| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <1190646257.8360.65.camel@gaivota>
Date: Mon, 24 Sep 2007 12:04:17 -0300
From: Mauro Carvalho Chehab <mchehab@...radead.org>
To: Andres Salomon <dilinger@...ued.net>
Cc: video4linux-list@...hat.com, linux-kernel@...r.kernel.org,
v4l-dvb-maintainer@...uxtv.org, akpm@...ux-foundation.org,
corbet@....net
Subject: Re: [v4l-dvb-maintainer] [PATCH] cafe_ccic: default to allocating
DMA buffers at probe time
Hi Andres,
Still missing on your patch is your SOB ;) From what I got from Jon, he
is ok with your patch.
Cheers,
Mauro.
Em Qua, 2007-09-19 às 01:44 -0400, Andres Salomon escreveu:
> By default, we allocate DMA buffers when actually reading from the video
> capture device. On a system with 128MB or 256MB of ram, it's very easy
> for that memory to quickly become fragmented. We've had users report
> having 30+MB of memory free, but the cafe_ccic driver is still unable to
> allocate DMA buffers.
>
> Our workaround has been to make use of the 'alloc_bufs_at_load' parameter
> to allocate DMA buffers during device probing. This patch makes DMA
> buffer allocation happen during device probe by default, and changes
> the parameter to 'alloc_bufs_at_read'. The camera hardware is there,
> if the cafe_ccic driver is enabled/loaded it should do its best to ensure
> that the camera is actually usable; delaying DMA buffer allocation
> saves an insignicant amount of memory, and causes the driver to be much
> less useful.
> ---
>
> drivers/media/video/cafe_ccic.c | 18 +++++++++---------
> 1 files changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/media/video/cafe_ccic.c b/drivers/media/video/cafe_ccic.c
> index ef53618..3588a59 100644
> --- a/drivers/media/video/cafe_ccic.c
> +++ b/drivers/media/video/cafe_ccic.c
> @@ -63,13 +63,13 @@ MODULE_SUPPORTED_DEVICE("Video");
> */
>
> #define MAX_DMA_BUFS 3
> -static int alloc_bufs_at_load = 0;
> -module_param(alloc_bufs_at_load, bool, 0444);
> -MODULE_PARM_DESC(alloc_bufs_at_load,
> - "Non-zero value causes DMA buffers to be allocated at module "
> - "load time. This increases the chances of successfully getting "
> - "those buffers, but at the cost of nailing down the memory from "
> - "the outset.");
> +static int alloc_bufs_at_read = 0;
> +module_param(alloc_bufs_at_read, bool, 0444);
> +MODULE_PARM_DESC(alloc_bufs_at_read,
> + "Non-zero value causes DMA buffers to be allocated when the "
> + "video capture device is read, rather than at module load "
> + "time. This saves memory, but decreases the chances of "
> + "successfully getting those buffers.");
>
> static int n_dma_bufs = 3;
> module_param(n_dma_bufs, uint, 0644);
> @@ -1503,7 +1503,7 @@ static int cafe_v4l_release(struct inode *inode, struct file *filp)
> }
> if (cam->users == 0) {
> cafe_ctlr_power_down(cam);
> - if (! alloc_bufs_at_load)
> + if (alloc_bufs_at_read)
> cafe_free_dma_bufs(cam);
> }
> mutex_unlock(&cam->s_mutex);
> @@ -2162,7 +2162,7 @@ static int cafe_pci_probe(struct pci_dev *pdev,
> /*
> * If so requested, try to get our DMA buffers now.
> */
> - if (alloc_bufs_at_load) {
> + if (!alloc_bufs_at_read) {
> if (cafe_alloc_dma_bufs(cam, 1))
> cam_warn(cam, "Unable to alloc DMA buffers at load"
> " will try again later.");
>
> _______________________________________________
> v4l-dvb-maintainer mailing list
> v4l-dvb-maintainer@...uxtv.org
> http://www.linuxtv.org/cgi-bin/mailman/listinfo/v4l-dvb-maintainer
--
Cheers,
Mauro
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists