linux-kernel - Re: [PATCH] RDMA/core: reduce IB_POLL

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Message-ID: <1e7c373f-21bd-4d45-3dd6-68467bf09d0d@mellanox.com>
Date:   Wed, 28 Feb 2018 11:50:46 +0200
From:   Max Gurtovoy <maxg@...lanox.com>
To:     Bart Van Assche <bart.vanassche@....com>,
        Jason Gunthorpe <jgg@...pe.ca>,
        Sagi Grimberg <sagi@...mberg.me>
CC:     Chuck Lever <chuck.lever@...cle.com>,
        "arnd@...db.de" <arnd@...db.de>,
        "dledford@...hat.com" <dledford@...hat.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "leonro@...lanox.com" <leonro@...lanox.com>,
        "linux-rdma@...r.kernel.org" <linux-rdma@...r.kernel.org>
Subject: Re: [PATCH] RDMA/core: reduce IB_POLL_BATCH constant



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.

> 
> Thanks,
> 
> Bart.

-Max.