From: Benjamin Poirier <benjamin.poirier@polymtl.ca>
Date: Mon, 10 Aug 2009 20:13:40 +0000 (-0400)
Subject: Do not use pkfree_skb events for synchronization
X-Git-Tag: v0.12.26~54
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=85c9417b6ebc1e1cd25d479389c91926eb6948dc;p=lttv.git

Do not use pkfree_skb events for synchronization

Don't rely on events indicating when sk_buff structures are freed. After a
receive, we wait for another event indicating that this receive was for TCP
data. In the case where the data was not TCP, instead of keeping information
about the receive, we used to discard it when the skb was freed.  It turns out
that it faster (and simpler) not to look at pkfree_skb events and keep the
information around anyways. Since sk_buff's are allocated in a pool, the
information will get overwritten and the size of pendingRecv will not grow
infinitely.

Signed-off-by: Benjamin Poirier <benjamin.poirier@polymtl.ca>
---

diff --git a/lttv/lttv/sync/event_processing_lttv_common.c b/lttv/lttv/sync/event_processing_lttv_common.c
index 59c7c0f2..e225db71 100644
--- a/lttv/lttv/sync/event_processing_lttv_common.c
+++ b/lttv/lttv/sync/event_processing_lttv_common.c
@@ -40,10 +40,6 @@
 		.channelName= LTT_CHANNEL_NET,\
 		.eventName= LTT_EVENT_DEV_RECEIVE,\
 		.fields= FIELD_ARRAY(LTT_FIELD_SKB, LTT_FIELD_PROTOCOL),\
-	}, {\
-		.channelName= LTT_CHANNEL_NET,\
-		.eventName= LTT_EVENT_PKFREE_SKB,\
-		.fields= FIELD_ARRAY(LTT_FIELD_SKB),\
 	}, {\
 		.channelName= LTT_CHANNEL_NET,\
 		.eventName= LTT_EVENT_TCPV4_RCV,\
@@ -84,7 +80,6 @@ void createQuarks()
 
 	LTT_EVENT_DEV_XMIT= g_quark_from_static_string("dev_xmit");
 	LTT_EVENT_DEV_RECEIVE= g_quark_from_static_string("dev_receive");
-	LTT_EVENT_PKFREE_SKB= g_quark_from_static_string("pkfree_skb");
 	LTT_EVENT_TCPV4_RCV= g_quark_from_static_string("tcpv4_rcv");
 	LTT_EVENT_NETWORK_IPV4_INTERFACE=
 		g_quark_from_static_string("network_ipv4_interface");
diff --git a/lttv/lttv/sync/event_processing_lttv_common.h b/lttv/lttv/sync/event_processing_lttv_common.h
index de57a650..31c2a649 100644
--- a/lttv/lttv/sync/event_processing_lttv_common.h
+++ b/lttv/lttv/sync/event_processing_lttv_common.h
@@ -31,7 +31,6 @@ GQuark
 GQuark
 	LTT_EVENT_DEV_XMIT,
 	LTT_EVENT_DEV_RECEIVE,
-	LTT_EVENT_PKFREE_SKB,
 	LTT_EVENT_TCPV4_RCV,
 	LTT_EVENT_NETWORK_IPV4_INTERFACE;
 
diff --git a/lttv/lttv/sync/event_processing_lttv_standard.c b/lttv/lttv/sync/event_processing_lttv_standard.c
index cef9f2b9..f67ab107 100644
--- a/lttv/lttv/sync/event_processing_lttv_standard.c
+++ b/lttv/lttv/sync/event_processing_lttv_standard.c
@@ -461,7 +461,7 @@ static gboolean processEventLTTVStandard(void* hookData, void* callData)
 				lttv_trace_get_hook_field(traceHook, 0));
 			inE->packetKey= NULL;
 
-			g_hash_table_insert(processingData->pendingRecv[traceNum],
+			g_hash_table_replace(processingData->pendingRecv[traceNum],
 				inE->skb, inE);
 
 			g_debug("Adding inE %p for skb %p to pendingRecv\n", inE, inE->skb);
@@ -531,27 +531,6 @@ static gboolean processEventLTTVStandard(void* hookData, void* callData)
 			g_debug("Input event %p for skb %p done\n", inE, skb);
 		}
 	}
-	else if (info->name == LTT_EVENT_PKFREE_SKB)
-	{
-		gboolean result;
-		void* skb;
-
-		// Search pendingRecv for an event with the same skb
-		skb= (void*) (long) ltt_event_get_long_unsigned(event,
-			lttv_trace_get_hook_field(traceHook, 0));
-
-		result= g_hash_table_remove(processingData->pendingRecv[traceNum],
-			skb);
-		if (result == FALSE)
-		{
-			g_debug("No matching pending receive event found, \"shaddow"
-				"skb\" %p\n", skb);
-		}
-		else
-		{
-			g_debug("Non-TCP skb %p\n", skb);
-		}
-	}
 	else if (info->name == LTT_EVENT_NETWORK_IPV4_INTERFACE)
 	{
 		char* name;