linux-kernel - Re: [Freedreno] [PATCH 00/14] drm/msm: de-struct_mutex-ification

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Date:   Mon, 5 Oct 2020 20:25:21 -0700
From:   Rob Clark <robdclark@...il.com>
To:     Daniel Vetter <daniel@...ll.ch>
Cc:     Kristian Høgsberg <hoegsberg@...il.com>,
        Rob Clark <robdclark@...omium.org>,
        "open list:DRM DRIVER FOR MSM ADRENO GPU" 
        <freedreno@...ts.freedesktop.org>,
        Emil Velikov <emil.velikov@...labora.com>,
        Jonathan Marek <jonathan@...ek.ca>,
        "open list:DRM DRIVER FOR MSM ADRENO GPU" 
        <linux-arm-msm@...r.kernel.org>,
        Sharat Masetty <smasetty@...eaurora.org>,
        open list <linux-kernel@...r.kernel.org>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        "moderated list:DMA BUFFER SHARING FRAMEWORK" 
        <linaro-mm-sig@...ts.linaro.org>,
        Ben Dooks <ben.dooks@...ethink.co.uk>,
        AngeloGioacchino Del Regno <kholk11@...il.com>,
        Sam Ravnborg <sam@...nborg.org>,
        "open list:DMA BUFFER SHARING FRAMEWORK" 
        <linux-media@...r.kernel.org>
Subject: Re: [Freedreno] [PATCH 00/14] drm/msm: de-struct_mutex-ification

On Mon, Oct 5, 2020 at 11:20 AM Daniel Vetter <daniel@...ll.ch> wrote:
>
> On Mon, Oct 5, 2020 at 6:24 PM Kristian Høgsberg <hoegsberg@...il.com> wrote:
> >
> > On Sun, Oct 4, 2020 at 9:21 PM Rob Clark <robdclark@...il.com> wrote:
> > >
> > > From: Rob Clark <robdclark@...omium.org>
> > >
> > > This doesn't remove *all* the struct_mutex, but it covers the worst
> > > of it, ie. shrinker/madvise/free/retire.  The submit path still uses
> > > struct_mutex, but it still needs *something* serialize a portion of
> > > the submit path, and lock_stat mostly just shows the lock contention
> > > there being with other submits.  And there are a few other bits of
> > > struct_mutex usage in less critical paths (debugfs, etc).  But this
> > > seems like a reasonable step in the right direction.
> >
> > What a great patch set. Daniel has some good points and nothing that
> > requires big changes, but on the other hand, I'm not sure it's
> > something that needs to block this set either.
>
> Personally I'd throw the lockdep priming on top to make sure this
> stays correct (it's 3 lines), but yes imo this is all good to go. Just
> figured I'll sprinkle the latest in terms of gem locking over the
> series while it's here :-)

Yeah, I'll defn throw the lockdep priming into v2.. and I've got using
obj->resv for locking on the todo list but looks like enough churn
that it will probably be it's own series (but seems like there is room
to introduce some lock/unlock helpers that don't really change
anything but make an obj->lock transition easier)

BR,
-R

> -Daniel
>
> > Either way, for the series
> >
> > Reviewed-by: Kristian H. Kristensen <hoegsberg@...gle.com>
> >
> > > Rob Clark (14):
> > >   drm/msm: Use correct drm_gem_object_put() in fail case
> > >   drm/msm: Drop chatty trace
> > >   drm/msm: Move update_fences()
> > >   drm/msm: Add priv->mm_lock to protect active/inactive lists
> > >   drm/msm: Document and rename preempt_lock
> > >   drm/msm: Protect ring->submits with it's own lock
> > >   drm/msm: Refcount submits
> > >   drm/msm: Remove obj->gpu
> > >   drm/msm: Drop struct_mutex from the retire path
> > >   drm/msm: Drop struct_mutex in free_object() path
> > >   drm/msm: remove msm_gem_free_work
> > >   drm/msm: drop struct_mutex in madvise path
> > >   drm/msm: Drop struct_mutex in shrinker path
> > >   drm/msm: Don't implicit-sync if only a single ring
> > >
> > >  drivers/gpu/drm/msm/adreno/a5xx_gpu.c     |  4 +-
> > >  drivers/gpu/drm/msm/adreno/a5xx_preempt.c | 12 +--
> > >  drivers/gpu/drm/msm/adreno/a6xx_gpu.c     |  4 +-
> > >  drivers/gpu/drm/msm/msm_debugfs.c         |  7 ++
> > >  drivers/gpu/drm/msm/msm_drv.c             | 15 +---
> > >  drivers/gpu/drm/msm/msm_drv.h             | 19 +++--
> > >  drivers/gpu/drm/msm/msm_gem.c             | 76 ++++++------------
> > >  drivers/gpu/drm/msm/msm_gem.h             | 53 +++++++++----
> > >  drivers/gpu/drm/msm/msm_gem_shrinker.c    | 58 ++------------
> > >  drivers/gpu/drm/msm/msm_gem_submit.c      | 17 ++--
> > >  drivers/gpu/drm/msm/msm_gpu.c             | 96 ++++++++++++++---------
> > >  drivers/gpu/drm/msm/msm_gpu.h             |  5 +-
> > >  drivers/gpu/drm/msm/msm_ringbuffer.c      |  3 +-
> > >  drivers/gpu/drm/msm/msm_ringbuffer.h      | 13 ++-
> > >  14 files changed, 188 insertions(+), 194 deletions(-)
> > >
> > > --
> > > 2.26.2
> > >
> > > _______________________________________________
> > > Freedreno mailing list
> > > Freedreno@...ts.freedesktop.org
> > > https://lists.freedesktop.org/mailman/listinfo/freedreno
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel@...ts.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
>
>
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch

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