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From:   Rob Clark <robdclark@gmail.com>
Date:   Mon, 30 Oct 2023 11:26:59 -0700
Message-ID: <CAF6AEGsq+LApqQQA9z9p+ce4CN-eant==y5hcOzNZ0PccHFCnQ@mail.gmail.com>
Subject: Re: [PATCH 6/7] drm/exec: Pass in initial # of objects
To:     =?UTF-8?Q?Christian_K=C3=B6nig?= <ckoenig.leichtzumerken@gmail.com>
Cc:     =?UTF-8?Q?Christian_K=C3=B6nig?= <christian.koenig@amd.com>,
        Kefeng Wang <wangkefeng.wang@huawei.com>,
        Karol Herbst <kherbst@redhat.com>,
        "open list:DRM DRIVER FOR NVIDIA GEFORCE/QUADRO GPUS" 
        <nouveau@lists.freedesktop.org>, dri-devel@lists.freedesktop.org,
        Mario Limonciello <mario.limonciello@amd.com>,
        Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>,
        David Airlie <airlied@gmail.com>,
        Rob Clark <robdclark@chromium.org>,
        Guchun Chen <guchun.chen@amd.com>,
        Shashank Sharma <shashank.sharma@amd.com>,
        "open list:RADEON and AMDGPU DRM DRIVERS" 
        <amd-gfx@lists.freedesktop.org>,
        Dong Chenchen <dongchenchen2@huawei.com>,
        Luben Tuikov <luben.tuikov@amd.com>,
        Philip Yang <Philip.Yang@amd.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@amd.com>,
        linux-arm-msm@vger.kernel.org,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Suren Baghdasaryan <surenb@google.com>,
        Jack Xiao <Jack.Xiao@amd.com>,
        Jonathan Kim <jonathan.kim@amd.com>,
        freedreno@lists.freedesktop.org,
        Felix Kuehling <Felix.Kuehling@amd.com>,
        "Pan, Xinhui" <Xinhui.Pan@amd.com>,
        open list <linux-kernel@vger.kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Alex Deucher <alexander.deucher@amd.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Lang Yu <Lang.Yu@amd.com>
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On Mon, Oct 30, 2023 at 9:01=E2=80=AFAM Christian K=C3=B6nig
<ckoenig.leichtzumerken@gmail.com> wrote:
>
> Am 30.10.23 um 14:38 schrieb Rob Clark:
> > On Mon, Oct 30, 2023 at 1:05=E2=80=AFAM Christian K=C3=B6nig
> > <christian.koenig@amd.com> wrote:
> >> Am 27.10.23 um 18:58 schrieb Rob Clark:
> >>> From: Rob Clark <robdclark@chromium.org>
> >>>
> >>> In cases where the # is known ahead of time, it is silly to do the ta=
ble
> >>> resize dance.
> >> Ah, yes that was my initial implementation as well, but I ditched that
> >> because nobody actually used it.
> >>
> >> One comment below.
> >>
> >>> Signed-off-by: Rob Clark <robdclark@chromium.org>
> >>> ---
> >>>    drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c  |  2 +-
> >>>    drivers/gpu/drm/amd/amdgpu/amdgpu_csa.c |  4 ++--
> >>>    drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c |  4 ++--
> >>>    drivers/gpu/drm/amd/amdgpu/amdgpu_mes.c |  4 ++--
> >>>    drivers/gpu/drm/drm_exec.c              | 15 ++++++++++++---
> >>>    drivers/gpu/drm/nouveau/nouveau_exec.c  |  2 +-
> >>>    drivers/gpu/drm/nouveau/nouveau_uvmm.c  |  2 +-
> >>>    include/drm/drm_exec.h                  |  2 +-
> >>>    8 files changed, 22 insertions(+), 13 deletions(-)
> >>>
> >>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm=
/amd/amdgpu/amdgpu_cs.c
> >>> index efdb1c48f431..d27ca8f61929 100644
> >>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> >>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> >>> @@ -65,7 +65,7 @@ static int amdgpu_cs_parser_init(struct amdgpu_cs_p=
arser *p,
> >>>        }
> >>>
> >>>        amdgpu_sync_create(&p->sync);
> >>> -     drm_exec_init(&p->exec, DRM_EXEC_INTERRUPTIBLE_WAIT);
> >>> +     drm_exec_init(&p->exec, DRM_EXEC_INTERRUPTIBLE_WAIT, 0);
> >>>        return 0;
> >>>    }
> >>>
> >>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_csa.c b/drivers/gpu/dr=
m/amd/amdgpu/amdgpu_csa.c
> >>> index 720011019741..796fa6f1420b 100644
> >>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_csa.c
> >>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_csa.c
> >>> @@ -70,7 +70,7 @@ int amdgpu_map_static_csa(struct amdgpu_device *ade=
v, struct amdgpu_vm *vm,
> >>>        struct drm_exec exec;
> >>>        int r;
> >>>
> >>> -     drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT);
> >>> +     drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT, 0);
> >>>        drm_exec_until_all_locked(&exec) {
> >>>                r =3D amdgpu_vm_lock_pd(vm, &exec, 0);
> >>>                if (likely(!r))
> >>> @@ -110,7 +110,7 @@ int amdgpu_unmap_static_csa(struct amdgpu_device =
*adev, struct amdgpu_vm *vm,
> >>>        struct drm_exec exec;
> >>>        int r;
> >>>
> >>> -     drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT);
> >>> +     drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT, 0);
> >>>        drm_exec_until_all_locked(&exec) {
> >>>                r =3D amdgpu_vm_lock_pd(vm, &exec, 0);
> >>>                if (likely(!r))
> >>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/dr=
m/amd/amdgpu/amdgpu_gem.c
> >>> index ca4d2d430e28..16f1715148ad 100644
> >>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
> >>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
> >>> @@ -203,7 +203,7 @@ static void amdgpu_gem_object_close(struct drm_ge=
m_object *obj,
> >>>        struct drm_exec exec;
> >>>        long r;
> >>>
> >>> -     drm_exec_init(&exec, DRM_EXEC_IGNORE_DUPLICATES);
> >>> +     drm_exec_init(&exec, DRM_EXEC_IGNORE_DUPLICATES, 0);
> >>>        drm_exec_until_all_locked(&exec) {
> >>>                r =3D drm_exec_prepare_obj(&exec, &bo->tbo.base, 1);
> >>>                drm_exec_retry_on_contention(&exec);
> >>> @@ -739,7 +739,7 @@ int amdgpu_gem_va_ioctl(struct drm_device *dev, v=
oid *data,
> >>>        }
> >>>
> >>>        drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT |
> >>> -                   DRM_EXEC_IGNORE_DUPLICATES);
> >>> +                   DRM_EXEC_IGNORE_DUPLICATES, 0);
> >>>        drm_exec_until_all_locked(&exec) {
> >>>                if (gobj) {
> >>>                        r =3D drm_exec_lock_obj(&exec, gobj);
> >>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.c b/drivers/gpu/dr=
m/amd/amdgpu/amdgpu_mes.c
> >>> index b6015157763a..3c351941701e 100644
> >>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.c
> >>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.c
> >>> @@ -1105,7 +1105,7 @@ int amdgpu_mes_ctx_map_meta_data(struct amdgpu_=
device *adev,
> >>>
> >>>        amdgpu_sync_create(&sync);
> >>>
> >>> -     drm_exec_init(&exec, 0);
> >>> +     drm_exec_init(&exec, 0, 0);
> >>>        drm_exec_until_all_locked(&exec) {
> >>>                r =3D drm_exec_lock_obj(&exec,
> >>>                                      &ctx_data->meta_data_obj->tbo.ba=
se);
> >>> @@ -1176,7 +1176,7 @@ int amdgpu_mes_ctx_unmap_meta_data(struct amdgp=
u_device *adev,
> >>>        struct drm_exec exec;
> >>>        long r;
> >>>
> >>> -     drm_exec_init(&exec, 0);
> >>> +     drm_exec_init(&exec, 0, 0);
> >>>        drm_exec_until_all_locked(&exec) {
> >>>                r =3D drm_exec_lock_obj(&exec,
> >>>                                      &ctx_data->meta_data_obj->tbo.ba=
se);
> >>> diff --git a/drivers/gpu/drm/drm_exec.c b/drivers/gpu/drm/drm_exec.c
> >>> index 5d2809de4517..27d11c20d148 100644
> >>> --- a/drivers/gpu/drm/drm_exec.c
> >>> +++ b/drivers/gpu/drm/drm_exec.c
> >>> @@ -69,16 +69,25 @@ static void drm_exec_unlock_all(struct drm_exec *=
exec)
> >>>     * drm_exec_init - initialize a drm_exec object
> >>>     * @exec: the drm_exec object to initialize
> >>>     * @flags: controls locking behavior, see DRM_EXEC_* defines
> >>> + * @nr: the initial # of objects
> >>>     *
> >>>     * Initialize the object and make sure that we can track locked ob=
jects.
> >>> + *
> >>> + * If nr is non-zero then it is used as the initial objects table si=
ze.
> >>> + * In either case, the table will grow (be re-allocated) on demand.
> >>>     */
> >>> -void drm_exec_init(struct drm_exec *exec, uint32_t flags)
> >>> +void drm_exec_init(struct drm_exec *exec, uint32_t flags, unsigned n=
r)
> >>>    {
> >>> +     size_t sz =3D PAGE_SIZE;
> >>> +
> >>> +     if (nr)
> >>> +             sz =3D (size_t)nr * sizeof(void *);
> >>> +
> >>>        exec->flags =3D flags;
> >>> -     exec->objects =3D kmalloc(PAGE_SIZE, GFP_KERNEL);
> >>> +     exec->objects =3D kmalloc(sz, GFP_KERNEL);
> >> Please use k*v*malloc() here since we can't predict how large that wil=
l be.
> > or __GFP_NOWARN?  If userspace (or kasan) is cheeky and asks for ~0
> > objects, we should probably just fail?
>
> Oh, good point! If this value is controlled by userspace we must be much
> more careful.
>
> Instead of __GFP_NOWARN or any other workaround we should use
> kvmalloc_array() here.
>
> Maybe turn the code upside down, in other words something like this here:
>
> if (!nr)
>      nr =3D PAGE_SIZE / sizeof(void *);
>
> exec->objects =3D kvmalloc_array(nr, sizeof(void *), GFP_KERNEL);
> exec->max_objects =3D exec->objects ? nr : 0;

oh, good point

BR,
-R

>
> Regards,
> Christian.
>
> >
> > BR,
> > -R
> >
> >> With that fixed the patch is Reviewed-by: Christian K=C3=B6nig
> >> <christian.koenig@amd.com>.
> >>
> >> Regards,
> >> Christian.
> >>
> >>>        /* If allocation here fails, just delay that till the first us=
e */
> >>> -     exec->max_objects =3D exec->objects ? PAGE_SIZE / sizeof(void *=
) : 0;
> >>> +     exec->max_objects =3D exec->objects ? sz / sizeof(void *) : 0;
> >>>        exec->num_objects =3D 0;
> >>>        exec->contended =3D DRM_EXEC_DUMMY;
> >>>        exec->prelocked =3D NULL;
> >>> diff --git a/drivers/gpu/drm/nouveau/nouveau_exec.c b/drivers/gpu/drm=
/nouveau/nouveau_exec.c
> >>> index 19024ce21fbb..f5930cc0b3fb 100644
> >>> --- a/drivers/gpu/drm/nouveau/nouveau_exec.c
> >>> +++ b/drivers/gpu/drm/nouveau/nouveau_exec.c
> >>> @@ -103,7 +103,7 @@ nouveau_exec_job_submit(struct nouveau_job *job)
> >>>
> >>>        nouveau_uvmm_lock(uvmm);
> >>>        drm_exec_init(exec, DRM_EXEC_INTERRUPTIBLE_WAIT |
> >>> -                         DRM_EXEC_IGNORE_DUPLICATES);
> >>> +                         DRM_EXEC_IGNORE_DUPLICATES, 0);
> >>>        drm_exec_until_all_locked(exec) {
> >>>                struct drm_gpuva *va;
> >>>
> >>> diff --git a/drivers/gpu/drm/nouveau/nouveau_uvmm.c b/drivers/gpu/drm=
/nouveau/nouveau_uvmm.c
> >>> index aae780e4a4aa..3a9331a1c830 100644
> >>> --- a/drivers/gpu/drm/nouveau/nouveau_uvmm.c
> >>> +++ b/drivers/gpu/drm/nouveau/nouveau_uvmm.c
> >>> @@ -1288,7 +1288,7 @@ nouveau_uvmm_bind_job_submit(struct nouveau_job=
 *job)
> >>>        }
> >>>
> >>>        drm_exec_init(exec, DRM_EXEC_INTERRUPTIBLE_WAIT |
> >>> -                         DRM_EXEC_IGNORE_DUPLICATES);
> >>> +                         DRM_EXEC_IGNORE_DUPLICATES, 0);
> >>>        drm_exec_until_all_locked(exec) {
> >>>                list_for_each_op(op, &bind_job->ops) {
> >>>                        struct drm_gpuva_op *va_op;
> >>> diff --git a/include/drm/drm_exec.h b/include/drm/drm_exec.h
> >>> index b5bf0b6da791..f1a66c048721 100644
> >>> --- a/include/drm/drm_exec.h
> >>> +++ b/include/drm/drm_exec.h
> >>> @@ -135,7 +135,7 @@ static inline bool drm_exec_is_contended(struct d=
rm_exec *exec)
> >>>        return !!exec->contended;
> >>>    }
> >>>
> >>> -void drm_exec_init(struct drm_exec *exec, uint32_t flags);
> >>> +void drm_exec_init(struct drm_exec *exec, uint32_t flags, unsigned n=
r);
> >>>    void drm_exec_fini(struct drm_exec *exec);
> >>>    bool drm_exec_cleanup(struct drm_exec *exec);
> >>>    int drm_exec_lock_obj(struct drm_exec *exec, struct drm_gem_object=
 *obj);
>