From: David Miller <davem@davemloft.net>
To: eric.dumazet@gmail.com
Cc: netdev@vger.kernel.org
Subject: Re: [PATCH net-next] tcp: add a force_schedule argument to sk_stream_alloc_skb()
Date: Thu, 21 May 2015 16:58:13 -0400 (EDT) [thread overview]
Message-ID: <20150521.165813.1925516530964458536.davem@davemloft.net> (raw)
In-Reply-To: <1432067215.621.70.camel@edumazet-glaptop2.roam.corp.google.com>
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Tue, 19 May 2015 13:26:55 -0700
> From: Eric Dumazet <edumazet@google.com>
>
> In commit 8e4d980ac215 ("tcp: fix behavior for epoll edge trigger")
> we fixed a possible hang of TCP sockets under memory pressure,
> by allowing sk_stream_alloc_skb() to use sk_forced_mem_schedule()
> if no packet is in socket write queue.
>
> It turns out there are other cases where we want to force memory
> schedule :
>
> tcp_fragment() & tso_fragment() need to split a big TSO packet into
> two smaller ones. If we block here because of TCP memory pressure,
> we can effectively block TCP socket from sending new data.
> If no further ACK is coming, this hang would be definitive, and socket
> has no chance to effectively reduce its memory usage.
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
Looks good, applied, thanks Eric.
prev parent reply other threads:[~2015-05-21 20:58 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-19 20:26 [PATCH net-next] tcp: add a force_schedule argument to sk_stream_alloc_skb() Eric Dumazet
2015-05-21 20:58 ` David Miller [this message]
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