From: NeilBrown <neilb@suse.de>
To: Mel Gorman <mgorman@suse.de>
Cc: Linux-MM <linux-mm@kvack.org>,
Linux-Netdev <netdev@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
David Miller <davem@davemloft.net>,
Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [PATCH 09/13] netvm: Set PF_MEMALLOC as appropriate during SKB processing
Date: Tue, 26 Apr 2011 22:21:57 +1000 [thread overview]
Message-ID: <20110426222157.33a461f8@notabene.brown> (raw)
In-Reply-To: <1303803414-5937-10-git-send-email-mgorman@suse.de>
On Tue, 26 Apr 2011 08:36:50 +0100 Mel Gorman <mgorman@suse.de> wrote:
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 3871bf6..2d79a20 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -3095,6 +3095,27 @@ static void vlan_on_bond_hook(struct sk_buff *skb)
> }
> }
>
> +/*
> + * Limit which protocols can use the PFMEMALLOC reserves to those that are
> + * expected to be used for communication with swap.
> + */
> +static bool skb_pfmemalloc_protocol(struct sk_buff *skb)
> +{
> + if (skb_pfmemalloc(skb))
> + switch (skb->protocol) {
> + case __constant_htons(ETH_P_ARP):
> + case __constant_htons(ETH_P_IP):
> + case __constant_htons(ETH_P_IPV6):
> + case __constant_htons(ETH_P_8021Q):
> + break;
> +
> + default:
> + return false;
> + }
> +
> + return true;
> +}
This sort of thing really bugs me :-)
Neither the comment nor the function name actually describe what the function
is doing. The function is checking *2* things.
is_pfmemalloc_skb_or_pfmemalloc_protocol()
might be a more correct name, but is too verbose.
I would prefer the skb_pfmemalloc test were removed from here and ....
> + if (!skb_pfmemalloc_protocol(skb))
> + goto drop;
> +
...added here so this becomes:
if (!skb_pfmemalloc(skb) && !skb_pfmemalloc_protocol(skb))
goto drop;
which actually makes sense.
Thanks,
NeilBrown
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next prev parent reply other threads:[~2011-04-26 12:22 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-26 7:36 [PATCH 00/13] Swap-over-NBD without deadlocking Mel Gorman
2011-04-26 7:36 ` [PATCH 01/13] mm: Serialize access to min_free_kbytes Mel Gorman
2011-04-26 7:36 ` [PATCH 02/13] mm: sl[au]b: Add knowledge of PFMEMALLOC reserve pages Mel Gorman
2011-04-26 11:15 ` NeilBrown
2011-04-26 11:33 ` Mel Gorman
2011-04-26 12:05 ` NeilBrown
2011-04-26 11:37 ` NeilBrown
2011-04-26 13:59 ` Mel Gorman
2011-04-27 23:21 ` NeilBrown
2011-04-28 9:46 ` Mel Gorman
2011-04-26 7:36 ` [PATCH 03/13] mm: Introduce __GFP_MEMALLOC to allow access to emergency reserves Mel Gorman
2011-04-26 9:49 ` NeilBrown
2011-04-26 10:36 ` Mel Gorman
2011-04-26 10:53 ` NeilBrown
2011-04-26 14:00 ` Mel Gorman
2011-04-26 7:36 ` [PATCH 04/13] mm: allow PF_MEMALLOC from softirq context Mel Gorman
2011-04-26 7:36 ` [PATCH 05/13] mm: Ignore mempolicies when using ALLOC_NO_WATERMARK Mel Gorman
2011-04-26 7:36 ` [PATCH 06/13] net: Introduce sk_allocation() to allow addition of GFP flags depending on the individual socket Mel Gorman
2011-04-26 7:36 ` [PATCH 07/13] netvm: Allow the use of __GFP_MEMALLOC by specific sockets Mel Gorman
2011-04-26 7:36 ` [PATCH 08/13] netvm: Allow skb allocation to use PFMEMALLOC reserves Mel Gorman
2011-04-26 7:36 ` [PATCH 09/13] netvm: Set PF_MEMALLOC as appropriate during SKB processing Mel Gorman
2011-04-26 12:21 ` NeilBrown [this message]
2011-04-26 14:10 ` Mel Gorman
2011-04-26 23:22 ` NeilBrown
2011-04-26 7:36 ` [PATCH 10/13] mm: Micro-optimise slab to avoid a function call Mel Gorman
2011-04-26 7:36 ` [PATCH 11/13] nbd: Set SOCK_MEMALLOC for access to PFMEMALLOC reserves Mel Gorman
2011-04-26 7:36 ` [PATCH 12/13] mm: Throttle direct reclaimers if PF_MEMALLOC reserves are low and swap is backed by network storage Mel Gorman
2011-04-26 12:30 ` NeilBrown
2011-04-26 14:26 ` Mel Gorman
2011-04-26 23:18 ` NeilBrown
2011-04-27 8:36 ` Mel Gorman
2011-04-26 7:36 ` [PATCH 13/13] mm: Account for the number of times direct reclaimers get throttled Mel Gorman
2011-04-26 12:35 ` NeilBrown
2011-04-26 14:26 ` Mel Gorman
2011-04-26 14:23 ` [PATCH 00/13] Swap-over-NBD without deadlocking Peter Zijlstra
2011-04-26 14:46 ` Mel Gorman
2011-04-26 14:50 ` Peter Zijlstra
2011-04-27 8:43 ` Mel Gorman
2011-04-28 13:31 ` Pavel Machek
2011-04-28 13:42 ` Mel Gorman
-- strict thread matches above, loose matches on Subject: below --
2011-04-27 16:07 [PATCH 00/13] Swap-over-NBD without deadlocking v3 Mel Gorman
2011-04-27 16:08 ` [PATCH 09/13] netvm: Set PF_MEMALLOC as appropriate during SKB processing Mel Gorman
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