From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from madras.collabora.co.uk (madras.collabora.co.uk [46.235.227.172]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 55C9F4C6A for ; Wed, 8 Nov 2023 15:30:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b="EZRQ2kfI" Received: from [100.98.136.55] (cola.collaboradmins.com [195.201.22.229]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: benjamin.gaignard) by madras.collabora.co.uk (Postfix) with ESMTPSA id B783D660768F; Wed, 8 Nov 2023 15:30:41 +0000 (GMT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1699457442; bh=Oc5ucHgBclSu4tvtR6ouULV4VWeFLo0Vi71T2so0T1E=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=EZRQ2kfIX7g6DNxyPFg+xoeMBDkIkPoQ0fcYlPC70AG4A5O7P35PjTsOx4iHw85gY s3qdc5DWZWfTuwU7/8IHP55uhG36Ygw+h+F/mWWHPGYBvxV9TpRktTzgKeD6XHmhZU U9I6Sm9RyMbHMV2XnXPHFls6oi0+O3crsdfuOWODtc3CXhMjxUDCW8eRr5lWYgDhtf fOmLI2Jh/6UEOmEr8EfmcZzajjc81gCjBxMaA1O15Tjfvz60a07fzXo70A57zrTVvq bm6Ogfvn92sct8WUU2/mAWxgGJtDqlypcrf4h27EMB4xnjSKi9B0td0hwKE3ztubek db5gXWPOD9RWQ== Message-ID: Date: Wed, 8 Nov 2023 16:30:39 +0100 Precedence: bulk X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v14 52/56] media: core: Add bitmap manage bufs array entries Content-Language: en-US To: Tomasz Figa Cc: mchehab@kernel.org, m.szyprowski@samsung.com, ming.qian@nxp.com, ezequiel@vanguardiasur.com.ar, p.zabel@pengutronix.de, gregkh@linuxfoundation.org, hverkuil-cisco@xs4all.nl, nicolas.dufresne@collabora.com, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-arm-msm@vger.kernel.org, linux-rockchip@lists.infradead.org, linux-staging@lists.linux.dev, kernel@collabora.com References: <20231031163104.112469-1-benjamin.gaignard@collabora.com> <20231031163104.112469-53-benjamin.gaignard@collabora.com> <20231108104439.oxpbbd2yro7u57t4@chromium.org> From: Benjamin Gaignard In-Reply-To: <20231108104439.oxpbbd2yro7u57t4@chromium.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Le 08/11/2023 à 11:44, Tomasz Figa a écrit : > On Tue, Oct 31, 2023 at 05:31:00PM +0100, Benjamin Gaignard wrote: >> Add a bitmap field to know which of bufs array entries are >> used or not. >> Remove no more used num_buffers field from queue structure. >> Use bitmap_find_next_zero_area() to find the first possible >> range when creating new buffers to fill the gaps. >> >> Signed-off-by: Benjamin Gaignard >> --- >> .../media/common/videobuf2/videobuf2-core.c | 42 +++++++++++++++---- >> include/media/videobuf2-core.h | 15 ++++--- >> 2 files changed, 42 insertions(+), 15 deletions(-) >> >> diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c >> index 2c8cf479a962..6e88406fcae9 100644 >> --- a/drivers/media/common/videobuf2/videobuf2-core.c >> +++ b/drivers/media/common/videobuf2/videobuf2-core.c >> @@ -416,11 +416,12 @@ static void init_buffer_cache_hints(struct vb2_queue *q, struct vb2_buffer *vb) >> */ >> static void vb2_queue_add_buffer(struct vb2_queue *q, struct vb2_buffer *vb, unsigned int index) >> { >> - WARN_ON(index >= q->max_num_buffers || q->bufs[index]); >> + WARN_ON(index >= q->max_num_buffers || test_bit(index, q->bufs_bitmap)); >> >> q->bufs[index] = vb; >> vb->index = index; >> vb->vb2_queue = q; >> + set_bit(index, q->bufs_bitmap); >> } >> >> /** >> @@ -429,6 +430,7 @@ static void vb2_queue_add_buffer(struct vb2_queue *q, struct vb2_buffer *vb, uns >> */ >> static void vb2_queue_remove_buffer(struct vb2_buffer *vb) >> { >> + clear_bit(vb->index, vb->vb2_queue->bufs_bitmap); >> vb->vb2_queue->bufs[vb->index] = NULL; >> vb->vb2_queue = NULL; >> } >> @@ -450,11 +452,12 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory, >> unsigned long index; >> int ret; >> >> - /* Ensure that the number of already queue + num_buffers is below q->max_num_buffers */ >> + /* Ensure that vb2_get_num_buffers(q) + num_buffers is no more than q->max_num_buffers */ >> num_buffers = min_t(unsigned int, num_buffers, >> q->max_num_buffers - vb2_get_num_buffers(q)); >> >> - index = vb2_get_num_buffers(q); >> + index = bitmap_find_next_zero_area(q->bufs_bitmap, q->max_num_buffers, >> + 0, num_buffers, 0); >> >> *first_index = index; >> >> @@ -656,7 +659,6 @@ static void __vb2_queue_free(struct vb2_queue *q, unsigned int buffers) >> kfree(vb); >> } >> >> - q->num_buffers -= buffers; >> if (!vb2_get_num_buffers(q)) { >> q->memory = VB2_MEMORY_UNKNOWN; >> INIT_LIST_HEAD(&q->queued_list); >> @@ -874,6 +876,14 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory, >> q->bufs = kcalloc(q->max_num_buffers, sizeof(*q->bufs), GFP_KERNEL); >> if (!q->bufs) >> ret = -ENOMEM; >> + >> + if (!q->bufs_bitmap) >> + q->bufs_bitmap = bitmap_zalloc(q->max_num_buffers, GFP_KERNEL); >> + if (!q->bufs_bitmap) { >> + ret = -ENOMEM; >> + kfree(q->bufs); >> + q->bufs = NULL; >> + } >> q->memory = memory; >> mutex_unlock(&q->mmap_lock); >> if (ret) >> @@ -943,7 +953,6 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory, >> } >> >> mutex_lock(&q->mmap_lock); >> - q->num_buffers = allocated_buffers; >> >> if (ret < 0) { >> /* >> @@ -970,6 +979,10 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory, >> mutex_lock(&q->mmap_lock); >> q->memory = VB2_MEMORY_UNKNOWN; >> mutex_unlock(&q->mmap_lock); >> + kfree(q->bufs); >> + q->bufs = NULL; >> + bitmap_free(q->bufs_bitmap); >> + q->bufs_bitmap = NULL; >> return ret; >> } >> EXPORT_SYMBOL_GPL(vb2_core_reqbufs); >> @@ -1006,9 +1019,19 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory, >> q->memory = memory; >> if (!q->bufs) >> q->bufs = kcalloc(q->max_num_buffers, sizeof(*q->bufs), GFP_KERNEL); >> - if (!q->bufs) >> + if (!q->bufs) { >> ret = -ENOMEM; >> + goto unlock; >> + } >> + if (!q->bufs_bitmap) >> + q->bufs_bitmap = bitmap_zalloc(q->max_num_buffers, GFP_KERNEL); > Same as with the kcalloc(). Why not just allocate this in the core code, > e.g. vb2_core_queue_init()? > > Actually, is it because we want to avoid allocating > resources early, before the need to actually use the vb2 queue? > If so, could this go to some other core function that runs later, e.g. __vb2_queue_alloc()? For the same reason :-) vb2_core_queue_init() and vb2_core_queue_release() aren't balanced so I can't use them for that. > >> + if (!q->bufs_bitmap) { >> + ret = -ENOMEM; >> + kfree(q->bufs); >> + q->bufs = NULL; >> + } >> mutex_unlock(&q->mmap_lock); >> +unlock: >> if (ret) >> return ret; >> q->waiting_for_buffers = !q->is_output; >> @@ -1070,7 +1093,6 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory, >> } >> >> mutex_lock(&q->mmap_lock); >> - q->num_buffers += allocated_buffers; >> >> if (ret < 0) { >> /* >> @@ -2549,7 +2571,9 @@ void vb2_core_queue_release(struct vb2_queue *q) >> __vb2_queue_free(q, q->max_num_buffers); >> kfree(q->bufs); >> q->bufs = NULL; >> - q->num_buffers = 0; >> + bitmap_free(q->bufs_bitmap); >> + q->bufs_bitmap = NULL; >> + >> mutex_unlock(&q->mmap_lock); >> } >> EXPORT_SYMBOL_GPL(vb2_core_queue_release); >> @@ -2904,7 +2928,7 @@ static size_t __vb2_perform_fileio(struct vb2_queue *q, char __user *data, size_ >> * Check if we need to dequeue the buffer. >> */ >> index = fileio->cur_index; >> - if (index >= q->num_buffers) { >> + if (!test_bit(index, q->bufs_bitmap)) { > I don't like this low level manipulation of queue internals here (after all > the work other patches did to use helpers). Why not just keep > vb2_get_num_buffers() here? I will change that and put it in patch 8 > >> struct vb2_buffer *b; >> >> /* >> diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h >> index 6986ff4b77cd..288477075a0e 100644 >> --- a/include/media/videobuf2-core.h >> +++ b/include/media/videobuf2-core.h >> @@ -346,7 +346,7 @@ struct vb2_buffer { >> * describes the requested number of planes and sizes\[\] >> * contains the requested plane sizes. In this case >> * \*num_buffers are being allocated additionally to >> - * q->num_buffers. If either \*num_planes or the requested >> + * queue buffers. If either \*num_planes or the requested > Perhaps "the buffers already in the queue"? ok > >> * sizes are invalid callback must return %-EINVAL. >> * @wait_prepare: release any locks taken while calling vb2 functions; >> * it is called before an ioctl needs to wait for a new >> @@ -557,7 +557,7 @@ struct vb2_buf_ops { >> * @memory: current memory type used >> * @dma_dir: DMA mapping direction. >> * @bufs: videobuf2 buffer structures >> - * @num_buffers: number of allocated/used buffers >> + * @bufs_bitmap: bitmap to manage bufs entries. > Perhaps "bitmap tracking whether each bufs[] entry is used"? ok > >> * @max_num_buffers: upper limit of number of allocated/used buffers >> * @queued_list: list of buffers currently queued from userspace >> * @queued_count: number of buffers queued and ready for streaming. >> @@ -621,7 +621,7 @@ struct vb2_queue { >> unsigned int memory; >> enum dma_data_direction dma_dir; >> struct vb2_buffer **bufs; >> - unsigned int num_buffers; >> + unsigned long *bufs_bitmap; >> unsigned int max_num_buffers; >> >> struct list_head queued_list; >> @@ -1150,7 +1150,10 @@ static inline bool vb2_fileio_is_active(struct vb2_queue *q) >> */ >> static inline unsigned int vb2_get_num_buffers(struct vb2_queue *q) >> { >> - return q->num_buffers; >> + if (!q->bufs_bitmap) >> + return 0; >> + >> + return bitmap_weight(q->bufs_bitmap, q->max_num_buffers); > Hmm, could we just cache the number of buffers we have, so that we don't > have to go over the entire bitmap every time? (Basically just keep the > code that we had for handling q->num_buffers before this patch.) I would prefer no duplicate how the number of buffers in a queue is computed and bitmap offer helpers for that. Why not use it ? > >> } >> >> /** >> @@ -1253,13 +1256,13 @@ static inline void vb2_clear_last_buffer_dequeued(struct vb2_queue *q) >> static inline struct vb2_buffer *vb2_get_buffer(struct vb2_queue *q, >> unsigned int index) >> { >> - if (!q->bufs) >> + if (!q->bufs_bitmap) >> return NULL; >> >> if (index >= q->max_num_buffers) >> return NULL; >> >> - if (index < q->num_buffers) >> + if (test_bit(index, q->bufs_bitmap)) > Aha, I see why we need the extra condition above now. Perhaps it should've > been added in this patch instead? For me it was more explicit do introduce it at the same time that max_num_buffers field. Regards, Benjamin > >> return q->bufs[index]; >> return NULL; >> } >> -- >> 2.39.2 >> > Best regards, > Tomasz