12-02-2010
Kernel/ user space and high/ low mem
Need some clarification on this....
1. how are kernel/ user spaces and high/low memory related?
2. What do they all mean when i have the kernel command line as:
"console=ttyS0,115200 root=/dev/sda2 rw mem=exactmap memmap=1M@0 memmap=96M@1M irqpoll"
or
2. what do mem and memmap mean in terms of user/kernel space and high/low mem?
10 More Discussions You Might Find Interesting
1. UNIX for Advanced & Expert Users
Hi,
I am seeing very high kernel usage and very high load averages on my system (Although we are not loading much data to our database). Here is the output of top...does anyone know what i should be looking at?
Thanks,
Lorraine
last pid: 13144; load averages: 22.32, 19.81, 16.78 ... (4 Replies)
Discussion started by: lorrainenineill
4 Replies
2. Linux
Hi All,
Kindly help me in optimizing the server as it displays a great amount of CPU & MEM being utilised when the mysql process executes.
Below are the stats ---
--------------------------------------------------------------------------
# top
15:51:57 up 23:22, 5 users, load average:... (1 Reply)
Discussion started by: gautamatul82
1 Replies
3. UNIX for Advanced & Expert Users
Can kernel process access user address space ? (2 Replies)
Discussion started by: subhotech
2 Replies
4. Shell Programming and Scripting
on the file Ftp'd from the mainframe ,do we have any UNIX command to replace mainframe low and values to space or null.
i tried using tr and it doesn't work ...
Thanks (1 Reply)
Discussion started by: rlmadhav
1 Replies
5. UNIX for Advanced & Expert Users
Hello, I'm searching for a proper way to let the kernel space ISR(implemented in a kernel module) wake up a user space thread on a hardware interrupt.
Except for sending a real-time signal, is it possible to use a semaphore?
I've searched it on google, but it seems impossible to share a... (0 Replies)
Discussion started by: aaronwong
0 Replies
6. Shell Programming and Scripting
Is it possible to have a bash script pick the highest and lowest values of four variables? I've been googling for this but haven't come up with anything. I have a script that assigns variables ($c0, $c1, $c2, and $c3) based on the coretemps from grep/sed statements of sensors. I'd like to also... (5 Replies)
Discussion started by: graysky
5 Replies
7. Linux
I recently started working with Linux and wrote my first device driver for a hardware chip controlled by a host CPU running Linux 2.6.x kernel.
1. The user space process makes an IOCTL call with pointer to a user memory buffer.
2. The kernel device driver in the big switch-case of IOCTL,... (1 Reply)
Discussion started by: agaurav
1 Replies
8. Shell Programming and Scripting
Hi guys,
i have a question about spliting a binary file into 2 chunks.
First chunk with all high bytes and the second one with all low bytes.
What unix tools can i use? And how can this be performed?
I looked in manpages of split and dd but this does not help.
Thanks (2 Replies)
Discussion started by: basta
2 Replies
9. AIX
Hello All
I have a system running AIX 61 shared uncapped partition (with 11 physical processors, 24 Virtual 72GB of Memory) .
The output from NMON, vmstat show a high run queue (60+) for continous periods of time intervals, but NO paging, relatively low I/o (6000) , CPU % is 40, Low network.... (9 Replies)
Discussion started by: IL-Malti
9 Replies
10. Red Hat
Hi team
I have three physical servers running on Red Hat Enterprise Linux Server release 6.2 with the following memory conditions:
# cat /proc/meminfo | grep -i mem
MemTotal: 8062888 kB
MemFree: 184540 kB
Shmem: 516 kB
and the following swap conditions:
... (6 Replies)
Discussion started by: hedkandi
6 Replies
LEARN ABOUT FREEBSD
conscontrol
CONSCONTROL(8) BSD System Manager's Manual CONSCONTROL(8)
NAME
conscontrol -- control physical console devices
SYNOPSIS
conscontrol [list]
conscontrol mute on | off
conscontrol add | delete console
conscontrol set | unset console
DESCRIPTION
The conscontrol utility is used to examine and modify the physical devices which back the virtual console devices. If no arguments (or only
the list command) are specified, the current console settings are shown.
There are two types of logical consoles; a high level console which is represented by /dev/console, and a low level console. The low level
console is used for kernel printf(9) and ddb(4) debugger support, while the high level console is used by user programs like syslogd(8).
Multiple device support is implemented only for the low level console; the high level console is set to the first device in the console list.
Multiple console support may be invoked by passing the kernel the -D flag from the boot loader, or by using conscontrol to change the list of
console devices after the system has booted.
The following options are available:
add | delete console
Add or delete a physical device from the logical console. The device must support low-level console operations. Adding a device
will place it at the front of the list of console devices; the first device is used for the high level console.
The console argument is the name of a console device in /dev; the name of the directory may be omitted.
mute on | off
Change the state of console muting. All console output is suppressed when console muting is on.
set | unset console
Set or unset the virtual console. When unset, output from the system, such as the kernel printf(9), always goes out to the real main
console. When set, it goes to another. This is an interface to the tty ioctl TIOCCONS.
SEE ALSO
sio(4), syscons(4), tty(4), vt(4), boot(8), loader(8)
HISTORY
The conscontrol utility first appeared in FreeBSD 5.0.
AUTHORS
Jonathan Lemon
BSD
April 14, 2011 BSD