diff options
Diffstat (limited to 'net/core/dst.c')
| -rw-r--r-- | net/core/dst.c | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/net/core/dst.c b/net/core/dst.c index 092861133023..45452fa62e24 100644 --- a/net/core/dst.c +++ b/net/core/dst.c @@ -44,6 +44,82 @@ const struct dst_metrics dst_default_metrics = { }; EXPORT_SYMBOL(dst_default_metrics); +#ifdef CONFIG_NET_DEV_REFCNT_TRACKER + +#define DST_TRACE_BUFFER_SIZE 8192 +static struct dst_trace_buffer { + struct dst_entry *dst; // no-ref + struct net_device *ndev; // no-ref + int seq; + int delta; + u32 caller_id; + int nr_entries; + unsigned long entries[20]; +} dst_trace_buffer[DST_TRACE_BUFFER_SIZE]; +static bool dst_trace_buffer_exhausted; + +void dump_dst_trace_buffer(const struct net_device *ndev) +{ + struct dst_trace_buffer *ptr; + int count, balance = 0; + int i; + + for (i = 0; i < DST_TRACE_BUFFER_SIZE; i++) { + ptr = &dst_trace_buffer[i]; + if (!ptr->dst || ptr->ndev != ndev) + continue; + count = ptr->delta; + balance += count; + pr_info("Call trace for %s@%p[%d] %+d %c%u at\n", ndev->name, ptr->dst, ptr->seq, + count, ptr->caller_id & 0x80000000 ? 'C' : 'T', + ptr->caller_id & ~0x80000000); + stack_trace_print(ptr->entries, ptr->nr_entries, 4); + } + if (!dst_trace_buffer_exhausted) + pr_info("balance for %s@dst_entry is %d\n", ndev->name, balance); + else + pr_info("balance for %s@dst_entry is unknown\n", ndev->name); +} + +static void erase_dst_trace_buffer(struct dst_entry *dst) +{ + int i; + + for (i = 0; i < DST_TRACE_BUFFER_SIZE; i++) + if (dst_trace_buffer[i].dst == dst) + dst_trace_buffer[i].dst = NULL; +} + +void save_dst_trace_buffer(struct dst_entry *dst, int delta) +{ + struct dst_trace_buffer *ptr; + unsigned long entries[ARRAY_SIZE(ptr->entries)]; + unsigned long nr_entries; + int i; + + if (!dst->dev) + return; + nr_entries = stack_trace_save(entries, ARRAY_SIZE(ptr->entries), 1); + nr_entries = trim_netdev_trace(entries, nr_entries); + for (i = 0; i < DST_TRACE_BUFFER_SIZE; i++) { + ptr = &dst_trace_buffer[i]; + if (!ptr->dst && !cmpxchg(&ptr->dst, NULL, dst)) { + ptr->ndev = dst->dev; + ptr->seq = atomic_inc_return(&dst->dst_trace_seq); + ptr->delta = delta; + ptr->caller_id = in_task() ? task_pid_nr(current) : + 0x80000000 + raw_smp_processor_id(); + ptr->nr_entries = nr_entries; + memmove(ptr->entries, entries, nr_entries * sizeof(unsigned long)); + return; + } + } + dst_trace_buffer_exhausted = true; +} +EXPORT_SYMBOL(save_dst_trace_buffer); + +#endif + void dst_init(struct dst_entry *dst, struct dst_ops *ops, struct net_device *dev, int initial_obsolete, unsigned short flags) @@ -67,6 +143,7 @@ void dst_init(struct dst_entry *dst, struct dst_ops *ops, #endif dst->lwtstate = NULL; rcuref_init(&dst->__rcuref, 1); + save_dst_trace_buffer(dst, 1); INIT_LIST_HEAD(&dst->rt_uncached); dst->rt_uncached_list = NULL; dst->__use = 0; @@ -116,6 +193,10 @@ static void dst_destroy(struct dst_entry *dst) lwtstate_put(dst->lwtstate); +#ifdef CONFIG_NET_DEV_REFCNT_TRACKER + erase_dst_trace_buffer(dst); +#endif + if (dst->flags & DST_METADATA) metadata_dst_free((struct metadata_dst *)dst); else @@ -165,6 +246,8 @@ static void dst_count_dec(struct dst_entry *dst) void dst_release(struct dst_entry *dst) { + if (dst) + save_dst_trace_buffer(dst, -1); if (dst && rcuref_put(&dst->__rcuref)) { #ifdef CONFIG_DST_CACHE if (dst->flags & DST_METADATA) { @@ -182,6 +265,8 @@ EXPORT_SYMBOL(dst_release); void dst_release_immediate(struct dst_entry *dst) { + if (dst) + save_dst_trace_buffer(dst, -1); if (dst && rcuref_put(&dst->__rcuref)) { dst_count_dec(dst); dst_destroy(dst); |