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;
Date:   Wed, 18 Apr 2018 13:45:07 -0400 (EDT)
Message-Id: <20180418.134507.1436128340000357572.davem@davemloft.net>
To:     eric.dumazet@gmail.com
Cc:     mpatocka@redhat.com, edumazet@google.com, joby.poriyath@citrix.com,
        bhutchings@solarflare.com, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: don't use kvzalloc for DMA memory
From:   David Miller <davem@davemloft.net>
In-Reply-To: <3e65977e-53cd-bf09-bc4b-0ce40e9091fe@gmail.com>
References: <alpine.LRH.2.02.1804181029270.19294@file01.intranet.prod.int.rdu2.redhat.com>
        <3e65977e-53cd-bf09-bc4b-0ce40e9091fe@gmail.com>
Mime-Version: 1.0
Content-Type: Text/Plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Wed, 18 Apr 2018 09:05:54 -0700

> Each virtio_net should probably allocate the exact amount of
> DMA-memory it wants, instead of expecting core networking stack to
> have a huge chunk of DMA-memory for everything.

Yes, if you need DMA'able memory, allocate DMA'able memory separately
and hang it off of the netdev instead of assuming you can just DMA
in/out of it.