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	Refreshed all patches. Compile-tested on: ipq40xx, apm821xx Runtime-tested on: ipq40xx Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
		
			
				
	
	
		
			86 lines
		
	
	
		
			2.9 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
			
		
		
	
	
			86 lines
		
	
	
		
			2.9 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
| From: Eric Dumazet <edumazet@google.com>
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| Date: Sat, 11 Nov 2017 15:54:12 -0800
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| Subject: [PATCH] tcp: allow drivers to tweak TSQ logic
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| MIME-Version: 1.0
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| Content-Type: text/plain; charset=UTF-8
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| Content-Transfer-Encoding: 8bit
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| 
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| I had many reports that TSQ logic breaks wifi aggregation.
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| 
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| Current logic is to allow up to 1 ms of bytes to be queued into qdisc
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| and drivers queues.
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| 
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| But Wifi aggregation needs a bigger budget to allow bigger rates to
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| be discovered by various TCP Congestion Controls algorithms.
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| 
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| This patch adds an extra socket field, allowing wifi drivers to select
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| another log scale to derive TCP Small Queue credit from current pacing
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| rate.
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| 
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| Initial value is 10, meaning that this patch does not change current
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| behavior.
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| 
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| We expect wifi drivers to set this field to smaller values (tests have
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| been done with values from 6 to 9)
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| 
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| They would have to use following template :
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| 
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| if (skb->sk && skb->sk->sk_pacing_shift != MY_PACING_SHIFT)
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|      skb->sk->sk_pacing_shift = MY_PACING_SHIFT;
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| 
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| Ref: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1670041
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| Signed-off-by: Eric Dumazet <edumazet@google.com>
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| Cc: Johannes Berg <johannes.berg@intel.com>
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| Cc: Toke Høiland-Jørgensen <toke@toke.dk>
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| Cc: Kir Kolyshkin <kir@openvz.org>
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| ---
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| --- a/include/net/sock.h
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| +++ b/include/net/sock.h
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| @@ -267,6 +267,7 @@ struct sock_common {
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|    *	@sk_gso_type: GSO type (e.g. %SKB_GSO_TCPV4)
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|    *	@sk_gso_max_size: Maximum GSO segment size to build
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|    *	@sk_gso_max_segs: Maximum number of GSO segments
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| +  *	@sk_pacing_shift: scaling factor for TCP Small Queues
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|    *	@sk_lingertime: %SO_LINGER l_linger setting
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|    *	@sk_backlog: always used with the per-socket spinlock held
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|    *	@sk_callback_lock: used with the callbacks in the end of this struct
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| @@ -446,6 +447,8 @@ struct sock {
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|  				sk_type      : 16;
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|  #define SK_PROTOCOL_MAX U8_MAX
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|  	u16			sk_gso_max_segs;
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| +#define sk_pacing_shift sk_pacing_shift /* for backport checks */
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| +	u8			sk_pacing_shift;
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|  	unsigned long	        sk_lingertime;
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|  	struct proto		*sk_prot_creator;
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|  	rwlock_t		sk_callback_lock;
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| --- a/net/core/sock.c
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| +++ b/net/core/sock.c
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| @@ -2745,6 +2745,7 @@ void sock_init_data(struct socket *sock,
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|  
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|  	sk->sk_max_pacing_rate = ~0U;
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|  	sk->sk_pacing_rate = ~0U;
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| +	sk->sk_pacing_shift = 10;
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|  	sk->sk_incoming_cpu = -1;
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|  	/*
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|  	 * Before updating sk_refcnt, we must commit prior changes to memory
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| --- a/net/ipv4/tcp_output.c
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| +++ b/net/ipv4/tcp_output.c
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| @@ -1697,7 +1697,7 @@ u32 tcp_tso_autosize(const struct sock *
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|  {
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|  	u32 bytes, segs;
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|  
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| -	bytes = min(sk->sk_pacing_rate >> 10,
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| +	bytes = min(sk->sk_pacing_rate >> sk->sk_pacing_shift,
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|  		    sk->sk_gso_max_size - 1 - MAX_TCP_HEADER);
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|  
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|  	/* Goal is to send at least one packet per ms,
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| @@ -2215,7 +2215,7 @@ static bool tcp_small_queue_check(struct
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|  {
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|  	unsigned int limit;
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|  
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| -	limit = max(2 * skb->truesize, sk->sk_pacing_rate >> 10);
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| +	limit = max(2 * skb->truesize, sk->sk_pacing_rate >> sk->sk_pacing_shift);
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|  	limit = min_t(u32, limit, sysctl_tcp_limit_output_bytes);
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|  	limit <<= factor;
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|  
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