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Date: Wed, 13 Jan 2016 10:38:25 -0500 (EST)
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Subject: Re: [PATCH] net: add per device sg_max_frags for skb
From: David Miller <davem@davemloft.net>
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From: Eric Dumazet <edumazet@google.com>
Date: Wed, 13 Jan 2016 06:19:11 -0800

> 2) TCP stack has coalescing support. write(2) or sendmsg(2) should
> append data into the last skb in write queue, and still use 32 KB
> frags.

Another way to get pathological SKBs is to do lots of tiny sendpage()
calls over discontiguous areas of the file.