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[PATCH v11] dma-buf: add some tracepoints to debug.

Xiang Gao posted 1 patch 1 month, 1 week ago
There is a newer version of this series
drivers/dma-buf/dma-buf.c      |  48 +++++++++-
include/trace/events/dma_buf.h | 159 +++++++++++++++++++++++++++++++++
2 files changed, 205 insertions(+), 2 deletions(-)
create mode 100644 include/trace/events/dma_buf.h
[PATCH v11] dma-buf: add some tracepoints to debug.
Posted by Xiang Gao 1 month, 1 week 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>
---

Changes since v10: https://lore.kernel.org/all/20251224013455.1649879-1-gxxa03070307@gmail.com/
Changes since v9: https://lore.kernel.org/all/20251223032749.1371913-1-gxxa03070307@gmail.com/
Changes since v8: https://lore.kernel.org/all/20251218062853.819744-1-gxxa03070307@gmail.com/
Changes since v7: https://lore.kernel.org/all/20251217105132.643300-1-gxxa03070307@gmail.com/
Changes since v6: https://lore.kernel.org/all/20251216063952.516364-1-gxxa03070307@gmail.com/
Changes since v5: https://lore.kernel.org/all/20251201112148.843572-1-gxxa03070307@gmail.com/
Changes since v4: https://lore.kernel.org/all/20251128085215.550100-1-gxxa03070307@gmail.com/
Changes since v3: https://lore.kernel.org/all/20251127004352.376307-1-gxxa03070307@gmail.com/
Changes since v2: https://lore.kernel.org/all/20251125162949.220488-1-gxxa03070307@gmail.com/
Changes since v1: https://lore.kernel.org/all/20251124133648.72668-1-gxxa03070307@gmail.com/

 drivers/dma-buf/dma-buf.c      |  48 +++++++++-
 include/trace/events/dma_buf.h | 159 +++++++++++++++++++++++++++++++++
 2 files changed, 205 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..dee59d4c0b12 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -35,6 +35,26 @@
 
 #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 {								\
+		/* Always expose lock if lockdep is enabled */		\
+		if (IS_ENABLED(CONFIG_LOCKDEP) || FUNC##_enabled()) {	\
+			guard(spinlock)(&dmabuf->name_lock);		\
+			FUNC(__VA_ARGS__);				\
+		}							\
+	} while (0)
+
 static inline int is_dma_buf_file(struct file *);
 
 static DEFINE_MUTEX(dmabuf_list_mutex);
@@ -220,6 +240,8 @@ 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 +767,8 @@ 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 +792,15 @@ 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);
+	DMA_BUF_TRACE(trace_dma_buf_fd, dmabuf, fd);
+
+	return fd;
 }
 EXPORT_SYMBOL_NS_GPL(dma_buf_fd, "DMA_BUF");
 
@@ -786,6 +815,7 @@ 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 +827,11 @@ 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 +851,8 @@ 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 +1007,9 @@ 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 +1054,9 @@ 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 +1522,8 @@ 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..3bb88d05bcc8
--- /dev/null
+++ b/include/trace/events/dma_buf.h
@@ -0,0 +1,159 @@
+/* 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_CONDITION(dma_buf_fd, dma_buf_fd,
+
+	TP_PROTO(struct dma_buf *dmabuf, int fd),
+
+	TP_ARGS(dmabuf, fd),
+
+	TP_CONDITION(fd >= 0)
+);
+
+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 v11] dma-buf: add some tracepoints to debug.
Posted by Steven Rostedt 1 month, 1 week ago 
On Thu, 25 Dec 2025 20:11:19 +0800
Xiang Gao <gxxa03070307@gmail.com> 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
> 
> Signed-off-by: Xiang Gao <gaoxiang17@xiaomi.com>
> ---
> 
> Changes since v10: https://lore.kernel.org/all/20251224013455.1649879-1-gxxa03070307@gmail.com/

You only need to show the last revision (but since you haven't showed the
others, before it's good to show them now). But you also want to say "what changed"

For example:

- Used DEFINE_EVENT_CONDITION() to move the condition branch into the tracepoint.


> Changes since v9: https://lore.kernel.org/all/20251223032749.1371913-1-gxxa03070307@gmail.com/
> Changes since v8: https://lore.kernel.org/all/20251218062853.819744-1-gxxa03070307@gmail.com/
> Changes since v7: https://lore.kernel.org/all/20251217105132.643300-1-gxxa03070307@gmail.com/
> Changes since v6: https://lore.kernel.org/all/20251216063952.516364-1-gxxa03070307@gmail.com/
> Changes since v5: https://lore.kernel.org/all/20251201112148.843572-1-gxxa03070307@gmail.com/
> Changes since v4: https://lore.kernel.org/all/20251128085215.550100-1-gxxa03070307@gmail.com/
> Changes since v3: https://lore.kernel.org/all/20251127004352.376307-1-gxxa03070307@gmail.com/
> Changes since v2: https://lore.kernel.org/all/20251125162949.220488-1-gxxa03070307@gmail.com/
> Changes since v1: https://lore.kernel.org/all/20251124133648.72668-1-gxxa03070307@gmail.com/
> 
>  drivers/dma-buf/dma-buf.c      |  48 +++++++++-
>  include/trace/events/dma_buf.h | 159 +++++++++++++++++++++++++++++++++
>  2 files changed, 205 insertions(+), 2 deletions(-)
>  create mode 100644 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 {								\
> +		/* Always expose lock if lockdep is enabled */		\
> +		if (IS_ENABLED(CONFIG_LOCKDEP) || FUNC##_enabled()) {	\
> +			guard(spinlock)(&dmabuf->name_lock);		\
> +			FUNC(__VA_ARGS__);				\
> +		}							\
> +	} while (0)
> +
>  static inline int is_dma_buf_file(struct file *);
>  

> +
> +DEFINE_EVENT_CONDITION(dma_buf_fd, dma_buf_fd,
> +
> +	TP_PROTO(struct dma_buf *dmabuf, int fd),
> +
> +	TP_ARGS(dmabuf, fd),
> +
> +	TP_CONDITION(fd >= 0)
> +);
> +


From a tracing point of view (It's up to the dma maintainers to decide to
take this patch):

Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>

-- Steve

Patchew 2.1-devel-b67e4c2

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