Re: allocation failed: out of vmalloc space error treating andVIDEO1394 IOC LISTEN CHANNEL ioctl failed problem

[Stefan Richter]

On 14 Jan, Arjan van de Ven wrote:
> vmalloc space is limited; you really can't assume you can get any more
> than 64Mb or so (and even then it's thight on some systems already);

I suppose "grep VmallocChunk /proc/meminfo" shows what is available?

> it really sounds like vmalloc space isn't the right solution for your
> problem whatever it is (context is lost in the quoted mail)...
> can you restate the problem to see if there's a better solution
> possible?

Thanks. Below is Peter's message to linux1394-devel. The previous
discussion went over libdc1394-devel which I don't receive. Obviously he
wants a really large buffer for reception of an isochronous stream. I
guess his reason is highly application specific...

| Hi all,
| 
| I've been trying to get a resolution to the problem with vmalloc error (the 
| <<allocation failed: out of vmalloc space - use vmalloc=<size> to increase 
| size.>> kernel error message thing). The plan how to resolve the issue is 
| simple; get the buffer size that we try to allocate (vmmap.nb_buffers * 
| vmmap.buf_size) and compare it to the VMALLOC_RESERVED. If too big, error 
| with explanation how to fix it. If small, other error (usual out of mem). 
| Problem is: how to get the VMALLOC_RESERVED value for the kernel that is 
| running? I couldn't find any standard way to do that (something to apply to 
| GNU Linux and the like). All the things I could get were the default value 
| being 128MiB :) and that is it. Now, I could just put 128, but what if 
| somebody changes that, or in some new distro suddenly decides to make it 
| different? Even worse, what if it is an old kernel with 64 setting?
| 
| Currently, in the SVN version, Damien was kind to change so that a message 
| gets printed with a full explanation of how to treat it. Still, this is a 
| compromise solution and not the elegant one that I was looking for. I believe 
| and hope that maybe somebody had this issue before and could help with some 
| suggestions...
| 
| So, my question is: anybody knows the way to get to the kernel value like 
| VMALLOC_RESERVED or something around this area (a function like getpagesize 
| or sysconf)? It will do a great deal to solve the problematic error treatment 
| in the library...
| 
| Thank you.
| 
| For your reference, this is in response to this line of thinking or the 
| libdc1394-devel thread:
| [...]
| > > When I set NUM_BUFFERS (number of DMA buffers) to a value greater than 5
| > > the program dies like this:
| > >
| > > (dc1394_capture.c) VIDEO1394_IOC_LISTEN_CHANNEL ioctl failed!
| > > Libdc1394 error (dc1394_capture.c:dc1394_capture_setup_dma:382): Capture
| > > is not set : Could not setup DMA capture
| [...]
| > > [17723533.496000] video1394_0: Iso receive DMA: 8 buffers of size
| > > 6627328 allocated for a frame size 6624000, each with 1619 prgs
| > > [17723533.516000] video1394_0: iso context 0 listen on channel 1
| > > [17723533.712000] ieee1394: Node [1-01:1023] wants to release broadcast
| > > channel 31.  Ignoring.
| > > [17723534.448000] video1394_1: mask: 0000000000000004 usage:
| > > 0000000000000000
| > > [17723534.448000]
| > > [17723534.508000] video1394_1: Iso receive DMA: 8 buffers of size
| > > 6627328 allocated for a frame size 6624000, each with 1619 prgs
| > > [17723534.532000] video1394_1: iso context 0 listen on channel 2
| > > [17723534.728000] ieee1394: Node [2-01:1023] wants to release broadcast
| > > channel 31.  Ignoring.
| > > [17723535.464000] video1394_2: mask: 0000000000000008 usage:
| > > 0000000000000000
| > > [17723535.464000]
| > > [17723535.464000] printk: 11 messages suppressed.
| > > [17723535.464000] allocation failed: out of vmalloc space - use
| > > vmalloc=<size> to increase size.
| > > [17723535.464000] dma_region_alloc: vmalloc_32() failed
| > > [17723535.464000] video1394_2: Failed to allocate dma buffer
| > > [17723535.464000] video1394_2: Couldn't allocate ir context
| > > [17723535.668000] video1394_0: On release: Iso receive context 0 stop
| > > listening on channel 1
| > > [17723535.676000] video1394_1: On release: Iso receive context 0 stop
| > > listening on channel 2
| [...]
| > ------------------------------
| >
| > Message: 2
| > Date: Fri, 05 Jan 2007 17:30:39 +0100
| > From: Martin Peris <xxxxxxxxxxxxxxxxxxx>
| > Subject: Re: [libdc1394-devel] [SPAM RBL] Re:
| >         VIDEO1394_IOC_LISTEN_CHANNEL    ioctl failed! and Bad images
| > To: Damien Douxchamps <xxxxxxxxxxxxxxxxxxxxx>
| > Cc: libdc1394-devel <xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
| [...]
| > I think I have some answers...
| >
| > I've been investigating a bit, and the  problem with the limit in the
| > size of the allocated DMA buffer  is not so obscure.
| >
| > vmalloc_32() allocate virtually contiguous memory (32bit addressable),
| > the default maximum amount of memory reserved for this depends on each
| > kernel compilation, and in my case it was set to 128Mbytes that's why I
| > had an error if tried to allocate too many buffers.
| >
| >  but at boot time you can specify how much virtually contiguous memory
| > you want with the parameter vmalloc, so if you want about 512Mbytes of
| > memory for vmalloc you should add the parameter vmalloc=536870912 to the
| > line that defines the kernel parameters. (If you use grub there should
| > be a line like this on /boot/grub/menu.lst)
| >
| > kernel          /boot/vmlinuz-2.6.15-27-686 root=/dev/sda2
| > vmalloc=536870912 ro quiet splash
| >
| >
| > That killed my problem with:
| >
| > dc1394_capture.c) VIDEO1394_IOC_LISTEN_CHANNEL ioctl failed!
| > Libdc1394 error (dc1394_capture.c:dc1394_capture_setup_dma:382): Capture
| > is not set : Could not setup DMA capture
| [...]



-- 
Stefan Richter
-=====-=-=== ---= -===-
http://arcgraph.de/sr/

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