diff options
Diffstat (limited to 'kernel/bpf/cpumap.c')
| -rw-r--r-- | kernel/bpf/cpumap.c | 105 |
1 files changed, 48 insertions, 57 deletions
diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c index 8dff08768087..ef49e17ae47c 100644 --- a/kernel/bpf/cpumap.c +++ b/kernel/bpf/cpumap.c @@ -32,14 +32,19 @@ /* General idea: XDP packets getting XDP redirected to another CPU, * will maximum be stored/queued for one driver ->poll() call. It is - * guaranteed that setting flush bit and flush operation happen on + * guaranteed that queueing the frame and the flush operation happen on * same CPU. Thus, cpu_map_flush operation can deduct via this_cpu_ptr() * which queue in bpf_cpu_map_entry contains packets. */ #define CPU_MAP_BULK_SIZE 8 /* 8 == one cacheline on 64-bit archs */ +struct bpf_cpu_map_entry; +struct bpf_cpu_map; + struct xdp_bulk_queue { void *q[CPU_MAP_BULK_SIZE]; + struct list_head flush_node; + struct bpf_cpu_map_entry *obj; unsigned int count; }; @@ -52,6 +57,8 @@ struct bpf_cpu_map_entry { /* XDP can run multiple RX-ring queues, need __percpu enqueue store */ struct xdp_bulk_queue __percpu *bulkq; + struct bpf_cpu_map *cmap; + /* Queue with potential multi-producers, and single-consumer kthread */ struct ptr_ring *queue; struct task_struct *kthread; @@ -65,23 +72,17 @@ struct bpf_cpu_map { struct bpf_map map; /* Below members specific for map type */ struct bpf_cpu_map_entry **cpu_map; - unsigned long __percpu *flush_needed; + struct list_head __percpu *flush_list; }; -static int bq_flush_to_queue(struct bpf_cpu_map_entry *rcpu, - struct xdp_bulk_queue *bq, bool in_napi_ctx); - -static u64 cpu_map_bitmap_size(const union bpf_attr *attr) -{ - return BITS_TO_LONGS(attr->max_entries) * sizeof(unsigned long); -} +static int bq_flush_to_queue(struct xdp_bulk_queue *bq, bool in_napi_ctx); static struct bpf_map *cpu_map_alloc(union bpf_attr *attr) { struct bpf_cpu_map *cmap; int err = -ENOMEM; + int ret, cpu; u64 cost; - int ret; if (!capable(CAP_SYS_ADMIN)) return ERR_PTR(-EPERM); @@ -105,7 +106,7 @@ static struct bpf_map *cpu_map_alloc(union bpf_attr *attr) /* make sure page count doesn't overflow */ cost = (u64) cmap->map.max_entries * sizeof(struct bpf_cpu_map_entry *); - cost += cpu_map_bitmap_size(attr) * num_possible_cpus(); + cost += sizeof(struct list_head) * num_possible_cpus(); /* Notice returns -EPERM on if map size is larger than memlock limit */ ret = bpf_map_charge_init(&cmap->map.memory, cost); @@ -114,12 +115,13 @@ static struct bpf_map *cpu_map_alloc(union bpf_attr *attr) goto free_cmap; } - /* A per cpu bitfield with a bit per possible CPU in map */ - cmap->flush_needed = __alloc_percpu(cpu_map_bitmap_size(attr), - __alignof__(unsigned long)); - if (!cmap->flush_needed) + cmap->flush_list = alloc_percpu(struct list_head); + if (!cmap->flush_list) goto free_charge; + for_each_possible_cpu(cpu) + INIT_LIST_HEAD(per_cpu_ptr(cmap->flush_list, cpu)); + /* Alloc array for possible remote "destination" CPUs */ cmap->cpu_map = bpf_map_area_alloc(cmap->map.max_entries * sizeof(struct bpf_cpu_map_entry *), @@ -129,7 +131,7 @@ static struct bpf_map *cpu_map_alloc(union bpf_attr *attr) return &cmap->map; free_percpu: - free_percpu(cmap->flush_needed); + free_percpu(cmap->flush_list); free_charge: bpf_map_charge_finish(&cmap->map.memory); free_cmap: @@ -334,7 +336,8 @@ static struct bpf_cpu_map_entry *__cpu_map_entry_alloc(u32 qsize, u32 cpu, { gfp_t gfp = GFP_KERNEL | __GFP_NOWARN; struct bpf_cpu_map_entry *rcpu; - int numa, err; + struct xdp_bulk_queue *bq; + int numa, err, i; /* Have map->numa_node, but choose node of redirect target CPU */ numa = cpu_to_node(cpu); @@ -349,6 +352,11 @@ static struct bpf_cpu_map_entry *__cpu_map_entry_alloc(u32 qsize, u32 cpu, if (!rcpu->bulkq) goto free_rcu; + for_each_possible_cpu(i) { + bq = per_cpu_ptr(rcpu->bulkq, i); + bq->obj = rcpu; + } + /* Alloc queue */ rcpu->queue = kzalloc_node(sizeof(*rcpu->queue), gfp, numa); if (!rcpu->queue) @@ -405,7 +413,7 @@ static void __cpu_map_entry_free(struct rcu_head *rcu) struct xdp_bulk_queue *bq = per_cpu_ptr(rcpu->bulkq, cpu); /* No concurrent bq_enqueue can run at this point */ - bq_flush_to_queue(rcpu, bq, false); + bq_flush_to_queue(bq, false); } free_percpu(rcpu->bulkq); /* Cannot kthread_stop() here, last put free rcpu resources */ @@ -488,6 +496,7 @@ static int cpu_map_update_elem(struct bpf_map *map, void *key, void *value, rcpu = __cpu_map_entry_alloc(qsize, key_cpu, map->id); if (!rcpu) return -ENOMEM; + rcpu->cmap = cmap; } rcu_read_lock(); __cpu_map_entry_replace(cmap, key_cpu, rcpu); @@ -514,14 +523,14 @@ static void cpu_map_free(struct bpf_map *map) synchronize_rcu(); /* To ensure all pending flush operations have completed wait for flush - * bitmap to indicate all flush_needed bits to be zero on _all_ cpus. - * Because the above synchronize_rcu() ensures the map is disconnected - * from the program we can assume no new bits will be set. + * list be empty on _all_ cpus. Because the above synchronize_rcu() + * ensures the map is disconnected from the program we can assume no new + * items will be added to the list. */ for_each_online_cpu(cpu) { - unsigned long *bitmap = per_cpu_ptr(cmap->flush_needed, cpu); + struct list_head *flush_list = per_cpu_ptr(cmap->flush_list, cpu); - while (!bitmap_empty(bitmap, cmap->map.max_entries)) + while (!list_empty(flush_list)) cond_resched(); } @@ -538,7 +547,7 @@ static void cpu_map_free(struct bpf_map *map) /* bq flush and cleanup happens after RCU graze-period */ __cpu_map_entry_replace(cmap, i, NULL); /* call_rcu */ } - free_percpu(cmap->flush_needed); + free_percpu(cmap->flush_list); bpf_map_area_free(cmap->cpu_map); kfree(cmap); } @@ -590,9 +599,9 @@ const struct bpf_map_ops cpu_map_ops = { .map_check_btf = map_check_no_btf, }; -static int bq_flush_to_queue(struct bpf_cpu_map_entry *rcpu, - struct xdp_bulk_queue *bq, bool in_napi_ctx) +static int bq_flush_to_queue(struct xdp_bulk_queue *bq, bool in_napi_ctx) { + struct bpf_cpu_map_entry *rcpu = bq->obj; unsigned int processed = 0, drops = 0; const int to_cpu = rcpu->cpu; struct ptr_ring *q; @@ -621,6 +630,8 @@ static int bq_flush_to_queue(struct bpf_cpu_map_entry *rcpu, bq->count = 0; spin_unlock(&q->producer_lock); + __list_del_clearprev(&bq->flush_node); + /* Feedback loop via tracepoints */ trace_xdp_cpumap_enqueue(rcpu->map_id, processed, drops, to_cpu); return 0; @@ -631,10 +642,11 @@ static int bq_flush_to_queue(struct bpf_cpu_map_entry *rcpu, */ static int bq_enqueue(struct bpf_cpu_map_entry *rcpu, struct xdp_frame *xdpf) { + struct list_head *flush_list = this_cpu_ptr(rcpu->cmap->flush_list); struct xdp_bulk_queue *bq = this_cpu_ptr(rcpu->bulkq); if (unlikely(bq->count == CPU_MAP_BULK_SIZE)) - bq_flush_to_queue(rcpu, bq, true); + bq_flush_to_queue(bq, true); /* Notice, xdp_buff/page MUST be queued here, long enough for * driver to code invoking us to finished, due to driver @@ -646,6 +658,10 @@ static int bq_enqueue(struct bpf_cpu_map_entry *rcpu, struct xdp_frame *xdpf) * operation, when completing napi->poll call. */ bq->q[bq->count++] = xdpf; + + if (!bq->flush_node.prev) + list_add(&bq->flush_node, flush_list); + return 0; } @@ -665,41 +681,16 @@ int cpu_map_enqueue(struct bpf_cpu_map_entry *rcpu, struct xdp_buff *xdp, return 0; } -void __cpu_map_insert_ctx(struct bpf_map *map, u32 bit) -{ - struct bpf_cpu_map *cmap = container_of(map, struct bpf_cpu_map, map); - unsigned long *bitmap = this_cpu_ptr(cmap->flush_needed); - - __set_bit(bit, bitmap); -} - void __cpu_map_flush(struct bpf_map *map) { struct bpf_cpu_map *cmap = container_of(map, struct bpf_cpu_map, map); - unsigned long *bitmap = this_cpu_ptr(cmap->flush_needed); - u32 bit; - - /* The napi->poll softirq makes sure __cpu_map_insert_ctx() - * and __cpu_map_flush() happen on same CPU. Thus, the percpu - * bitmap indicate which percpu bulkq have packets. - */ - for_each_set_bit(bit, bitmap, map->max_entries) { - struct bpf_cpu_map_entry *rcpu = READ_ONCE(cmap->cpu_map[bit]); - struct xdp_bulk_queue *bq; - - /* This is possible if entry is removed by user space - * between xdp redirect and flush op. - */ - if (unlikely(!rcpu)) - continue; - - __clear_bit(bit, bitmap); + struct list_head *flush_list = this_cpu_ptr(cmap->flush_list); + struct xdp_bulk_queue *bq, *tmp; - /* Flush all frames in bulkq to real queue */ - bq = this_cpu_ptr(rcpu->bulkq); - bq_flush_to_queue(rcpu, bq, true); + list_for_each_entry_safe(bq, tmp, flush_list, flush_node) { + bq_flush_to_queue(bq, true); /* If already running, costs spin_lock_irqsave + smb_mb */ - wake_up_process(rcpu->kthread); + wake_up_process(bq->obj->kthread); } } |