On Wed, 24 Dec 2025 09:34:55 +0800 Xiang Gao <[email protected]> wrote:
> From: gaoxiang17 <[email protected]> > > 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 <[email protected]> > --- BTW, it's sometimes nice to have in new versions of a patch with a list of changes below the above "---" (here): Changes since v9: https://lore.kernel.org/all/[email protected]/ - <list changes here> That way it keeps a nice history of all the versions of the patch. No need to resend. Just giving you some advice for future patches. > drivers/dma-buf/dma-buf.c | 49 +++++++++- > include/trace/events/dma_buf.h | 157 +++++++++++++++++++++++++++++++++ > 2 files changed, 204 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..5e6f65cd0306 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) I'm curious. Are the above backslashes lined up nicely in the code? > + > 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 +792,16 @@ 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); Instead of adding the above if statement in the code, you can make the event conditional (See below). Then this could just be: - return FD_ADD(flags, dmabuf->file); + fd = FD_ADD(flags, dmabuf->file); + DMA_BUF_TRACE(trace_dma_buf_fd, dmabuf, fd); And not have the condition hit when tracing isn't enabled. > + > + return fd; > } > EXPORT_SYMBOL_NS_GPL(dma_buf_fd, "DMA_BUF"); > [..] > diff --git a/include/trace/events/dma_buf.h b/include/trace/events/dma_buf.h > new file mode 100644 > index 000000000000..2c9ba8533467 > --- /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_fd, dma_buf_fd, > + > + TP_PROTO(struct dma_buf *dmabuf, int fd), > + > + TP_ARGS(dmabuf, fd) > +); If fd needs to be greater or equal to zero, you can make the above: 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) ); This places the "fd >= 0" into the code that is called when the tracepoint is enabled. If the condition isn't met, then the tracepoint doesn't get recorded. -- Steve > + > +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>
