Message-ID: <1337075234.27694.9.camel@twins>
Subject: Re: [PATCH 01/12] netvm: Prevent a stream-specific deadlock
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Mel Gorman <mgorman@suse.de>
Cc: David Miller <davem@davemloft.net>, akpm@linux-foundation.org,
        linux-mm@kvack.org, netdev@vger.kernel.org, linux-nfs@vger.kernel.org,
        linux-kernel@vger.kernel.org, Trond.Myklebust@netapp.com,
        neilb@suse.de, hch@infradead.org, michaelc@cs.wisc.edu,
        emunson@mgebm.net
Date: Tue, 15 May 2012 11:47:14 +0200
In-Reply-To: <20120515091402.GG29102@suse.de>
References: <1336658065-24851-2-git-send-email-mgorman@suse.de>
	 <20120511.011034.557833140906762226.davem@davemloft.net>
	 <20120514105604.GB29102@suse.de>
	 <20120514.162634.1094732813264319951.davem@davemloft.net>
	 <20120515091402.GG29102@suse.de>
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7BIT
Mime-Version: 1.0
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1142
Lines: 26

On Tue, 2012-05-15 at 10:14 +0100, Mel Gorman wrote:
> @@ -289,6 +289,18 @@ void sk_clear_memalloc(struct sock *sk)
>         sock_reset_flag(sk, SOCK_MEMALLOC);
>         sk->sk_allocation &= ~__GFP_MEMALLOC;
>         static_key_slow_dec(&memalloc_socks);
> +
> +       /*
> +        * SOCK_MEMALLOC is allowed to ignore rmem limits to ensure forward
> +        * progress of swapping. However, if SOCK_MEMALLOC is cleared while
> +        * it has rmem allocations there is a risk that the user of the
> +        * socket cannot make forward progress due to exceeding the rmem
> +        * limits. By rights, sk_clear_memalloc() should only be called
> +        * on sockets being torn down but warn and reset the accounting if
> +        * that assumption breaks.
> +        */
> +       if (WARN_ON(sk->sk_forward_alloc))

WARN_ON_ONCE() perhaps?

> +               sk_mem_reclaim(sk);
>  } 
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/