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![Martin KaFai Lau](/assets/img/avatar_default.png)
After doing map_perf_test with a much bigger BPF_F_NO_COMMON_LRU map, the perf report shows a lot of time spent in rotating the inactive list (i.e. __bpf_lru_list_rotate_inactive): > map_perf_test 32 8 10000 1000000 | awk '{sum += $3}END{print sum}' 19644783 (19M/s) > map_perf_test 32 8 10000000 10000000 | awk '{sum += $3}END{print sum}' 6283930 (6.28M/s) By inactive, it usually means the element is not in cache. Hence, there is a need to tune the PERCPU_NR_SCANS value. This patch finds a better number of elements to scan during each list rotation. The PERCPU_NR_SCANS (which is defined the same as PERCPU_FREE_TARGET) decreases from 16 elements to 4 elements. This change only affects the BPF_F_NO_COMMON_LRU map. The test_lru_dist does not show meaningful difference between 16 and 4. Our production L4 load balancer which uses the LRU map for conntrack-ing also shows little change in cache hit rate. Since both benchmark and production data show no cache-hit difference, PERCPU_NR_SCANS is lowered from 16 to 4. We can consider making it configurable if we find a usecase later that shows another value works better and/or use a different rotation strategy. After this change: > map_perf_test 32 8 10000000 10000000 | awk '{sum += $3}END{print sum}' 9240324 (9.2M/s) i.e. 6.28M/s -> 9.2M/s The test_lru_dist has not shown meaningful difference: > test_lru_dist zipf.100k.a1_01.out 4000 1: nr_misses: 31575 (Before) vs 31566 (After) > test_lru_dist zipf.100k.a0_01.out 40000 1 nr_misses: 67036 (Before) vs 67031 (After) Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
697 lines
18 KiB
C
697 lines
18 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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#include <linux/cpumask.h>
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#include <linux/spinlock.h>
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#include <linux/percpu.h>
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#include "bpf_lru_list.h"
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#define LOCAL_FREE_TARGET (128)
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#define LOCAL_NR_SCANS LOCAL_FREE_TARGET
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#define PERCPU_FREE_TARGET (4)
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#define PERCPU_NR_SCANS PERCPU_FREE_TARGET
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/* Helpers to get the local list index */
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#define LOCAL_LIST_IDX(t) ((t) - BPF_LOCAL_LIST_T_OFFSET)
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#define LOCAL_FREE_LIST_IDX LOCAL_LIST_IDX(BPF_LRU_LOCAL_LIST_T_FREE)
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#define LOCAL_PENDING_LIST_IDX LOCAL_LIST_IDX(BPF_LRU_LOCAL_LIST_T_PENDING)
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#define IS_LOCAL_LIST_TYPE(t) ((t) >= BPF_LOCAL_LIST_T_OFFSET)
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static int get_next_cpu(int cpu)
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{
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cpu = cpumask_next(cpu, cpu_possible_mask);
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if (cpu >= nr_cpu_ids)
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cpu = cpumask_first(cpu_possible_mask);
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return cpu;
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}
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/* Local list helpers */
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static struct list_head *local_free_list(struct bpf_lru_locallist *loc_l)
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{
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return &loc_l->lists[LOCAL_FREE_LIST_IDX];
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}
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static struct list_head *local_pending_list(struct bpf_lru_locallist *loc_l)
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{
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return &loc_l->lists[LOCAL_PENDING_LIST_IDX];
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}
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/* bpf_lru_node helpers */
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static bool bpf_lru_node_is_ref(const struct bpf_lru_node *node)
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{
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return node->ref;
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}
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static void bpf_lru_list_count_inc(struct bpf_lru_list *l,
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enum bpf_lru_list_type type)
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{
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if (type < NR_BPF_LRU_LIST_COUNT)
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l->counts[type]++;
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}
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static void bpf_lru_list_count_dec(struct bpf_lru_list *l,
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enum bpf_lru_list_type type)
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{
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if (type < NR_BPF_LRU_LIST_COUNT)
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l->counts[type]--;
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}
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static void __bpf_lru_node_move_to_free(struct bpf_lru_list *l,
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struct bpf_lru_node *node,
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struct list_head *free_list,
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enum bpf_lru_list_type tgt_free_type)
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{
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if (WARN_ON_ONCE(IS_LOCAL_LIST_TYPE(node->type)))
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return;
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/* If the removing node is the next_inactive_rotation candidate,
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* move the next_inactive_rotation pointer also.
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*/
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if (&node->list == l->next_inactive_rotation)
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l->next_inactive_rotation = l->next_inactive_rotation->prev;
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bpf_lru_list_count_dec(l, node->type);
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node->type = tgt_free_type;
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list_move(&node->list, free_list);
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}
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/* Move nodes from local list to the LRU list */
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static void __bpf_lru_node_move_in(struct bpf_lru_list *l,
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struct bpf_lru_node *node,
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enum bpf_lru_list_type tgt_type)
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{
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if (WARN_ON_ONCE(!IS_LOCAL_LIST_TYPE(node->type)) ||
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WARN_ON_ONCE(IS_LOCAL_LIST_TYPE(tgt_type)))
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return;
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bpf_lru_list_count_inc(l, tgt_type);
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node->type = tgt_type;
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node->ref = 0;
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list_move(&node->list, &l->lists[tgt_type]);
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}
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/* Move nodes between or within active and inactive list (like
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* active to inactive, inactive to active or tail of active back to
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* the head of active).
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*/
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static void __bpf_lru_node_move(struct bpf_lru_list *l,
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struct bpf_lru_node *node,
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enum bpf_lru_list_type tgt_type)
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{
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if (WARN_ON_ONCE(IS_LOCAL_LIST_TYPE(node->type)) ||
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WARN_ON_ONCE(IS_LOCAL_LIST_TYPE(tgt_type)))
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return;
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if (node->type != tgt_type) {
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bpf_lru_list_count_dec(l, node->type);
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bpf_lru_list_count_inc(l, tgt_type);
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node->type = tgt_type;
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}
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node->ref = 0;
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/* If the moving node is the next_inactive_rotation candidate,
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* move the next_inactive_rotation pointer also.
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*/
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if (&node->list == l->next_inactive_rotation)
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l->next_inactive_rotation = l->next_inactive_rotation->prev;
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list_move(&node->list, &l->lists[tgt_type]);
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}
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static bool bpf_lru_list_inactive_low(const struct bpf_lru_list *l)
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{
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return l->counts[BPF_LRU_LIST_T_INACTIVE] <
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l->counts[BPF_LRU_LIST_T_ACTIVE];
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}
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/* Rotate the active list:
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* 1. Start from tail
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* 2. If the node has the ref bit set, it will be rotated
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* back to the head of active list with the ref bit cleared.
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* Give this node one more chance to survive in the active list.
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* 3. If the ref bit is not set, move it to the head of the
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* inactive list.
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* 4. It will at most scan nr_scans nodes
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*/
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static void __bpf_lru_list_rotate_active(struct bpf_lru *lru,
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struct bpf_lru_list *l)
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{
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struct list_head *active = &l->lists[BPF_LRU_LIST_T_ACTIVE];
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struct bpf_lru_node *node, *tmp_node, *first_node;
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unsigned int i = 0;
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first_node = list_first_entry(active, struct bpf_lru_node, list);
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list_for_each_entry_safe_reverse(node, tmp_node, active, list) {
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if (bpf_lru_node_is_ref(node))
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__bpf_lru_node_move(l, node, BPF_LRU_LIST_T_ACTIVE);
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else
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__bpf_lru_node_move(l, node, BPF_LRU_LIST_T_INACTIVE);
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if (++i == lru->nr_scans || node == first_node)
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break;
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}
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}
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/* Rotate the inactive list. It starts from the next_inactive_rotation
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* 1. If the node has ref bit set, it will be moved to the head
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* of active list with the ref bit cleared.
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* 2. If the node does not have ref bit set, it will leave it
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* at its current location (i.e. do nothing) so that it can
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* be considered during the next inactive_shrink.
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* 3. It will at most scan nr_scans nodes
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*/
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static void __bpf_lru_list_rotate_inactive(struct bpf_lru *lru,
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struct bpf_lru_list *l)
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{
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struct list_head *inactive = &l->lists[BPF_LRU_LIST_T_INACTIVE];
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struct list_head *cur, *last, *next = inactive;
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struct bpf_lru_node *node;
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unsigned int i = 0;
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if (list_empty(inactive))
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return;
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last = l->next_inactive_rotation->next;
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if (last == inactive)
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last = last->next;
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cur = l->next_inactive_rotation;
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while (i < lru->nr_scans) {
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if (cur == inactive) {
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cur = cur->prev;
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continue;
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}
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node = list_entry(cur, struct bpf_lru_node, list);
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next = cur->prev;
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if (bpf_lru_node_is_ref(node))
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__bpf_lru_node_move(l, node, BPF_LRU_LIST_T_ACTIVE);
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if (cur == last)
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break;
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cur = next;
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i++;
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}
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l->next_inactive_rotation = next;
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}
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/* Shrink the inactive list. It starts from the tail of the
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* inactive list and only move the nodes without the ref bit
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* set to the designated free list.
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*/
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static unsigned int
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__bpf_lru_list_shrink_inactive(struct bpf_lru *lru,
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struct bpf_lru_list *l,
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unsigned int tgt_nshrink,
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struct list_head *free_list,
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enum bpf_lru_list_type tgt_free_type)
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{
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struct list_head *inactive = &l->lists[BPF_LRU_LIST_T_INACTIVE];
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struct bpf_lru_node *node, *tmp_node;
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unsigned int nshrinked = 0;
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unsigned int i = 0;
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list_for_each_entry_safe_reverse(node, tmp_node, inactive, list) {
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if (bpf_lru_node_is_ref(node)) {
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__bpf_lru_node_move(l, node, BPF_LRU_LIST_T_ACTIVE);
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} else if (lru->del_from_htab(lru->del_arg, node)) {
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__bpf_lru_node_move_to_free(l, node, free_list,
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tgt_free_type);
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if (++nshrinked == tgt_nshrink)
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break;
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}
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if (++i == lru->nr_scans)
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break;
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}
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return nshrinked;
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}
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/* 1. Rotate the active list (if needed)
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* 2. Always rotate the inactive list
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*/
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static void __bpf_lru_list_rotate(struct bpf_lru *lru, struct bpf_lru_list *l)
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{
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if (bpf_lru_list_inactive_low(l))
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__bpf_lru_list_rotate_active(lru, l);
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__bpf_lru_list_rotate_inactive(lru, l);
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}
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/* Calls __bpf_lru_list_shrink_inactive() to shrink some
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* ref-bit-cleared nodes and move them to the designated
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* free list.
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*
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* If it cannot get a free node after calling
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* __bpf_lru_list_shrink_inactive(). It will just remove
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* one node from either inactive or active list without
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* honoring the ref-bit. It prefers inactive list to active
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* list in this situation.
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*/
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static unsigned int __bpf_lru_list_shrink(struct bpf_lru *lru,
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struct bpf_lru_list *l,
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unsigned int tgt_nshrink,
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struct list_head *free_list,
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enum bpf_lru_list_type tgt_free_type)
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{
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struct bpf_lru_node *node, *tmp_node;
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struct list_head *force_shrink_list;
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unsigned int nshrinked;
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nshrinked = __bpf_lru_list_shrink_inactive(lru, l, tgt_nshrink,
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free_list, tgt_free_type);
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if (nshrinked)
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return nshrinked;
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/* Do a force shrink by ignoring the reference bit */
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if (!list_empty(&l->lists[BPF_LRU_LIST_T_INACTIVE]))
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force_shrink_list = &l->lists[BPF_LRU_LIST_T_INACTIVE];
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else
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force_shrink_list = &l->lists[BPF_LRU_LIST_T_ACTIVE];
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list_for_each_entry_safe_reverse(node, tmp_node, force_shrink_list,
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list) {
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if (lru->del_from_htab(lru->del_arg, node)) {
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__bpf_lru_node_move_to_free(l, node, free_list,
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tgt_free_type);
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return 1;
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}
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}
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return 0;
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}
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/* Flush the nodes from the local pending list to the LRU list */
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static void __local_list_flush(struct bpf_lru_list *l,
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struct bpf_lru_locallist *loc_l)
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{
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struct bpf_lru_node *node, *tmp_node;
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list_for_each_entry_safe_reverse(node, tmp_node,
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local_pending_list(loc_l), list) {
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if (bpf_lru_node_is_ref(node))
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__bpf_lru_node_move_in(l, node, BPF_LRU_LIST_T_ACTIVE);
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else
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__bpf_lru_node_move_in(l, node,
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BPF_LRU_LIST_T_INACTIVE);
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}
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}
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static void bpf_lru_list_push_free(struct bpf_lru_list *l,
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struct bpf_lru_node *node)
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{
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unsigned long flags;
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if (WARN_ON_ONCE(IS_LOCAL_LIST_TYPE(node->type)))
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return;
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raw_spin_lock_irqsave(&l->lock, flags);
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__bpf_lru_node_move(l, node, BPF_LRU_LIST_T_FREE);
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raw_spin_unlock_irqrestore(&l->lock, flags);
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}
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static void bpf_lru_list_pop_free_to_local(struct bpf_lru *lru,
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struct bpf_lru_locallist *loc_l)
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{
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struct bpf_lru_list *l = &lru->common_lru.lru_list;
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struct bpf_lru_node *node, *tmp_node;
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unsigned int nfree = 0;
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raw_spin_lock(&l->lock);
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__local_list_flush(l, loc_l);
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__bpf_lru_list_rotate(lru, l);
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list_for_each_entry_safe(node, tmp_node, &l->lists[BPF_LRU_LIST_T_FREE],
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list) {
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__bpf_lru_node_move_to_free(l, node, local_free_list(loc_l),
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BPF_LRU_LOCAL_LIST_T_FREE);
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if (++nfree == LOCAL_FREE_TARGET)
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break;
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}
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if (nfree < LOCAL_FREE_TARGET)
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__bpf_lru_list_shrink(lru, l, LOCAL_FREE_TARGET - nfree,
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local_free_list(loc_l),
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BPF_LRU_LOCAL_LIST_T_FREE);
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raw_spin_unlock(&l->lock);
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}
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static void __local_list_add_pending(struct bpf_lru *lru,
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struct bpf_lru_locallist *loc_l,
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int cpu,
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struct bpf_lru_node *node,
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u32 hash)
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{
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*(u32 *)((void *)node + lru->hash_offset) = hash;
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node->cpu = cpu;
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node->type = BPF_LRU_LOCAL_LIST_T_PENDING;
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node->ref = 0;
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list_add(&node->list, local_pending_list(loc_l));
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}
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static struct bpf_lru_node *
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__local_list_pop_free(struct bpf_lru_locallist *loc_l)
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{
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struct bpf_lru_node *node;
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node = list_first_entry_or_null(local_free_list(loc_l),
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struct bpf_lru_node,
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list);
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if (node)
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list_del(&node->list);
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return node;
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}
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static struct bpf_lru_node *
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__local_list_pop_pending(struct bpf_lru *lru, struct bpf_lru_locallist *loc_l)
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{
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struct bpf_lru_node *node;
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bool force = false;
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ignore_ref:
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/* Get from the tail (i.e. older element) of the pending list. */
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list_for_each_entry_reverse(node, local_pending_list(loc_l),
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list) {
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if ((!bpf_lru_node_is_ref(node) || force) &&
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lru->del_from_htab(lru->del_arg, node)) {
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list_del(&node->list);
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return node;
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}
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}
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if (!force) {
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force = true;
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goto ignore_ref;
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}
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return NULL;
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}
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static struct bpf_lru_node *bpf_percpu_lru_pop_free(struct bpf_lru *lru,
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u32 hash)
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{
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struct list_head *free_list;
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struct bpf_lru_node *node = NULL;
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struct bpf_lru_list *l;
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unsigned long flags;
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int cpu = raw_smp_processor_id();
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l = per_cpu_ptr(lru->percpu_lru, cpu);
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raw_spin_lock_irqsave(&l->lock, flags);
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__bpf_lru_list_rotate(lru, l);
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free_list = &l->lists[BPF_LRU_LIST_T_FREE];
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if (list_empty(free_list))
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__bpf_lru_list_shrink(lru, l, PERCPU_FREE_TARGET, free_list,
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BPF_LRU_LIST_T_FREE);
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if (!list_empty(free_list)) {
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node = list_first_entry(free_list, struct bpf_lru_node, list);
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*(u32 *)((void *)node + lru->hash_offset) = hash;
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node->ref = 0;
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__bpf_lru_node_move(l, node, BPF_LRU_LIST_T_INACTIVE);
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}
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raw_spin_unlock_irqrestore(&l->lock, flags);
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return node;
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}
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static struct bpf_lru_node *bpf_common_lru_pop_free(struct bpf_lru *lru,
|
|
u32 hash)
|
|
{
|
|
struct bpf_lru_locallist *loc_l, *steal_loc_l;
|
|
struct bpf_common_lru *clru = &lru->common_lru;
|
|
struct bpf_lru_node *node;
|
|
int steal, first_steal;
|
|
unsigned long flags;
|
|
int cpu = raw_smp_processor_id();
|
|
|
|
loc_l = per_cpu_ptr(clru->local_list, cpu);
|
|
|
|
raw_spin_lock_irqsave(&loc_l->lock, flags);
|
|
|
|
node = __local_list_pop_free(loc_l);
|
|
if (!node) {
|
|
bpf_lru_list_pop_free_to_local(lru, loc_l);
|
|
node = __local_list_pop_free(loc_l);
|
|
}
|
|
|
|
if (node)
|
|
__local_list_add_pending(lru, loc_l, cpu, node, hash);
|
|
|
|
raw_spin_unlock_irqrestore(&loc_l->lock, flags);
|
|
|
|
if (node)
|
|
return node;
|
|
|
|
/* No free nodes found from the local free list and
|
|
* the global LRU list.
|
|
*
|
|
* Steal from the local free/pending list of the
|
|
* current CPU and remote CPU in RR. It starts
|
|
* with the loc_l->next_steal CPU.
|
|
*/
|
|
|
|
first_steal = loc_l->next_steal;
|
|
steal = first_steal;
|
|
do {
|
|
steal_loc_l = per_cpu_ptr(clru->local_list, steal);
|
|
|
|
raw_spin_lock_irqsave(&steal_loc_l->lock, flags);
|
|
|
|
node = __local_list_pop_free(steal_loc_l);
|
|
if (!node)
|
|
node = __local_list_pop_pending(lru, steal_loc_l);
|
|
|
|
raw_spin_unlock_irqrestore(&steal_loc_l->lock, flags);
|
|
|
|
steal = get_next_cpu(steal);
|
|
} while (!node && steal != first_steal);
|
|
|
|
loc_l->next_steal = steal;
|
|
|
|
if (node) {
|
|
raw_spin_lock_irqsave(&loc_l->lock, flags);
|
|
__local_list_add_pending(lru, loc_l, cpu, node, hash);
|
|
raw_spin_unlock_irqrestore(&loc_l->lock, flags);
|
|
}
|
|
|
|
return node;
|
|
}
|
|
|
|
struct bpf_lru_node *bpf_lru_pop_free(struct bpf_lru *lru, u32 hash)
|
|
{
|
|
if (lru->percpu)
|
|
return bpf_percpu_lru_pop_free(lru, hash);
|
|
else
|
|
return bpf_common_lru_pop_free(lru, hash);
|
|
}
|
|
|
|
static void bpf_common_lru_push_free(struct bpf_lru *lru,
|
|
struct bpf_lru_node *node)
|
|
{
|
|
unsigned long flags;
|
|
|
|
if (WARN_ON_ONCE(node->type == BPF_LRU_LIST_T_FREE) ||
|
|
WARN_ON_ONCE(node->type == BPF_LRU_LOCAL_LIST_T_FREE))
|
|
return;
|
|
|
|
if (node->type == BPF_LRU_LOCAL_LIST_T_PENDING) {
|
|
struct bpf_lru_locallist *loc_l;
|
|
|
|
loc_l = per_cpu_ptr(lru->common_lru.local_list, node->cpu);
|
|
|
|
raw_spin_lock_irqsave(&loc_l->lock, flags);
|
|
|
|
if (unlikely(node->type != BPF_LRU_LOCAL_LIST_T_PENDING)) {
|
|
raw_spin_unlock_irqrestore(&loc_l->lock, flags);
|
|
goto check_lru_list;
|
|
}
|
|
|
|
node->type = BPF_LRU_LOCAL_LIST_T_FREE;
|
|
node->ref = 0;
|
|
list_move(&node->list, local_free_list(loc_l));
|
|
|
|
raw_spin_unlock_irqrestore(&loc_l->lock, flags);
|
|
return;
|
|
}
|
|
|
|
check_lru_list:
|
|
bpf_lru_list_push_free(&lru->common_lru.lru_list, node);
|
|
}
|
|
|
|
static void bpf_percpu_lru_push_free(struct bpf_lru *lru,
|
|
struct bpf_lru_node *node)
|
|
{
|
|
struct bpf_lru_list *l;
|
|
unsigned long flags;
|
|
|
|
l = per_cpu_ptr(lru->percpu_lru, node->cpu);
|
|
|
|
raw_spin_lock_irqsave(&l->lock, flags);
|
|
|
|
__bpf_lru_node_move(l, node, BPF_LRU_LIST_T_FREE);
|
|
|
|
raw_spin_unlock_irqrestore(&l->lock, flags);
|
|
}
|
|
|
|
void bpf_lru_push_free(struct bpf_lru *lru, struct bpf_lru_node *node)
|
|
{
|
|
if (lru->percpu)
|
|
bpf_percpu_lru_push_free(lru, node);
|
|
else
|
|
bpf_common_lru_push_free(lru, node);
|
|
}
|
|
|
|
static void bpf_common_lru_populate(struct bpf_lru *lru, void *buf,
|
|
u32 node_offset, u32 elem_size,
|
|
u32 nr_elems)
|
|
{
|
|
struct bpf_lru_list *l = &lru->common_lru.lru_list;
|
|
u32 i;
|
|
|
|
for (i = 0; i < nr_elems; i++) {
|
|
struct bpf_lru_node *node;
|
|
|
|
node = (struct bpf_lru_node *)(buf + node_offset);
|
|
node->type = BPF_LRU_LIST_T_FREE;
|
|
node->ref = 0;
|
|
list_add(&node->list, &l->lists[BPF_LRU_LIST_T_FREE]);
|
|
buf += elem_size;
|
|
}
|
|
}
|
|
|
|
static void bpf_percpu_lru_populate(struct bpf_lru *lru, void *buf,
|
|
u32 node_offset, u32 elem_size,
|
|
u32 nr_elems)
|
|
{
|
|
u32 i, pcpu_entries;
|
|
int cpu;
|
|
struct bpf_lru_list *l;
|
|
|
|
pcpu_entries = nr_elems / num_possible_cpus();
|
|
|
|
i = 0;
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
struct bpf_lru_node *node;
|
|
|
|
l = per_cpu_ptr(lru->percpu_lru, cpu);
|
|
again:
|
|
node = (struct bpf_lru_node *)(buf + node_offset);
|
|
node->cpu = cpu;
|
|
node->type = BPF_LRU_LIST_T_FREE;
|
|
node->ref = 0;
|
|
list_add(&node->list, &l->lists[BPF_LRU_LIST_T_FREE]);
|
|
i++;
|
|
buf += elem_size;
|
|
if (i == nr_elems)
|
|
break;
|
|
if (i % pcpu_entries)
|
|
goto again;
|
|
}
|
|
}
|
|
|
|
void bpf_lru_populate(struct bpf_lru *lru, void *buf, u32 node_offset,
|
|
u32 elem_size, u32 nr_elems)
|
|
{
|
|
if (lru->percpu)
|
|
bpf_percpu_lru_populate(lru, buf, node_offset, elem_size,
|
|
nr_elems);
|
|
else
|
|
bpf_common_lru_populate(lru, buf, node_offset, elem_size,
|
|
nr_elems);
|
|
}
|
|
|
|
static void bpf_lru_locallist_init(struct bpf_lru_locallist *loc_l, int cpu)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < NR_BPF_LRU_LOCAL_LIST_T; i++)
|
|
INIT_LIST_HEAD(&loc_l->lists[i]);
|
|
|
|
loc_l->next_steal = cpu;
|
|
|
|
raw_spin_lock_init(&loc_l->lock);
|
|
}
|
|
|
|
static void bpf_lru_list_init(struct bpf_lru_list *l)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < NR_BPF_LRU_LIST_T; i++)
|
|
INIT_LIST_HEAD(&l->lists[i]);
|
|
|
|
for (i = 0; i < NR_BPF_LRU_LIST_COUNT; i++)
|
|
l->counts[i] = 0;
|
|
|
|
l->next_inactive_rotation = &l->lists[BPF_LRU_LIST_T_INACTIVE];
|
|
|
|
raw_spin_lock_init(&l->lock);
|
|
}
|
|
|
|
int bpf_lru_init(struct bpf_lru *lru, bool percpu, u32 hash_offset,
|
|
del_from_htab_func del_from_htab, void *del_arg)
|
|
{
|
|
int cpu;
|
|
|
|
if (percpu) {
|
|
lru->percpu_lru = alloc_percpu(struct bpf_lru_list);
|
|
if (!lru->percpu_lru)
|
|
return -ENOMEM;
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
struct bpf_lru_list *l;
|
|
|
|
l = per_cpu_ptr(lru->percpu_lru, cpu);
|
|
bpf_lru_list_init(l);
|
|
}
|
|
lru->nr_scans = PERCPU_NR_SCANS;
|
|
} else {
|
|
struct bpf_common_lru *clru = &lru->common_lru;
|
|
|
|
clru->local_list = alloc_percpu(struct bpf_lru_locallist);
|
|
if (!clru->local_list)
|
|
return -ENOMEM;
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
struct bpf_lru_locallist *loc_l;
|
|
|
|
loc_l = per_cpu_ptr(clru->local_list, cpu);
|
|
bpf_lru_locallist_init(loc_l, cpu);
|
|
}
|
|
|
|
bpf_lru_list_init(&clru->lru_list);
|
|
lru->nr_scans = LOCAL_NR_SCANS;
|
|
}
|
|
|
|
lru->percpu = percpu;
|
|
lru->del_from_htab = del_from_htab;
|
|
lru->del_arg = del_arg;
|
|
lru->hash_offset = hash_offset;
|
|
|
|
return 0;
|
|
}
|
|
|
|
void bpf_lru_destroy(struct bpf_lru *lru)
|
|
{
|
|
if (lru->percpu)
|
|
free_percpu(lru->percpu_lru);
|
|
else
|
|
free_percpu(lru->common_lru.local_list);
|
|
}
|