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	This patch writes 'node->ref = 1' only if node->ref is 0.
The number of lookups/s for a ~1M entries LRU map increased by
~30% (260097 to 343313).
Other writes on 'node->ref = 0' is not changed.  In those cases, the
same cache line has to be changed anyway.
First column: Size of the LRU hash
Second column: Number of lookups/s
Before:
> echo "$((2**20+1)): $(./map_perf_test 1024 1 $((2**20+1)) 10000000 | awk '{print $3}')"
1048577: 260097
After:
> echo "$((2**20+1)): $(./map_perf_test 1024 1 $((2**20+1)) 10000000 | awk '{print $3}')"
1048577: 343313
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
		
	
			
		
			
				
	
	
		
			85 lines
		
	
	
	
		
			2.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			85 lines
		
	
	
	
		
			2.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/* Copyright (c) 2016 Facebook
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 *
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 * This program is free software; you can redistribute it and/or
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 * modify it under the terms of version 2 of the GNU General Public
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 * License as published by the Free Software Foundation.
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 */
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#ifndef __BPF_LRU_LIST_H_
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#define __BPF_LRU_LIST_H_
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#include <linux/list.h>
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#include <linux/spinlock_types.h>
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#define NR_BPF_LRU_LIST_T	(3)
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#define NR_BPF_LRU_LIST_COUNT	(2)
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#define NR_BPF_LRU_LOCAL_LIST_T (2)
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#define BPF_LOCAL_LIST_T_OFFSET NR_BPF_LRU_LIST_T
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enum bpf_lru_list_type {
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	BPF_LRU_LIST_T_ACTIVE,
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	BPF_LRU_LIST_T_INACTIVE,
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	BPF_LRU_LIST_T_FREE,
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	BPF_LRU_LOCAL_LIST_T_FREE,
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	BPF_LRU_LOCAL_LIST_T_PENDING,
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};
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struct bpf_lru_node {
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	struct list_head list;
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	u16 cpu;
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	u8 type;
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	u8 ref;
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};
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struct bpf_lru_list {
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	struct list_head lists[NR_BPF_LRU_LIST_T];
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	unsigned int counts[NR_BPF_LRU_LIST_COUNT];
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	/* The next inacitve list rotation starts from here */
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	struct list_head *next_inactive_rotation;
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	raw_spinlock_t lock ____cacheline_aligned_in_smp;
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};
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struct bpf_lru_locallist {
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	struct list_head lists[NR_BPF_LRU_LOCAL_LIST_T];
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	u16 next_steal;
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	raw_spinlock_t lock;
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};
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struct bpf_common_lru {
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	struct bpf_lru_list lru_list;
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	struct bpf_lru_locallist __percpu *local_list;
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};
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typedef bool (*del_from_htab_func)(void *arg, struct bpf_lru_node *node);
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struct bpf_lru {
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	union {
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		struct bpf_common_lru common_lru;
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		struct bpf_lru_list __percpu *percpu_lru;
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	};
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	del_from_htab_func del_from_htab;
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	void *del_arg;
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	unsigned int hash_offset;
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	unsigned int nr_scans;
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	bool percpu;
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};
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static inline void bpf_lru_node_set_ref(struct bpf_lru_node *node)
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{
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	/* ref is an approximation on access frequency.  It does not
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	 * have to be very accurate.  Hence, no protection is used.
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	 */
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	if (!node->ref)
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		node->ref = 1;
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}
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int bpf_lru_init(struct bpf_lru *lru, bool percpu, u32 hash_offset,
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		 del_from_htab_func del_from_htab, void *delete_arg);
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void bpf_lru_populate(struct bpf_lru *lru, void *buf, u32 node_offset,
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		      u32 elem_size, u32 nr_elems);
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void bpf_lru_destroy(struct bpf_lru *lru);
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struct bpf_lru_node *bpf_lru_pop_free(struct bpf_lru *lru, u32 hash);
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void bpf_lru_push_free(struct bpf_lru *lru, struct bpf_lru_node *node);
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void bpf_lru_promote(struct bpf_lru *lru, struct bpf_lru_node *node);
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#endif
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