Messages in this thread | | | Date | Fri, 28 Jul 2023 14:55:21 +0800 | Subject | Re: [PATCH v3 04/11] media: videobuf2: Stop define VB2_MAX_FRAME as global | From | Hsia-Jun Li <> |
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On 7/28/23 14:46, Tomasz Figa wrote: > CAUTION: Email originated externally, do not click links or open attachments unless you recognize the sender and know the content is safe. > > > On Mon, Jul 17, 2023 at 4:44 PM Hsia-Jun Li <Randy.Li@synaptics.com> wrote: >> >> >> On 7/12/23 18:48, Tomasz Figa wrote: >>> CAUTION: Email originated externally, do not click links or open attachments unless you recognize the sender and know the content is safe. >>> >>> >>> On Mon, Jul 03, 2023 at 04:35:30PM +0800, Hsia-Jun Li wrote: >>>> On 7/3/23 16:09, Benjamin Gaignard wrote: >>>>> CAUTION: Email originated externally, do not click links or open >>>>> attachments unless you recognize the sender and know the content is >>>>> safe. >>>>> >>>>> >>>>> Le 30/06/2023 à 11:51, Hsia-Jun Li a écrit : >>>>>> On 6/22/23 21:13, Benjamin Gaignard wrote: >>>>>>> CAUTION: Email originated externally, do not click links or open >>>>>>> attachments unless you recognize the sender and know the content is >>>>>>> safe. >>>>>>> >>>>>>> >>>>>>> After changing bufs arrays to a dynamic allocated array >>>>>>> VB2_MAX_FRAME doesn't mean anything for videobuf2 core. >>>>>> I think make it 64 which is the VB2_MAX_FRAME in Android GKI kernel is >>>>>> more reasonable. >>>>>> >>>>>> It would be hard to iterate the whole array, it would go worse with a >>>>>> filter. Such iterate may need to go twice because you mix >>>>>> post-processing buffer and decoding buffer(with MV) in the same array. >>>>> Here I don't want to change drivers behavior so I keep the same value. >>>>> If it happens that they need more buffers, like for dynamic resolution >>>>> change >>>>> feature for Verisilicon VP9 decoder, case by case patches will be needed. >>>>> >>>> I just don't like the idea that using a variant length array here. >>>> >>> "I don't like" is not an argument. We had a number of arguments for >>> using a generic helper (originally idr, but later decided to go with >>> XArray, because the former is now deprecated) that we pointed out in >>> our review comments for previous revisions. It wasn't really about the >>> size being variable, but rather avoiding open coding things in vb2 and >>> duplicating what's already implemented in generic code. >> >> I just want to say I don't think we need a variable length array to >> store the buffer here. >> >> And the below is the reason that such a case could be avoided in the >> first place. >> >>> >>>> And I could explain why you won't need so many buffers for the performance >>>> of decoding. >>>> >>>> VP9 could support 10 reference frames in dpb. >>>> >>>> Even for those frequent resolution changing test set, it would only happen >>>> to two resolutions, >>>> >>>> 32 would be enough for 20 buffers of two resolution plus golden frames. It >>>> also leaves enough slots for re-order latency. >>>> >>>> If your case had more two resolutions, likes low->medium->high. >>>> >>>> I would suggest just skip the medium resolutions, just allocate the lower >>>> one first for fast playback then the highest for all the possible >>>> >>>> medium cases. Reallocation happens frequently would only cause memory >>>> fragment, nothing benefits your performance. >>>> >>> We have mechanisms in the kernel to deal with memory fragmentation >>> (migration/compaction) and it would still only matters for the >>> pathologic cases of hardware that require physically contiguous memory. >>> Modern hardware with proper DMA capabilities can either scatter-gather >>> or are equipped with an IOMMU, so the allocation always happens in page >>> granularity and fragmentation is avoided. >> >> Unfortunately, there are more devices that didn't have a IOMMU attached >> to it, supporting scatter gather is more odd. >> >> It would be more likely that IOMMU would be disabled for the performance >> reason. > > These days IOMMU is totally mandatory if you want to think about > having any level of security in your system. Sure, there could be some > systems that are completely isolated from any external environment, > like some offline industry automation machines, but then arguably > their running conditions would also be quite static and require very > little memory re-allocation. Vendor just decided not to included such hardware. That is why From ION to DMA-heap, people like to allocate from a cavout out memory. > > I also don't buy the performance reason. CPUs have been behind MMUs > for ages and nobody is running them with paging disabled for > performance reasons. Similarly, most of the modern consumer systems Page lookup would increase the delay. Besides a few upstream devices prove them only use a level 1 page table without TBL. > (mobile phones, PCs) run with IOMMUs enabled for pretty much anything > because of the security reason and they don't seem to be having any If the page is secure, you can't operate it in a insecure IOMMU or MMU. The most security way here, we should use a dedicated memory(or a zone in unified memory). I believe there are more users in mobile for DMA-heap than kernel's dma allocation API. > performance issues. In fact, it can improve the performance, because > memory allocation is much easier and without contiguous careouts (as > we used to have long ago on Android devices) the extra memory can be > used for buffers and caches to improve system performance. > > Best regards, > Tomasz > >> >>> >>> Best regards, >>> Tomasz >>> >>>>>>> Remove it from the core definitions but keep it for drivers internal >>>>>>> needs. >>>>>>> >>>>>>> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com> >>>>>>> --- >>>>>>> drivers/media/common/videobuf2/videobuf2-core.c | 2 ++ >>>>>>> drivers/media/platform/amphion/vdec.c | 1 + >>>>>>> .../media/platform/mediatek/vcodec/vdec/vdec_vp9_req_lat_if.c | 2 ++ >>>>>>> drivers/media/platform/qcom/venus/hfi.h | 2 ++ >>>>>>> drivers/media/platform/verisilicon/hantro_hw.h | 2 ++ >>>>>>> drivers/staging/media/ipu3/ipu3-v4l2.c | 2 ++ >>>>>>> include/media/videobuf2-core.h | 1 - >>>>>>> include/media/videobuf2-v4l2.h | 4 ---- >>>>>>> 8 files changed, 11 insertions(+), 5 deletions(-) >>>>>>> >>>>>>> diff --git a/drivers/media/common/videobuf2/videobuf2-core.c >>>>>>> b/drivers/media/common/videobuf2/videobuf2-core.c >>>>>>> index 86e1e926fa45..899783f67580 100644 >>>>>>> --- a/drivers/media/common/videobuf2/videobuf2-core.c >>>>>>> +++ b/drivers/media/common/videobuf2/videobuf2-core.c >>>>>>> @@ -31,6 +31,8 @@ >>>>>>> >>>>>>> #include <trace/events/vb2.h> >>>>>>> >>>>>>> +#define VB2_MAX_FRAME 32 >>>>>>> + >>>>>>> static int debug; >>>>>>> module_param(debug, int, 0644); >>>>>>> >>>>>>> diff --git a/drivers/media/platform/amphion/vdec.c >>>>>>> b/drivers/media/platform/amphion/vdec.c >>>>>>> index 3fa1a74a2e20..b3219f6d17fa 100644 >>>>>>> --- a/drivers/media/platform/amphion/vdec.c >>>>>>> +++ b/drivers/media/platform/amphion/vdec.c >>>>>>> @@ -28,6 +28,7 @@ >>>>>>> >>>>>>> #define VDEC_MIN_BUFFER_CAP 8 >>>>>>> #define VDEC_MIN_BUFFER_OUT 8 >>>>>>> +#define VB2_MAX_FRAME 32 >>>>>>> >>>>>>> struct vdec_fs_info { >>>>>>> char name[8]; >>>>>>> diff --git >>>>>>> a/drivers/media/platform/mediatek/vcodec/vdec/vdec_vp9_req_lat_if.c >>>>>>> b/drivers/media/platform/mediatek/vcodec/vdec/vdec_vp9_req_lat_if.c >>>>>>> index 6532a69f1fa8..a1e0f24bb91c 100644 >>>>>>> --- a/drivers/media/platform/mediatek/vcodec/vdec/vdec_vp9_req_lat_if.c >>>>>>> +++ b/drivers/media/platform/mediatek/vcodec/vdec/vdec_vp9_req_lat_if.c >>>>>>> @@ -16,6 +16,8 @@ >>>>>>> #include "../vdec_drv_if.h" >>>>>>> #include "../vdec_vpu_if.h" >>>>>>> >>>>>>> +#define VB2_MAX_FRAME 32 >>>>>>> + >>>>>>> /* reset_frame_context defined in VP9 spec */ >>>>>>> #define VP9_RESET_FRAME_CONTEXT_NONE0 0 >>>>>>> #define VP9_RESET_FRAME_CONTEXT_NONE1 1 >>>>>>> diff --git a/drivers/media/platform/qcom/venus/hfi.h >>>>>>> b/drivers/media/platform/qcom/venus/hfi.h >>>>>>> index f25d412d6553..bd5ca5a8b945 100644 >>>>>>> --- a/drivers/media/platform/qcom/venus/hfi.h >>>>>>> +++ b/drivers/media/platform/qcom/venus/hfi.h >>>>>>> @@ -10,6 +10,8 @@ >>>>>>> >>>>>>> #include "hfi_helper.h" >>>>>>> >>>>>>> +#define VB2_MAX_FRAME 32 >>>>>>> + >>>>>>> #define VIDC_SESSION_TYPE_VPE 0 >>>>>>> #define VIDC_SESSION_TYPE_ENC 1 >>>>>>> #define VIDC_SESSION_TYPE_DEC 2 >>>>>>> diff --git a/drivers/media/platform/verisilicon/hantro_hw.h >>>>>>> b/drivers/media/platform/verisilicon/hantro_hw.h >>>>>>> index e83f0c523a30..9e8faf7ba6fb 100644 >>>>>>> --- a/drivers/media/platform/verisilicon/hantro_hw.h >>>>>>> +++ b/drivers/media/platform/verisilicon/hantro_hw.h >>>>>>> @@ -15,6 +15,8 @@ >>>>>>> #include <media/v4l2-vp9.h> >>>>>>> #include <media/videobuf2-core.h> >>>>>>> >>>>>>> +#define VB2_MAX_FRAME 32 >>>>>>> + >>>>>>> #define DEC_8190_ALIGN_MASK 0x07U >>>>>>> >>>>>>> #define MB_DIM 16 >>>>>>> diff --git a/drivers/staging/media/ipu3/ipu3-v4l2.c >>>>>>> b/drivers/staging/media/ipu3/ipu3-v4l2.c >>>>>>> index e530767e80a5..6627b5c2d4d6 100644 >>>>>>> --- a/drivers/staging/media/ipu3/ipu3-v4l2.c >>>>>>> +++ b/drivers/staging/media/ipu3/ipu3-v4l2.c >>>>>>> @@ -10,6 +10,8 @@ >>>>>>> #include "ipu3.h" >>>>>>> #include "ipu3-dmamap.h" >>>>>>> >>>>>>> +#define VB2_MAX_FRAME 32 >>>>>>> + >>>>>>> /******************** v4l2_subdev_ops ********************/ >>>>>>> >>>>>>> #define IPU3_RUNNING_MODE_VIDEO 0 >>>>>>> diff --git a/include/media/videobuf2-core.h >>>>>>> b/include/media/videobuf2-core.h >>>>>>> index 77921cf894ef..080b783d608d 100644 >>>>>>> --- a/include/media/videobuf2-core.h >>>>>>> +++ b/include/media/videobuf2-core.h >>>>>>> @@ -20,7 +20,6 @@ >>>>>>> #include <media/media-request.h> >>>>>>> #include <media/frame_vector.h> >>>>>>> >>>>>>> -#define VB2_MAX_FRAME (32) >>>>>>> #define VB2_MAX_PLANES (8) >>>>>>> >>>>>>> /** >>>>>>> diff --git a/include/media/videobuf2-v4l2.h >>>>>>> b/include/media/videobuf2-v4l2.h >>>>>>> index 5a845887850b..88a7a565170e 100644 >>>>>>> --- a/include/media/videobuf2-v4l2.h >>>>>>> +++ b/include/media/videobuf2-v4l2.h >>>>>>> @@ -15,10 +15,6 @@ >>>>>>> #include <linux/videodev2.h> >>>>>>> #include <media/videobuf2-core.h> >>>>>>> >>>>>>> -#if VB2_MAX_FRAME != VIDEO_MAX_FRAME >>>>>>> -#error VB2_MAX_FRAME != VIDEO_MAX_FRAME >>>>>>> -#endif >>>>>>> - >>>>>>> #if VB2_MAX_PLANES != VIDEO_MAX_PLANES >>>>>>> #error VB2_MAX_PLANES != VIDEO_MAX_PLANES >>>>>>> #endif >>>>>>> -- >>>>>>> 2.39.2 >>>>>>> >>>> -- >>>> Hsia-Jun(Randy) Li >>>> >> -- >> Hsia-Jun(Randy) Li >>
-- Hsia-Jun(Randy) Li
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