This patch uses the GPU cgroup charge/uncharge APIs to charge buffers allocated by any DMA-BUF exporter that exports a buffer with a GPU cgroup device association.
By doing so, it becomes possible to track who allocated/exported a DMA-BUF even after the allocating process drops all references to a buffer.
Originally-by: Hridya Valsaraju hridya@google.com Signed-off-by: T.J. Mercier tjmercier@google.com
--- v4 changes Fix uninitialized return code error for dmabuf_try_charge error case.
v3 changes Use more common dual author commit message format per John Stultz.
v2 changes Move dma-buf cgroup charging/uncharging from a dma_buf_op defined by every heap to a single dma-buf function for all heaps per Daniel Vetter and Christian König. --- drivers/dma-buf/dma-buf.c | 58 +++++++++++++++++++++++++++++++++++++++ include/linux/dma-buf.h | 20 ++++++++++++-- 2 files changed, 76 insertions(+), 2 deletions(-)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 602b12d7470d..1ee5c60d3d6d 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -56,6 +56,53 @@ static char *dmabuffs_dname(struct dentry *dentry, char *buffer, int buflen) dentry->d_name.name, ret > 0 ? name : ""); }
+#ifdef CONFIG_CGROUP_GPU +static inline struct gpucg_device * +exp_info_gpucg_dev(const struct dma_buf_export_info *exp_info) +{ + return exp_info->gpucg_dev; +} + +static int dmabuf_try_charge(struct dma_buf *dmabuf, + struct gpucg_device *gpucg_dev) +{ + int ret; + + dmabuf->gpucg = gpucg_get(current); + dmabuf->gpucg_dev = gpucg_dev; + + ret = gpucg_try_charge(dmabuf->gpucg, dmabuf->gpucg_dev, dmabuf->size); + if (ret) { + gpucg_put(dmabuf->gpucg); + dmabuf->gpucg = NULL; + dmabuf->gpucg_dev = NULL; + } + return ret; +} + +static void dmabuf_uncharge(struct dma_buf *dmabuf) +{ + if (dmabuf->gpucg && dmabuf->gpucg_dev) { + gpucg_uncharge(dmabuf->gpucg, dmabuf->gpucg_dev, dmabuf->size); + gpucg_put(dmabuf->gpucg); + } +} +#else /* CONFIG_CGROUP_GPU */ +static inline struct gpucg_device *exp_info_gpucg_dev( +const struct dma_buf_export_info *exp_info) +{ + return NULL; +} + +static inline int dmabuf_try_charge(struct dma_buf *dmabuf, + struct gpucg_device *gpucg_dev)) +{ + return 0; +} + +static inline void dmabuf_uncharge(struct dma_buf *dmabuf) {} +#endif /* CONFIG_CGROUP_GPU */ + static void dma_buf_release(struct dentry *dentry) { struct dma_buf *dmabuf; @@ -79,6 +126,8 @@ static void dma_buf_release(struct dentry *dentry) if (dmabuf->resv == (struct dma_resv *)&dmabuf[1]) dma_resv_fini(dmabuf->resv);
+ dmabuf_uncharge(dmabuf); + WARN_ON(!list_empty(&dmabuf->attachments)); module_put(dmabuf->owner); kfree(dmabuf->name); @@ -484,6 +533,7 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) { struct dma_buf *dmabuf; struct dma_resv *resv = exp_info->resv; + struct gpucg_device *gpucg_dev = exp_info_gpucg_dev(exp_info); struct file *file; size_t alloc_size = sizeof(struct dma_buf); int ret; @@ -534,6 +584,12 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) } dmabuf->resv = resv;
+ if (gpucg_dev) { + ret = dmabuf_try_charge(dmabuf, gpucg_dev); + if (ret) + goto err_charge; + } + file = dma_buf_getfile(dmabuf, exp_info->flags); if (IS_ERR(file)) { ret = PTR_ERR(file); @@ -565,6 +621,8 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) file->f_path.dentry->d_fsdata = NULL; fput(file); err_dmabuf: + dmabuf_uncharge(dmabuf); +err_charge: kfree(dmabuf); err_module: module_put(exp_info->owner); diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 7ab50076e7a6..742f29c3daaf 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -13,6 +13,7 @@ #ifndef __DMA_BUF_H__ #define __DMA_BUF_H__
+#include <linux/cgroup_gpu.h> #include <linux/dma-buf-map.h> #include <linux/file.h> #include <linux/err.h> @@ -303,7 +304,7 @@ struct dma_buf { /** * @size: * - * Size of the buffer; invariant over the lifetime of the buffer. + * Size of the buffer in bytes; invariant over the lifetime of the buffer. */ size_t size;
@@ -453,6 +454,17 @@ struct dma_buf { struct dma_buf *dmabuf; } *sysfs_entry; #endif + +#ifdef CONFIG_CGROUP_GPU + /** @gpucg: Pointer to the cgroup this buffer currently belongs to. */ + struct gpucg *gpucg; + + /** @gpucg_dev: + * + * Pointer to the cgroup GPU device whence this buffer originates. + */ + struct gpucg_device *gpucg_dev; +#endif };
/** @@ -529,9 +541,10 @@ struct dma_buf_attachment { * @exp_name: name of the exporter - useful for debugging. * @owner: pointer to exporter module - used for refcounting kernel module * @ops: Attach allocator-defined dma buf ops to the new buffer - * @size: Size of the buffer - invariant over the lifetime of the buffer + * @size: Size of the buffer in bytes - invariant over the lifetime of the buffer * @flags: mode flags for the file * @resv: reservation-object, NULL to allocate default one + * @gpucg_dev: pointer to the gpu cgroup device this buffer belongs to * @priv: Attach private data of allocator to this buffer * * This structure holds the information required to export the buffer. Used @@ -544,6 +557,9 @@ struct dma_buf_export_info { size_t size; int flags; struct dma_resv *resv; +#ifdef CONFIG_CGROUP_GPU + struct gpucg_device *gpucg_dev; +#endif void *priv; };