From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-lf0-x242.google.com ([2a00:1450:4010:c07::242]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1fKrYS-0008EV-SP for ath10k@lists.infradead.org; Mon, 21 May 2018 20:37:18 +0000 Received: by mail-lf0-x242.google.com with SMTP id w202-v6so25773945lff.12 for ; Mon, 21 May 2018 13:37:05 -0700 (PDT) Date: Mon, 21 May 2018 22:37:01 +0200 From: Niklas Cassel Subject: Re: [PATCH] ath10k: transmit queued frames after waking queues Message-ID: <20180521203701.GA7619@localhost.localdomain> References: <20180517231512.13085-1-niklas.cassel@linaro.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "ath10k" Errors-To: ath10k-bounces+kvalo=adurom.com@lists.infradead.org To: Adrian Chadd Cc: netdev@vger.kernel.org, linux-wireless@vger.kernel.org, Linux Kernel Mailing List , ath10k@lists.infradead.org, Kalle Valo , David Miller On Thu, May 17, 2018 at 03:26:25PM -0700, Adrian Chadd wrote: > On Thu, 17 May 2018 at 16:16, Niklas Cassel > wrote: > > > diff --git a/drivers/net/wireless/ath/ath10k/txrx.c > b/drivers/net/wireless/ath/ath10k/txrx.c > > index cda164f6e9f6..1d3b2d2c3fee 100644 > > --- a/drivers/net/wireless/ath/ath10k/txrx.c > > +++ b/drivers/net/wireless/ath/ath10k/txrx.c > > @@ -95,6 +95,9 @@ int ath10k_txrx_tx_unref(struct ath10k_htt *htt, > > wake_up(&htt->empty_tx_wq); > > spin_unlock_bh(&htt->tx_lock); > > > + if (htt->num_pending_tx <= 3 && !list_empty(&ar->txqs)) > > + ath10k_mac_tx_push_pending(ar); > > + > > Just sanity checking - what's protecting htt->num_pending_tx? or is it > serialised some other way? Hello Adrian, I did not take the htt->tx_lock lock for this since it should not be needed. There are however some compiler optimizations that you have to look out for: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/memory-barriers.txt?h=v4.17-rc6#n1547 I can't see that any of the examples applies, but let's add READ_ONCE(), to make sure that the compiler doesn't try to optimize this. Will send a V2 for this. Regards, Niklas > > > dma_unmap_single(dev, skb_cb->paddr, msdu->len, DMA_TO_DEVICE); > > > ath10k_report_offchan_tx(htt->ar, msdu); > > -- > > 2.17.0 _______________________________________________ ath10k mailing list ath10k@lists.infradead.org http://lists.infradead.org/mailman/listinfo/ath10k From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-lf0-f66.google.com ([209.85.215.66]:38336 "EHLO mail-lf0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751108AbeEUUhF (ORCPT ); Mon, 21 May 2018 16:37:05 -0400 Received: by mail-lf0-f66.google.com with SMTP id z142-v6so25802287lff.5 for ; Mon, 21 May 2018 13:37:05 -0700 (PDT) Date: Mon, 21 May 2018 22:37:01 +0200 From: Niklas Cassel To: Adrian Chadd Cc: Kalle Valo , David Miller , ath10k@lists.infradead.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, Linux Kernel Mailing List Subject: Re: [PATCH] ath10k: transmit queued frames after waking queues Message-ID: <20180521203701.GA7619@localhost.localdomain> (sfid-20180521_223728_285923_023C6B64) References: <20180517231512.13085-1-niklas.cassel@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Sender: linux-wireless-owner@vger.kernel.org List-ID: On Thu, May 17, 2018 at 03:26:25PM -0700, Adrian Chadd wrote: > On Thu, 17 May 2018 at 16:16, Niklas Cassel > wrote: > > > diff --git a/drivers/net/wireless/ath/ath10k/txrx.c > b/drivers/net/wireless/ath/ath10k/txrx.c > > index cda164f6e9f6..1d3b2d2c3fee 100644 > > --- a/drivers/net/wireless/ath/ath10k/txrx.c > > +++ b/drivers/net/wireless/ath/ath10k/txrx.c > > @@ -95,6 +95,9 @@ int ath10k_txrx_tx_unref(struct ath10k_htt *htt, > > wake_up(&htt->empty_tx_wq); > > spin_unlock_bh(&htt->tx_lock); > > > + if (htt->num_pending_tx <= 3 && !list_empty(&ar->txqs)) > > + ath10k_mac_tx_push_pending(ar); > > + > > Just sanity checking - what's protecting htt->num_pending_tx? or is it > serialised some other way? Hello Adrian, I did not take the htt->tx_lock lock for this since it should not be needed. There are however some compiler optimizations that you have to look out for: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/memory-barriers.txt?h=v4.17-rc6#n1547 I can't see that any of the examples applies, but let's add READ_ONCE(), to make sure that the compiler doesn't try to optimize this. Will send a V2 for this. Regards, Niklas > > > dma_unmap_single(dev, skb_cb->paddr, msdu->len, DMA_TO_DEVICE); > > > ath10k_report_offchan_tx(htt->ar, msdu); > > -- > > 2.17.0