Message-ID: <1392178661.1752.1.camel@edumazet-glaptop2.roam.corp.google.com>
Subject: Re: 3.14-mw regression: rtl8169 WARNING: DMA-API: exceeded 7
 overlapping mappings of pfn 55ebe
From: Eric Dumazet <eric.dumazet@gmail.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Sander Eikelenboom <linux@eikelenboom.it>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        Wei Liu <wei.liu2@citrix.com>, Francois Romieu <romieu@fr.zoreil.com>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Dave Jones <davej@redhat.com>
Date: Tue, 11 Feb 2014 20:17:41 -0800
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On Tue, 2014-02-11 at 18:07 -0800, Dan Williams wrote:

> The overlap granularity is too large.  Multiple dma_map_single
> mappings are allowed to a given page as long as they don't collide on
> the same cache line.
> 

I am not sure why you try number of mappings of a page.

Try launching 100 concurrent netperf -t TCP_SENFILE

Same page might be mapped more than 100 times, more than 10000 times in
some cases.


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