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From: David Laight <David.Laight@ACULAB.COM>
To: 'Hans Verkuil' <hverkuil-cisco@xs4all.nl>,
	'Laurent Pinchart' <laurent.pinchart@ideasonboard.com>,
	Benjamin Gaignard <benjamin.gaignard@collabora.com>
Cc: "tfiga@chromium.org" <tfiga@chromium.org>,
	"m.szyprowski@samsung.com" <m.szyprowski@samsung.com>,
	"mchehab@kernel.org" <mchehab@kernel.org>,
	"ming.qian@nxp.com" <ming.qian@nxp.com>,
	"shijie.qin@nxp.com" <shijie.qin@nxp.com>,
	"eagle.zhou@nxp.com" <eagle.zhou@nxp.com>,
	"bin.liu@mediatek.com" <bin.liu@mediatek.com>,
	"matthias.bgg@gmail.com" <matthias.bgg@gmail.com>,
	"angelogioacchino.delregno@collabora.com" 
	<angelogioacchino.delregno@collabora.com>,
	"tiffany.lin@mediatek.com" <tiffany.lin@mediatek.com>,
	"andrew-ct.chen@mediatek.com" <andrew-ct.chen@mediatek.com>,
	"yunfei.dong@mediatek.com" <yunfei.dong@mediatek.com>,
	"stanimir.k.varbanov@gmail.com" <stanimir.k.varbanov@gmail.com>,
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	"agross@kernel.org" <agross@kernel.org>,
	"andersson@kernel.org" <andersson@kernel.org>,
	"konrad.dybcio@linaro.org" <konrad.dybcio@linaro.org>,
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	"p.zabel@pengutronix.de" <p.zabel@pengutronix.de>,
	"daniel.almeida@collabora.com" <daniel.almeida@collabora.com>,
	"linux-media@vger.kernel.org" <linux-media@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"linux-mediatek@lists.infradead.org" 
	<linux-mediatek@lists.infradead.org>,
	"linux-arm-msm@vger.kernel.org" <linux-arm-msm@vger.kernel.org>,
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	"kernel@collabora.com" <kernel@collabora.com>
Subject: RE: [RFC 2/4] media: videobuf2: Replace bufs array by a list
Date: Tue, 14 Mar 2023 10:11:07 +0000	[thread overview]
Message-ID: <dc04d48e34ed40e58f43badd001a81d0@AcuMS.aculab.com> (raw)
In-Reply-To: <e704b505-86d8-c6f2-8546-adccdab72622@xs4all.nl>

From: Hans Verkuil
> Sent: 14 March 2023 08:55
...
> Why not start with a dynamically allocated array of 32 vb2_buffer pointers?
> And keep doubling the size (reallocing) whenever more buffers are needed,
> up to some maximum (1024 would be a good initial value for that, I think).
> This max could be even a module option.

I don't know the typical uses (or the code at all).
But it might be worth having a small array in the structure itself.
Useful if there are typically always (say) less than 8 buffers.
For larger sizes use the (IIRC) kmalloc_size() to find the actual
size of the structure that will be allocate and set the array
size appropriately.

	David

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Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

  reply	other threads:[~2023-03-14 10:21 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-13 13:59 [RFC 0/4] Allow more than 32 vb2 buffers per queue Benjamin Gaignard
2023-03-13 13:59 ` [RFC 1/4] media: videobuf2: Use vb2_get_buffer() as helper everywhere Benjamin Gaignard
2023-03-13 16:51   ` Andrzej Pietrasiewicz
2023-03-13 16:56     ` Benjamin Gaignard
2023-03-13 18:01   ` Laurent Pinchart
2023-03-13 18:04     ` Laurent Pinchart
2023-03-13 13:59 ` [RFC 2/4] media: videobuf2: Replace bufs array by a list Benjamin Gaignard
2023-03-13 18:11   ` Laurent Pinchart
2023-03-13 23:16     ` David Laight
2023-03-14  8:55       ` Hans Verkuil
2023-03-14 10:11         ` David Laight [this message]
2023-03-14 10:42           ` Hans Verkuil
2023-03-19 23:33             ` Laurent Pinchart
2023-03-22 14:50               ` Nicolas Dufresne
2023-03-22 15:01                 ` Laurent Pinchart
2023-03-24 15:14                   ` Nicolas Dufresne
2023-03-24 15:18                     ` Hans Verkuil
2023-03-24 15:34                       ` Nicolas Dufresne
2023-03-24 20:21                         ` Laurent Pinchart
2023-03-15 13:57     ` Nicolas Dufresne
2023-03-19 23:33       ` Laurent Pinchart
2023-03-13 13:59 ` [RFC 3/4] media: videobuf2: Use bitmap to manage vb2 index Benjamin Gaignard
2023-03-13 18:14   ` Laurent Pinchart
2023-03-14  2:10   ` [EXT] " Ming Qian
2023-03-13 13:59 ` [RFC 4/4] media: videobuf2: Stop define VB2_MAX_FRAME as global Benjamin Gaignard

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