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Message-ID: <CAF=yD-+KLSGwTsD7RawmruurjJmVpQxccwtMSqtRD5WWgCTG3A@mail.gmail.com>
Date: Thu, 15 Feb 2018 15:42:23 -0500
From: Willem de Bruijn <willemdebruijn.kernel@...il.com>
To: Santosh Shilimkar <santosh.shilimkar@...cle.com>
Cc: Sowmini Varadhan <sowmini.varadhan@...cle.com>,
Network Development <netdev@...r.kernel.org>,
David Miller <davem@...emloft.net>, rds-devel@....oracle.com
Subject: Re: [PATCH v3 net-next 5/7] rds: zerocopy Tx support.
On Thu, Feb 15, 2018 at 2:47 PM, Santosh Shilimkar
<santosh.shilimkar@...cle.com> wrote:
> On 2/15/2018 10:49 AM, Sowmini Varadhan wrote:
>>
>> If the MSG_ZEROCOPY flag is specified with rds_sendmsg(), and,
>> if the SO_ZEROCOPY socket option has been set on the PF_RDS socket,
>> application pages sent down with rds_sendmsg() are pinned.
>>
>> The pinning uses the accounting infrastructure added by
>> Commit a91dbff551a6 ("sock: ulimit on MSG_ZEROCOPY pages")
>>
>> The payload bytes in the message may not be modified for the
>> duration that the message has been pinned. A multi-threaded
>> application using this infrastructure may thus need to be notified
>> about send-completion so that it can free/reuse the buffers
>> passed to rds_sendmsg(). Notification of send-completion will
>> identify each message-buffer by a cookie that the application
>> must specify as ancillary data to rds_sendmsg().
>> The ancillary data in this case has cmsg_level == SOL_RDS
>> and cmsg_type == RDS_CMSG_ZCOPY_COOKIE.
>>
>> Signed-off-by: Sowmini Varadhan <sowmini.varadhan@...cle.com>
>> ---
>
>
> Acked-by: Santosh Shilimkar <santosh.shilimkar@...cle.com>
Acked-by: Willem de Bruijn <willemb@...gle.com>
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