Re: [PATCH v3] dma-buf: add some tracepoints to debug.
From: Christian König <christian.koenig@amd.com>
Date: 2025-11-27 09:49:16
Also in:
dri-devel, linux-media, lkml
On 11/27/25 01:43, Xiang Gao wrote:
quoted hunk ↗ jump to hunk
From: gaoxiang17 <redacted> I want to track the status of dmabuf in real time in the production environment. But now we can only check it by traversing the fd in the process or dmabuf_list. For example: binder:2962_2-2962 [005] ...1. 208.453940: dma_buf_export: exp_name=qcom,system name=(null) size=28672 ino=2580 f_refcnt=2 binder:2962_2-2962 [005] ...1. 208.453943: dma_buf_fd: exp_name=qcom,system name=(null) size=28672 ino=2580 fd=9 f_refcnt=2 binder:2962_2-2962 [005] ...1. 208.453977: dma_buf_mmap_internal: exp_name=qcom,system name=qcom,system size=28672 ino=2580 f_refcnt=4 kworker/5:2-194 [005] ...1. 208.460580: dma_buf_put: exp_name=qcom,system name=ab pid [8176] size=28672 ino=2580 f_refcnt=3 RenderThread-11305 [007] ...1. 208.599094: dma_buf_get: exp_name=qcom,system name=ab pid [8176] size=217088 ino=2579 fd=1114 f_refcnt=7 RenderThread-11305 [007] ...1. 208.599098: dma_buf_attach: dev_name=kgsl-3d0 exp_name=qcom,system name=ab pid [8176] size=217088 ino=2579 f_refcnt=7 <...>-14 [001] ...1. 208.726359: dma_buf_detach: dev_name=kgsl-3d0 exp_name=qcom,system name=ab pid [3317] size=217088 ino=2581 f_refcnt=3 Signed-off-by: Xiang Gao <redacted> --- drivers/dma-buf/dma-buf.c | 57 ++++++++++- include/trace/events/dma_buf.h | 166 +++++++++++++++++++++++++++++++++ 2 files changed, 222 insertions(+), 1 deletion(-) create mode 100644 include/trace/events/dma_buf.hdiff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 2bcf9ceca997..7cef816ddcac 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c@@ -35,6 +35,18 @@ #include "dma-buf-sysfs-stats.h" +#define CREATE_TRACE_POINTS +#include <trace/events/dma_buf.h> + +EXPORT_TRACEPOINT_SYMBOL(dma_buf_export); +EXPORT_TRACEPOINT_SYMBOL(dma_buf_mmap_internal); +EXPORT_TRACEPOINT_SYMBOL(dma_buf_mmap); +EXPORT_TRACEPOINT_SYMBOL(dma_buf_put); +EXPORT_TRACEPOINT_SYMBOL(dma_buf_attach); +EXPORT_TRACEPOINT_SYMBOL(dma_buf_detach); +EXPORT_TRACEPOINT_SYMBOL(dma_buf_fd); +EXPORT_TRACEPOINT_SYMBOL(dma_buf_get);
Exporting the tracepoints is unecessary as far as I can see
quoted hunk ↗ jump to hunk
+ static inline int is_dma_buf_file(struct file *); static DEFINE_MUTEX(dmabuf_list_mutex);@@ -220,6 +232,11 @@ static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma) dmabuf->size >> PAGE_SHIFT) return -EINVAL; + if (trace_dma_buf_mmap_internal_enabled()) { + guard(spinlock)(&dmabuf->name_lock); + trace_dma_buf_mmap_internal(dmabuf); + } + return dmabuf->ops->mmap(dmabuf, vma); }@@ -745,6 +762,11 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) __dma_buf_list_add(dmabuf); + if (trace_dma_buf_export_enabled()) { + guard(spinlock)(&dmabuf->name_lock); + trace_dma_buf_export(dmabuf); + } + return dmabuf; err_dmabuf:@@ -779,6 +801,11 @@ int dma_buf_fd(struct dma_buf *dmabuf, int flags) fd_install(fd, dmabuf->file); + if (trace_dma_buf_fd_enabled()) { + guard(spinlock)(&dmabuf->name_lock); + trace_dma_buf_fd(dmabuf, fd); + } + return fd; } EXPORT_SYMBOL_NS_GPL(dma_buf_fd, "DMA_BUF");@@ -794,6 +821,7 @@ 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);@@ -805,7 +833,14 @@ struct dma_buf *dma_buf_get(int fd) return ERR_PTR(-EINVAL); } - return file->private_data; + dmabuf = file->private_data; + + if (trace_dma_buf_get_enabled()) { + guard(spinlock)(&dmabuf->name_lock); + trace_dma_buf_get(dmabuf, fd); + } + + return dmabuf; } EXPORT_SYMBOL_NS_GPL(dma_buf_get, "DMA_BUF");@@ -825,6 +860,11 @@ void dma_buf_put(struct dma_buf *dmabuf) return; fput(dmabuf->file); + + if (trace_dma_buf_put_enabled()) { + guard(spinlock)(&dmabuf->name_lock); + trace_dma_buf_put(dmabuf); + } } EXPORT_SYMBOL_NS_GPL(dma_buf_put, "DMA_BUF");@@ -998,6 +1038,11 @@ EXPORT_SYMBOL_NS_GPL(dma_buf_dynamic_attach, "DMA_BUF"); struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, struct device *dev) { + if (trace_dma_buf_attach_enabled()) { + guard(spinlock)(&dmabuf->name_lock); + trace_dma_buf_attach(dmabuf, dev); + } + return dma_buf_dynamic_attach(dmabuf, dev, NULL, NULL); } EXPORT_SYMBOL_NS_GPL(dma_buf_attach, "DMA_BUF");@@ -1023,6 +1068,11 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach) if (dmabuf->ops->detach) dmabuf->ops->detach(dmabuf, attach); + if (trace_dma_buf_detach_enabled()) { + guard(spinlock)(&dmabuf->name_lock); + trace_dma_buf_detach(dmabuf, attach->dev); + } + kfree(attach); } EXPORT_SYMBOL_NS_GPL(dma_buf_detach, "DMA_BUF");@@ -1488,6 +1538,11 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma, vma_set_file(vma, dmabuf->file); vma->vm_pgoff = pgoff; + if (trace_dma_buf_mmap_enabled()) { + guard(spinlock)(&dmabuf->name_lock); + 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..fe9da89bacd0 --- /dev/null +++ b/include/trace/events/dma_buf.h@@ -0,0 +1,166 @@ +/* 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) + __string(name, dmabuf->name) + __field(size_t, size) + __field(ino_t, ino) + __field(long, f_refcnt) + ), + + TP_fast_assign( + __assign_str(exp_name); + __assign_str(name); + __entry->size = dmabuf->size; + __entry->ino = dmabuf->file->f_inode->i_ino; + __entry->f_refcnt = file_count(dmabuf->file); + ), + + TP_printk("exp_name=%s name=%s size=%zu ino=%lu f_refcnt=%ld", + __get_str(exp_name), + __get_str(name), + __entry->size, + __entry->ino, + __entry->f_refcnt)
I can't come up with a reason why we should have the file refcount in the trace logs. Same for most other places.
+);
+
+DECLARE_EVENT_CLASS(dma_buf_attach_dev,
+
+ TP_PROTO(struct dma_buf *dmabuf, struct device *dev),
+
+ TP_ARGS(dmabuf, dev),
+
+ TP_STRUCT__entry(
+ __string(dname, dev_name(dev))
+ __string(exp_name, dmabuf->exp_name)
+ __string(name, dmabuf->name)
+ __field(size_t, size)
+ __field(ino_t, ino)
+ __field(long, f_refcnt)
+ ),
+
+ TP_fast_assign(
+ __assign_str(dname);
+ __assign_str(exp_name);
+ __assign_str(name);
+ __entry->size = dmabuf->size;
+ __entry->ino = dmabuf->file->f_inode->i_ino;
+ __entry->f_refcnt = file_count(dmabuf->file);
+ ),
+
+ TP_printk("dev_name=%s exp_name=%s name=%s size=%zu ino=%lu f_refcnt=%ld",
+ __get_str(dname),
+ __get_str(exp_name),
+ __get_str(name),
+ __entry->size,
+ __entry->ino,
+ __entry->f_refcnt)Print the dev_name last, it's the external device which attaches to the DMA-buf. Additional to that it would be nice to know if the attachment is dynamic or not. Regards, Christian.
+);
+
+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)
+ __string(name, dmabuf->name)
+ __field(size_t, size)
+ __field(ino_t, ino)
+ __field(int, fd)
+ __field(long, f_refcnt)
+ ),
+
+ TP_fast_assign(
+ __assign_str(exp_name);
+ __assign_str(name);
+ __entry->size = dmabuf->size;
+ __entry->ino = dmabuf->file->f_inode->i_ino;
+ __entry->fd = fd;
+ __entry->f_refcnt = file_count(dmabuf->file);
+ ),
+
+ TP_printk("exp_name=%s name=%s size=%zu ino=%lu fd=%d f_refcnt=%ld",
+ __get_str(exp_name),
+ __get_str(name),
+ __entry->size,
+ __entry->ino,
+ __entry->fd,
+ __entry->f_refcnt)
+);
+
+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_attach,
+
+ TP_PROTO(struct dma_buf *dmabuf, struct device *dev),
+
+ TP_ARGS(dmabuf, dev)
+);
+
+DEFINE_EVENT(dma_buf_attach_dev, dma_buf_detach,
+
+ TP_PROTO(struct dma_buf *dmabuf, struct device *dev),
+
+ TP_ARGS(dmabuf, 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>