From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0AE59C02198 for ; Mon, 10 Feb 2025 13:18:18 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 64E0E10E527; Mon, 10 Feb 2025 13:18:18 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=collabora.com header.i=@collabora.com header.b="qz8glQyK"; dkim-atps=neutral Received: from bali.collaboradmins.com (bali.collaboradmins.com [148.251.105.195]) by gabe.freedesktop.org (Postfix) with ESMTPS id 6B4B210E527 for ; Mon, 10 Feb 2025 13:18:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1739193496; bh=DloKvxbxSfL+Efk0iq0/fks3+nhvwnrxNc4TYB83bYs=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=qz8glQyKOhMMmK59TKev8gLh2kiq0i64t6ENe9n7kVtZT2RfAszOqpysaCEJtnmfd 0932Mg3LwU4WfRCUA50RQUJx17k2epTHp5c4P+P1u8XFswn0LKGsPcoELjJ70itHxb 02m3jgs3P2+F19+wx/RK2FDODb1fR9Oh6PFaqfLP0uuq578Rt/O74yJGECQuJkPSC+ TkIGlnhbF7uPIdDn+P5EVtEStNztAyZPMNNp3qlMa0/3TggCH+W7ZlxUKNvUOfVzP/ Wn934nkT5jqH4R44oklpiMX5EPd62+7RGENx4x6PfVy734cPNtCA+214qZA4ofVBIO jW9FvFWHUNQ9Q== Received: from localhost (unknown [IPv6:2a01:e0a:2c:6930:5cf4:84a1:2763:fe0d]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: bbrezillon) by bali.collaboradmins.com (Postfix) with ESMTPSA id 8D45A17E0FCC; Mon, 10 Feb 2025 14:18:15 +0100 (CET) Date: Mon, 10 Feb 2025 14:18:07 +0100 From: Boris Brezillon To: =?UTF-8?B?QWRyacOhbg==?= Larumbe Cc: Steven Price , Liviu Dudau , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Mihail Atanassov , kernel@collabora.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] drm/panthor: Avoid sleep locking in the internal BO size path Message-ID: <20250210141807.064ccacf@collabora.com> In-Reply-To: <20250210124203.124191-2-adrian.larumbe@collabora.com> References: <20250210124203.124191-1-adrian.larumbe@collabora.com> <20250210124203.124191-2-adrian.larumbe@collabora.com> Organization: Collabora X-Mailer: Claws Mail 4.3.0 (GTK 3.24.43; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Mon, 10 Feb 2025 12:42:00 +0000 Adri=C3=A1n Larumbe wrote: > A previous commit dealt with a similar situation, whereby upon enabling > some mutex debug features, a warning about sleep muteces being used in a ^ mutexes =20 > /proc file read atomic context was being triggered. >=20 > Because in this case replacing the heap mutex with a spinlock isn't > feasible, the fdinfo handler no longer traverses the list of heaps for > every single VM associated with an open DRM file. Instad, when a new heap > chunk is allocated, its size is accumulated into a VM-wide tally, which > also makes the atomic context code path somewhat faster. >=20 > Signed-off-by: Adri=C3=A1n Larumbe > Fixes: 3e2c8c718567 ("drm/panthor: Expose size of driver internal BO's ov= er fdinfo") > --- > drivers/gpu/drm/panthor/panthor_heap.c | 38 ++++++++------------------ > drivers/gpu/drm/panthor/panthor_heap.h | 2 -- > drivers/gpu/drm/panthor/panthor_mmu.c | 18 +++++++----- > drivers/gpu/drm/panthor/panthor_mmu.h | 1 + > 4 files changed, 23 insertions(+), 36 deletions(-) >=20 > diff --git a/drivers/gpu/drm/panthor/panthor_heap.c b/drivers/gpu/drm/pan= thor/panthor_heap.c > index db0285ce5812..686f209f5b09 100644 > --- a/drivers/gpu/drm/panthor/panthor_heap.c > +++ b/drivers/gpu/drm/panthor/panthor_heap.c > @@ -127,6 +127,8 @@ static void panthor_free_heap_chunk(struct panthor_vm= *vm, > heap->chunk_count--; > mutex_unlock(&heap->lock); > =20 > + panthor_vm_heaps_accumulate(vm, -heap->chunk_size); > + > panthor_kernel_bo_destroy(chunk->bo); > kfree(chunk); > } > @@ -180,6 +182,8 @@ static int panthor_alloc_heap_chunk(struct panthor_de= vice *ptdev, > heap->chunk_count++; > mutex_unlock(&heap->lock); > =20 > + panthor_vm_heaps_accumulate(vm, heap->chunk_size); > + > return 0; > =20 > err_destroy_bo: > @@ -389,6 +393,7 @@ int panthor_heap_return_chunk(struct panthor_heap_poo= l *pool, > removed =3D chunk; > list_del(&chunk->node); > heap->chunk_count--; > + panthor_vm_heaps_accumulate(chunk->bo->vm, -heap->chunk_size); > break; > } > } > @@ -560,6 +565,8 @@ panthor_heap_pool_create(struct panthor_device *ptdev= , struct panthor_vm *vm) > if (ret) > goto err_destroy_pool; > =20 > + panthor_vm_heaps_accumulate(vm, pool->gpu_contexts->obj->size); > + > return pool; > =20 > err_destroy_pool: > @@ -594,8 +601,11 @@ void panthor_heap_pool_destroy(struct panthor_heap_p= ool *pool) > xa_for_each(&pool->xa, i, heap) > drm_WARN_ON(&pool->ptdev->base, panthor_heap_destroy_locked(pool, i)); > =20 > - if (!IS_ERR_OR_NULL(pool->gpu_contexts)) > + if (!IS_ERR_OR_NULL(pool->gpu_contexts)) { > + panthor_vm_heaps_accumulate(pool->gpu_contexts->vm, > + -pool->gpu_contexts->obj->size); > panthor_kernel_bo_destroy(pool->gpu_contexts); > + } > =20 > /* Reflects the fact the pool has been destroyed. */ > pool->vm =3D NULL; > @@ -603,29 +613,3 @@ void panthor_heap_pool_destroy(struct panthor_heap_p= ool *pool) > =20 > panthor_heap_pool_put(pool); > } > - > -/** > - * panthor_heap_pool_size() - Calculate size of all chunks across all he= aps in a pool > - * @pool: Pool whose total chunk size to calculate. > - * > - * This function adds the size of all heap chunks across all heaps in the > - * argument pool. It also adds the size of the gpu contexts kernel bo. > - * It is meant to be used by fdinfo for displaying the size of internal > - * driver BO's that aren't exposed to userspace through a GEM handle. > - * > - */ > -size_t panthor_heap_pool_size(struct panthor_heap_pool *pool) > -{ > - struct panthor_heap *heap; > - unsigned long i; > - size_t size =3D 0; > - > - down_read(&pool->lock); > - xa_for_each(&pool->xa, i, heap) > - size +=3D heap->chunk_size * heap->chunk_count; > - up_read(&pool->lock); > - > - size +=3D pool->gpu_contexts->obj->size; > - > - return size; > -} > diff --git a/drivers/gpu/drm/panthor/panthor_heap.h b/drivers/gpu/drm/pan= thor/panthor_heap.h > index e3358d4e8edb..25a5f2bba445 100644 > --- a/drivers/gpu/drm/panthor/panthor_heap.h > +++ b/drivers/gpu/drm/panthor/panthor_heap.h > @@ -27,8 +27,6 @@ struct panthor_heap_pool * > panthor_heap_pool_get(struct panthor_heap_pool *pool); > void panthor_heap_pool_put(struct panthor_heap_pool *pool); > =20 > -size_t panthor_heap_pool_size(struct panthor_heap_pool *pool); > - > int panthor_heap_grow(struct panthor_heap_pool *pool, > u64 heap_gpu_va, > u32 renderpasses_in_flight, > diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c b/drivers/gpu/drm/pant= hor/panthor_mmu.c > index 0a4e352b5505..aaad1a560805 100644 > --- a/drivers/gpu/drm/panthor/panthor_mmu.c > +++ b/drivers/gpu/drm/panthor/panthor_mmu.c > @@ -345,6 +345,10 @@ struct panthor_vm { > =20 > /** @heaps.lock: Lock used to protect access to @pool. */ > struct mutex lock; > + > + /** @heaps.size: Size of all chunks across all heaps in the pool. */ > + ssize_t size; Let's put that into an fdinfo struct. > + Drop the extra blank-line. > } heaps; > =20 > /** @node: Used to insert the VM in the panthor_mmu::vm::list. */ > @@ -1539,6 +1543,7 @@ static void panthor_vm_destroy(struct panthor_vm *v= m) > mutex_lock(&vm->heaps.lock); > panthor_heap_pool_destroy(vm->heaps.pool); > vm->heaps.pool =3D NULL; > + vm->heaps.size =3D 0; > mutex_unlock(&vm->heaps.lock); > =20 > drm_WARN_ON(&vm->ptdev->base, > @@ -1963,13 +1968,7 @@ void panthor_vm_heaps_sizes(struct panthor_file *p= file, struct drm_memory_stats > =20 > xa_lock(&pfile->vms->xa); > xa_for_each(&pfile->vms->xa, i, vm) { > - size_t size =3D 0; > - > - mutex_lock(&vm->heaps.lock); > - if (vm->heaps.pool) > - size =3D panthor_heap_pool_size(vm->heaps.pool); > - mutex_unlock(&vm->heaps.lock); > - > + size_t size =3D vm->heaps.size; > stats->resident +=3D size; > if (vm->as.id >=3D 0) > stats->active +=3D size; > @@ -1977,6 +1976,11 @@ void panthor_vm_heaps_sizes(struct panthor_file *p= file, struct drm_memory_stats > xa_unlock(&pfile->vms->xa); > } > =20 > +void panthor_vm_heaps_accumulate(struct panthor_vm *vm, ssize_t acc) > +{ Either there's some lock protecting this operation and we want a lockdep_assert_held(), or we need to make it an atomic operation (and make the size an atomic_t) to avoid races. > + vm->heaps.size +=3D acc; > +} > + > static u64 mair_to_memattr(u64 mair, bool coherent) > { > u64 memattr =3D 0; > diff --git a/drivers/gpu/drm/panthor/panthor_mmu.h b/drivers/gpu/drm/pant= hor/panthor_mmu.h > index fc274637114e..b6686896f8ef 100644 > --- a/drivers/gpu/drm/panthor/panthor_mmu.h > +++ b/drivers/gpu/drm/panthor/panthor_mmu.h > @@ -39,6 +39,7 @@ struct panthor_heap_pool * > panthor_vm_get_heap_pool(struct panthor_vm *vm, bool create); > =20 > void panthor_vm_heaps_sizes(struct panthor_file *pfile, struct drm_memor= y_stats *stats); > +void panthor_vm_heaps_accumulate(struct panthor_vm *vm, ssize_t acc); > =20 > struct panthor_vm *panthor_vm_get(struct panthor_vm *vm); > void panthor_vm_put(struct panthor_vm *vm);