* [PATCH v13] dma-buf: add some tracepoints to debug.
[not found] <7e126504-1966-4c63-8db5-dfe57e206169@amd.com/>
@ 2026-01-09 11:54 ` Xiang Gao
2026-01-29 18:10 ` Steven Rostedt
0 siblings, 1 reply; 2+ messages in thread
From: Xiang Gao @ 2026-01-09 11:54 UTC (permalink / raw)
To: sumit.semwal, christian.koenig, rostedt, mhiramat
Cc: linux-media, dri-devel, linux-kernel, mathieu.desnoyers, dhowells,
kuba, brauner, akpm, linux-trace-kernel, gaoxiang17
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 v12: https://lore.kernel.org/all/20251229031547.59272-1-gxxa03070307@gmail.com/
- list history changes
Changes since v11: https://lore.kernel.org/all/20251225121119.2194228-1-gxxa03070307@gmail.com/
- Lined up the backslashes nicely for the macro DMA_BUF_TRACE.
- Used DEFINE_EVENT_CONDITION() to move the condition branch into the tracepoint.
Changes since v10: https://lore.kernel.org/all/20251224013455.1649879-1-gxxa03070307@gmail.com/
- Always expose dmabuf->name_lock if lockdep is enabled.
Changes since v9: https://lore.kernel.org/all/20251223032749.1371913-1-gxxa03070307@gmail.com/
- Fixed some whitespace issues with the macro DMA_BUF_TRACE again.
Changes since v8: https://lore.kernel.org/all/20251218062853.819744-1-gxxa03070307@gmail.com/
- Expose dmabuf->name_lock when lockdep is enabled but trace event is not.
Changes since v7: https://lore.kernel.org/all/20251217105132.643300-1-gxxa03070307@gmail.com/
- Fixed some whitespace issues with the macro DMA_BUF_TRACE.
Changes since v6: https://lore.kernel.org/all/20251216063952.516364-1-gxxa03070307@gmail.com/
- Add a comment for the macro DMA_BUF_TRACE.
Changes since v5: https://lore.kernel.org/all/20251201112148.843572-1-gxxa03070307@gmail.com/
- Add the macro DMA_BUF_TRACE.
- Modify the commit message.
Changes since v4: https://lore.kernel.org/all/20251128085215.550100-1-gxxa03070307@gmail.com/
- Remove the tracepoints exporting.
- Remove the file refcount for the trace.
- Print the dev_name last.
- Add the parameter of whether dma_buf attachment is dynamic.
Changes since v3: https://lore.kernel.org/all/20251127004352.376307-1-gxxa03070307@gmail.com/
- Take the dmabuf->name_lock around the tracepoint call itself.
- Used DECLARE_EVENT_CLASS() and a DEFINE_EVENT().
Changes since v2: https://lore.kernel.org/all/20251125162949.220488-1-gxxa03070307@gmail.com/
- Add more explanation to the commit message.
drivers/dma-buf/dma-buf.c | 9 ++----
include/trace/events/dma_buf.h | 50 ++++++++++++++++++----------------
2 files changed, 29 insertions(+), 30 deletions(-)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index a4d8f2ff94e4..ac4238063ec1 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -48,12 +48,10 @@
*/
#define DMA_BUF_TRACE(FUNC, ...) \
do { \
- if (FUNC##_enabled()) { \
+ /* Always expose lock if lockdep is enabled */ \
+ if (IS_ENABLED(CONFIG_LOCKDEP) || 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)
@@ -806,8 +804,7 @@ int dma_buf_fd(struct dma_buf *dmabuf, int flags)
return -EINVAL;
fd = FD_ADD(flags, dmabuf->file);
- if (fd >= 0)
- DMA_BUF_TRACE(trace_dma_buf_fd, dmabuf, fd);
+ DMA_BUF_TRACE(trace_dma_buf_fd, dmabuf, fd);
return fd;
}
diff --git a/include/trace/events/dma_buf.h b/include/trace/events/dma_buf.h
index 35f8140095f4..3bb88d05bcc8 100644
--- a/include/trace/events/dma_buf.h
+++ b/include/trace/events/dma_buf.h
@@ -15,15 +15,15 @@ DECLARE_EVENT_CLASS(dma_buf,
TP_ARGS(dmabuf),
TP_STRUCT__entry(
- __string(exp_name, dmabuf->exp_name)
- __field(size_t, size)
- __field(ino_t, ino)
+ __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;
+ __entry->size = dmabuf->size;
+ __entry->ino = dmabuf->file->f_inode->i_ino;
),
TP_printk("exp_name=%s size=%zu ino=%lu",
@@ -40,21 +40,21 @@ DECLARE_EVENT_CLASS(dma_buf_attach_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)
+ __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;
+ __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",
@@ -73,17 +73,17 @@ DECLARE_EVENT_CLASS(dma_buf_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)
+ __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;
+ __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",
@@ -137,11 +137,13 @@ DEFINE_EVENT(dma_buf_attach_dev, dma_buf_detach,
TP_ARGS(dmabuf, attach, is_dynamic, dev)
);
-DEFINE_EVENT(dma_buf_fd, dma_buf_fd,
+DEFINE_EVENT_CONDITION(dma_buf_fd, dma_buf_fd,
TP_PROTO(struct dma_buf *dmabuf, int fd),
- TP_ARGS(dmabuf, fd)
+ TP_ARGS(dmabuf, fd),
+
+ TP_CONDITION(fd >= 0)
);
DEFINE_EVENT(dma_buf_fd, dma_buf_get,
--
2.34.1
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