Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Received-SPF: Pass (protection.outlook.com: domain of mellanox.com designates
 193.47.165.134 as permitted sender) receiver=protection.outlook.com;
 client-ip=193.47.165.134; helo=mtlcas13.mtl.com;
Subject: Re: [PATCH] RDMA/core: reduce IB_POLL_BATCH constant
To:     Doug Ledford <dledford@redhat.com>,
        Bart Van Assche <bart.vanassche@wdc.com>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        Sagi Grimberg <sagi@grimberg.me>
CC:     Chuck Lever <chuck.lever@oracle.com>,
        "arnd@arndb.de" <arnd@arndb.de>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "leonro@mellanox.com" <leonro@mellanox.com>,
        "linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>
References: <20180220205924.2035765-1-arnd@arndb.de>
 <1519161268.3737.12.camel@wdc.com>
 <F2FB1034-BFB6-45ED-878E-6FADD756157D@oracle.com>
 <c3eab137-1c37-0e6c-a53a-df2cf80653d2@grimberg.me>
 <0f90134c-3d40-1d24-711f-e4ab32802bd8@mellanox.com>
 <c1bcd5cc-381d-2d94-1278-f9fb5c9c0b14@grimberg.me>
 <20180227220958.GA21714@ziepe.ca>
 <193aaf91-c9d1-38b1-a89f-45f129ca5798@mellanox.com>
 <d2875648-20d9-43b9-abf1-8ecbf049c4bf@wdc.com>
 <1e7c373f-21bd-4d45-3dd6-68467bf09d0d@mellanox.com>
 <1519844114.28560.216.camel@redhat.com>
From:   Max Gurtovoy <maxg@mellanox.com>
Message-ID: <efc0302c-90e2-2e09-7525-dc9b9e247e73@mellanox.com>
Date:   Thu, 1 Mar 2018 11:36:50 +0200
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101
 Thunderbird/52.6.0
MIME-Version: 1.0
In-Reply-To: <1519844114.28560.216.camel@redhat.com>
Content-Type: text/plain; charset="utf-8"; format=flowed
Content-Language: he
Content-Transfer-Encoding: 7bit
SpamDiagnosticOutput: 1:99
SpamDiagnosticMetadata: NSPM
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 01 Mar 2018 09:36:52.9333
 (UTC)
X-MS-Exchange-CrossTenant-Network-Message-Id: 721b721a-a347-4506-7567-08d57f57f752
X-MS-Exchange-CrossTenant-Id: a652971c-7d2e-4d9b-a6a4-d149256f461b
X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=a652971c-7d2e-4d9b-a6a4-d149256f461b;Ip=[193.47.165.134];Helo=[mtlcas13.mtl.com]
X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem
X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM4PR05MB3249
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org


On 2/28/2018 8:55 PM, Doug Ledford wrote:
> On Wed, 2018-02-28 at 11:50 +0200, Max Gurtovoy wrote:
>>
>> On 2/28/2018 2:21 AM, Bart Van Assche wrote:
>>> On 02/27/18 14:15, Max Gurtovoy wrote:
>>>> -static int __ib_process_cq(struct ib_cq *cq, int budget, struct ib_wc
>>>> *poll_wc)
>>>> +static int __ib_process_cq(struct ib_cq *cq, int budget, struct ib_wc
>>>> *poll_wc,
>>>> +                          int batch)
>>>>    {
>>>> -       int i, n, completed = 0;
>>>> -       struct ib_wc *wcs = poll_wc ? : cq->wc;
>>>> +       int i, n, ib_poll_batch, completed = 0;
>>>> +       struct ib_wc *wcs;
>>>> +
>>>> +       if (poll_wc) {
>>>> +               wcs = poll_wc;
>>>> +               ib_poll_batch = batch;
>>>> +       } else {
>>>> +               wcs = cq->wc;
>>>> +               ib_poll_batch = IB_POLL_BATCH;
>>>> +       }
>>>
>>> Since this code has to be touched I think that we can use this
>>> opportunity to get rid of the "poll_wc ? : cq->wc" conditional and
>>> instead use what the caller passes. That will require to update all
>>> __ib_process_cq(..., ..., NULL) calls. I also propose to let the caller
>>> pass ib_poll_batch instead of figuring it out in this function.
>>> Otherwise the approach of this patch looks fine to me.
>>
>> Thanks Bart.
>> I'll make these changes and submit.
> 
> That sounds reasonable to me too, thanks for reworking and resubmitting.
> 

Sure, NP.
We've run NVMe-oF and SRP with the new patch.
I'll send it through Mellanox maintainers pull request.

Thanks for reporting and reviewing.

-Max.