Re: [RFC 3/6] drm: Add fdinfo memory stats

[Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxxxxxxx>]

On 17/04/2023 20:39, Rob Clark wrote:
> On Mon, Apr 17, 2023 at 8:56 AM Tvrtko Ursulin
> <tvrtko.ursulin@xxxxxxxxxxxxxxx> wrote:
> > From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
> >
> > Add support to dump GEM stats to fdinfo.
> >
> > Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
> > ---
> >   Documentation/gpu/drm-usage-stats.rst | 12 +++++++
> >   drivers/gpu/drm/drm_file.c            | 52 +++++++++++++++++++++++++++
> >   include/drm/drm_drv.h                 |  7 ++++
> >   include/drm/drm_file.h                |  8 +++++
> >   4 files changed, 79 insertions(+)
> >
> > diff --git a/Documentation/gpu/drm-usage-stats.rst b/Documentation/gpu/drm-usage-stats.rst
> > index 2ab32c40e93c..8273a41b2fb0 100644
> > --- a/Documentation/gpu/drm-usage-stats.rst
> > +++ b/Documentation/gpu/drm-usage-stats.rst
> > @@ -21,6 +21,7 @@ File format specification
> >
> >   - File shall contain one key value pair per one line of text.
> >   - Colon character (`:`) must be used to delimit keys and values.
> > +- Caret (`^`) is also a reserved character.
>
> this doesn't solve the problem that led me to drm-$CATEGORY-memory... ;-)

Could you explain or remind me with a link to a previous explanation?

What tool barfs on it and how? Spirit of drm-usage-stats.pl is that for 
both drm-engine-<str>: and drm-memory-<str>: generic userspace is 
supposed to take the whole <std> as opaque and just enumerate all it finds.

Gputop manages to do that with engines names it knows _nothing_ about. 
If it worked with memory regions it would just show the list of new 
regions as for example "system^resident", "system^active". Then tools 
can be extended to understand it better and provide a sub-breakdown if 
wanted.

Ugly not, we can change from caret to something nicer, unless I am 
missing something it works, no?

Regards,

Tvrtko

> (also, it is IMHO rather ugly)
>
> BR,
> -R
>
> >   - All keys shall be prefixed with `drm-`.
> >   - Whitespace between the delimiter and first non-whitespace character shall be
> >     ignored when parsing.
> > @@ -105,6 +106,17 @@ object belong to this client, in the respective memory region.
> >   Default unit shall be bytes with optional unit specifiers of 'KiB' or 'MiB'
> >   indicating kibi- or mebi-bytes.
> >
> > +- drm-memory-<str>^size:      <uint> [KiB|MiB]
> > +- drm-memory-<str>^shared:    <uint> [KiB|MiB]
> > +- drm-memory-<str>^resident:  <uint> [KiB|MiB]
> > +- drm-memory-<str>^purgeable: <uint> [KiB|MiB]
> > +- drm-memory-<str>^active:    <uint> [KiB|MiB]
> > +
> > +Resident category is identical to the drm-memory-<str> key and two should be
> > +mutually exclusive.
> > +
> > +TODO more description text...
> > +
> >   - drm-cycles-<str> <uint>
> >
> >   Engine identifier string must be the same as the one specified in the
> > diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
> > index 37b4f76a5191..e202f79e816d 100644
> > --- a/drivers/gpu/drm/drm_file.c
> > +++ b/drivers/gpu/drm/drm_file.c
> > @@ -42,6 +42,7 @@
> >   #include <drm/drm_client.h>
> >   #include <drm/drm_drv.h>
> >   #include <drm/drm_file.h>
> > +#include <drm/drm_gem.h>
> >   #include <drm/drm_print.h>
> >
> >   #include "drm_crtc_internal.h"
> > @@ -871,6 +872,54 @@ void drm_send_event(struct drm_device *dev, struct drm_pending_event *e)
> >   }
> >   EXPORT_SYMBOL(drm_send_event);
> >
> > +static void
> > +print_stat(struct drm_printer *p, const char *stat, const char *region, u64 sz)
> > +{
> > +       const char *units[] = {"", " KiB", " MiB"};
> > +       unsigned int u;
> > +
> > +       if (sz == ~0ull) /* Not supported by the driver. */
> > +               return;
> > +
> > +       for (u = 0; u < ARRAY_SIZE(units) - 1; u++) {
> > +               if (sz < SZ_1K)
> > +                       break;
> > +               sz = div_u64(sz, SZ_1K);
> > +       }
> > +
> > +       drm_printf(p, "drm-memory-%s^%s:\t%llu%s\n",
> > +                  region, stat, sz, units[u]);
> > +}
> > +
> > +static void print_memory_stats(struct drm_printer *p, struct drm_file *file)
> > +{
> > +       struct drm_device *dev = file->minor->dev;
> > +       struct drm_fdinfo_memory_stat *stats;
> > +       unsigned int num, i;
> > +       char **regions;
> > +
> > +       regions = dev->driver->query_fdinfo_memory_regions(dev, &num);
> > +
> > +       stats = kcalloc(num, sizeof(*stats), GFP_KERNEL);
> > +       if (!stats)
> > +               return;
> > +
> > +       dev->driver->query_fdinfo_memory_stats(file, stats);
> > +
> > +       for (i = 0; i < num; i++) {
> > +               if (!regions[i]) /* Allow sparse name arrays. */
> > +                       continue;
> > +
> > +               print_stat(p, "size", regions[i], stats[i].size);
> > +               print_stat(p, "shared", regions[i], stats[i].shared);
> > +               print_stat(p, "resident", regions[i], stats[i].resident);
> > +               print_stat(p, "purgeable", regions[i], stats[i].purgeable);
> > +               print_stat(p, "active", regions[i], stats[i].active);
> > +       }
> > +
> > +       kfree(stats);
> > +}
> > +
> >   /**
> >    * drm_show_fdinfo - helper for drm file fops
> >    * @seq_file: output stream
> > @@ -900,6 +949,9 @@ void drm_show_fdinfo(struct seq_file *m, struct file *f)
> >
> >          if (dev->driver->show_fdinfo)
> >                  dev->driver->show_fdinfo(&p, file);
> > +
> > +       if (dev->driver->query_fdinfo_memory_regions)
> > +               print_memory_stats(&p, file);
> >   }
> >   EXPORT_SYMBOL(drm_show_fdinfo);
> >
> > diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
> > index 89e2706cac56..ccc1cd98d2aa 100644
> > --- a/include/drm/drm_drv.h
> > +++ b/include/drm/drm_drv.h
> > @@ -35,6 +35,7 @@
> >   #include <drm/drm_device.h>
> >
> >   struct drm_file;
> > +struct drm_fdinfo_memory_stat;
> >   struct drm_gem_object;
> >   struct drm_master;
> >   struct drm_minor;
> > @@ -408,6 +409,12 @@ struct drm_driver {
> >           */
> >          void (*show_fdinfo)(struct drm_printer *p, struct drm_file *f);
> >
> > +       char ** (*query_fdinfo_memory_regions)(struct drm_device *dev,
> > +                                              unsigned int *num);
> > +
> > +       void (*query_fdinfo_memory_stats)(struct drm_file *f,
> > +                                         struct drm_fdinfo_memory_stat *stat);
> > +
> >          /** @major: driver major number */
> >          int major;
> >          /** @minor: driver minor number */
> > diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
> > index 7d9b3c65cbc1..00d48beeac5c 100644
> > --- a/include/drm/drm_file.h
> > +++ b/include/drm/drm_file.h
> > @@ -375,6 +375,14 @@ struct drm_file {
> >   #endif
> >   };
> >
> > +struct drm_fdinfo_memory_stat {
> > +       u64 size;
> > +       u64 shared;
> > +       u64 resident;
> > +       u64 purgeable;
> > +       u64 active;
> > +};
> > +
> >   /**
> >    * drm_is_primary_client - is this an open file of the primary node
> >    * @file_priv: DRM file
> > --
> > 2.37.2