Add support for kvm x86 specific tracepoints

[lttng-modules.git] / lttng-context-vppid.c

diff --git a/lttng-context-vppid.c b/lttng-context-vppid.c
index 4abf784613afebf844f9be3ed92946519dbff31f..e36b55523feae1df2344001e1711a29613823b83 100644 (file)
--- a/lttng-context-vppid.c
+++ b/lttng-context-vppid.c
@@ -1,27 +1,40 @@
 /*
- * (C) Copyright       2009-2011 -
- *             Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * lttng-context-vppid.c
  *
  * LTTng vPPID context.
  *
- * Dual LGPL v2.1/GPL v2 license.
+ * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; only
+ * version 2.1 of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
 #include <linux/syscalls.h>
-#include "ltt-events.h"
+#include "lttng-events.h"
 #include "wrapper/ringbuffer/frontend_types.h"
 #include "wrapper/vmalloc.h"
-#include "ltt-tracer.h"
+#include "lttng-tracer.h"
 
 static
 size_t vppid_get_size(size_t offset)
 {
        size_t size = 0;
 
-       size += lib_ring_buffer_align(offset, ltt_alignof(pid_t));
+       size += lib_ring_buffer_align(offset, lttng_alignof(pid_t));
        size += sizeof(pid_t);
        return size;
 }
@@ -29,14 +42,32 @@ size_t vppid_get_size(size_t offset)
 static
 void vppid_record(struct lttng_ctx_field *field,
                  struct lib_ring_buffer_ctx *ctx,
-                 struct ltt_channel *chan)
+                 struct lttng_channel *chan)
 {
+       struct task_struct *parent;
        pid_t vppid;
 
+       /*
+        * current nsproxy can be NULL when scheduled out of exit. pid_vnr uses
+        * the current thread nsproxy to perform the lookup.
+        */
+
+       /*
+        * TODO: when we eventually add RCU subsystem instrumentation,
+        * taking the rcu read lock here will trigger RCU tracing
+        * recursively. We should modify the kernel synchronization so
+        * it synchronizes both for RCU and RCU sched, and rely on
+        * rcu_read_lock_sched_notrace.
+        */
+
        rcu_read_lock();
-       vppid = task_tgid_vnr(current->real_parent);
+       parent = rcu_dereference(current->real_parent);
+       if (!current->nsproxy)
+               vppid = 0;
+       else
+               vppid = task_tgid_vnr(parent);
        rcu_read_unlock();
-       lib_ring_buffer_align_ctx(ctx, ltt_alignof(vppid));
+       lib_ring_buffer_align_ctx(ctx, lttng_alignof(vppid));
        chan->ops->event_write(ctx, &vppid, sizeof(vppid));
 }
 
@@ -54,8 +85,8 @@ int lttng_add_vppid_to_ctx(struct lttng_ctx **ctx)
        field->event_field.name = "vppid";
        field->event_field.type.atype = atype_integer;
        field->event_field.type.u.basic.integer.size = sizeof(pid_t) * CHAR_BIT;
-       field->event_field.type.u.basic.integer.alignment = ltt_alignof(pid_t) * CHAR_BIT;
-       field->event_field.type.u.basic.integer.signedness = is_signed_type(pid_t);
+       field->event_field.type.u.basic.integer.alignment = lttng_alignof(pid_t) * CHAR_BIT;
+       field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(pid_t);
        field->event_field.type.u.basic.integer.reverse_byte_order = 0;
        field->event_field.type.u.basic.integer.base = 10;
        field->event_field.type.u.basic.integer.encoding = lttng_encode_none;