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From: Suresh Jayaraman <sjayaraman@suse.de>
To: Linus Torvalds <torvalds@linux-foundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org
Cc: netdev@vger.kernel.org, Neil Brown <neilb@suse.de>,
	Miklos Szeredi <mszeredi@suse.cz>, Wouter Verhelst <w@uter.be>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	trond.myklebust@fys.uio.no, Suresh Jayaraman <sjayaraman@suse.de>
Subject: [PATCH 19/31] netvm: filter emergency skbs.
Date: Thu,  1 Oct 2009 19:38:25 +0530	[thread overview]
Message-ID: <1254406105-16336-1-git-send-email-sjayaraman@suse.de> (raw)

From: Peter Zijlstra <a.p.zijlstra@chello.nl> 

Toss all emergency packets not for a SOCK_MEMALLOC socket. This ensures our
precious memory reserve doesn't get stuck waiting for user-space.

The correctness of this approach relies on the fact that networks must be
assumed lossy.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
---
 net/core/filter.c |    3 +++
 1 file changed, 3 insertions(+)

Index: mmotm/net/core/filter.c
===================================================================
--- mmotm.orig/net/core/filter.c
+++ mmotm/net/core/filter.c
@@ -81,6 +81,9 @@ int sk_filter(struct sock *sk, struct sk
 	int err;
 	struct sk_filter *filter;
 
+	if (skb_emergency(skb) && !sk_has_memalloc(sk))
+		return -ENOMEM;
+
 	err = security_sock_rcv_skb(sk, skb);
 	if (err)
 		return err;

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                 reply	other threads:[~2009-10-01 14:08 UTC|newest]

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