[PATCH v2] dma-buf: Add DmaBufTotal counter in meminfo

[PATCH v2] dma-buf: Add DmaBufTotal counter in meminfo

[Peter Enderborg]

This adds a total used dma-buf memory. Details
can be found in debugfs, however it is not for everyone
and not always available. dma-buf are indirect allocated by
userspace. So with this value we can monitor and detect
userspace applications that have problems.

Signed-off-by: Peter Enderborg <peter.enderborg@sony.com>
---
 drivers/dma-buf/dma-buf.c | 12 ++++++++++++
 fs/proc/meminfo.c         |  5 ++++-
 include/linux/dma-buf.h   |  1 +
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index f264b70c383e..9f88171b394c 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -37,6 +37,7 @@ struct dma_buf_list {
 };
 
 static struct dma_buf_list db_list;
+static atomic_long_t dma_buf_size;
 
 static char *dmabuffs_dname(struct dentry *dentry, char *buffer, int buflen)
 {
@@ -79,6 +80,7 @@ static void dma_buf_release(struct dentry *dentry)
 	if (dmabuf->resv == (struct dma_resv *)&dmabuf[1])
 		dma_resv_fini(dmabuf->resv);
 
+	atomic_long_sub(dmabuf->size, &dma_buf_size);
 	module_put(dmabuf->owner);
 	kfree(dmabuf->name);
 	kfree(dmabuf);
@@ -586,6 +588,7 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
 	mutex_lock(&db_list.lock);
 	list_add(&dmabuf->list_node, &db_list.head);
 	mutex_unlock(&db_list.lock);
+	atomic_long_add(dmabuf->size, &dma_buf_size);
 
 	return dmabuf;
 
@@ -1346,6 +1349,15 @@ void dma_buf_vunmap(struct dma_buf *dmabuf, struct dma_buf_map *map)
 }
 EXPORT_SYMBOL_GPL(dma_buf_vunmap);
 
+/**
+ * dma_buf_get_size - Return the used nr pages by dma-buf
+ */
+long dma_buf_get_size(void)
+{
+	return atomic_long_read(&dma_buf_size) >> PAGE_SHIFT;
+}
+EXPORT_SYMBOL_GPL(dma_buf_get_size);
+
 #ifdef CONFIG_DEBUG_FS
 static int dma_buf_debug_show(struct seq_file *s, void *unused)
 {
diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c
index 6fa761c9cc78..178f6ffb1618 100644
--- a/fs/proc/meminfo.c
+++ b/fs/proc/meminfo.c
@@ -16,6 +16,7 @@
 #ifdef CONFIG_CMA
 #include <linux/cma.h>
 #endif
+#include <linux/dma-buf.h>
 #include <asm/page.h>
 #include "internal.h"
 
@@ -145,7 +146,9 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
 	show_val_kb(m, "CmaFree:        ",
 		    global_zone_page_state(NR_FREE_CMA_PAGES));
 #endif
-
+#ifdef CONFIG_DMA_SHARED_BUFFER
+	show_val_kb(m, "DmaBufTotal:    ", dma_buf_get_size());
+#endif
 	hugetlb_report_meminfo(m);
 
 	arch_report_meminfo(m);
diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index efdc56b9d95f..f6481315a377 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -507,4 +507,5 @@ int dma_buf_mmap(struct dma_buf *, struct vm_area_struct *,
 		 unsigned long);
 int dma_buf_vmap(struct dma_buf *dmabuf, struct dma_buf_map *map);
 void dma_buf_vunmap(struct dma_buf *dmabuf, struct dma_buf_map *map);
+long dma_buf_get_size(void);
 #endif /* __DMA_BUF_H__ */
-- 
2.17.1

Re: [PATCH v2] dma-buf: Add DmaBufTotal counter in meminfo

[Christian König]

Am 16.04.21 um 14:33 schrieb Peter Enderborg:
> This adds a total used dma-buf memory. Details
> can be found in debugfs, however it is not for everyone
> and not always available. dma-buf are indirect allocated by
> userspace. So with this value we can monitor and detect
> userspace applications that have problems.
>
> Signed-off-by: Peter Enderborg <peter.enderborg@sony.com>
> ---
>   drivers/dma-buf/dma-buf.c | 12 ++++++++++++
>   fs/proc/meminfo.c         |  5 ++++-
>   include/linux/dma-buf.h   |  1 +
>   3 files changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
> index f264b70c383e..9f88171b394c 100644
> --- a/drivers/dma-buf/dma-buf.c
> +++ b/drivers/dma-buf/dma-buf.c
> @@ -37,6 +37,7 @@ struct dma_buf_list {
>   };
>   
>   static struct dma_buf_list db_list;
> +static atomic_long_t dma_buf_size;

Probably better to call this and the get function something like 
global_allocated.

Christian.

>   
>   static char *dmabuffs_dname(struct dentry *dentry, char *buffer, int buflen)
>   {
> @@ -79,6 +80,7 @@ static void dma_buf_release(struct dentry *dentry)
>   	if (dmabuf->resv == (struct dma_resv *)&dmabuf[1])
>   		dma_resv_fini(dmabuf->resv);
>   
> +	atomic_long_sub(dmabuf->size, &dma_buf_size);
>   	module_put(dmabuf->owner);
>   	kfree(dmabuf->name);
>   	kfree(dmabuf);
> @@ -586,6 +588,7 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
>   	mutex_lock(&db_list.lock);
>   	list_add(&dmabuf->list_node, &db_list.head);
>   	mutex_unlock(&db_list.lock);
> +	atomic_long_add(dmabuf->size, &dma_buf_size);
>   
>   	return dmabuf;
>   
> @@ -1346,6 +1349,15 @@ void dma_buf_vunmap(struct dma_buf *dmabuf, struct dma_buf_map *map)
>   }
>   EXPORT_SYMBOL_GPL(dma_buf_vunmap);
>   
> +/**
> + * dma_buf_get_size - Return the used nr pages by dma-buf
> + */
> +long dma_buf_get_size(void)
> +{
> +	return atomic_long_read(&dma_buf_size) >> PAGE_SHIFT;
> +}
> +EXPORT_SYMBOL_GPL(dma_buf_get_size);
> +
>   #ifdef CONFIG_DEBUG_FS
>   static int dma_buf_debug_show(struct seq_file *s, void *unused)
>   {
> diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c
> index 6fa761c9cc78..178f6ffb1618 100644
> --- a/fs/proc/meminfo.c
> +++ b/fs/proc/meminfo.c
> @@ -16,6 +16,7 @@
>   #ifdef CONFIG_CMA
>   #include <linux/cma.h>
>   #endif
> +#include <linux/dma-buf.h>
>   #include <asm/page.h>
>   #include "internal.h"
>   
> @@ -145,7 +146,9 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
>   	show_val_kb(m, "CmaFree:        ",
>   		    global_zone_page_state(NR_FREE_CMA_PAGES));
>   #endif
> -
> +#ifdef CONFIG_DMA_SHARED_BUFFER
> +	show_val_kb(m, "DmaBufTotal:    ", dma_buf_get_size());
> +#endif
>   	hugetlb_report_meminfo(m);
>   
>   	arch_report_meminfo(m);
> diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
> index efdc56b9d95f..f6481315a377 100644
> --- a/include/linux/dma-buf.h
> +++ b/include/linux/dma-buf.h
> @@ -507,4 +507,5 @@ int dma_buf_mmap(struct dma_buf *, struct vm_area_struct *,
>   		 unsigned long);
>   int dma_buf_vmap(struct dma_buf *dmabuf, struct dma_buf_map *map);
>   void dma_buf_vunmap(struct dma_buf *dmabuf, struct dma_buf_map *map);
> +long dma_buf_get_size(void);
>   #endif /* __DMA_BUF_H__ */

Re: [PATCH v2] dma-buf: Add DmaBufTotal counter in meminfo

[Peter.Enderborg]

On 4/20/21 3:34 PM, Daniel Stone wrote:
> Hi Peter,
>
> On Fri, 16 Apr 2021 at 13:34, Peter Enderborg <peter.enderborg@sony.com <mailto:peter.enderborg@sony.com>> wrote:
>
>     This adds a total used dma-buf memory. Details
>     can be found in debugfs, however it is not for everyone
>     and not always available. dma-buf are indirect allocated by
>     userspace. So with this value we can monitor and detect
>     userspace applications that have problems.
>
>
> FWIW, this won't work super well for Android where gralloc is implemented as a system service, so all graphics usage will instantly be accounted to it.
>
> Cheers,
> Daniel 

This resource allocation is a big part of why we need it. Why should it not work? 

Re: [PATCH v2] dma-buf: Add DmaBufTotal counter in meminfo

[Peter.Enderborg]

On 4/20/21 4:48 PM, Daniel Stone wrote:
> On Tue, 20 Apr 2021 at 14:46, <Peter.Enderborg@sony.com <mailto:Peter.Enderborg@sony.com>> wrote:
>
>     On 4/20/21 3:34 PM, Daniel Stone wrote:
>     > On Fri, 16 Apr 2021 at 13:34, Peter Enderborg <peter.enderborg@sony.com <mailto:peter.enderborg@sony.com> <mailto:peter.enderborg@sony.com <mailto:peter.enderborg@sony.com>>> wrote:
>     >     This adds a total used dma-buf memory. Details
>     >     can be found in debugfs, however it is not for everyone
>     >     and not always available. dma-buf are indirect allocated by
>     >     userspace. So with this value we can monitor and detect
>     >     userspace applications that have problems.
>     >
>     >
>     > FWIW, this won't work super well for Android where gralloc is implemented as a system service, so all graphics usage will instantly be accounted to it.
>
>     This resource allocation is a big part of why we need it. Why should it not work?
>
>
> Sorry, I'd somehow completely misread that as being locally rather than globally accounted. Given that, it's more correct, just also not super useful.
>
> Some drivers export allocation tracepoints which you could use if you have a decent userspace tracing infrastructure. Short of that, many drivers export this kind of thing through debugfs already. I think a better long-term direction is probably getting accounting from dma-heaps rather than extending core dmabuf itself.
>
> Cheers,
> Daniel 

Debugfs and traces are useful when you pin down your problem.  Debugfs does not exist on commercial devices so we need some hints on what going on, and trace points needs active debugging
and before the problem occurs. A metric on dma-buf can be sent with a bugreport.