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Date:   Wed, 26 Sep 2018 11:06:55 -0600
From:   Jason Gunthorpe <jgg@ziepe.ca>
To:     Jan Dakinevich <jan.dakinevich@virtuozzo.com>
Cc:     Doug Ledford <dledford@redhat.com>,
        Yishai Hadas <yishaih@mellanox.com>,
        Leon Romanovsky <leon@kernel.org>,
        Parav Pandit <parav@mellanox.com>,
        Mark Bloch <markb@mellanox.com>,
        Daniel Jurgens <danielj@mellanox.com>,
        Kees Cook <keescook@chromium.org>,
        Kamal Heib <kamalheib1@gmail.com>,
        Bart Van Assche <bvanassche@acm.org>,
        linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org,
        Denis Lunev <den@virtuozzo.com>,
        Konstantin Khorenko <khorenko@virtuozzo.com>
Subject: Re: [PATCH 0/4] IB: decrease large contigous allocation
Message-ID: <20180926170655.GC16163@ziepe.ca>
References: <1537275826-27247-1-git-send-email-jan.dakinevich@virtuozzo.com>
 <20180918144623.GI11367@ziepe.ca>
 <20180926184809.5d37cdb7@virtuozzo.com>
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On Wed, Sep 26, 2018 at 06:48:09PM +0300, Jan Dakinevich wrote:
> On Tue, 18 Sep 2018 08:46:23 -0600
> Jason Gunthorpe <jgg@ziepe.ca> wrote:
> 
> > On Tue, Sep 18, 2018 at 04:03:42PM +0300, Jan Dakinevich wrote:
> > > The size of mlx4_ib_device became too large to be allocated as
> > > whole contigous block of memory. Currently it takes about 55K. On
> > > architecture with 4K page it means 3rd order.
> > > 
> > > This patch series makes an attempt to split mlx4_ib_device into
> > > several parts and allocate them with less expensive kvzalloc
> > 
> > Why split it up? Any reason not to just allocate the whole thing with
> > kvzalloc?
> > 
> 
> To allocate whole ib_device with kvmalloc I will need replace kzalloc()
> by kvzalloc() in ib_alloc_device() and then review allocation, to make
> sure that no one uses this memory for DMA.

I would be shocked if some driver was DMA'ing out of struct ib_device
memory..

Jason