[PATCH v2] dma-buf: Delete the DMA-BUF attachment sysfs statistics
Christian König
christian.koenig at amd.com
Tue Jul 20 09:11:43 UTC 2021
Am 13.07.21 um 06:07 schrieb Hridya Valsaraju:
> The DMA-BUF attachment statistics form a subset of the DMA-BUF
> sysfs statistics that recently merged to the drm-misc tree. They are not
> UABI yet since they have not merged to the upstream Linux kernel.
>
> Since there has been a reported a performance regression due to the
> overhead of sysfs directory creation/teardown during
> dma_buf_attach()/dma_buf_detach(), this patch deletes the DMA-BUF
> attachment statistics from sysfs.
>
> Fixes: bdb8d06dfefd (dmabuf: Add the capability to expose DMA-BUF stats
> in sysfs)
> Signed-off-by: Hridya Valsaraju <hridya at google.com>
> Reviewed-by: Christian König <christian.koenig at amd.com>
> Reviewed-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
> ---
>
> Changes in v2:
> Updated commit message to clarify that the sysfs files being removed
> have not yet merged to upstream Linux and are hence not ABI.
>
> Hi Christian,
>
> I have updated the commit message as per your suggestion. Please do take
> another look when you get a chance.
I've just pushed that one to drm-misc-next. Sorry for the delay.
Regards,
Christian.
>
> Thanks,
> Hridya
>
> .../ABI/testing/sysfs-kernel-dmabuf-buffers | 28 ----
> drivers/dma-buf/dma-buf-sysfs-stats.c | 140 +-----------------
> drivers/dma-buf/dma-buf-sysfs-stats.h | 27 ----
> drivers/dma-buf/dma-buf.c | 16 --
> include/linux/dma-buf.h | 17 ---
> 5 files changed, 4 insertions(+), 224 deletions(-)
>
> diff --git a/Documentation/ABI/testing/sysfs-kernel-dmabuf-buffers b/Documentation/ABI/testing/sysfs-kernel-dmabuf-buffers
> index a243984ed420..5d3bc997dc64 100644
> --- a/Documentation/ABI/testing/sysfs-kernel-dmabuf-buffers
> +++ b/Documentation/ABI/testing/sysfs-kernel-dmabuf-buffers
> @@ -22,31 +22,3 @@ KernelVersion: v5.13
> Contact: Hridya Valsaraju <hridya at google.com>
> Description: This file is read-only and specifies the size of the DMA-BUF in
> bytes.
> -
> -What: /sys/kernel/dmabuf/buffers/<inode_number>/attachments
> -Date: May 2021
> -KernelVersion: v5.13
> -Contact: Hridya Valsaraju <hridya at google.com>
> -Description: This directory will contain subdirectories representing every
> - attachment of the DMA-BUF.
> -
> -What: /sys/kernel/dmabuf/buffers/<inode_number>/attachments/<attachment_uid>
> -Date: May 2021
> -KernelVersion: v5.13
> -Contact: Hridya Valsaraju <hridya at google.com>
> -Description: This directory will contain information on the attached device
> - and the number of current distinct device mappings.
> -
> -What: /sys/kernel/dmabuf/buffers/<inode_number>/attachments/<attachment_uid>/device
> -Date: May 2021
> -KernelVersion: v5.13
> -Contact: Hridya Valsaraju <hridya at google.com>
> -Description: This file is read-only and is a symlink to the attached device's
> - sysfs entry.
> -
> -What: /sys/kernel/dmabuf/buffers/<inode_number>/attachments/<attachment_uid>/map_counter
> -Date: May 2021
> -KernelVersion: v5.13
> -Contact: Hridya Valsaraju <hridya at google.com>
> -Description: This file is read-only and contains a map_counter indicating the
> - number of distinct device mappings of the attachment.
> diff --git a/drivers/dma-buf/dma-buf-sysfs-stats.c b/drivers/dma-buf/dma-buf-sysfs-stats.c
> index a2638e84199c..053baadcada9 100644
> --- a/drivers/dma-buf/dma-buf-sysfs-stats.c
> +++ b/drivers/dma-buf/dma-buf-sysfs-stats.c
> @@ -40,14 +40,11 @@
> *
> * * ``/sys/kernel/dmabuf/buffers/<inode_number>/exporter_name``
> * * ``/sys/kernel/dmabuf/buffers/<inode_number>/size``
> - * * ``/sys/kernel/dmabuf/buffers/<inode_number>/attachments/<attach_uid>/device``
> - * * ``/sys/kernel/dmabuf/buffers/<inode_number>/attachments/<attach_uid>/map_counter``
> *
> - * The information in the interface can also be used to derive per-exporter and
> - * per-device usage statistics. The data from the interface can be gathered
> - * on error conditions or other important events to provide a snapshot of
> - * DMA-BUF usage. It can also be collected periodically by telemetry to monitor
> - * various metrics.
> + * The information in the interface can also be used to derive per-exporter
> + * statistics. The data from the interface can be gathered on error conditions
> + * or other important events to provide a snapshot of DMA-BUF usage.
> + * It can also be collected periodically by telemetry to monitor various metrics.
> *
> * Detailed documentation about the interface is present in
> * Documentation/ABI/testing/sysfs-kernel-dmabuf-buffers.
> @@ -121,120 +118,6 @@ static struct kobj_type dma_buf_ktype = {
> .default_groups = dma_buf_stats_default_groups,
> };
>
> -#define to_dma_buf_attach_entry_from_kobj(x) container_of(x, struct dma_buf_attach_sysfs_entry, kobj)
> -
> -struct dma_buf_attach_stats_attribute {
> - struct attribute attr;
> - ssize_t (*show)(struct dma_buf_attach_sysfs_entry *sysfs_entry,
> - struct dma_buf_attach_stats_attribute *attr, char *buf);
> -};
> -#define to_dma_buf_attach_stats_attr(x) container_of(x, struct dma_buf_attach_stats_attribute, attr)
> -
> -static ssize_t dma_buf_attach_stats_attribute_show(struct kobject *kobj,
> - struct attribute *attr,
> - char *buf)
> -{
> - struct dma_buf_attach_stats_attribute *attribute;
> - struct dma_buf_attach_sysfs_entry *sysfs_entry;
> -
> - attribute = to_dma_buf_attach_stats_attr(attr);
> - sysfs_entry = to_dma_buf_attach_entry_from_kobj(kobj);
> -
> - if (!attribute->show)
> - return -EIO;
> -
> - return attribute->show(sysfs_entry, attribute, buf);
> -}
> -
> -static const struct sysfs_ops dma_buf_attach_stats_sysfs_ops = {
> - .show = dma_buf_attach_stats_attribute_show,
> -};
> -
> -static ssize_t map_counter_show(struct dma_buf_attach_sysfs_entry *sysfs_entry,
> - struct dma_buf_attach_stats_attribute *attr,
> - char *buf)
> -{
> - return sysfs_emit(buf, "%u\n", sysfs_entry->map_counter);
> -}
> -
> -static struct dma_buf_attach_stats_attribute map_counter_attribute =
> - __ATTR_RO(map_counter);
> -
> -static struct attribute *dma_buf_attach_stats_default_attrs[] = {
> - &map_counter_attribute.attr,
> - NULL,
> -};
> -ATTRIBUTE_GROUPS(dma_buf_attach_stats_default);
> -
> -static void dma_buf_attach_sysfs_release(struct kobject *kobj)
> -{
> - struct dma_buf_attach_sysfs_entry *sysfs_entry;
> -
> - sysfs_entry = to_dma_buf_attach_entry_from_kobj(kobj);
> - kfree(sysfs_entry);
> -}
> -
> -static struct kobj_type dma_buf_attach_ktype = {
> - .sysfs_ops = &dma_buf_attach_stats_sysfs_ops,
> - .release = dma_buf_attach_sysfs_release,
> - .default_groups = dma_buf_attach_stats_default_groups,
> -};
> -
> -void dma_buf_attach_stats_teardown(struct dma_buf_attachment *attach)
> -{
> - struct dma_buf_attach_sysfs_entry *sysfs_entry;
> -
> - sysfs_entry = attach->sysfs_entry;
> - if (!sysfs_entry)
> - return;
> -
> - sysfs_delete_link(&sysfs_entry->kobj, &attach->dev->kobj, "device");
> -
> - kobject_del(&sysfs_entry->kobj);
> - kobject_put(&sysfs_entry->kobj);
> -}
> -
> -int dma_buf_attach_stats_setup(struct dma_buf_attachment *attach,
> - unsigned int uid)
> -{
> - struct dma_buf_attach_sysfs_entry *sysfs_entry;
> - int ret;
> - struct dma_buf *dmabuf;
> -
> - if (!attach)
> - return -EINVAL;
> -
> - dmabuf = attach->dmabuf;
> -
> - sysfs_entry = kzalloc(sizeof(struct dma_buf_attach_sysfs_entry),
> - GFP_KERNEL);
> - if (!sysfs_entry)
> - return -ENOMEM;
> -
> - sysfs_entry->kobj.kset = dmabuf->sysfs_entry->attach_stats_kset;
> -
> - attach->sysfs_entry = sysfs_entry;
> -
> - ret = kobject_init_and_add(&sysfs_entry->kobj, &dma_buf_attach_ktype,
> - NULL, "%u", uid);
> - if (ret)
> - goto kobj_err;
> -
> - ret = sysfs_create_link(&sysfs_entry->kobj, &attach->dev->kobj,
> - "device");
> - if (ret)
> - goto link_err;
> -
> - return 0;
> -
> -link_err:
> - kobject_del(&sysfs_entry->kobj);
> -kobj_err:
> - kobject_put(&sysfs_entry->kobj);
> - attach->sysfs_entry = NULL;
> -
> - return ret;
> -}
> void dma_buf_stats_teardown(struct dma_buf *dmabuf)
> {
> struct dma_buf_sysfs_entry *sysfs_entry;
> @@ -243,7 +126,6 @@ void dma_buf_stats_teardown(struct dma_buf *dmabuf)
> if (!sysfs_entry)
> return;
>
> - kset_unregister(sysfs_entry->attach_stats_kset);
> kobject_del(&sysfs_entry->kobj);
> kobject_put(&sysfs_entry->kobj);
> }
> @@ -290,7 +172,6 @@ int dma_buf_stats_setup(struct dma_buf *dmabuf)
> {
> struct dma_buf_sysfs_entry *sysfs_entry;
> int ret;
> - struct kset *attach_stats_kset;
>
> if (!dmabuf || !dmabuf->file)
> return -EINVAL;
> @@ -315,21 +196,8 @@ int dma_buf_stats_setup(struct dma_buf *dmabuf)
> if (ret)
> goto err_sysfs_dmabuf;
>
> - /* create the directory for attachment stats */
> - attach_stats_kset = kset_create_and_add("attachments",
> - &dmabuf_sysfs_no_uevent_ops,
> - &sysfs_entry->kobj);
> - if (!attach_stats_kset) {
> - ret = -ENOMEM;
> - goto err_sysfs_attach;
> - }
> -
> - sysfs_entry->attach_stats_kset = attach_stats_kset;
> -
> return 0;
>
> -err_sysfs_attach:
> - kobject_del(&sysfs_entry->kobj);
> err_sysfs_dmabuf:
> kobject_put(&sysfs_entry->kobj);
> dmabuf->sysfs_entry = NULL;
> diff --git a/drivers/dma-buf/dma-buf-sysfs-stats.h b/drivers/dma-buf/dma-buf-sysfs-stats.h
> index 5f4703249117..a49c6e2650cc 100644
> --- a/drivers/dma-buf/dma-buf-sysfs-stats.h
> +++ b/drivers/dma-buf/dma-buf-sysfs-stats.h
> @@ -14,23 +14,8 @@ int dma_buf_init_sysfs_statistics(void);
> void dma_buf_uninit_sysfs_statistics(void);
>
> int dma_buf_stats_setup(struct dma_buf *dmabuf);
> -int dma_buf_attach_stats_setup(struct dma_buf_attachment *attach,
> - unsigned int uid);
> -static inline void dma_buf_update_attachment_map_count(struct dma_buf_attachment *attach,
> - int delta)
> -{
> - struct dma_buf_attach_sysfs_entry *entry = attach->sysfs_entry;
>
> - entry->map_counter += delta;
> -}
> void dma_buf_stats_teardown(struct dma_buf *dmabuf);
> -void dma_buf_attach_stats_teardown(struct dma_buf_attachment *attach);
> -static inline unsigned int dma_buf_update_attach_uid(struct dma_buf *dmabuf)
> -{
> - struct dma_buf_sysfs_entry *entry = dmabuf->sysfs_entry;
> -
> - return entry->attachment_uid++;
> -}
> #else
>
> static inline int dma_buf_init_sysfs_statistics(void)
> @@ -44,19 +29,7 @@ static inline int dma_buf_stats_setup(struct dma_buf *dmabuf)
> {
> return 0;
> }
> -static inline int dma_buf_attach_stats_setup(struct dma_buf_attachment *attach,
> - unsigned int uid)
> -{
> - return 0;
> -}
>
> static inline void dma_buf_stats_teardown(struct dma_buf *dmabuf) {}
> -static inline void dma_buf_attach_stats_teardown(struct dma_buf_attachment *attach) {}
> -static inline void dma_buf_update_attachment_map_count(struct dma_buf_attachment *attach,
> - int delta) {}
> -static inline unsigned int dma_buf_update_attach_uid(struct dma_buf *dmabuf)
> -{
> - return 0;
> -}
> #endif
> #endif // _DMA_BUF_SYSFS_STATS_H
> diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
> index 510b42771974..b1a6db71c656 100644
> --- a/drivers/dma-buf/dma-buf.c
> +++ b/drivers/dma-buf/dma-buf.c
> @@ -738,7 +738,6 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev,
> {
> struct dma_buf_attachment *attach;
> int ret;
> - unsigned int attach_uid;
>
> if (WARN_ON(!dmabuf || !dev))
> return ERR_PTR(-EINVAL);
> @@ -764,13 +763,8 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev,
> }
> dma_resv_lock(dmabuf->resv, NULL);
> list_add(&attach->node, &dmabuf->attachments);
> - attach_uid = dma_buf_update_attach_uid(dmabuf);
> dma_resv_unlock(dmabuf->resv);
>
> - ret = dma_buf_attach_stats_setup(attach, attach_uid);
> - if (ret)
> - goto err_sysfs;
> -
> /* When either the importer or the exporter can't handle dynamic
> * mappings we cache the mapping here to avoid issues with the
> * reservation object lock.
> @@ -797,7 +791,6 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev,
> dma_resv_unlock(attach->dmabuf->resv);
> attach->sgt = sgt;
> attach->dir = DMA_BIDIRECTIONAL;
> - dma_buf_update_attachment_map_count(attach, 1 /* delta */);
> }
>
> return attach;
> @@ -814,7 +807,6 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev,
> if (dma_buf_is_dynamic(attach->dmabuf))
> dma_resv_unlock(attach->dmabuf->resv);
>
> -err_sysfs:
> dma_buf_detach(dmabuf, attach);
> return ERR_PTR(ret);
> }
> @@ -864,7 +856,6 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
> dma_resv_lock(attach->dmabuf->resv, NULL);
>
> __unmap_dma_buf(attach, attach->sgt, attach->dir);
> - dma_buf_update_attachment_map_count(attach, -1 /* delta */);
>
> if (dma_buf_is_dynamic(attach->dmabuf)) {
> dmabuf->ops->unpin(attach);
> @@ -878,7 +869,6 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
> if (dmabuf->ops->detach)
> dmabuf->ops->detach(dmabuf, attach);
>
> - dma_buf_attach_stats_teardown(attach);
> kfree(attach);
> }
> EXPORT_SYMBOL_GPL(dma_buf_detach);
> @@ -1020,10 +1010,6 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
> }
> }
> #endif /* CONFIG_DMA_API_DEBUG */
> -
> - if (!IS_ERR(sg_table))
> - dma_buf_update_attachment_map_count(attach, 1 /* delta */);
> -
> return sg_table;
> }
> EXPORT_SYMBOL_GPL(dma_buf_map_attachment);
> @@ -1061,8 +1047,6 @@ void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
> if (dma_buf_is_dynamic(attach->dmabuf) &&
> !IS_ENABLED(CONFIG_DMABUF_MOVE_NOTIFY))
> dma_buf_unpin(attach);
> -
> - dma_buf_update_attachment_map_count(attach, -1 /* delta */);
> }
> EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment);
>
> diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
> index 2b814fde0d11..678b2006be78 100644
> --- a/include/linux/dma-buf.h
> +++ b/include/linux/dma-buf.h
> @@ -444,15 +444,6 @@ struct dma_buf {
> struct dma_buf_sysfs_entry {
> struct kobject kobj;
> struct dma_buf *dmabuf;
> -
> - /**
> - * @sysfs_entry.attachment_uid:
> - *
> - * This is protected by the dma_resv_lock() on @resv and is
> - * incremented on each attach.
> - */
> - unsigned int attachment_uid;
> - struct kset *attach_stats_kset;
> } *sysfs_entry;
> #endif
> };
> @@ -504,7 +495,6 @@ struct dma_buf_attach_ops {
> * @importer_ops: importer operations for this attachment, if provided
> * dma_buf_map/unmap_attachment() must be called with the dma_resv lock held.
> * @importer_priv: importer specific attachment data.
> - * @sysfs_entry: For exposing information about this attachment in sysfs.
> *
> * This structure holds the attachment information between the dma_buf buffer
> * and its user device(s). The list contains one attachment struct per device
> @@ -525,13 +515,6 @@ struct dma_buf_attachment {
> const struct dma_buf_attach_ops *importer_ops;
> void *importer_priv;
> void *priv;
> -#ifdef CONFIG_DMABUF_SYSFS_STATS
> - /* for sysfs stats */
> - struct dma_buf_attach_sysfs_entry {
> - struct kobject kobj;
> - unsigned int map_counter;
> - } *sysfs_entry;
> -#endif
> };
>
> /**
More information about the dri-devel
mailing list