General :: Division Of Logical Memory Space In To User Space And Kernel Space

Jan 4, 2010

Logical Memory Space of 4GB is divided in to 3GB User Space and 1GB Kernel Space. Always. Correct?

1. How can we change it? (just changing value of PAGE_OFFSET is okay?)

2. If system have only 256MB of memory (embedded system) and suppose Kernel Modules eat away all the memory during boot. User space will be left will no memory. Is this case possible?

View 2 Replies


ADVERTISEMENT

General :: Calling User Space Callback Function From Kernel Space?

Sep 22, 2009

I am writing device driver in which i have to call callback function from kernel space, which are saving my data. But the callback functions are in userspace. While accessing them i am getting segmentation fault.

View 1 Replies View Related

Programming :: Passing Data Between Kernel Space To User Space In Asynchronous Way

Dec 13, 2010

I am developing a I2C CDROM client driver. The CDROM firmware supports TOC information read through a I2C command. It sends the TOC information in burst ( Interrupts a GPIO pin when it is ready ) and my CPU does a I2C read to read the TOC. When the CDROM firmware finishes sending the last data burst , it informs my CPU that it is done with the TOC, by a flag in the last data burst. I would like to know, which is the most efficinet way I can send these TOC information to userspace?

View 4 Replies View Related

Programming :: Function In Kernel Space Called Form User Space

Jul 7, 2009

I wanna write a file in kernel space but from my searching I can to know that instead of writeing file in kernel space ,I can write data to user space by copy_to_user space.

But link is missing ...I dont know how will my user space will access kernel space means my function in kernel space which will do copy_to_user /....How my user space function will call my kernel level function ..

Can any one of you provide me with some example file which are doing this .I know every char driver is using it ...but i could not trace back how user level function is accessing it ...i m confused between user space and kernel space.

View 2 Replies View Related

Programming :: Call Socket Prog Code Written In User Space From Kernel Space?

Jul 14, 2009

How to use execv from kernel space to call a user space program writtenfor socket prog.

I tried to write code for socket in kernel but its not working.

Socket code in kernel is also needed.

View 2 Replies View Related

Programming :: Signal From Kernel Space To User Space?

Jul 21, 2011

I have the following requirement in my module. The driver gets some data from the external device. After getting 1MB of data it has to send it to the user space application. What is the best thing to implement for this in driver.? Is it ok to implement like, after getting data, the driver will send a signal to the user space application. Then the user space application sends an ioctl to read the data. Is there any alternate, that the driver directly sends the data without the user space application asks for it.?

View 4 Replies View Related

General :: Measure Kernel Space Time And User Space Time?

Nov 28, 2010

measure kernel space time and user space time?

View 1 Replies View Related

General :: Virtual Space Seen By Each New Process In User Space?

Jun 21, 2010

In a 32-bit system, max memory addressable is 4GB. Now Linux kernel does memory mapping division of 1GB for kernel address space and 3GB for user address space. That means 4GB of virtual address space is divided between kernel (1GB) and user (3GB).

Q1. All virtual mapping utilizes the available physical RAM without any division? I mean to say that if RAM is 512MB then a page in kernel space can lie any where RAM (leave aside old PCI dma accesses)? (How this fits to fact that kernel memory is non-pageble)

Q2. If a process is created in user space, it has visibility 4GB address space or 3GB address space?

View 2 Replies View Related

Hardware :: How To Read Logical Block From User Space

Feb 18, 2010

I have a list of Logical Block Addresses that I need to read from the disk. Is there any way to do this from user space?

View 1 Replies View Related

General :: Tools To View/edit User Space Memory Of Running Processes?

Nov 2, 2010

Are there any tools to view/edit user space memory of running processes on Linux?

It would be a great learning tool.

View 1 Replies View Related

General :: Mapping Kernel Virtual Address Space To Physical Memory Zones?

Nov 4, 2010

As i undertsand - out of 1GB of the virtual Address space for Kernel from 3GB to 4GB of the process address space, Kernel image (code, data, bss, stack, heap) resides staring @0x0 address. Vmalloc area starts either at the end of Physical ram size or at 896M. This 896M cap is mandated to ensure that minimum of 128MB is reserved as vmalloc_reserve for vmalloc,kmap etc.

Is the understanding correct? Now trying to map Physical Zones into this 1GB address space

Initial 16MB is mapped to ZONE_DMA
16MB - 896MB is mapped to ZONE_NORMAL
896MB - 1024MB is mapped to ZONE_HIGHMEM

Does this mean that Kernel image is residing in ZONE_DMA area? Any call to vmalloc() in kernel code will return address beyond 896M? insmod of any LKM will internally invoke vmalloc() to obtain contiguous area - where will this code physically located along with rest of kernel code in ZONE_DMA or in ZONE_HIGHMEM?

View 1 Replies View Related

General :: Kernel Module Run In It / User Space?

Oct 25, 2010

I'm pretty new to this whole (micro)kernel architecture story.

Im wondering if a kernel module is running in kernel or in user space?

Is a driver running as kernel module slower than a driver build into kernel?
If so, are there some current articles, benchmarks?

View 4 Replies View Related

General :: Difference Between User And Kernel Space?

Jul 12, 2010

what difference between user and kernel space.

View 2 Replies View Related

General :: Shared Buffer Between User And Kernel Space

May 3, 2010

I need a shared buffer between user and kernel space. I read that one way is to allocated buffer in kernel and then call mmap from the user space. I searched for an example but couldn't find something useful. If you know, could you please send me any links or sample code that does this..

View 1 Replies View Related

General :: Scripting - Cp A List Of Files Which Starts With - Or Space Without - Or Space?

Oct 14, 2009

I have a list of files in a directory which starts with - or have space.

I need to copy them back without the space or -?

linux1[sim]% ls linux1[sim]% cp ./-* ./*

View 8 Replies View Related

General :: Use Free Space To Extend The Space Of A Drive?

Jul 5, 2011

My system is dual boot with win7 and ubuntu. I have free space of around 10 gb. I want to add this free space to my ubuntu drive. How can i do that?

View 4 Replies View Related

Hardware :: Obtain A Real Memory Address From User Space - Mmap() And /dev/mem

Feb 25, 2010

I'm running an embedded Linux kernel, and I want to obtain a real memory address from user space. After goggeling a little, I found that the only way was to use mmap to access /dev/mem. But I never used mmap. I want to load a program in memory, in order to make it available from another processor, that has access to the DDR, but not to the flash memory where program is stored. Here is the code I use:

Code: // Open file and get its size
FILE* program = fopen(argv[3],"rb");
fseek(program, 0, SEEK_END);
long program_size = ftell(program);
fseek(program, 0, SEEK_SET);
// Prepare memory to copy it in
void* program_address = malloc(program_size+1);
FILE* memory_stream = fmemopen(program_real_address, program_size + 1, "wb");
[Code]....

View 5 Replies View Related

Kernel :: Syscall Accessing User Space?

Feb 22, 2010

If the calling process passes me the virtual address of an its array for example, how can I access it without using copy_from_user?

View 2 Replies View Related

General :: Application Virtual Address Space Memory Allocation - Memory Does Not Get Free

Apr 20, 2010

I am using malloc and frees a lot in my program. It shows its allocated but when i remove it doesnt show as the memory is removed(I am using the top command to view VIRT memory usage). If this continously grows what would happen to my program (Will it go out of memory?)

View 4 Replies View Related

Ubuntu :: Dual Boot Linux / Change Drive Space Configuration For More Space

Mar 6, 2010

I have linux and windowsxp on one machine. I have only 3gigs free on the windowxp machine and 20gigs free on the linux machine. I want to transfer space from the linux box to the windows machine.Is this possible and what steps would I need to follow to do this?

View 1 Replies View Related

Debian :: Create An Unallocated Space The Space Will Stay In That Extended Partition

Mar 20, 2010

my home partition is an extended one, and when i want to create an unallocated space the space will stay in that extended partition. but there is also an 7 gb unallocated space which i want to merge with the other unallocated space. I also cannot extend that partition over that 7 gb. how can i overcome that problem?

i m also uploading a screenshot of gparted.[URL]..

View 4 Replies View Related

Slackware :: Disk Space Lost- Root Partition Has Very Little Space Left

Jan 31, 2010

Today I was installing a lot of software since I'm just setting up my Slackware system again after a fresh install, and I realized that my root partition has very little space left.

Here is the output of df -h:


Code:

As you can see, I have a 20G (19G here for some reason) root partition, 8G /var, and 86G of /home. I thought this would be plenty since many recent recommendations for / are 10-15G. Now, though, 17G are used up for some reason! How is this possible? I thought a full slackware install only had about 4G of software! I don't have any music or movies or any crazy huge files that I know of, and those would be in my /home directory anyway. Is there any way I can see which files are taking up all this space?

If it's necessary to allocate more space to my / partition, is it still possible to boot up a GParted live Cd, shrink /home a bit, move some partitions to the right, and expand my root partition? I would REALLY prefer I don't have to reinstall since I just spent a ton of time setting up my system again, but if worst comes to worst ... :'-(

In case you're curious, here's my /etc/fstab:

Code:

View 14 Replies View Related

General :: Add / Of 3000mb In The Remaining 20380mb Free Space It Showing An Error Message That No Free Space Is Available

Jul 25, 2010

I have 160gb laptop. i installed vista in c primary partition which is 25gb and installed ubuntu in d primary partition which is 20gb. A remainig for my data. Now i tried to install CENT OS by formatting ubuntu. I inserted CENT OS DVD and restarted and i selected to delete my /dev/sda2 which is showing 20480mb and it shown me free space. but i tried to add partion /boot of 100mb it got added. but, when i am trying to add / of 3000mb in the remaining 20380mb free space it showing an error message that no free space is available.

View 4 Replies View Related

General :: Getting Backslash+space Instead Of Just Space?

Jul 26, 2010

I just mounted my drobo(NTFS) on my slackbox using NTFS-3g, and I can read all my files and see them all, but any file name with a space in it turns into EX: (File Name)... instead of (File Name)I am worried that my Sync software will not recognize the name.Does anyone have any tips Except to not put Spaces in the names of files?

View 3 Replies View Related

Fedora Installation :: Convert Unallocated Space To Free Space?

Jun 7, 2010

I was trying to install Fedora 13, on to my laptop. I have 30 GB of unallocated space in extended partition. When trying to install Fedora 13, I got stuck, as the installer says that there is no free space for installation.can convert the unallocated space into free space.

View 1 Replies View Related

Ubuntu :: How To Turn Unallocated Space Into Usable 'free' Space?

May 25, 2010

i used gddrescure to clone an 80gb harddrive and this is the result ROFL.i guess you can only do this making sure the target drive is the same size, you see i didnt know lol so..i now have THIS problem.can anyone tell me how to turn my unallocated space into a usable 'free' space? i could play with gparted right now but i dont wanna do anything wrong, so if theres anyone who can tell me how to do this.

View 1 Replies View Related

Hardware :: Reduced Disk Space / Use The Total Amount Of Space?

Aug 25, 2009

OS: RHEL AS 5 64-bit

HDD:300 GB Hardware mirror (HP blade bl460c)

While installing OS, in partition window after OS file system structure I've left 277 GB. But after installation it shows Size - 255GB and available disk space is 242 GB.

Isn't it weired? How can I use the total amount of space in Linux? I need the whole 277GB exactly. What should be my workaround?

View 6 Replies View Related

Red Hat :: Showing 0 Byte Free Space Istaed Of Freeing The Space

Dec 30, 2010

I have red hat linux server and it has mysql installed whenever i write on terminal command mysql -u root it shows error "ERROR 2002 (HY000): can't connect to local MYSQL server through '/var/lib/mysql/mysql.sock (111) "

And another problem is that it is showing 0 byte free space istaed of freeing the space. it may seems that both problems are dependent on each other.

View 6 Replies View Related

Programming :: Make A (user Space )process Pre Emptive / In 2.6 Kernel?

Dec 10, 2008

I am writing a program which i dont want the kernel scheduler to preempt before certain time duration. I am using the system call sched_get_priority_max to set the maximum priority. However it is not producing results.

View 3 Replies View Related

Ubuntu Installation :: Add More Space To Sda2 From Free Space?

Jul 22, 2010

i made space by shrinking my window partition and so i have unallocated and would like to add to sda2 to have more space. Check out this pic. How can i do this?

View 1 Replies View Related







Copyrights 2005-15 www.BigResource.com, All rights reserved