[PATCH v9] dma-buf: add some tracepoints to debug.

Xiang Gao posted 1 patch 1 month, 2 weeks ago
There is a newer version of this series
drivers/dma-buf/dma-buf.c      |  51 ++++++++++-
include/trace/events/dma_buf.h | 157 +++++++++++++++++++++++++++++++++
2 files changed, 206 insertions(+), 2 deletions(-)
create mode 100644 include/trace/events/dma_buf.h
[PATCH v9] dma-buf: add some tracepoints to debug.
Posted by Xiang Gao 1 month, 2 weeks ago
From: gaoxiang17 <gaoxiang17@xiaomi.com>

Since we can only inspect dmabuf by iterating over process FDs or the
dmabuf_list, we need to add our own tracepoints to track its status in
real time in production.

For example:
   binder:3016_1-3102    [006] ...1.   255.126521: dma_buf_export: exp_name=qcom,system size=12685312 ino=2738
   binder:3016_1-3102    [006] ...1.   255.126528: dma_buf_fd: exp_name=qcom,system size=12685312 ino=2738 fd=8
   binder:3016_1-3102    [006] ...1.   255.126642: dma_buf_mmap_internal: exp_name=qcom,system size=28672 ino=2739
     kworker/6:1-86      [006] ...1.   255.127194: dma_buf_put: exp_name=qcom,system size=12685312 ino=2738
    RenderThread-9293    [006] ...1.   316.618179: dma_buf_get: exp_name=qcom,system size=12771328 ino=2762 fd=176
    RenderThread-9293    [006] ...1.   316.618195: dma_buf_dynamic_attach: exp_name=qcom,system size=12771328 ino=2762 attachment:ffffff880a18dd00 is_dynamic=0 dev_name=kgsl-3d0
    RenderThread-9293    [006] ...1.   318.878220: dma_buf_detach: exp_name=qcom,system size=12771328 ino=2762 attachment:ffffff880a18dd00 is_dynamic=0 dev_name=kgsl-3d0

Signed-off-by: Xiang Gao <gaoxiang17@xiaomi.com>
---
 drivers/dma-buf/dma-buf.c      |  51 ++++++++++-
 include/trace/events/dma_buf.h | 157 +++++++++++++++++++++++++++++++++
 2 files changed, 206 insertions(+), 2 deletions(-)
 create mode 100644 include/trace/events/dma_buf.h

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index edaa9e4ee4ae..59a5261cb26b 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -35,6 +35,28 @@
 
 #include "dma-buf-sysfs-stats.h"
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/dma_buf.h>
+
+/*
+ * dmabuf->name must be accessed with holding dmabuf->name_lock.
+ * we need to take the lock around the tracepoint call itself where
+ * it is called in the code.
+ *
+ * Note: FUNC##_enabled() is a static branch that will only
+ *       be set when the trace event is enabled.
+ */
+#define DMA_BUF_TRACE(FUNC, ...)					\
+	do {											\
+		if (FUNC##_enabled()) {						\
+			guard(spinlock)(&dmabuf->name_lock);	\
+			FUNC(__VA_ARGS__);						\
+		} else if (IS_ENABLED(CONFIG_LOCKDEP)) {	\
+			/* Expose this lock when lockdep is enabled */	\
+			guard(spinlock)(&dmabuf->name_lock);	\
+		}											\
+	} while (0)
+
 static inline int is_dma_buf_file(struct file *);
 
 static DEFINE_MUTEX(dmabuf_list_mutex);
@@ -220,6 +242,8 @@ static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
 	    dmabuf->size >> PAGE_SHIFT)
 		return -EINVAL;
 
+	DMA_BUF_TRACE(trace_dma_buf_mmap_internal, dmabuf);
+
 	return dmabuf->ops->mmap(dmabuf, vma);
 }
 
@@ -745,6 +769,8 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
 
 	__dma_buf_list_add(dmabuf);
 
+	DMA_BUF_TRACE(trace_dma_buf_export, dmabuf);
+
 	return dmabuf;
 
 err_dmabuf:
@@ -768,10 +794,16 @@ EXPORT_SYMBOL_NS_GPL(dma_buf_export, "DMA_BUF");
  */
 int dma_buf_fd(struct dma_buf *dmabuf, int flags)
 {
+	int fd;
+
 	if (!dmabuf || !dmabuf->file)
 		return -EINVAL;
 
-	return FD_ADD(flags, dmabuf->file);
+	fd = FD_ADD(flags, dmabuf->file);
+	if (fd >= 0)
+		DMA_BUF_TRACE(trace_dma_buf_fd, dmabuf, fd);
+
+	return fd;
 }
 EXPORT_SYMBOL_NS_GPL(dma_buf_fd, "DMA_BUF");
 
@@ -786,6 +818,7 @@ EXPORT_SYMBOL_NS_GPL(dma_buf_fd, "DMA_BUF");
 struct dma_buf *dma_buf_get(int fd)
 {
 	struct file *file;
+	struct dma_buf *dmabuf;
 
 	file = fget(fd);
 
@@ -797,7 +830,11 @@ struct dma_buf *dma_buf_get(int fd)
 		return ERR_PTR(-EINVAL);
 	}
 
-	return file->private_data;
+	dmabuf = file->private_data;
+
+	DMA_BUF_TRACE(trace_dma_buf_get, dmabuf, fd);
+
+	return dmabuf;
 }
 EXPORT_SYMBOL_NS_GPL(dma_buf_get, "DMA_BUF");
 
@@ -817,6 +854,8 @@ void dma_buf_put(struct dma_buf *dmabuf)
 		return;
 
 	fput(dmabuf->file);
+
+	DMA_BUF_TRACE(trace_dma_buf_put, dmabuf);
 }
 EXPORT_SYMBOL_NS_GPL(dma_buf_put, "DMA_BUF");
 
@@ -971,6 +1010,9 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev,
 	list_add(&attach->node, &dmabuf->attachments);
 	dma_resv_unlock(dmabuf->resv);
 
+	DMA_BUF_TRACE(trace_dma_buf_dynamic_attach, dmabuf, attach,
+		dma_buf_attachment_is_dynamic(attach), dev);
+
 	return attach;
 
 err_attach:
@@ -1015,6 +1057,9 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
 	if (dmabuf->ops->detach)
 		dmabuf->ops->detach(dmabuf, attach);
 
+	DMA_BUF_TRACE(trace_dma_buf_detach, dmabuf, attach,
+		dma_buf_attachment_is_dynamic(attach), attach->dev);
+
 	kfree(attach);
 }
 EXPORT_SYMBOL_NS_GPL(dma_buf_detach, "DMA_BUF");
@@ -1480,6 +1525,8 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
 	vma_set_file(vma, dmabuf->file);
 	vma->vm_pgoff = pgoff;
 
+	DMA_BUF_TRACE(trace_dma_buf_mmap, dmabuf);
+
 	return dmabuf->ops->mmap(dmabuf, vma);
 }
 EXPORT_SYMBOL_NS_GPL(dma_buf_mmap, "DMA_BUF");
diff --git a/include/trace/events/dma_buf.h b/include/trace/events/dma_buf.h
new file mode 100644
index 000000000000..8c49341f60ef
--- /dev/null
+++ b/include/trace/events/dma_buf.h
@@ -0,0 +1,157 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM dma_buf
+
+#if !defined(_TRACE_DMA_BUF_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_DMA_BUF_H
+
+#include <linux/dma-buf.h>
+#include <linux/tracepoint.h>
+
+DECLARE_EVENT_CLASS(dma_buf,
+
+	TP_PROTO(struct dma_buf *dmabuf),
+
+	TP_ARGS(dmabuf),
+
+	TP_STRUCT__entry(
+		__string(	exp_name,		dmabuf->exp_name)
+		__field(	size_t,			size)
+		__field(	ino_t,			ino)
+	),
+
+	TP_fast_assign(
+		__assign_str(exp_name);
+		__entry->size	= dmabuf->size;
+		__entry->ino	= dmabuf->file->f_inode->i_ino;
+	),
+
+	TP_printk("exp_name=%s size=%zu ino=%lu",
+		  __get_str(exp_name),
+		  __entry->size,
+		  __entry->ino)
+);
+
+DECLARE_EVENT_CLASS(dma_buf_attach_dev,
+
+	TP_PROTO(struct dma_buf *dmabuf, struct dma_buf_attachment *attach,
+		bool is_dynamic, struct device *dev),
+
+	TP_ARGS(dmabuf, attach, is_dynamic, dev),
+
+	TP_STRUCT__entry(
+		__string(	dev_name,						dev_name(dev))
+		__string(	exp_name,						dmabuf->exp_name)
+		__field(	size_t,							size)
+		__field(	ino_t,							ino)
+		__field(	struct dma_buf_attachment *,	attach)
+		__field(	bool,							is_dynamic)
+	),
+
+	TP_fast_assign(
+		__assign_str(dev_name);
+		__assign_str(exp_name);
+		__entry->size		= dmabuf->size;
+		__entry->ino		= dmabuf->file->f_inode->i_ino;
+		__entry->is_dynamic	= is_dynamic;
+		__entry->attach		= attach;
+	),
+
+	TP_printk("exp_name=%s size=%zu ino=%lu attachment:%p is_dynamic=%d dev_name=%s",
+		  __get_str(exp_name),
+		  __entry->size,
+		  __entry->ino,
+		  __entry->attach,
+		  __entry->is_dynamic,
+		  __get_str(dev_name))
+);
+
+DECLARE_EVENT_CLASS(dma_buf_fd,
+
+	TP_PROTO(struct dma_buf *dmabuf, int fd),
+
+	TP_ARGS(dmabuf, fd),
+
+	TP_STRUCT__entry(
+		__string(	exp_name,		dmabuf->exp_name)
+		__field(	size_t,			size)
+		__field(	ino_t,			ino)
+		__field(	int,			fd)
+	),
+
+	TP_fast_assign(
+		__assign_str(exp_name);
+		__entry->size	= dmabuf->size;
+		__entry->ino	= dmabuf->file->f_inode->i_ino;
+		__entry->fd		= fd;
+	),
+
+	TP_printk("exp_name=%s size=%zu ino=%lu fd=%d",
+		  __get_str(exp_name),
+		  __entry->size,
+		  __entry->ino,
+		  __entry->fd)
+);
+
+DEFINE_EVENT(dma_buf, dma_buf_export,
+
+	TP_PROTO(struct dma_buf *dmabuf),
+
+	TP_ARGS(dmabuf)
+);
+
+DEFINE_EVENT(dma_buf, dma_buf_mmap_internal,
+
+	TP_PROTO(struct dma_buf *dmabuf),
+
+	TP_ARGS(dmabuf)
+);
+
+DEFINE_EVENT(dma_buf, dma_buf_mmap,
+
+	TP_PROTO(struct dma_buf *dmabuf),
+
+	TP_ARGS(dmabuf)
+);
+
+DEFINE_EVENT(dma_buf, dma_buf_put,
+
+	TP_PROTO(struct dma_buf *dmabuf),
+
+	TP_ARGS(dmabuf)
+);
+
+DEFINE_EVENT(dma_buf_attach_dev, dma_buf_dynamic_attach,
+
+	TP_PROTO(struct dma_buf *dmabuf, struct dma_buf_attachment *attach,
+		bool is_dynamic, struct device *dev),
+
+	TP_ARGS(dmabuf, attach, is_dynamic, dev)
+);
+
+DEFINE_EVENT(dma_buf_attach_dev, dma_buf_detach,
+
+	TP_PROTO(struct dma_buf *dmabuf, struct dma_buf_attachment *attach,
+		bool is_dynamic, struct device *dev),
+
+	TP_ARGS(dmabuf, attach, is_dynamic, dev)
+);
+
+DEFINE_EVENT(dma_buf_fd, dma_buf_fd,
+
+	TP_PROTO(struct dma_buf *dmabuf, int fd),
+
+	TP_ARGS(dmabuf, fd)
+);
+
+DEFINE_EVENT(dma_buf_fd, dma_buf_get,
+
+	TP_PROTO(struct dma_buf *dmabuf, int fd),
+
+	TP_ARGS(dmabuf, fd)
+);
+
+#endif /* _TRACE_DMA_BUF_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
-- 
2.34.1
Re: [PATCH v9] dma-buf: add some tracepoints to debug.
Posted by Christian König 1 month ago
On 12/23/25 04:27, Xiang Gao wrote:
> From: gaoxiang17 <gaoxiang17@xiaomi.com>
> 
> Since we can only inspect dmabuf by iterating over process FDs or the
> dmabuf_list, we need to add our own tracepoints to track its status in
> real time in production.
> 
> For example:
>    binder:3016_1-3102    [006] ...1.   255.126521: dma_buf_export: exp_name=qcom,system size=12685312 ino=2738
>    binder:3016_1-3102    [006] ...1.   255.126528: dma_buf_fd: exp_name=qcom,system size=12685312 ino=2738 fd=8
>    binder:3016_1-3102    [006] ...1.   255.126642: dma_buf_mmap_internal: exp_name=qcom,system size=28672 ino=2739
>      kworker/6:1-86      [006] ...1.   255.127194: dma_buf_put: exp_name=qcom,system size=12685312 ino=2738
>     RenderThread-9293    [006] ...1.   316.618179: dma_buf_get: exp_name=qcom,system size=12771328 ino=2762 fd=176
>     RenderThread-9293    [006] ...1.   316.618195: dma_buf_dynamic_attach: exp_name=qcom,system size=12771328 ino=2762 attachment:ffffff880a18dd00 is_dynamic=0 dev_name=kgsl-3d0
>     RenderThread-9293    [006] ...1.   318.878220: dma_buf_detach: exp_name=qcom,system size=12771328 ino=2762 attachment:ffffff880a18dd00 is_dynamic=0 dev_name=kgsl-3d0
> 

I've already pushed this patch to drm-misc-next, if you still want to apply some style changes please rebase on what is currently upstream.

> Signed-off-by: Xiang Gao <gaoxiang17@xiaomi.com>
> ---
>  drivers/dma-buf/dma-buf.c      |  51 ++++++++++-
>  include/trace/events/dma_buf.h | 157 +++++++++++++++++++++++++++++++++
>  2 files changed, 206 insertions(+), 2 deletions(-)
>  create mode 100644 include/trace/events/dma_buf.h
> 
> diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
> index edaa9e4ee4ae..59a5261cb26b 100644
> --- a/drivers/dma-buf/dma-buf.c
> +++ b/drivers/dma-buf/dma-buf.c
> @@ -35,6 +35,28 @@
>  
>  #include "dma-buf-sysfs-stats.h"
>  
> +#define CREATE_TRACE_POINTS
> +#include <trace/events/dma_buf.h>
> +
> +/*
> + * dmabuf->name must be accessed with holding dmabuf->name_lock.
> + * we need to take the lock around the tracepoint call itself where
> + * it is called in the code.
> + *
> + * Note: FUNC##_enabled() is a static branch that will only
> + *       be set when the trace event is enabled.
> + */
> +#define DMA_BUF_TRACE(FUNC, ...)					\
> +	do {											\
> +		if (FUNC##_enabled()) {						\
> +			guard(spinlock)(&dmabuf->name_lock);	\
> +			FUNC(__VA_ARGS__);						\
> +		} else if (IS_ENABLED(CONFIG_LOCKDEP)) {	\
> +			/* Expose this lock when lockdep is enabled */	\
> +			guard(spinlock)(&dmabuf->name_lock);	\
> +		}											\
> +	} while (0)
> +

The indentation of the \ on those lines seems to be completely of. Some editor setting is clearl not correct here.

Regards,
Christian.

>  static inline int is_dma_buf_file(struct file *);
>  
>  static DEFINE_MUTEX(dmabuf_list_mutex);
> @@ -220,6 +242,8 @@ static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
>  	    dmabuf->size >> PAGE_SHIFT)
>  		return -EINVAL;
>  
> +	DMA_BUF_TRACE(trace_dma_buf_mmap_internal, dmabuf);
> +
>  	return dmabuf->ops->mmap(dmabuf, vma);
>  }
>  
> @@ -745,6 +769,8 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
>  
>  	__dma_buf_list_add(dmabuf);
>  
> +	DMA_BUF_TRACE(trace_dma_buf_export, dmabuf);
> +
>  	return dmabuf;
>  
>  err_dmabuf:
> @@ -768,10 +794,16 @@ EXPORT_SYMBOL_NS_GPL(dma_buf_export, "DMA_BUF");
>   */
>  int dma_buf_fd(struct dma_buf *dmabuf, int flags)
>  {
> +	int fd;
> +
>  	if (!dmabuf || !dmabuf->file)
>  		return -EINVAL;
>  
> -	return FD_ADD(flags, dmabuf->file);
> +	fd = FD_ADD(flags, dmabuf->file);
> +	if (fd >= 0)
> +		DMA_BUF_TRACE(trace_dma_buf_fd, dmabuf, fd);
> +
> +	return fd;
>  }
>  EXPORT_SYMBOL_NS_GPL(dma_buf_fd, "DMA_BUF");
>  
> @@ -786,6 +818,7 @@ EXPORT_SYMBOL_NS_GPL(dma_buf_fd, "DMA_BUF");
>  struct dma_buf *dma_buf_get(int fd)
>  {
>  	struct file *file;
> +	struct dma_buf *dmabuf;
>  
>  	file = fget(fd);
>  
> @@ -797,7 +830,11 @@ struct dma_buf *dma_buf_get(int fd)
>  		return ERR_PTR(-EINVAL);
>  	}
>  
> -	return file->private_data;
> +	dmabuf = file->private_data;
> +
> +	DMA_BUF_TRACE(trace_dma_buf_get, dmabuf, fd);
> +
> +	return dmabuf;
>  }
>  EXPORT_SYMBOL_NS_GPL(dma_buf_get, "DMA_BUF");
>  
> @@ -817,6 +854,8 @@ void dma_buf_put(struct dma_buf *dmabuf)
>  		return;
>  
>  	fput(dmabuf->file);
> +
> +	DMA_BUF_TRACE(trace_dma_buf_put, dmabuf);
>  }
>  EXPORT_SYMBOL_NS_GPL(dma_buf_put, "DMA_BUF");
>  
> @@ -971,6 +1010,9 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev,
>  	list_add(&attach->node, &dmabuf->attachments);
>  	dma_resv_unlock(dmabuf->resv);
>  
> +	DMA_BUF_TRACE(trace_dma_buf_dynamic_attach, dmabuf, attach,
> +		dma_buf_attachment_is_dynamic(attach), dev);
> +
>  	return attach;
>  
>  err_attach:
> @@ -1015,6 +1057,9 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
>  	if (dmabuf->ops->detach)
>  		dmabuf->ops->detach(dmabuf, attach);
>  
> +	DMA_BUF_TRACE(trace_dma_buf_detach, dmabuf, attach,
> +		dma_buf_attachment_is_dynamic(attach), attach->dev);
> +
>  	kfree(attach);
>  }
>  EXPORT_SYMBOL_NS_GPL(dma_buf_detach, "DMA_BUF");
> @@ -1480,6 +1525,8 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
>  	vma_set_file(vma, dmabuf->file);
>  	vma->vm_pgoff = pgoff;
>  
> +	DMA_BUF_TRACE(trace_dma_buf_mmap, dmabuf);
> +
>  	return dmabuf->ops->mmap(dmabuf, vma);
>  }
>  EXPORT_SYMBOL_NS_GPL(dma_buf_mmap, "DMA_BUF");
> diff --git a/include/trace/events/dma_buf.h b/include/trace/events/dma_buf.h
> new file mode 100644
> index 000000000000..8c49341f60ef
> --- /dev/null
> +++ b/include/trace/events/dma_buf.h
> @@ -0,0 +1,157 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#undef TRACE_SYSTEM
> +#define TRACE_SYSTEM dma_buf
> +
> +#if !defined(_TRACE_DMA_BUF_H) || defined(TRACE_HEADER_MULTI_READ)
> +#define _TRACE_DMA_BUF_H
> +
> +#include <linux/dma-buf.h>
> +#include <linux/tracepoint.h>
> +
> +DECLARE_EVENT_CLASS(dma_buf,
> +
> +	TP_PROTO(struct dma_buf *dmabuf),
> +
> +	TP_ARGS(dmabuf),
> +
> +	TP_STRUCT__entry(
> +		__string(	exp_name,		dmabuf->exp_name)
> +		__field(	size_t,			size)
> +		__field(	ino_t,			ino)
> +	),
> +
> +	TP_fast_assign(
> +		__assign_str(exp_name);
> +		__entry->size	= dmabuf->size;
> +		__entry->ino	= dmabuf->file->f_inode->i_ino;
> +	),
> +
> +	TP_printk("exp_name=%s size=%zu ino=%lu",
> +		  __get_str(exp_name),
> +		  __entry->size,
> +		  __entry->ino)
> +);
> +
> +DECLARE_EVENT_CLASS(dma_buf_attach_dev,
> +
> +	TP_PROTO(struct dma_buf *dmabuf, struct dma_buf_attachment *attach,
> +		bool is_dynamic, struct device *dev),
> +
> +	TP_ARGS(dmabuf, attach, is_dynamic, dev),
> +
> +	TP_STRUCT__entry(
> +		__string(	dev_name,						dev_name(dev))
> +		__string(	exp_name,						dmabuf->exp_name)
> +		__field(	size_t,							size)
> +		__field(	ino_t,							ino)
> +		__field(	struct dma_buf_attachment *,	attach)
> +		__field(	bool,							is_dynamic)
> +	),
> +
> +	TP_fast_assign(
> +		__assign_str(dev_name);
> +		__assign_str(exp_name);
> +		__entry->size		= dmabuf->size;
> +		__entry->ino		= dmabuf->file->f_inode->i_ino;
> +		__entry->is_dynamic	= is_dynamic;
> +		__entry->attach		= attach;
> +	),
> +
> +	TP_printk("exp_name=%s size=%zu ino=%lu attachment:%p is_dynamic=%d dev_name=%s",
> +		  __get_str(exp_name),
> +		  __entry->size,
> +		  __entry->ino,
> +		  __entry->attach,
> +		  __entry->is_dynamic,
> +		  __get_str(dev_name))
> +);
> +
> +DECLARE_EVENT_CLASS(dma_buf_fd,
> +
> +	TP_PROTO(struct dma_buf *dmabuf, int fd),
> +
> +	TP_ARGS(dmabuf, fd),
> +
> +	TP_STRUCT__entry(
> +		__string(	exp_name,		dmabuf->exp_name)
> +		__field(	size_t,			size)
> +		__field(	ino_t,			ino)
> +		__field(	int,			fd)
> +	),
> +
> +	TP_fast_assign(
> +		__assign_str(exp_name);
> +		__entry->size	= dmabuf->size;
> +		__entry->ino	= dmabuf->file->f_inode->i_ino;
> +		__entry->fd		= fd;
> +	),
> +
> +	TP_printk("exp_name=%s size=%zu ino=%lu fd=%d",
> +		  __get_str(exp_name),
> +		  __entry->size,
> +		  __entry->ino,
> +		  __entry->fd)
> +);
> +
> +DEFINE_EVENT(dma_buf, dma_buf_export,
> +
> +	TP_PROTO(struct dma_buf *dmabuf),
> +
> +	TP_ARGS(dmabuf)
> +);
> +
> +DEFINE_EVENT(dma_buf, dma_buf_mmap_internal,
> +
> +	TP_PROTO(struct dma_buf *dmabuf),
> +
> +	TP_ARGS(dmabuf)
> +);
> +
> +DEFINE_EVENT(dma_buf, dma_buf_mmap,
> +
> +	TP_PROTO(struct dma_buf *dmabuf),
> +
> +	TP_ARGS(dmabuf)
> +);
> +
> +DEFINE_EVENT(dma_buf, dma_buf_put,
> +
> +	TP_PROTO(struct dma_buf *dmabuf),
> +
> +	TP_ARGS(dmabuf)
> +);
> +
> +DEFINE_EVENT(dma_buf_attach_dev, dma_buf_dynamic_attach,
> +
> +	TP_PROTO(struct dma_buf *dmabuf, struct dma_buf_attachment *attach,
> +		bool is_dynamic, struct device *dev),
> +
> +	TP_ARGS(dmabuf, attach, is_dynamic, dev)
> +);
> +
> +DEFINE_EVENT(dma_buf_attach_dev, dma_buf_detach,
> +
> +	TP_PROTO(struct dma_buf *dmabuf, struct dma_buf_attachment *attach,
> +		bool is_dynamic, struct device *dev),
> +
> +	TP_ARGS(dmabuf, attach, is_dynamic, dev)
> +);
> +
> +DEFINE_EVENT(dma_buf_fd, dma_buf_fd,
> +
> +	TP_PROTO(struct dma_buf *dmabuf, int fd),
> +
> +	TP_ARGS(dmabuf, fd)
> +);
> +
> +DEFINE_EVENT(dma_buf_fd, dma_buf_get,
> +
> +	TP_PROTO(struct dma_buf *dmabuf, int fd),
> +
> +	TP_ARGS(dmabuf, fd)
> +);
> +
> +#endif /* _TRACE_DMA_BUF_H */
> +
> +/* This part must be outside protection */
> +#include <trace/define_trace.h>
Re: [PATCH v9] dma-buf: add some tracepoints to debug.
Posted by Steven Rostedt 1 month, 2 weeks ago
On Tue, 23 Dec 2025 11:27:49 +0800
Xiang Gao <gxxa03070307@gmail.com> wrote:

>  
> +#define CREATE_TRACE_POINTS
> +#include <trace/events/dma_buf.h>
> +
> +/*
> + * dmabuf->name must be accessed with holding dmabuf->name_lock.
> + * we need to take the lock around the tracepoint call itself where
> + * it is called in the code.
> + *
> + * Note: FUNC##_enabled() is a static branch that will only
> + *       be set when the trace event is enabled.
> + */
> +#define DMA_BUF_TRACE(FUNC, ...)					\
> +	do {											\
> +		if (FUNC##_enabled()) {						\
> +			guard(spinlock)(&dmabuf->name_lock);	\
> +			FUNC(__VA_ARGS__);						\
> +		} else if (IS_ENABLED(CONFIG_LOCKDEP)) {	\
> +			/* Expose this lock when lockdep is enabled */	\
> +			guard(spinlock)(&dmabuf->name_lock);	\
> +		}											\
> +	} while (0)
> +

I hate to make another comment here, but I was just thinking that this can
be made to look a little nicer. Basically, we want to make sure that when
LOCKDEP is active, we always take the lock. But we also need to take the
lock when tracing is enabled. The tracepoint itself is a static branch,
which means it is a nop when not active, so there's no real problem with
calling it. Thus, this could look better as:

#define DMA_BUF_TRACE(FUNC, ...)					\
	do {								\
		/* Always expose lock if lockdep is enabled */		\
		if (IS_ENABLED(CONFIG_LOCKDEP) || FUNC##_enabled()) {	\
			guard(spinlock)(&dmabuf->name_lock);		\
			FUNC(__VA_ARGS__);				\
		}							\
	} while (0)


-- Steve