Re: kernel memory allocation
Hi, On Thu, Dec 22, 2011 at 6:33 PM, J.Hwan Kim wrote: > Hi, everyone > > How can I allocated contiguous kernel memory over 128MB ? > When I use _get_free_pages() function, it returns error. > I guess the memory size is greater than the amount which the function > can allocate. You can use bootmem to reserve the memory at boot time, and then use the bootmem allocator to alloocate from that reserved memory/ There is also some new code called CMA (Contiguous Memory Allocator) which hasn't hit the mainline yet, but it could also be used. See: http://lwn.net/Articles/468044/ for further details. -- Dave Hylands Shuswap, BC, Canada http://www.davehylands.com ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
kernel memory allocation
Hi, everyone How can I allocated contiguous kernel memory over 128MB ? When I use _get_free_pages() function, it returns error. I guess the memory size is greater than the amount which the function can allocate. Thanks in advance. Best Regards, J.Hwan Kim ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
RE: kernel memory allocation
> -Original Message- > From: kernelnewbies-boun...@kernelnewbies.org [mailto:kernelnewbies- > boun...@kernelnewbies.org] On Behalf Of João Eduardo Luís > Sent: Friday, June 03, 2011 12:40 PM > To: Amirali Shambayati > Cc: kernelnewbies > Subject: Re: kernel memory allocation > > Hi. > > In future replies, please CC the list. > > Does it panic in during the kmalloc, or afterwards? Are you checking if > 'newBun' is NULL? > > I may be missing something obvious in that code, but unless you are out of > memory or with some past corruption, I don't think that should panic the > kernel. > > In any case, the panic trace should help. > > > Cheers. > > --- > João Eduardo Luís > gpg key: 477C26E5 from pool.keyserver.eu > > > > > > On Jun 3, 2011, at 7:50 PM, Amirali Shambayati wrote: > > > thanks for your guidance. I just want to allocate memory for a struct. I use > this: > > > > struct bundle* newBun; > > newBun = kmalloc(sizeof(*newBun), GFP_KERNEL); > > > > but it goes to panic state. > > Just guessing, but the most likely reason for the above call to kmalloc() to cause a panic is it's being called in atomic context. Are you seeing anything like "scheduling while atomic" in the panic back trace? If so, that's your problem and the solution is most likely to replace the above GFP_KERNEL with GFP_ATOMIC. The alternative would be to restructure the code so that the allocation doesn't happen in atomic context. Jeff Haran Bytemobile ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: kernel memory allocation
Hello, Once again, I would pretty much enjoy if you CC'ed the list on replies. On Jun 3, 2011, at 8:49 PM, Amirali Shambayati wrote: > I set breakpoint before kmalloc. panic happens after kmalloc. > >> 2011/6/4 Amirali Shambayati >> ofcourse it's null before allocate it. I make an instantiation of it. then >> I want to allocate memory for it.What else I should do? I meant, are you checking if 'newBun' is NULL _AFTER_ the kmalloc? The kmalloc call will return NULL instead of a pointer to newly allocated memory whenever an error occurs. If by any chance you are not checking if 'newBun' is NULL after the kmalloc, then you should do it. Also, if the panic happens _after_ the kmalloc, and not _during_ the kmalloc, I would say there's a slim chance of kmalloc being the cause of the panic. --- João Eduardo Luís gpg key: 477C26E5 from pool.keyserver.eu PGP.sig Description: This is a digitally signed message part ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: kernel memory allocation
Hi. In future replies, please CC the list. Does it panic in during the kmalloc, or afterwards? Are you checking if 'newBun' is NULL? I may be missing something obvious in that code, but unless you are out of memory or with some past corruption, I don't think that should panic the kernel. In any case, the panic trace should help. Cheers. --- João Eduardo Luís gpg key: 477C26E5 from pool.keyserver.eu On Jun 3, 2011, at 7:50 PM, Amirali Shambayati wrote: > thanks for your guidance. I just want to allocate memory for a struct. I use > this: > > struct bundle* newBun; > newBun = kmalloc(sizeof(*newBun), GFP_KERNEL); > > but it goes to panic state. > > 2011/6/3 João Eduardo Luís > Hi. > > From [1] I'm lead to believe the only difference between the regular > kmalloc() arguments and those of kmalloc_node() is the one specifying which > node you want to allocate the memory on. > > Aside from the third argument, which seems to be related with NUMA (with > which I never worked on kernel-context), I would suggest you to read [2]. > > If on the other hand you only want to allocate memory locally, maybe you > should use kmalloc() or one of its variants [3]. > > > Cheers. > > > [1] - http://www.kernel.org/doc/htmldocs/kernel-api/API-kmalloc-node.html > [2] - http://www.kernel.org/doc/htmldocs/kernel-api/API-kcalloc.html > [3] - http://www.kernel.org/doc/htmldocs/kernel-api/mm.html#id408507 > --- > João Eduardo Luís > gpg key: 477C26E5 from pool.keyserver.eu > > > > > > On Jun 3, 2011, at 7:07 PM, Amirali Shambayati wrote: > > > > > Hello all, > > > > I just want to allocate memory for a struct instantiation. Would anyone > > guide me what arguments I should pass to "kmalloc_node"? > > Regards, > > -- > > Amirali Shambayati > > Bachelor Student > > Computer Engineering Department > > Sharif University of Technology > > Tehran, Iran > > > > ___ > > Kernelnewbies mailing list > > Kernelnewbies@kernelnewbies.org > > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > > > > > -- > Amirali Shambayati > Bachelor Student > Computer Engineering Department > Sharif University of Technology > Tehran, Iran > PGP.sig Description: This is a digitally signed message part ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: kernel memory allocation
Hi. From [1] I'm lead to believe the only difference between the regular kmalloc() arguments and those of kmalloc_node() is the one specifying which node you want to allocate the memory on. Aside from the third argument, which seems to be related with NUMA (with which I never worked on kernel-context), I would suggest you to read [2]. If on the other hand you only want to allocate memory locally, maybe you should use kmalloc() or one of its variants [3]. Cheers. [1] - http://www.kernel.org/doc/htmldocs/kernel-api/API-kmalloc-node.html [2] - http://www.kernel.org/doc/htmldocs/kernel-api/API-kcalloc.html [3] - http://www.kernel.org/doc/htmldocs/kernel-api/mm.html#id408507 --- João Eduardo Luís gpg key: 477C26E5 from pool.keyserver.eu On Jun 3, 2011, at 7:07 PM, Amirali Shambayati wrote: > > Hello all, > > I just want to allocate memory for a struct instantiation. Would anyone guide > me what arguments I should pass to "kmalloc_node"? > Regards, > -- > Amirali Shambayati > Bachelor Student > Computer Engineering Department > Sharif University of Technology > Tehran, Iran > > ___ > Kernelnewbies mailing list > Kernelnewbies@kernelnewbies.org > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies PGP.sig Description: This is a digitally signed message part ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
kernel memory allocation
Hello all, I just want to allocate memory for a struct instantiation. Would anyone guide me what arguments I should pass to "kmalloc_node"? Regards, -- Amirali Shambayati Bachelor Student Computer Engineering Department Sharif University of Technology Tehran, Iran ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Check Kernel Memory Allocation
Hello, I wanted to know how much kernel and userspace memory is available on the Linux system during run-time either by some C code or some procfile. Do you know how to do that? Thanks, Dev ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Check Kernel Memory Allocation
Hi Dev, > I wanted to know how much kernel and userspace memory is available on the > Linux system during run-time either by some C code or some procfile. > > Do you know how to do that? You can look in /proc/meminfo http://unixfoo.blogspot.com/2008/02/know-about-procmeminfo.html The memory is shared between userspace and kernel space and the amount of memory available changes dynamically as the system is running. Be aware that Cached memory is quite dynamic, and the system will throw away cache pages to make space if it needs to. -- Dave Hylands Shuswap, BC, Canada http://www.davehylands.com ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Check Kernel Memory Allocation
On Fri, Jun 3, 2011 at 01:05, Dev Null wrote: > I wanted to know how much kernel and userspace memory is available on the > Linux system during run-time either by some C code or some procfile. have you checked /proc/meminfo and its handler? -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Fwd: Check Kernel Memory Allocation
-- Forwarded message -- From: Dev Null Date: Tue, May 31, 2011 at 4:08 PM Subject: Check Kernel Memory Allocation To: kernelnewbies Newbies Hello, I wanted to know how much kernel and userspace memory is available on the Linux system during run-time either by some C code or some procfile. Do you know how to do that? Thanks, Dev ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
