| Message ID | 20220204140813.4007173-1-imagedong@tencent.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [v5,net-next] net: drop_monitor: support drop reason | expand |
On Fri, Feb 4, 2022 at 10:08 PM <menglong8.dong@gmail.com> wrote: > > From: Menglong Dong <imagedong@tencent.com> > > In the commit c504e5c2f964 ("net: skb: introduce kfree_skb_reason()") > drop reason is introduced to the tracepoint of kfree_skb. Therefore, > drop_monitor is able to report the drop reason to users by netlink. > > The drop reasons are reported as string to users, which is exactly > the same as what we do when reporting it to ftrace. > > Signed-off-by: Menglong Dong <imagedong@tencent.com> > --- > v5: > - check if drop reason larger than SKB_DROP_REASON_MAX > > v4: > - report drop reasons as string > > v3: > - referring to cb->reason and cb->pc directly in > net_dm_packet_report_fill() > > v2: > - get a pointer to struct net_dm_skb_cb instead of local var for > each field > --- > include/uapi/linux/net_dropmon.h | 1 + > net/core/drop_monitor.c | 29 +++++++++++++++++++++++++---- > 2 files changed, 26 insertions(+), 4 deletions(-) > > diff --git a/include/uapi/linux/net_dropmon.h b/include/uapi/linux/net_dropmon.h > index 66048cc5d7b3..1bbea8f0681e 100644 > --- a/include/uapi/linux/net_dropmon.h > +++ b/include/uapi/linux/net_dropmon.h > @@ -93,6 +93,7 @@ enum net_dm_attr { > NET_DM_ATTR_SW_DROPS, /* flag */ > NET_DM_ATTR_HW_DROPS, /* flag */ > NET_DM_ATTR_FLOW_ACTION_COOKIE, /* binary */ > + NET_DM_ATTR_REASON, /* string */ > > __NET_DM_ATTR_MAX, > NET_DM_ATTR_MAX = __NET_DM_ATTR_MAX - 1 > diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c > index 7b288a121a41..2d1c8e8dec83 100644 > --- a/net/core/drop_monitor.c > +++ b/net/core/drop_monitor.c > @@ -48,6 +48,16 @@ > static int trace_state = TRACE_OFF; > static bool monitor_hw; > > +#undef EM > +#undef EMe > + > +#define EM(a, b) [a] = #b, > +#define EMe(a, b) [a] = #b > + > +static const char *drop_reasons[SKB_DROP_REASON_MAX + 1] = { > + TRACE_SKB_DROP_REASON > +}; > + > /* net_dm_mutex > * > * An overall lock guarding every operation coming from userspace. > @@ -126,6 +136,7 @@ struct net_dm_skb_cb { > struct devlink_trap_metadata *hw_metadata; > void *pc; > }; > + enum skb_drop_reason reason; > }; > > #define NET_DM_SKB_CB(__skb) ((struct net_dm_skb_cb *)&((__skb)->cb[0])) > @@ -498,6 +509,7 @@ static void net_dm_packet_trace_kfree_skb_hit(void *ignore, > { > ktime_t tstamp = ktime_get_real(); > struct per_cpu_dm_data *data; > + struct net_dm_skb_cb *cb; > struct sk_buff *nskb; > unsigned long flags; > > @@ -508,7 +520,9 @@ static void net_dm_packet_trace_kfree_skb_hit(void *ignore, > if (!nskb) > return; > > - NET_DM_SKB_CB(nskb)->pc = location; > + cb = NET_DM_SKB_CB(nskb); > + cb->reason = reason; > + cb->pc = location; > /* Override the timestamp because we care about the time when the > * packet was dropped. > */ > @@ -606,8 +620,9 @@ static int net_dm_packet_report_in_port_put(struct sk_buff *msg, int ifindex, > static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb, > size_t payload_len) > { > - u64 pc = (u64)(uintptr_t) NET_DM_SKB_CB(skb)->pc; > + struct net_dm_skb_cb *cb = NET_DM_SKB_CB(skb); > char buf[NET_DM_MAX_SYMBOL_LEN]; > + enum skb_drop_reason reason; > struct nlattr *attr; > void *hdr; > int rc; > @@ -620,10 +635,16 @@ static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb, > if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_SW)) > goto nla_put_failure; > > - if (nla_put_u64_64bit(msg, NET_DM_ATTR_PC, pc, NET_DM_ATTR_PAD)) > + if (nla_put_u64_64bit(msg, NET_DM_ATTR_PC, (u64)(uintptr_t)cb->pc, > + NET_DM_ATTR_PAD)) > + goto nla_put_failure; > + > + reason = cb->reason; > + if (reason < SKB_DROP_REASON_MAX && > + nla_put_string(msg, NET_DM_ATTR_REASON, drop_reasons[reason])) > goto nla_put_failure; I guess I made a mistake here: assuming that the enum is unsigned. Please ignore this version, I'll make a new one. Thanks! Menglong Dong > > - snprintf(buf, sizeof(buf), "%pS", NET_DM_SKB_CB(skb)->pc); > + snprintf(buf, sizeof(buf), "%pS", cb->pc); > if (nla_put_string(msg, NET_DM_ATTR_SYMBOL, buf)) > goto nla_put_failure; > > -- > 2.34.1 >
diff --git a/include/uapi/linux/net_dropmon.h b/include/uapi/linux/net_dropmon.h index 66048cc5d7b3..1bbea8f0681e 100644 --- a/include/uapi/linux/net_dropmon.h +++ b/include/uapi/linux/net_dropmon.h @@ -93,6 +93,7 @@ enum net_dm_attr { NET_DM_ATTR_SW_DROPS, /* flag */ NET_DM_ATTR_HW_DROPS, /* flag */ NET_DM_ATTR_FLOW_ACTION_COOKIE, /* binary */ + NET_DM_ATTR_REASON, /* string */ __NET_DM_ATTR_MAX, NET_DM_ATTR_MAX = __NET_DM_ATTR_MAX - 1 diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c index 7b288a121a41..2d1c8e8dec83 100644 --- a/net/core/drop_monitor.c +++ b/net/core/drop_monitor.c @@ -48,6 +48,16 @@ static int trace_state = TRACE_OFF; static bool monitor_hw; +#undef EM +#undef EMe + +#define EM(a, b) [a] = #b, +#define EMe(a, b) [a] = #b + +static const char *drop_reasons[SKB_DROP_REASON_MAX + 1] = { + TRACE_SKB_DROP_REASON +}; + /* net_dm_mutex * * An overall lock guarding every operation coming from userspace. @@ -126,6 +136,7 @@ struct net_dm_skb_cb { struct devlink_trap_metadata *hw_metadata; void *pc; }; + enum skb_drop_reason reason; }; #define NET_DM_SKB_CB(__skb) ((struct net_dm_skb_cb *)&((__skb)->cb[0])) @@ -498,6 +509,7 @@ static void net_dm_packet_trace_kfree_skb_hit(void *ignore, { ktime_t tstamp = ktime_get_real(); struct per_cpu_dm_data *data; + struct net_dm_skb_cb *cb; struct sk_buff *nskb; unsigned long flags; @@ -508,7 +520,9 @@ static void net_dm_packet_trace_kfree_skb_hit(void *ignore, if (!nskb) return; - NET_DM_SKB_CB(nskb)->pc = location; + cb = NET_DM_SKB_CB(nskb); + cb->reason = reason; + cb->pc = location; /* Override the timestamp because we care about the time when the * packet was dropped. */ @@ -606,8 +620,9 @@ static int net_dm_packet_report_in_port_put(struct sk_buff *msg, int ifindex, static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb, size_t payload_len) { - u64 pc = (u64)(uintptr_t) NET_DM_SKB_CB(skb)->pc; + struct net_dm_skb_cb *cb = NET_DM_SKB_CB(skb); char buf[NET_DM_MAX_SYMBOL_LEN]; + enum skb_drop_reason reason; struct nlattr *attr; void *hdr; int rc; @@ -620,10 +635,16 @@ static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb, if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_SW)) goto nla_put_failure; - if (nla_put_u64_64bit(msg, NET_DM_ATTR_PC, pc, NET_DM_ATTR_PAD)) + if (nla_put_u64_64bit(msg, NET_DM_ATTR_PC, (u64)(uintptr_t)cb->pc, + NET_DM_ATTR_PAD)) + goto nla_put_failure; + + reason = cb->reason; + if (reason < SKB_DROP_REASON_MAX && + nla_put_string(msg, NET_DM_ATTR_REASON, drop_reasons[reason])) goto nla_put_failure; - snprintf(buf, sizeof(buf), "%pS", NET_DM_SKB_CB(skb)->pc); + snprintf(buf, sizeof(buf), "%pS", cb->pc); if (nla_put_string(msg, NET_DM_ATTR_SYMBOL, buf)) goto nla_put_failure;