] (drv_start+0x40/0x5c [mac80211])
> [<bf8a7a04>] (drv_start [mac80211]) from [<bf8b7cf8>]
> (ieee80211_do_open+0x170/0x82c [mac80211])
> [<bf8b7cf8>] (ieee80211_do_open [mac80211]) from
> [<c056afc8>] (__dev_open+0xa0/0xf4)
> [21053.491752] Normal: 641*4kB (UEMR) 505*8kB (UEMR) 330*16kB (UEMR)
> 126*32kB (UEMR) 762*64kB (UEMR) 237*128kB (UEMR) 1*256kB (M) 0*512kB
> 0*1024kB 0*2048kB 0*4096kB = 95276kB
>
> Signed-off-by: Mohammed Shafi Shajakhan <mohammed at qti.qualcomm.com>
> ---
>  drivers/net/wireless/ath/ath10k/core.c   |  5 +--
>  drivers/net/wireless/ath/ath10k/htt.h    |  6 +++-
>  drivers/net/wireless/ath/ath10k/htt_tx.c | 54 +++++++++++++++++++++++++-------
>  3 files changed, 51 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c
> index 5bc6847..f7ea4de 100644
> --- a/drivers/net/wireless/ath/ath10k/core.c
> +++ b/drivers/net/wireless/ath/ath10k/core.c
> @@ -1857,7 +1857,7 @@ int ath10k_core_start(struct ath10k *ar, enum ath10k_firmware_mode mode,
>                 goto err_wmi_detach;
>         }
>
> -       status = ath10k_htt_tx_alloc(&ar->htt);
> +       status = ath10k_htt_tx_start(&ar->htt);
>         if (status) {
>                 ath10k_err(ar, "failed to alloc htt tx: %d\n", status);
>                 goto err_wmi_detach;
> @@ -2052,7 +2052,7 @@ void ath10k_core_stop(struct ath10k *ar)
>                 ath10k_wait_for_suspend(ar, WMI_PDEV_SUSPEND_AND_DISABLE_INTR);
>
>         ath10k_hif_stop(ar);
> -       ath10k_htt_tx_free(&ar->htt);
> +       ath10k_htt_tx_stop(&ar->htt);
>         ath10k_htt_rx_free(&ar->htt);
>         ath10k_wmi_detach(ar);
>  }
> @@ -2385,6 +2385,7 @@ void ath10k_core_destroy(struct ath10k *ar)
>         destroy_workqueue(ar->workqueue_aux);
>
>         ath10k_debug_destroy(ar);
> +       ath10k_htt_tx_destroy(&ar->htt);
>         ath10k_wmi_free_host_mem(ar);
>         ath10k_mac_destroy(ar);
>  }
> diff --git a/drivers/net/wireless/ath/ath10k/htt.h b/drivers/net/wireless/ath/ath10k/htt.h
> index 0d2ed09..96bf7bf 100644
> --- a/drivers/net/wireless/ath/ath10k/htt.h
> +++ b/drivers/net/wireless/ath/ath10k/htt.h
> @@ -1692,6 +1692,8 @@ struct ath10k_htt {
>                 enum htt_tx_mode_switch_mode mode;
>                 enum htt_q_depth_type type;
>         } tx_q_state;
> +
> +       bool tx_mem_allocated;
>  };
>
>  #define RX_HTT_HDR_STATUS_LEN 64
> @@ -1754,7 +1756,9 @@ struct htt_rx_desc {
>  int ath10k_htt_init(struct ath10k *ar);
>  int ath10k_htt_setup(struct ath10k_htt *htt);
>
> -int ath10k_htt_tx_alloc(struct ath10k_htt *htt);
> +int ath10k_htt_tx_start(struct ath10k_htt *htt);
> +void ath10k_htt_tx_stop(struct ath10k_htt *htt);
> +void ath10k_htt_tx_destroy(struct ath10k_htt *htt);
>  void ath10k_htt_tx_free(struct ath10k_htt *htt);
>
>  int ath10k_htt_rx_alloc(struct ath10k_htt *htt);
> diff --git a/drivers/net/wireless/ath/ath10k/htt_tx.c b/drivers/net/wireless/ath/ath10k/htt_tx.c
> index ccbc8c03..27e49db 100644
> --- a/drivers/net/wireless/ath/ath10k/htt_tx.c
> +++ b/drivers/net/wireless/ath/ath10k/htt_tx.c
> @@ -350,21 +350,15 @@ static int ath10k_htt_tx_alloc_txdone_fifo(struct ath10k_htt *htt)
>         return ret;
>  }
>
> -int ath10k_htt_tx_alloc(struct ath10k_htt *htt)
> +static int ath10k_htt_tx_alloc_buf(struct ath10k_htt *htt)
>  {
>         struct ath10k *ar = htt->ar;
>         int ret;
>
> -       ath10k_dbg(ar, ATH10K_DBG_BOOT, "htt tx max num pending tx %d\n",
> -                  htt->max_num_pending_tx);
> -
> -       spin_lock_init(&htt->tx_lock);
> -       idr_init(&htt->pending_tx);
> -
>         ret = ath10k_htt_tx_alloc_cont_txbuf(htt);
>         if (ret) {
>                 ath10k_err(ar, "failed to alloc cont tx buffer: %d\n", ret);
> -               goto free_idr_pending_tx;
> +               return ret;
>         }
>
>         ret = ath10k_htt_tx_alloc_cont_frag_desc(htt);
> @@ -396,6 +390,31 @@ int ath10k_htt_tx_alloc(struct ath10k_htt *htt)
>  free_txbuf:
>         ath10k_htt_tx_free_cont_txbuf(htt);
>
> +       return ret;
> +}
> +
> +int ath10k_htt_tx_start(struct ath10k_htt *htt)
> +{
> +       struct ath10k *ar = htt->ar;
> +       int ret;
> +
> +       ath10k_dbg(ar, ATH10K_DBG_BOOT, "htt tx max num pending tx %d\n",
> +                  htt->max_num_pending_tx);
> +
> +       spin_lock_init(&htt->tx_lock);
> +       idr_init(&htt->pending_tx);
> +
> +       if (htt->tx_mem_allocated)
> +               return 0;
> +
> +       ret = ath10k_htt_tx_alloc_buf(htt);
> +       if (ret)
> +               goto free_idr_pending_tx;
> +
> +       htt->tx_mem_allocated = true;
> +
> +       return 0;
> +
>  free_idr_pending_tx:
>         idr_destroy(&htt->pending_tx);
>
> @@ -418,15 +437,28 @@ static int ath10k_htt_tx_clean_up_pending(int msdu_id, void *skb, void *ctx)
>         return 0;
>  }
>
> -void ath10k_htt_tx_free(struct ath10k_htt *htt)
> +void ath10k_htt_tx_destroy(struct ath10k_htt *htt)
>  {
> -       idr_for_each(&htt->pending_tx, ath10k_htt_tx_clean_up_pending, htt->ar);
> -       idr_destroy(&htt->pending_tx);
> +       if (!htt->tx_mem_allocated)
> +               return;
>
>         ath10k_htt_tx_free_cont_txbuf(htt);
>         ath10k_htt_tx_free_txq(htt);
>         ath10k_htt_tx_free_cont_frag_desc(htt);
>         ath10k_htt_tx_free_txdone_fifo(htt);
> +       htt->tx_mem_allocated = false;
> +}
> +
> +void ath10k_htt_tx_stop(struct ath10k_htt *htt)
> +{
> +       idr_for_each(&htt->pending_tx, ath10k_htt_tx_clean_up_pending, htt->ar);
> +       idr_destroy(&htt->pending_tx);
> +}
> +
> +void ath10k_htt_tx_free(struct ath10k_htt *htt)
> +{
> +       ath10k_htt_tx_stop(htt);
> +       ath10k_htt_tx_destroy(htt);
>  }
>
>  void ath10k_htt_htc_tx_complete(struct ath10k *ar, struct sk_buff *skb)
> --
> 1.9.1
>
>
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