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d="scan'208";a="89588975" Received: from smoticic-mobl.ger.corp.intel.com (HELO [10.245.246.223]) ([10.245.246.223]) by orviesa009-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Nov 2024 06:45:35 -0800 Message-ID: <747e7befa275ac0fcc95dc4e7e7aca27020e8dda.camel@linux.intel.com> Subject: Re: [PATCH v2 12/29] drm/xe: Add SVM garbage collector From: Thomas =?ISO-8859-1?Q?Hellstr=F6m?= To: Matthew Brost , intel-xe@lists.freedesktop.org, dri-devel@lists.freedesktop.org Cc: apopple@nvidia.com, airlied@gmail.com, christian.koenig@amd.com, simona.vetter@ffwll.ch, felix.kuehling@amd.com, dakr@kernel.org Date: Tue, 19 Nov 2024 15:45:33 +0100 In-Reply-To: <20241016032518.539495-13-matthew.brost@intel.com> References: <20241016032518.539495-1-matthew.brost@intel.com> <20241016032518.539495-13-matthew.brost@intel.com> Autocrypt: addr=thomas.hellstrom@linux.intel.com; prefer-encrypt=mutual; keydata=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 Organization: Intel Sweden AB, Registration Number: 556189-6027 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.50.4 (3.50.4-3.fc39) MIME-Version: 1.0 X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" On Tue, 2024-10-15 at 20:25 -0700, Matthew Brost wrote: > Add basic SVM garbage collector which can destroy an SVM range upon > an > MMU UNMAP event. >=20 > v2: > =C2=A0- Flush garbage collector in xe_svm_close >=20 > Signed-off-by: Matthew Brost > --- > =C2=A0drivers/gpu/drm/xe/xe_svm.c=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 | 87 > +++++++++++++++++++++++++++++++- > =C2=A0drivers/gpu/drm/xe/xe_svm.h=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 |=C2=A0 1= + > =C2=A0drivers/gpu/drm/xe/xe_vm.c=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 |=C2= =A0 4 ++ > =C2=A0drivers/gpu/drm/xe/xe_vm_types.h |=C2=A0 5 ++ > =C2=A04 files changed, 95 insertions(+), 2 deletions(-) >=20 > diff --git a/drivers/gpu/drm/xe/xe_svm.c > b/drivers/gpu/drm/xe/xe_svm.c > index a9addaea316d..9c2f44cba166 100644 > --- a/drivers/gpu/drm/xe/xe_svm.c > +++ b/drivers/gpu/drm/xe/xe_svm.c > @@ -30,6 +30,7 @@ xe_svm_range_alloc(struct drm_gpusvm *gpusvm) > =C2=A0 if (!range) > =C2=A0 return ERR_PTR(-ENOMEM); > =C2=A0 > + INIT_LIST_HEAD(&range->garbage_collector_link); > =C2=A0 xe_vm_get(gpusvm_to_vm(gpusvm)); > =C2=A0 > =C2=A0 return &range->base; > @@ -46,6 +47,24 @@ static struct xe_svm_range *to_xe_range(struct > drm_gpusvm_range *r) > =C2=A0 return container_of(r, struct xe_svm_range, base); > =C2=A0} > =C2=A0 > +static void > +xe_svm_garbage_collector_add_range(struct xe_vm *vm, struct > xe_svm_range *range, > + =C2=A0=C2=A0 const struct mmu_notifier_range > *mmu_range) > +{ > + struct xe_device *xe =3D vm->xe; > + > + drm_gpusvm_range_set_unmapped(&range->base, mmu_range); > + > + spin_lock(&vm->svm.garbage_collector.lock); > + if (list_empty(&range->garbage_collector_link)) > + list_add_tail(&range->garbage_collector_link, > + =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 &vm- > >svm.garbage_collector.range_list); > + spin_unlock(&vm->svm.garbage_collector.lock); > + > + queue_work(xe_device_get_root_tile(xe)->primary_gt- > >usm.pf_wq, > + =C2=A0=C2=A0 &vm->svm.garbage_collector.work); > +} > + > =C2=A0static u8 > =C2=A0xe_svm_range_notifier_event_begin(struct xe_vm *vm, struct > drm_gpusvm_range *r, > =C2=A0 =C2=A0 const struct mmu_notifier_range > *mmu_range, > @@ -88,7 +107,9 @@ xe_svm_range_notifier_event_end(struct xe_vm *vm, > struct drm_gpusvm_range *r, > =C2=A0 struct drm_gpusvm_ctx ctx =3D { .in_notifier =3D true, }; > =C2=A0 > =C2=A0 drm_gpusvm_range_unmap_pages(&vm->svm.gpusvm, r, &ctx); > - /* TODO: Add range to garbage collector */ > + if (mmu_range->event =3D=3D MMU_NOTIFY_UNMAP) > + xe_svm_garbage_collector_add_range(vm, > to_xe_range(r), > + =C2=A0=C2=A0 mmu_range); > =C2=A0} > =C2=A0 > =C2=A0static void xe_svm_invalidate(struct drm_gpusvm *gpusvm, > @@ -184,6 +205,58 @@ static void xe_svm_invalidate(struct drm_gpusvm > *gpusvm, > =C2=A0 xe_svm_range_notifier_event_end(vm, r, mmu_range); > =C2=A0} > =C2=A0 > +static int __xe_svm_garbage_collector(struct xe_vm *vm, > + =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 struct xe_svm_range *range) > +{ > + /* TODO: Do unbind */ > + > + drm_gpusvm_range_remove(&vm->svm.gpusvm, &range->base); > + > + return 0; > +} > + > +static int xe_svm_garbage_collector(struct xe_vm *vm) > +{ > + struct xe_svm_range *range, *next; > + int err; > + > + lockdep_assert_held_write(&vm->lock); > + > + if (xe_vm_is_closed_or_banned(vm)) > + return -ENOENT; > + > + spin_lock(&vm->svm.garbage_collector.lock); > + list_for_each_entry_safe(range, next, > + &vm- > >svm.garbage_collector.range_list, > + garbage_collector_link) { > + list_del(&range->garbage_collector_link); > + spin_unlock(&vm->svm.garbage_collector.lock); This looks broken, what if someone removed the "next" entry here? You probably want to use list_next_entry_or_null(); > + > + err =3D __xe_svm_garbage_collector(vm, range); > + if (err) { > + drm_warn(&vm->xe->drm, > + "Garbage collection failed: %d\n", > err); > + xe_vm_kill(vm, true); > + return err; > + } > + > + spin_lock(&vm->svm.garbage_collector.lock); > + } > + spin_unlock(&vm->svm.garbage_collector.lock); > + > + return 0; > +} > + > +static void xe_svm_garbage_collector_work_func(struct work_struct > *w) > +{ > + struct xe_vm *vm =3D container_of(w, struct xe_vm, > + svm.garbage_collector.work); > + > + down_write(&vm->lock); > + xe_svm_garbage_collector(vm); > + up_write(&vm->lock); > +} > + > =C2=A0static const struct drm_gpusvm_ops gpusvm_ops =3D { > =C2=A0 .range_alloc =3D xe_svm_range_alloc, > =C2=A0 .range_free =3D xe_svm_range_free, > @@ -198,6 +271,11 @@ static const u64 fault_chunk_sizes[] =3D { > =C2=A0 > =C2=A0int xe_svm_init(struct xe_vm *vm) > =C2=A0{ > + spin_lock_init(&vm->svm.garbage_collector.lock); > + INIT_LIST_HEAD(&vm->svm.garbage_collector.range_list); > + INIT_WORK(&vm->svm.garbage_collector.work, > + =C2=A0 xe_svm_garbage_collector_work_func); > + > =C2=A0 return drm_gpusvm_init(&vm->svm.gpusvm, "Xe SVM", &vm->xe- > >drm, > =C2=A0 =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 current->mm, NULL, 0, vm->s= ize, > =C2=A0 =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 SZ_512M, &gpusvm_ops, > fault_chunk_sizes, > @@ -211,6 +289,8 @@ void xe_svm_close(struct xe_vm *vm) > =C2=A0 /* Flush running notifiers making xe_vm_close() visable */ > =C2=A0 xe_svm_notifier_lock(vm); > =C2=A0 xe_svm_notifier_unlock(vm); > + > + flush_work(&vm->svm.garbage_collector.work); > =C2=A0} > =C2=A0 > =C2=A0void xe_svm_fini(struct xe_vm *vm) > @@ -241,7 +321,10 @@ int xe_svm_handle_pagefault(struct xe_vm *vm, > struct xe_vma *vma, > =C2=A0 lockdep_assert_held_write(&vm->lock); > =C2=A0 > =C2=A0retry: > - /* TODO: Run garbage collector */ > + /* Always process UNMAPs first so view SVM ranges is current > */ > + err =3D xe_svm_garbage_collector(vm); > + if (err) > + return err; > =C2=A0 > =C2=A0 r =3D drm_gpusvm_range_find_or_insert(&vm->svm.gpusvm, > fault_addr, > =C2=A0 =C2=A0=C2=A0=C2=A0 xe_vma_start(vma), > xe_vma_end(vma), > diff --git a/drivers/gpu/drm/xe/xe_svm.h > b/drivers/gpu/drm/xe/xe_svm.h > index ee0bd1ae655b..06d90d0f71a6 100644 > --- a/drivers/gpu/drm/xe/xe_svm.h > +++ b/drivers/gpu/drm/xe/xe_svm.h > @@ -17,6 +17,7 @@ struct xe_vma; > =C2=A0 > =C2=A0struct xe_svm_range { > =C2=A0 struct drm_gpusvm_range base; > + struct list_head garbage_collector_link; > =C2=A0 u8 tile_present; > =C2=A0 u8 tile_invalidated; > =C2=A0}; > diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c > index 63aa0a25d3b7..399cbbdbddd5 100644 > --- a/drivers/gpu/drm/xe/xe_vm.c > +++ b/drivers/gpu/drm/xe/xe_vm.c > @@ -3071,6 +3071,10 @@ int xe_vm_bind_ioctl(struct drm_device *dev, > void *data, struct drm_file *file) > =C2=A0 goto put_exec_queue; > =C2=A0 } > =C2=A0 > + /* Ensure all UNMAPs visable */ > + if (xe_vm_in_fault_mode(vm)) > + flush_work(&vm->svm.garbage_collector.work); Hmm, what is someone added an UNMAP here? Thanks, Thomas > + > =C2=A0 err =3D down_write_killable(&vm->lock); > =C2=A0 if (err) > =C2=A0 goto put_vm; > diff --git a/drivers/gpu/drm/xe/xe_vm_types.h > b/drivers/gpu/drm/xe/xe_vm_types.h > index b736e53779d2..2eae3575c409 100644 > --- a/drivers/gpu/drm/xe/xe_vm_types.h > +++ b/drivers/gpu/drm/xe/xe_vm_types.h > @@ -146,6 +146,11 @@ struct xe_vm { > =C2=A0 struct { > =C2=A0 /** @svm.gpusvm: base GPUSVM used to track fault > allocations */ > =C2=A0 struct drm_gpusvm gpusvm; > + struct { > + spinlock_t lock; > + struct list_head range_list; > + struct work_struct work; > + } garbage_collector; > =C2=A0 } svm; > =C2=A0 > =C2=A0 struct xe_device *xe;