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net: bulk free SKBs that were delay free'ed due to IRQ context

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The network stack defers SKBs free, in-case free happens in IRQ or
when IRQs are disabled. This happens in __dev_kfree_skb_irq() that
writes SKBs that were free'ed during IRQ to the softirq completion
queue (softnet_data.completion_queue).

These SKBs are naturally delayed, and cleaned up during NET_TX_SOFTIRQ
in function net_tx_action().  Take advantage of this a use the skb
defer and flush API, as we are already in softirq context.

For modern drivers this rarely happens. Although most drivers do call
dev_kfree_skb_any(), which detects the situation and calls
__dev_kfree_skb_irq() when needed.  This due to netpoll can call from
IRQ context.

Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jesper Dangaard Brouer
2016-02-08 13:15:04 +01:00
committed by David S. Miller
parent 795bb1c00d
commit 15fad714be
3 changed files with 14 additions and 3 deletions
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8
net/core/dev.c
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@ -3829,8 +3829,14 @@ static void net_tx_action(struct softirq_action *h)
trace_consume_skb(skb);
else
trace_kfree_skb(skb, net_tx_action);
__kfree_skb(skb);
if (skb->fclone != SKB_FCLONE_UNAVAILABLE)
__kfree_skb(skb);
else
__kfree_skb_defer(skb);
}
__kfree_skb_flush();
}
if (sd->output_queue) {