[PATCH v4 2/2] drm/xe/bo: add GPU memory trace points
Juston Li
justonli at chromium.org
Mon Jul 7 18:07:39 UTC 2025
On Thu, 2025-06-12 at 17:46 +0100, Tvrtko Ursulin wrote:
>
> On 12/06/2025 06:40, Lucas De Marchi wrote:
> > On Wed, Jun 11, 2025 at 03:51:24PM -0700, Juston Li wrote:
> > > Add TRACE_GPU_MEM tracepoints for tracking global and per-process
> > > GPU
> > > memory usage.
> > >
> > > These are required by VSR on Android 12+ for reporting GPU driver
> > > memory
> > > allocations.
> > >
> > > v3:
> > > - Use now configurable CONFIG_TRACE_GPU_MEM instead of adding a
> > > per-driver Kconfig (Lucas)
> > >
> > > v2:
> > > - Use u64 as preferred by checkpatch (Tvrtko)
> > > - Fix errors in comments/Kconfig description (Tvrtko)
> > > - drop redundant "CONFIG" in Kconfig
> > >
> > > Signed-off-by: Juston Li <justonli at chromium.org>
> > > Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at igalia.com>
> > > ---
> > > drivers/gpu/drm/xe/xe_bo.c | 47
> > > ++++++++++++++++++++++++++++
> > > drivers/gpu/drm/xe/xe_device_types.h | 16 ++++++++++
> > > 2 files changed, 63 insertions(+)
> > >
> > > diff --git a/drivers/gpu/drm/xe/xe_bo.c
> > > b/drivers/gpu/drm/xe/xe_bo.c
> > > index 4e39188a021ab..89a3d23e3b800 100644
> > > --- a/drivers/gpu/drm/xe/xe_bo.c
> > > +++ b/drivers/gpu/drm/xe/xe_bo.c
> > > @@ -19,6 +19,8 @@
> > >
> > > #include <kunit/static_stub.h>
> > >
> > > +#include <trace/events/gpu_mem.h>
> > > +
> > > #include "xe_device.h"
> > > #include "xe_dma_buf.h"
> > > #include "xe_drm_client.h"
> > > @@ -418,6 +420,35 @@ static void
> > > xe_ttm_tt_account_subtract(struct
> > > xe_device *xe, struct ttm_tt *tt)
> > > xe_shrinker_mod_pages(xe->mem.shrinker, -(long)tt-
> > > >num_pages, 0);
> > > }
> > >
> > > +#if IS_ENABLED(CONFIG_TRACE_GPU_MEM)
> > > +static void update_global_total_pages(struct ttm_device
> > > *ttm_dev,
> > > long num_pages)
> > > +{
> > > + struct xe_device *xe = ttm_to_xe_device(ttm_dev);
> > > + u64 global_total_pages =
> > > + atomic64_add_return(num_pages, &xe->global_total_pages);
> > > +
> > > + trace_gpu_mem_total(0, 0, global_total_pages << PAGE_SHIFT);
> > > +}
> > > +
> > > +static void update_process_mem(struct drm_file *file, ssize_t
> > > size)
> > > +{
> > > + struct xe_file *xef = to_xe_file(file);
> > > + u64 process_mem = atomic64_add_return(size, &xef-
> > > >process_mem);
> > > +
> > > + rcu_read_lock(); /* Locks file->pid! */
> > > + trace_gpu_mem_total(0, pid_nr(rcu_dereference(file->pid)),
> > > process_mem);
> >
> > Isn't the first arg supposed to be the gpu id? Doesn't this become
> > invalid when I have e.g. LNL + BMG and the trace is enabled?
>
> Good point.
>
> u32 gpu_id does not seem possible to map to anything useful.
>
> Shall we replace it with a string obtained from dev_name(struct
> device
> *) ? As only Android parses them I think we can get still away with
> changing the tracepoints ABI.
>
> >
> > > + rcu_read_unlock();
> > > +}
> > > +#else
> > > +static inline void update_global_total_pages(struct ttm_device
> > > *ttm_dev, long num_pages)
> > > +{
> > > +}
> > > +
> > > +static inline void update_process_mem(struct drm_file *file,
> > > ssize_t
> > > size)
> > > +{
> > > +}
> > > +#endif
> > > +
> > > static struct ttm_tt *xe_ttm_tt_create(struct ttm_buffer_object
> > > *ttm_bo,
> > > u32 page_flags)
> > > {
> > > @@ -525,6 +556,7 @@ static int xe_ttm_tt_populate(struct
> > > ttm_device
> > > *ttm_dev, struct ttm_tt *tt,
> > >
> > > xe_tt->purgeable = false;
> > > xe_ttm_tt_account_add(ttm_to_xe_device(ttm_dev), tt);
> > > + update_global_total_pages(ttm_dev, tt->num_pages);
> > >
> > > return 0;
> > > }
> > > @@ -541,6 +573,7 @@ static void xe_ttm_tt_unpopulate(struct
> > > ttm_device
> > > *ttm_dev, struct ttm_tt *tt)
> > >
> > > ttm_pool_free(&ttm_dev->pool, tt);
> > > xe_ttm_tt_account_subtract(xe, tt);
> > > + update_global_total_pages(ttm_dev, -(long)tt->num_pages);
> > > }
> > >
> > > static void xe_ttm_tt_destroy(struct ttm_device *ttm_dev, struct
> > > ttm_tt *tt)
> > > @@ -1653,6 +1686,15 @@ static void xe_gem_object_free(struct
> > > drm_gem_object *obj)
> > > ttm_bo_put(container_of(obj, struct ttm_buffer_object,
> > > base));
> > > }
> > >
> > > +#if IS_ENABLED(CONFIG_TRACE_GPU_MEM)
> > > +static int xe_gem_object_open(struct drm_gem_object *obj,
> > > + struct drm_file *file_priv)
> > > +{
> > > + update_process_mem(file_priv, obj->size);
> > > + return 0;
> > > +}
> > > +#endif
> > > +
> > > static void xe_gem_object_close(struct drm_gem_object *obj,
> > > struct drm_file *file_priv)
> > > {
> > > @@ -1665,6 +1707,8 @@ static void xe_gem_object_close(struct
> > > drm_gem_object *obj,
> > > ttm_bo_set_bulk_move(&bo->ttm, NULL);
> > > xe_bo_unlock(bo);
> > > }
> > > +
> > > + update_process_mem(file_priv, -obj->size);
> > > }
> > >
> > > static vm_fault_t xe_gem_fault(struct vm_fault *vmf)
> > > @@ -1762,6 +1806,9 @@ static const struct vm_operations_struct
> > > xe_gem_vm_ops = {
> > >
> > > static const struct drm_gem_object_funcs xe_gem_object_funcs = {
> > > .free = xe_gem_object_free,
> > > +#if IS_ENABLED(CONFIG_TRACE_GPU_MEM)
> > > + .open = xe_gem_object_open,
> > > +#endif
> > > .close = xe_gem_object_close,
> > > .mmap = drm_gem_ttm_mmap,
> > > .export = xe_gem_prime_export,
> > > diff --git a/drivers/gpu/drm/xe/xe_device_types.h
> > > b/drivers/gpu/drm/
> > > xe/xe_device_types.h
> > > index e5d02a47a5287..b797e766ccbc2 100644
> > > --- a/drivers/gpu/drm/xe/xe_device_types.h
> > > +++ b/drivers/gpu/drm/xe/xe_device_types.h
> > > @@ -641,6 +641,14 @@ struct xe_device {
> > > unsigned int fsb_freq, mem_freq, is_ddr3;
> > > };
> > > #endif
> > > +
> > > +#if IS_ENABLED(CONFIG_TRACE_GPU_MEM)
> > > + /**
> > > + * @global_total_pages: global GPU page usage tracked for
> > > gpu_mem
> > > + * tracepoints
> > > + */
> > > + atomic64_t global_total_pages;
> > > +#endif
> > > };
> > >
> > > /**
> > > @@ -702,6 +710,14 @@ struct xe_file {
> > >
> > > /** @refcount: ref count of this xe file */
> > > struct kref refcount;
> > > +
> > > +#if IS_ENABLED(CONFIG_TRACE_GPU_MEM)
> > > + /**
> > > + * @process_mem: per-process GPU memory usage tracked for
> > > gpu_mem
> > > + * tracepoints
> > > + */
> > > + atomic64_t process_mem;
> >
> > so... this is not per-process, it's actually "per dev node" open.
> > Does
> > this map correctly to the intended use and how it's handled in msm?
>
> Per struct drm_file. Yes it is the same, both do it via
> drm_gem_object_funcs->open/close.
Sorry this went over my head previously :)
It turns out this does cause issues; Since process_mem is getting
tracked per drm_file, a process with multiple drm_file opens will emit
traces mapping to the same PID entry causing it to overwrite each
other. Eg we actually end up showing the process_mem from the most
recent drm_file trace emitted for that PID, not the collective total of
all drm_file's for that PID...
We'd probably need to add a new field to the ABI; ~ctx_id and let
userspace combine them to get the actual process total.
For now though, it turns out the Android requirement will be satisfied
with just the global_total so for v5 I'll drop process_mem tracking and
evaluate how to add it back later as we have to worry about backwards-
compat for the gpu_trace ABI on Android.
Regards
Juston
> Regards,
>
> Tvrtko
>
> >
> > Lucas De Marchi
> >
> > > +#endif
> > > };
> > >
> > > #endif
> > > --
> > > 2.50.0.rc1.591.g9c95f17f64-goog
> > >
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