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From: Eric Dumazet <erdnetdev@gmail.com>
To: Jakub Kicinski <kuba@kernel.org>, Eric Dumazet <edumazet@google.com>
Cc: "David S . Miller" <davem@davemloft.net>,
	netdev <netdev@vger.kernel.org>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	Willem de Bruijn <willemb@google.com>,
	Antoine Tenart <antoine.tenart@bootlin.com>
Subject: Re: [PATCH net-next 1/5] net: tso: double TSO_HEADER_SIZE value
Date: Wed, 17 Jun 2020 17:14:06 -0700	[thread overview]
Message-ID: <1b5a59d6-ef9c-81e0-9a78-f0eedfc3a40b@gmail.com> (raw)
In-Reply-To: <20200617170229.04454d36@kicinski-fedora-PC1C0HJN>



On 6/17/20 5:02 PM, Jakub Kicinski wrote:
> On Wed, 17 Jun 2020 11:48:15 -0700 Eric Dumazet wrote:
>> Transport header size could be 60 bytes, and network header
>> size can also be 60 bytes. Add the Ethernet header and we
>> are above 128 bytes.
>>
>> Since drivers using net/core/tso.c usually allocates
>> one DMA coherent piece of memory per TX queue, this patch
>> might cause issues if a driver was using too many slots.
>>
>> For 1024 slots, we would need 256 KB of physically
>> contiguous memory instead of 128 KB.
>>
>> Alternative fix would be to add checks in the fast path,
>> but this involves more work in all drivers using net/core/tso.c.
>>
>> Fixes: f9cbe9a556af ("net: define the TSO header size in net/tso.h")
>> Signed-off-by: Eric Dumazet <edumazet@google.com>
>> Cc: Antoine Tenart <antoine.tenart@bootlin.com>
> 
> Some warnings popping up in this series with W=1 C=1:
> 
> drivers/net/ethernet/marvell/octeontx2/af/common.h:65:26: warning: cast truncates bits from constant value (100 becomes 0)
>

Nice, thanks I will take a look.


  reply	other threads:[~2020-06-18  0:14 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-17 18:48 [PATCH net-next 0/5] net: tso: expand to UDP support Eric Dumazet
2020-06-17 18:48 ` [PATCH net-next 1/5] net: tso: double TSO_HEADER_SIZE value Eric Dumazet
2020-06-18  0:02   ` Jakub Kicinski
2020-06-18  0:14     ` Eric Dumazet [this message]
2020-06-17 18:48 ` [PATCH net-next 2/5] net: tso: shrink struct tso_t Eric Dumazet
2020-06-17 18:48 ` [PATCH net-next 3/5] net: tso: constify tso_count_descs() and friends Eric Dumazet
2020-06-17 18:48 ` [PATCH net-next 4/5] net: tso: cache transport header length Eric Dumazet
2020-06-18  0:03   ` Jakub Kicinski
2020-06-17 18:48 ` [PATCH net-next 5/5] net: tso: add UDP segmentation support Eric Dumazet
  -- strict thread matches above, loose matches on Subject: below --
2020-06-17 18:44 [PATCH net-next 1/5] net: tso: double TSO_HEADER_SIZE value Eric Dumazet
2020-06-17 18:45 ` Eric Dumazet

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