Messages in this thread |  | | Subject | Re: [PATCH v3 2/2] dmabuf: Add dmabuf inode number to /proc/*/fdinfo | From | Christian König <> | Date | Fri, 5 Feb 2021 08:56:36 +0100 |
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Am 05.02.21 um 03:23 schrieb Kalesh Singh: > If a FD refers to a DMA buffer add the DMA buffer inode number to > /proc/<pid>/fdinfo/<FD> and /proc/<pid>/task/<tid>/fdindo/<FD>. > > The dmabuf inode number allows userspace to uniquely identify the buffer > and avoids a dependency on /proc/<pid>/fd/* when accounting per-process > DMA buffer sizes.
BTW: Why do we make this DMA-buf specific? Couldn't we always print the inode number for all fds?
Regards, Christian.
> > Signed-off-by: Kalesh Singh <kaleshsingh@google.com> > --- > Changes in v3: > - Add documentation in proc.rst > Changes in v2: > - Update patch description > > Documentation/filesystems/proc.rst | 17 +++++++++++++++++ > drivers/dma-buf/dma-buf.c | 1 + > 2 files changed, 18 insertions(+) > > diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst > index 2fa69f710e2a..fdd38676f57f 100644 > --- a/Documentation/filesystems/proc.rst > +++ b/Documentation/filesystems/proc.rst > @@ -2031,6 +2031,23 @@ details]. 'it_value' is remaining time until the timer expiration. > with TIMER_ABSTIME option which will be shown in 'settime flags', but 'it_value' > still exhibits timer's remaining time. > > +DMA Buffer files > +~~~~~~~~~~~~~~~~ > + > +:: > + > + pos: 0 > + flags: 04002 > + mnt_id: 9 > + dmabuf_inode_no: 63107 > + size: 32768 > + count: 2 > + exp_name: system-heap > + > +where 'dmabuf_inode_no' is the unique inode number of the DMA buffer file. > +'size' is the size of the DMA buffer in bytes. 'count' is the file count of > +the DMA buffer file. 'exp_name' is the name of the DMA buffer exporter. > + > 3.9 /proc/<pid>/map_files - Information about memory mapped files > --------------------------------------------------------------------- > This directory contains symbolic links which represent memory mapped files > diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c > index 9ad6397aaa97..d869099ede83 100644 > --- a/drivers/dma-buf/dma-buf.c > +++ b/drivers/dma-buf/dma-buf.c > @@ -414,6 +414,7 @@ static void dma_buf_show_fdinfo(struct seq_file *m, struct file *file) > { > struct dma_buf *dmabuf = file->private_data; > > + seq_printf(m, "dmabuf_inode_no:\t%lu\n", file_inode(file)->i_ino); > seq_printf(m, "size:\t%zu\n", dmabuf->size); > /* Don't count the temporary reference taken inside procfs seq_show */ > seq_printf(m, "count:\t%ld\n", file_count(dmabuf->file) - 1);
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