From mboxrd@z Thu Jan 1 00:00:00 1970 From: "T.J. Mercier" Subject: [RFC v3 5/8] dmabuf: Add gpu cgroup charge transfer function Date: Wed, 9 Mar 2022 16:52:15 +0000 Message-ID: <20220309165222.2843651-6-tjmercier@google.com> References: <20220309165222.2843651-1-tjmercier@google.com> Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc:content-transfer-encoding; bh=V8vMjTnKNpMlnc7JqoQhhcwCYCICGfVTjA11ueJBqJY=; b=HPhBJpTBiJVYDhNj0DZQIrh2V35TDbkma5Iio+WXF/hcMekPxUMRND2g0CCX8In7eA LEUpnnJ+An6CQt91VMdWJ16FK8gQvFAyqTsa5rlG5AWdns4o+hy7+0OojxnhgPcTuenF BMnLv3wL46KC+ysjzZ76R5d/tGOpuWkWCWCPvMAfXwR0a5KK3XjpjLwL9pQFigkgD89h UfwDU4EeBZ+AuUjNHIDB5TQ3ZOrtGFi86NY5EeNgywb7PE5VH443fnkWqKIiup1Y0udy R7MVYYHFJitKmNj3Z9u+ZFiGhMd6bk7xZU88I9EiTT+qF25ldxx/Q3auo1GI4V9pSZKP UyXw== In-Reply-To: <20220309165222.2843651-1-tjmercier@google.com> List-ID: Content-Type: text/plain; charset="iso-8859-1" To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , Jonathan Corbet , Greg Kroah-Hartman , =?UTF-8?q?Arve=20Hj=C3=B8nnev=C3=A5g?= , Todd Kjos , Martijn Coenen , Joel Fernandes , Christian Brauner , Hridya Valsaraju , Suren Baghdasaryan , Sumit Semwal , =?UTF-8?q?Christian=20K=C3=B6nig?= , Benjamin Gaignard , Liam Mark Cc: kaleshsingh@google.com, Kenny.Ho@amd.com, "T.J. Mercier" , dri-devel@lists.freedesktop.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org, cgroups@vger.kernel.org, linux-kselftest@vger.kernel.org From: Hridya Valsaraju The dma_buf_charge_transfer function provides a way for processes to transfer charge of a buffer to a different process. This is essential for the cases where a central allocator process does allocations for various subsystems, hands over the fd to the client who requested the memory and drops all references to the allocated memory. Signed-off-by: Hridya Valsaraju Signed-off-by: T.J. Mercier --- v3 changes Use more common dual author commit message format per John Stultz. v2 changes Move dma-buf cgroup charge transfer from a dma_buf_op defined by every heap to a single dma-buf function for all heaps per Daniel Vetter and Christian K=C3=B6nig. --- drivers/dma-buf/dma-buf.c | 48 +++++++++++++++++++++++++++++++++++++++ include/linux/dma-buf.h | 2 ++ 2 files changed, 50 insertions(+) diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 83d0d1b91547..55e1b982f840 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -1374,6 +1374,54 @@ void dma_buf_vunmap(struct dma_buf *dmabuf, struct d= ma_buf_map *map) } EXPORT_SYMBOL_NS_GPL(dma_buf_vunmap, DMA_BUF); =20 +/** + * dma_buf_charge_transfer - Change the GPU cgroup to which the provided d= ma_buf + * is charged. + * @dmabuf: [in] buffer whose charge will be migrated to a different GPU + * cgroup + * @gpucg: [in] the destination GPU cgroup for dmabuf's charge + * + * Only tasks that belong to the same cgroup the buffer is currently charg= ed to + * may call this function, otherwise it will return -EPERM. + * + * Returns 0 on success, or a negative errno code otherwise. + */ +int dma_buf_charge_transfer(struct dma_buf *dmabuf, struct gpucg *gpucg) +{ +#ifdef CONFIG_CGROUP_GPU + struct gpucg *current_gpucg; + int ret =3D 0; + + /* + * Verify that the cgroup of the process requesting the transfer is the + * same as the one the buffer is currently charged to. + */ + current_gpucg =3D gpucg_get(current); + mutex_lock(&dmabuf->lock); + if (current_gpucg !=3D dmabuf->gpucg) { + ret =3D -EPERM; + goto err; + } + + ret =3D gpucg_try_charge(gpucg, dmabuf->gpucg_dev, dmabuf->size); + if (ret) + goto err; + + dmabuf->gpucg =3D gpucg; + + /* uncharge the buffer from the cgroup it's currently charged to. */ + gpucg_uncharge(current_gpucg, dmabuf->gpucg_dev, dmabuf->size); + +err: + mutex_unlock(&dmabuf->lock); + gpucg_put(current_gpucg); + return ret; +#else + return 0; +#endif /* CONFIG_CGROUP_GPU */ +} +EXPORT_SYMBOL_NS_GPL(dma_buf_charge_transfer, DMA_BUF); + #ifdef CONFIG_DEBUG_FS static int dma_buf_debug_show(struct seq_file *s, void *unused) { diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 742f29c3daaf..85c940c08867 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -646,4 +646,6 @@ int dma_buf_mmap(struct dma_buf *, struct vm_area_struc= t *, 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); + +int dma_buf_charge_transfer(struct dma_buf *dmabuf, struct gpucg *gpucg); #endif /* __DMA_BUF_H__ */ --=20 2.35.1.616.g0bdcbb4464-goog