Clarification needed on register_netdevice_notifier behavior.
Hi all, I encountered a behavior of register_netdevice_notifier. Upon the registration a notifier, it calls the notifier looping through each net_device and invokes the notifier. If, at some instance, the notifier fails with error, it rollsback each of net_device it had been notified earlier. Pls take a look at the function. I am not sure whether the rolling back part is done for a reason. Does this not possibly cause undesirable behaviors in the notifier's client for the reason that it had been misinformed that all the net_devices' are unregistered? -- Regards, Paraneetharan C ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Need help understanding memory models, cpu modes and address translation
The document and osdev are very good and useful. Thanks a lot. - Paraneetharan C On 13 July 2011 14:23, amit mehta gmate.a...@gmail.com wrote: Tons of resource http://wiki.osdev.org/ On Wed, Jul 13, 2011 at 2:07 PM, Vaibhav Jain vjoss...@gmail.com wrote: Hi, Thanks for the link.I really appreciate but I need something more basic and something that explains these concepts from a broader perspective and not in the context of a particular cpu architecture.Please send me more such links if you come across any. Thanks Vaibhav Jain On Wed, Jul 13, 2011 at 1:14 AM, Daniel Baluta daniel.bal...@gmail.com wrote: Hi, I am eager to understand the basics of Memory models (flat, segmented etc) , CPU modes (real,protected) and address translation (physical to logical etc.) and how all of them work together. I am very confused about this and would really appreciate if someone could provide good references to these topics. You may find useful information inside i366 Programmers Manual. Anyhow, reading materials is the first step in understanding these concepts. You will have to actually read/write/debug pieces of code related to them. thanks, Daniel. [1] pdos.csail.mit.edu/6.828/2010/readings/i386.pdf ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies -- Life is elsewhere. Cross Frontiers. Fly away. - Salman Rushdie ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies -- Regards, Paraneetharan C ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: interview question how does application connects to device
I think the thread originator is asking about how the application knows which device file to read or write. This is done by h/w management system udev. udev creates/manages device nodes in /dev/ dir and notifes applications based on the udev rules written (via HAL events or DBUS signals). Thanks, Paraneetharan C On 5 July 2011 12:21, Philipp Ittershagen li...@gate-nine.de wrote: On 07/05/2011 06:15 AM, Bond wrote: But he was expecting some thing more complex. Well, to be honest, I also was expecting something more complex when I first looked at kernel programming and creating character devices ;) But the file_operations interface is really straight-forward and simple, very nice. Philipp ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies -- Regards, Paraneetharan C ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Basic HighMeM Question
On 29 June 2011 12:08, Mulyadi Santosa mulyadi.sant...@gmail.com wrote: Hi :) On Wed, Jun 29, 2011 at 13:30, piyush moghe pmker...@gmail.com wrote: Thanks Mulyadi and Prabhu for your enlightening description. You welcome :) What a plight!!! memory has become soo cheap nowadays that I don't have less than 1GB system and difficult to find someone in my knowledge having less than 1 GB memory. In embedded world, it's still common scenario so it depends on which side we see it :) That's the flexibility Linux kernel tries to show...it does well on big memory machine...but it can also run in small amount of memory... of course, with the right user space applications :) (hint: Linux slitaz, puppy, tiny core...) Although does this means that pages in FCOM will never have page fault? Everything mapped in kernel space ( I stress the word mapped) is designed to stay all the time in RAM in Linux kernel context. So based on that AFAIK, we won't get page fault in kernel space. This is strictly design choice IMHO. and if this is true is this the reason why we assign NULL to memory descriptor ( mm_struct ) for kernel threads? because kernel threads don't need to have specific address space owned to them. They can simply borrow last scheduled process' address space. After all, they just operate in kernel space, which is the same for all processes, be it kernel threads or normal task. Thanks Mulyadi for your clarifications! I am not getting the idea of borrowing last run process's address space. A kernel thread refers only the addresses in kernel's address space (low-mem area) which is mapped already, isnt it? How does the address space of last run task comes into picture? -- 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 -- Regards, Paraneetharan C ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
