MIssed interrupts

Hi, If a particual IRQ line has been disabled (disable_irq()), what happens if the device on that IRQ line generates interrupt? Does it result in missed interrupt? And in case of Uniprocessor machine, what happens if interrupts are generated while spinlock_irq_save() etc? TIA, Rick - To unsubsc

Copy-on-Write

Hi, I had read that the operating systems that use copy-on-write mechanism for fork(), it is better if they deliberately allow the CHILD to run first. This would be better because in 99% of the cases child will call exec() and the new address space will be allocated. Instead if the parent is exec

TLB Question

Hi, I'm trying to understand the MMU operations & am wondering where is the kernel code where the kernel interfaces with the this piece of hardware? Can some one help me in understanding that what all are the responsibilities of the kernel, and what is it the hardware takes care of automatically?

Porting linux kernel on Xilinx FPGA board

Hi, I need to port a customized linux kernel on the latest Xilinx Virtex-5 FPGA based board (PowerPC architecture). However, my question relates more to the Xilinx FPGA technology (EDK etc.) than the kernel. Considering that this is a completely new board, what all EDK related things I'll need to

Multithreaded debugging of kernel using kgdb

Hi List, I am debugging Linux kernel using gdb (KGDB patch). I am successsfully able to set breakpoints in the kernel and step though the code as far as a single thread of execution is concerned. However, I was curious so as to how can I simulate and debug a race condition that involves multiple

Re: Threading in linux

> NPTL on 2.4? this can be done only if you backport the features from 2.6 that were added in order to make NPTL possible ... redhat has done this, but really it's just a waste of time ... 2.4 is dead :P Could you hint upon the kernel features required for NPTL? May be a link? > pthreads on

Re: Threading in linux

On 4/24/07, Amol Lad <[EMAIL PROTECTED]> wrote: On Tue, 2007-04-24 at 12:08 +0530, Rick Brown wrote: > Hi list, > > I read that the kernel does not differentiate between threads and > processes. Only for scheduling. Kernel maintains thread level data structures to enable say f

Threading in linux

Hi list, I read that the kernel does not differentiate between threads and processes. That means, we can say that on a Linux system, the threading is purely provided by user level thread libraries, right? So as long as relevant system calls do not change, it should be possible to run any threadi

reader-writer spinlocks

Hi LIst, This is about reader-writer spinlocks. The Robert love's book says that Readers are given preference over writers, where as LDD3 says writers are given preference over readers. So which one is correct? And about reader-writer semaphores? Thanks, Rick - To unsubscribe from this list:

Re: Why is Linux not RTOS?

On 4/4/07, John Anthony Kazos Jr. <[EMAIL PROTECTED]> wrote: > Why is Linux kernel considered a (hard) realtime OS? I already > understand the basic reason is that the linux kernel does not > guarantee that a task will be completed on time. But I would > appreciate answers in terms of more of ker

Why is Linux not RTOS?

Hi, Why is Linux kernel considered a (hard) realtime OS? I already understand the basic reason is that the linux kernel does not guarantee that a task will be completed on time. But I would appreciate answers in terms of more of kernel jargons. What stops us from classifying kernel as hard RTOS?

fcntl v/s ioctl

Hi, Could some one please explain me the differences and similarities between fcntl and ioctl? Is one built upon the other? AFAIK, both are used for handling of very device specific commands by the driver. Thanks, Rick - To unsubscribe from this list: send the line "unsubscribe linux-newbie" in

regarding kernel preemption

Hi list, I had posted this on kernelnewbies, but did not get much response, and hence trying here. When we preempt_enable() / preempt_disable(), is the kernel preemption enabled or disabled for ALL the processors or just the local processor? TIA, Rick - To unsubscribe from this list: send the

kernel preemption

Hi list, When we preempt_enable() / preempt_disable(), is the kernel preemption enabled or disabled for ALL the processors or just the local processor? TIA, Rick - To unsubscribe from this list: send the line "unsubscribe linux-newbie" in the body of a message to [EMAIL PROTECTED] More majordom

need for 3G/1G split

Hi, Why is kernel restricted to use virtual addresses of only 1 GB? Or what is the need to split up the virtual address space into user addresses and kernel addresses? TIA, Rick - To unsubscribe from this list: send the line "unsubscribe linux-newbie" in the body of a message to [EMAIL PROTECTE

query related to different architectures

Hi, Please pardon me for this stupid question, but this is regarding a confusion I have developed regarding the architectures as listed in arch/ directory: 1) i386 - I understand this is the most commonly used intel IA32 architecture to which all the pentiums, xeons, and 386, 486 etc belong. It

kernel porting query

Hi, I have a very basic query regarding kernel porting on different boards. I understand that even if two boards have the very same processor core (say MIPS 4KE), we need to port linux for them seperately. I have heard things like it is because of certain "board level differences", I need to prov

Determining amout a physical RAM my kernel needs?

Hi list, I have a kernel image about 600 KB in size that I intend to program to flash memory on my target board (hence size required in flash=600 KB). 1) But how do I determine the size of the RAM required to run that image? (Since I believe the image will be uncompressed in RAM, plus will also

schedulting in SMP machine

Hi, If an executing process is interrupted by an interrupt, is it ensured that it won't get transferred to another idle CPU in the system?? This would mean that despite the fact that a CPU is idle in the system, still the process will wait untill the ISR finishes its execution? Thanks, Rick -

EXPORT_SYMBOL not mandatory in 2.4.x?

Hi, 1) I'm using two 2.4 based kernel modules. The first module defines a symbol but does not EXPORT_SYSMBOL() it. Would my second module be able to use that symbol? In 2.4? In 2.6? 2) Also, in 2.4, is it OK if I start using my device memory before request_mem_region()? Thanks, Rick - To unsub

request_mem_region() compulsory or advisory?

Hi, I'm trying to write a simple driver using some registers of my hardware. Is a call to request_mem_region() advisory ("recommended") or compulsory before I ioremap the memory? In other words, if I don't use request_mem_region() before I start using the memory; is my driver BOUND to fail, or

question regarding firmware

Hi list, Please pardon me for posting some what off the topic question here. I read that the driver has the reponsibility to download firmware onto a device. My understanding of "firmware" is that it is the code that runs IN the device without any help from the host (Hence there needs to be a pr