From: Jose Abreu <Jose.Abreu@synopsys.com>
To: Robin Murphy <robin.murphy@arm.com>,
Jose Abreu <Jose.Abreu@synopsys.com>,
Jon Hunter <jonathanh@nvidia.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"linux-stm32@st-md-mailman.stormreply.com"
<linux-stm32@st-md-mailman.stormreply.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>
Cc: Joao Pinto <Joao.Pinto@synopsys.com>,
Alexandre Torgue <alexandre.torgue@st.com>,
Maxime Ripard <maxime.ripard@bootlin.com>,
"Chen-Yu Tsai" <wens@csie.org>,
Maxime Coquelin <mcoquelin.stm32@gmail.com>,
linux-tegra <linux-tegra@vger.kernel.org>,
Giuseppe Cavallaro <peppe.cavallaro@st.com>,
"David S . Miller" <davem@davemloft.net>
Subject: RE: [PATCH net-next 3/3] net: stmmac: Introducing support for Page Pool
Date: Mon, 29 Jul 2019 14:08:29 +0000 [thread overview]
Message-ID: <MN2PR12MB3279ABF628C52883021123C5D3DD0@MN2PR12MB3279.namprd12.prod.outlook.com> (raw)
In-Reply-To: <fcf648d2-70cc-d734-871a-ca7f745791b7@arm.com>
[-- Attachment #1: Type: text/plain, Size: 4612 bytes --]
From: Robin Murphy <robin.murphy@arm.com>
Date: Jul/29/2019, 12:52:02 (UTC+00:00)
> On 29/07/2019 12:29, Jose Abreu wrote:
> > ++ Catalin, Will (ARM64 Maintainers)
> >
> > From: Jon Hunter <jonathanh@nvidia.com>
> > Date: Jul/29/2019, 11:55:18 (UTC+00:00)
> >
> >>
> >> On 29/07/2019 09:16, Jose Abreu wrote:
> >>> From: Jose Abreu <joabreu@synopsys.com>
> >>> Date: Jul/27/2019, 16:56:37 (UTC+00:00)
> >>>
> >>>> From: Jon Hunter <jonathanh@nvidia.com>
> >>>> Date: Jul/26/2019, 15:11:00 (UTC+00:00)
> >>>>
> >>>>>
> >>>>> On 25/07/2019 16:12, Jose Abreu wrote:
> >>>>>> From: Jon Hunter <jonathanh@nvidia.com>
> >>>>>> Date: Jul/25/2019, 15:25:59 (UTC+00:00)
> >>>>>>
> >>>>>>>
> >>>>>>> On 25/07/2019 14:26, Jose Abreu wrote:
> >>>>>>>
> >>>>>>> ...
> >>>>>>>
> >>>>>>>> Well, I wasn't expecting that :/
> >>>>>>>>
> >>>>>>>> Per documentation of barriers I think we should set descriptor fields
> >>>>>>>> and then barrier and finally ownership to HW so that remaining fields
> >>>>>>>> are coherent before owner is set.
> >>>>>>>>
> >>>>>>>> Anyway, can you also add a dma_rmb() after the call to
> >>>>>>>> stmmac_rx_status() ?
> >>>>>>>
> >>>>>>> Yes. I removed the debug print added the barrier, but that did not help.
> >>>>>>
> >>>>>> So, I was finally able to setup NFS using your replicated setup and I
> >>>>>> can't see the issue :(
> >>>>>>
> >>>>>> The only difference I have from yours is that I'm using TCP in NFS
> >>>>>> whilst you (I believe from the logs), use UDP.
> >>>>>
> >>>>> So I tried TCP by setting the kernel boot params to 'nfsvers=3' and
> >>>>> 'proto=tcp' and this does appear to be more stable, but not 100% stable.
> >>>>> It still appears to fail in the same place about 50% of the time.
> >>>>>
> >>>>>> You do have flow control active right ? And your HW FIFO size is >= 4k ?
> >>>>>
> >>>>> How can I verify if flow control is active?
> >>>>
> >>>> You can check it by dumping register MTL_RxQ_Operation_Mode (0xd30).
> >>
> >> Where would be the appropriate place to dump this? After probe? Maybe
> >> best if you can share a code snippet of where to dump this.
> >>
> >>>> Can you also add IOMMU debug in file "drivers/iommu/iommu.c" ?
> >>
> >> You can find a boot log here:
> >>
> >> https://urldefense.proofpoint.com/v2/url?u=https-3A__paste.ubuntu.com_p_qtRqtYKHGF_&d=DwICaQ&c=DPL6_X_6JkXFx7AXWqB0tg&r=WHDsc6kcWAl4i96Vm5hJ_19IJiuxx_p_Rzo2g-uHDKw&m=NrxsR2etpZHGb7HkN4XdgaGmKM1XYyldihNPL6qVSv0&s=CMATEcHVoqZw4sIrNOXc7SFE_kV_5CO5EU21-yJez6c&e=
> >>
> >>> And, please try attached debug patch.
> >>
> >> With this patch it appears to boot fine. So far no issues seen.
> >
> > Thank you for testing.
> >
> > Hi Catalin and Will,
> >
> > Sorry to add you in such a long thread but we are seeing a DMA issue
> > with stmmac driver in an ARM64 platform with IOMMU enabled.
> >
> > The issue seems to be solved when buffers allocation for DMA based
> > transfers are *not* mapped with the DMA_ATTR_SKIP_CPU_SYNC flag *OR*
> > when IOMMU is disabled.
> >
> > Notice that after transfer is done we do use
> > dma_sync_single_for_{cpu,device} and then we reuse *the same* page for
> > another transfer.
> >
> > Can you please comment on whether DMA_ATTR_SKIP_CPU_SYNC can not be used
> > in ARM64 platforms with IOMMU ?
>
> In terms of what they do, there should be no difference on arm64 between:
>
> dma_map_page(..., dir);
> ...
> dma_unmap_page(..., dir);
>
> and:
>
> dma_map_page_attrs(..., dir, DMA_ATTR_SKIP_CPU_SYNC);
> dma_sync_single_for_device(..., dir);
> ...
> dma_sync_single_for_cpu(..., dir);
> dma_unmap_page_attrs(..., dir, DMA_ATTR_SKIP_CPU_SYNC);
>
> provided that the first sync covers the whole buffer and any subsequent
> ones cover at least the parts of the buffer which may have changed. Plus
> for coherent hardware it's entirely moot either way.
Thanks for confirming. That's indeed what stmmac is doing when buffer is
received by syncing the packet size to CPU.
>
> Given Jon's previous findings, I would lean towards the idea that
> performing the extra (redundant) cache maintenance plus barrier in
> dma_unmap is mostly just perturbing timing in the same way as the debug
> print which also made things seem OK.
Mikko said that Tegra186 is not coherent so we have to explicit flush
pipeline but I don't understand why sync_single() is not doing it ...
Jon, can you please remove *all* debug prints, hacks, etc ... and test
this one in attach with plain -net tree ?
---
Thanks,
Jose Miguel Abreu
[-- Attachment #2: 0001-net-stmmac-Flush-all-data-cache-in-RX-path.patch --]
[-- Type: application/octet-stream, Size: 1647 bytes --]
From 1b512c799cd896c7b609be512db7c477def43c6b Mon Sep 17 00:00:00 2001
Message-Id: <1b512c799cd896c7b609be512db7c477def43c6b.1564408914.git.joabreu@synopsys.com>
From: Jose Abreu <joabreu@synopsys.com>
Date: Mon, 29 Jul 2019 16:01:36 +0200
Subject: [PATCH net] net: stmmac: Flush all data cache in RX path
Signed-off-by: Jose Abreu <joabreu@synopsys.com>
---
Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Jose Abreu <joabreu@synopsys.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: netdev@vger.kernel.org
Cc: linux-stm32@st-md-mailman.stormreply.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
---
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 98b1a5c6d537..ed7f0d6bd0bc 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -27,6 +27,7 @@
#include <linux/if.h>
#include <linux/if_vlan.h>
#include <linux/dma-mapping.h>
+#include <linux/dma-noncoherent.h>
#include <linux/slab.h>
#include <linux/prefetch.h>
#include <linux/pinctrl/consumer.h>
@@ -3420,6 +3421,8 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue)
continue;
}
+ arch_dma_prep_coherent(buf->page, frame_len);
+
dma_sync_single_for_cpu(priv->device, buf->addr,
frame_len, DMA_FROM_DEVICE);
skb_copy_to_linear_data(skb, page_address(buf->page),
--
2.7.4
next prev parent reply other threads:[~2019-07-29 14:09 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-03 10:37 [PATCH net-next 0/3] net: stmmac: Some performance improvements and a fix Jose Abreu
2019-07-03 10:37 ` [PATCH net-next 1/3] net: stmmac: Implement RX Coalesce Frames setting Jose Abreu
2019-07-03 20:41 ` Jakub Kicinski
2019-07-03 10:37 ` [PATCH net-next 2/3] net: stmmac: Fix descriptors address being in > 32 bits address space Jose Abreu
2019-07-03 10:37 ` [PATCH net-next 3/3] net: stmmac: Introducing support for Page Pool Jose Abreu
2019-07-03 10:40 ` Jose Abreu
2019-07-04 9:39 ` Jesper Dangaard Brouer
2019-07-04 14:45 ` Jose Abreu
2019-07-04 15:09 ` Jesper Dangaard Brouer
2019-07-04 15:18 ` Jose Abreu
2019-07-04 15:33 ` Jesper Dangaard Brouer
2019-07-04 9:48 ` Jesper Dangaard Brouer
2019-07-04 10:00 ` Jesper Dangaard Brouer
2019-07-04 10:13 ` Jose Abreu
2019-07-04 11:11 ` Ilias Apalodimas
2019-07-04 11:54 ` Jesper Dangaard Brouer
2019-07-04 12:04 ` Ilias Apalodimas
2019-07-04 12:59 ` Jose Abreu
2019-07-04 13:06 ` Ilias Apalodimas
2019-07-04 10:30 ` Ilias Apalodimas
2019-07-04 12:14 ` Arnd Bergmann
2019-07-04 12:49 ` Ilias Apalodimas
2019-07-17 18:58 ` Jon Hunter
2019-07-18 7:29 ` Jose Abreu
2019-07-18 7:48 ` Jose Abreu
2019-07-18 9:16 ` Jon Hunter
2019-07-19 7:51 ` Jose Abreu
2019-07-19 8:37 ` Jon Hunter
2019-07-19 8:44 ` Jose Abreu
2019-07-19 8:49 ` Jon Hunter
2019-07-19 10:25 ` Jose Abreu
2019-07-19 12:28 ` Jose Abreu
2019-07-19 13:33 ` Jon Hunter
2019-07-19 12:30 ` Jon Hunter
2019-07-19 12:32 ` Jose Abreu
2019-07-19 13:35 ` Jon Hunter
2019-07-22 7:23 ` Jose Abreu
2019-07-22 9:37 ` Jon Hunter
2019-07-22 9:47 ` Jose Abreu
2019-07-22 9:57 ` Jose Abreu
2019-07-22 10:27 ` Jon Hunter
2019-07-22 10:18 ` Ilias Apalodimas
2019-07-22 11:11 ` Lars Persson
2019-07-22 11:39 ` Jose Abreu
2019-07-22 12:05 ` Jon Hunter
2019-07-22 14:04 ` Jose Abreu
2019-07-23 8:14 ` Jose Abreu
2019-07-23 10:01 ` Jon Hunter
2019-07-23 10:07 ` Jose Abreu
2019-07-23 10:29 ` Robin Murphy
2019-07-23 11:22 ` Jose Abreu
2019-07-23 12:09 ` Jon Hunter
2019-07-23 13:19 ` Robin Murphy
2019-07-23 21:39 ` Jon Hunter
2019-07-24 10:03 ` Robin Murphy
2019-07-23 18:51 ` David Miller
2019-07-24 8:54 ` Ilias Apalodimas
2019-07-24 9:43 ` Jose Abreu
2019-07-24 9:53 ` Ilias Apalodimas
2019-07-24 10:04 ` Jose Abreu
2019-07-24 11:10 ` Jon Hunter
2019-07-24 11:34 ` Jose Abreu
2019-07-24 11:58 ` Jon Hunter
2019-07-25 7:44 ` Jose Abreu
2019-07-25 9:45 ` Jon Hunter
2019-07-25 11:39 ` Ilias Apalodimas
2019-07-23 10:38 ` Jon Hunter
2019-07-23 10:49 ` Jose Abreu
2019-07-23 11:58 ` Jon Hunter
2019-07-23 12:51 ` Jose Abreu
2019-07-23 13:34 ` Jon Hunter
2019-07-29 9:45 ` Mikko Perttunen
2019-07-25 13:20 ` Jon Hunter
2019-07-25 13:26 ` Jose Abreu
2019-07-25 14:25 ` Jon Hunter
2019-07-25 15:12 ` Jose Abreu
2019-07-26 14:11 ` Jon Hunter
2019-07-27 15:56 ` Jose Abreu
2019-07-29 8:16 ` Jose Abreu
2019-07-29 10:55 ` Jon Hunter
2019-07-29 11:29 ` Jose Abreu
2019-07-29 11:52 ` Robin Murphy
2019-07-29 14:08 ` Jose Abreu [this message]
2019-07-29 21:33 ` Jon Hunter
2019-07-30 9:39 ` Jose Abreu
2019-07-30 13:36 ` Jon Hunter
2019-07-30 13:58 ` Jose Abreu
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