net: Don't write to current task flags on every packet received. (9754e293) · Commits · 戴 / test

net/core/dev.c

+28 −18

Original line number	Diff line number	Diff line
		@@ -3457,7 +3457,7 @@ static bool skb_pfmemalloc_protocol(struct sk_buff *skb)
		}
		}

		static int __netif_receive_skb(struct sk_buff *skb)
		static int __netif_receive_skb_core(struct sk_buff *skb, bool pfmemalloc)
		{
		struct packet_type ptype, pt_prev;
		rx_handler_func_t *rx_handler;
		@@ -3466,24 +3466,11 @@ static int __netif_receive_skb(struct sk_buff *skb)
		bool deliver_exact = false;
		int ret = NET_RX_DROP;
		__be16 type;
		unsigned long pflags = current->flags;

		net_timestamp_check(!netdev_tstamp_prequeue, skb);

		trace_netif_receive_skb(skb);

		/*
		* PFMEMALLOC skbs are special, they should
		* - be delivered to SOCK_MEMALLOC sockets only
		* - stay away from userspace
		* - have bounded memory usage
		*
		* Use PF_MEMALLOC as this saves us from propagating the allocation
		* context down to all allocation sites.
		*/
		if (sk_memalloc_socks() && skb_pfmemalloc(skb))
		current->flags \|= PF_MEMALLOC;

		/* if we've gotten here through NAPI, check netpoll */
		if (netpoll_receive_skb(skb))
		goto out;
		@@ -3517,7 +3504,7 @@ another_round:
		}
		#endif

		if (sk_memalloc_socks() && skb_pfmemalloc(skb))
		if (pfmemalloc)
		goto skip_taps;

		list_for_each_entry_rcu(ptype, &ptype_all, list) {
		@@ -3536,8 +3523,7 @@ skip_taps:
		ncls:
		#endif

		if (sk_memalloc_socks() && skb_pfmemalloc(skb)
		&& !skb_pfmemalloc_protocol(skb))
		if (pfmemalloc && !skb_pfmemalloc_protocol(skb))
		goto drop;

		if (vlan_tx_tag_present(skb)) {
		@@ -3607,7 +3593,31 @@ drop:
		unlock:
		rcu_read_unlock();
		out:
		return ret;
		}

		static int __netif_receive_skb(struct sk_buff *skb)
		{
		int ret;

		if (sk_memalloc_socks() && skb_pfmemalloc(skb)) {
		unsigned long pflags = current->flags;

		/*
		* PFMEMALLOC skbs are special, they should
		* - be delivered to SOCK_MEMALLOC sockets only
		* - stay away from userspace
		* - have bounded memory usage
		*
		* Use PF_MEMALLOC as this saves us from propagating the allocation
		* context down to all allocation sites.
		*/
		current->flags \|= PF_MEMALLOC;
		ret = __netif_receive_skb_core(skb, true);
		tsk_restore_flags(current, pflags, PF_MEMALLOC);
		} else
		ret = __netif_receive_skb_core(skb, false);

		return ret;
		}

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