10-12-2008
10 More Discussions You Might Find Interesting
1. AIX
Hello AIX gurues...
In order to present the statistics of real memory usage I need to know how much real memory is used by the AIX 5L kernel. No the exact figures of course but some close to the reality.
The AIX is running in a 7GB real machine, it has a HACMP configuration and my concern is... (1 Reply)
Discussion started by: daniels
1 Replies
2. UNIX for Dummies Questions & Answers
Hellp all,
if there is 3G memory in my Unix server I want to know if all the 3G space can be used by ong sigle process. As i know, in Windows, one process can only access at most 1G memory despite there is probably more than 1G memory is equipped. (1 Reply)
Discussion started by: cy163
1 Replies
3. UNIX for Dummies Questions & Answers
Hi,
I need to know how to revoke the access/permission of Kernel for a group. In details, one of the group 'X' is having kernel access/permission and this group can control the Kernel at anytime. How can we revoke this permission/access ?
Thanks,
Rohit.. (13 Replies)
Discussion started by: ronix007
13 Replies
4. UNIX for Advanced & Expert Users
There is a tomcat webserver running that is used to host a java application. Sometime the service goes down with error logs. I see the following error messages in /var/log/messages:
kernel: Out of Memory: Killed process 2990 (co).
Out of Memory: Killed process 25671 (httpd)
Out of Memory:... (7 Replies)
Discussion started by: bsandeep_80
7 Replies
5. UNIX for Advanced & Expert Users
Can kernel process access user address space ? (2 Replies)
Discussion started by: subhotech
2 Replies
6. 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
7. UNIX for Dummies Questions & Answers
hi all,
i want to know y kernel is giving access for multiple users to access a file when one user may be the owner is executing that file. Because other user can manipulate that file when the other user is executing that file, it will give the unexpected result to owner . plz help me... (1 Reply)
Discussion started by: jimmyuk
1 Replies
8. Emergency UNIX and Linux Support
Can someone please help me with a script that will help in identifying the CPU & memory usage by a process name, rather than a process id.This is to primarily analyze the consumption of resources, for performance tweaking.
G (4 Replies)
Discussion started by: ggayathri
4 Replies
9. Solaris
Hi Experts,
Our servers running Solaris 10 with SAP Application. The memory utilization always >90%, but the process on SAP is too less even nothing.
Why memory utilization on solaris always looks high?
I have statement about memory on solaris, is this true:
Memory in solaris is used for... (4 Replies)
Discussion started by: edydsuranta
4 Replies
10. Solaris
Hi ,
In a server /tmp has almost reached 75% and i can see the File system utilization is 48Mb only , so i believe some process is using the /tmp space. I would like to know which process is using /tmp space.
# df -h /tmp
Filesystem size used avail capacity Mounted on
swap ... (9 Replies)
Discussion started by: chidori
9 Replies
LEARN ABOUT FREEBSD
ksyms
KSYMS(4) BSD Kernel Interfaces Manual KSYMS(4)
NAME
ksyms -- kernel symbol table interface
SYNOPSIS
device ksyms
DESCRIPTION
The /dev/ksyms character device provides a read-only interface to a snapshot of the kernel symbol table. The in-kernel symbol manager is
designed to be able to handle many types of symbols tables, however, only elf(5) symbol tables are supported by this device. The ELF format
image contains two sections: a symbol table and a corresponding string table.
Symbol Table
The SYMTAB section contains the symbol table entries present in the current running kernel, including the symbol table entries
of any loaded modules. The symbols are ordered by the kernel module load time starting with kernel file symbols first, followed
by the first loaded module's symbols and so on.
String Table
The STRTAB section contains the symbol name strings from the kernel and any loaded modules that the symbol table entries refer-
ence.
Elf formatted symbol table data read from the /dev/ksyms file represents the state of the kernel at the time when the device is opened.
Since /dev/ksyms has no text or data, most of the fields are initialized to NULL. The ksyms driver does not block the loading or unloading
of modules into the kernel while the /dev/ksyms file is open but may contain stale data.
IOCTLS
The ioctl(2) command codes below are defined in <sys/ksyms.h>.
The (third) argument to the ioctl(2) should be a pointer to the type indicated.
KIOCGSIZE (size_t)
Returns the total size of the current symbol table. This can be used when allocating a buffer to make a copy of the kernel
symbol table.
KIOCGADDR (void *)
Returns the address of the kernel symbol table mapped in the process memory.
FILES
/dev/ksyms
ERRORS
An open(2) of /dev/ksyms will fail if:
[EBUSY] The device is already open. A process must close /dev/ksyms before it can be opened again.
[ENOMEM] There is a resource shortage in the kernel.
[ENXIO] The driver was unsuccessful in creating a snapshot of the kernel symbol table. This may occur if the kernel was in the
process of loading or unloading a module.
SEE ALSO
ioctl(2), nlist(3), elf(5), kldload(8)
HISTORY
A ksyms device exists in many different operating systems. This implementation is similar in function to the Solaris and NetBSD ksyms
driver.
The ksyms driver first appeared in FreeBSD 8.0 to support lockstat(1).
AUTHORS
The ksyms driver was written by Stacey Son <sson@FreeBSD.org>.
BUGS
Because files can be dynamically linked into the kernel at any time the symbol information can vary. When you open the /dev/ksyms file, you
have access to an ELF image which represents a snapshot of the state of the kernel symbol information at that instant in time. Keeping the
device open does not block the loading or unloading of kernel modules. To get a new snapshot you must close and re-open the device.
A process is only allowed to open the /dev/ksyms file once at a time. The process must close the /dev/ksyms before it is allowed to open it
again.
The ksyms driver uses the calling process' memory address space to store the snapshot. ioctl(2) can be used to get the memory address where
the symbol table is stored to save kernel memory. mmap(2) may also be used but it will map it to another address.
BSD
April 5, 2009 BSD