[RFC,2/4] net: dropreason: use new __print_sym() in tracing
Commit Message
From: Johannes Berg <johannes.berg@intel.com>
The __print_symbolic() could only ever print the core
drop reasons, since that's the way the infrastructure
works. Now that we have __print_sym() with all the
advantages mentioned in that commit, convert to that
and get all the drop reasons from all subsystems. As
we already have a list of them, that's really easy.
This is a little bit of .text (~100 bytes in my build)
and saves a lot of .data (~17k).
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
include/net/dropreason.h | 5 +++++
include/trace/events/skb.h | 16 +++-----------
net/core/skbuff.c | 43 ++++++++++++++++++++++++++++++++++++++
3 files changed, 51 insertions(+), 13 deletions(-)
@@ -42,6 +42,11 @@ struct drop_reason_list {
extern const struct drop_reason_list __rcu *
drop_reasons_by_subsys[SKB_DROP_REASON_SUBSYS_NUM];
+#ifdef CONFIG_TRACEPOINTS
+const char *drop_reason_lookup(unsigned long long value);
+void drop_reason_show(struct seq_file *m);
+#endif
+
void drop_reasons_register_subsys(enum skb_drop_reason_subsys subsys,
const struct drop_reason_list *list);
void drop_reasons_unregister_subsys(enum skb_drop_reason_subsys subsys);
@@ -8,15 +8,9 @@
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/tracepoint.h>
+#include <net/dropreason.h>
-#undef FN
-#define FN(reason) TRACE_DEFINE_ENUM(SKB_DROP_REASON_##reason);
-DEFINE_DROP_REASON(FN, FN)
-
-#undef FN
-#undef FNe
-#define FN(reason) { SKB_DROP_REASON_##reason, #reason },
-#define FNe(reason) { SKB_DROP_REASON_##reason, #reason }
+TRACE_DEFINE_SYM_FNS(drop_reason, drop_reason_lookup, drop_reason_show);
/*
* Tracepoint for free an sk_buff:
@@ -44,13 +38,9 @@ TRACE_EVENT(kfree_skb,
TP_printk("skbaddr=%p protocol=%u location=%pS reason: %s",
__entry->skbaddr, __entry->protocol, __entry->location,
- __print_symbolic(__entry->reason,
- DEFINE_DROP_REASON(FN, FNe)))
+ __print_sym(__entry->reason, drop_reason ))
);
-#undef FN
-#undef FNe
-
TRACE_EVENT(consume_skb,
TP_PROTO(struct sk_buff *skb, void *location),
@@ -132,6 +132,49 @@ drop_reasons_by_subsys[SKB_DROP_REASON_SUBSYS_NUM] = {
};
EXPORT_SYMBOL(drop_reasons_by_subsys);
+#ifdef CONFIG_TRACEPOINTS
+const char *drop_reason_lookup(unsigned long long value)
+{
+ unsigned long long subsys_id = value >> SKB_DROP_REASON_SUBSYS_SHIFT;
+ u32 reason = value & ~SKB_DROP_REASON_SUBSYS_MASK;
+ const struct drop_reason_list *subsys;
+
+ if (subsys_id >= SKB_DROP_REASON_SUBSYS_NUM)
+ return NULL;
+
+ subsys = rcu_dereference(drop_reasons_by_subsys[subsys_id]);
+ if (!subsys)
+ return NULL;
+ if (reason >= subsys->n_reasons)
+ return NULL;
+ return subsys->reasons[reason];
+}
+
+void drop_reason_show(struct seq_file *m)
+{
+ u32 subsys_id;
+
+ rcu_read_lock();
+ for (subsys_id = 0; subsys_id < SKB_DROP_REASON_SUBSYS_NUM; subsys_id++) {
+ const struct drop_reason_list *subsys;
+ u32 i;
+
+ subsys = rcu_dereference(drop_reasons_by_subsys[subsys_id]);
+ if (!subsys)
+ continue;
+
+ for (i = 0; i < subsys->n_reasons; i++) {
+ if (!subsys->reasons[i])
+ continue;
+ seq_printf(m, ", { %u, \"%s\" }",
+ (subsys_id << SKB_DROP_REASON_SUBSYS_SHIFT) | i,
+ subsys->reasons[i]);
+ }
+ }
+ rcu_read_unlock();
+}
+#endif
+
/**
* drop_reasons_register_subsys - register another drop reason subsystem
* @subsys: the subsystem to register, must not be the core