solaris ssh

/etc/ssh/sshd_config

permitRootLogin yes

svcadm restart ssh

multipath at boot

• For Red Hat Enterprise Linux 4 or later, issue one of the following commands:
  • chkconfig multipathd on
  • chkconfig --level 345 multipathd on
    Note: This command enables multipathd service startup at boot.
• For SUSE Linux Enterprise Server 9 or later, issue one of the following commands:
  • chkconfig boot.multipath on
  • chkconfig --level 345 boot.multipath on
    Note: This command enables boot.multipath service startup at boot.
  After running one of these commands, issue one of these commands:
  • chkconfig multipathd on
  • chkconfig --level 345 multipathd on
    Note: This command enables multipathd service startup at boot.

mkinitrd

1. mkinitrd -c -k 2.6.27.7-smp -m reiserfs:jbd

create an initrd with module reiserfs & jbd

2. load initrd at boot time

ex: add in lilo.conf

# Linux bootable partition config begins

image = /boot/vmlinuz-generic-2.6.27.7-smp

initrd = /boot/initrd.gz

root = /dev/hda6

label = Lnx26277smp

read-only

# Linux bootable partition config ends

/etc/modprobe.conf  

Specifies SCSI modules to be loaded  and  module options to be used.

install modulename command... This is the most powerful primitive in modprobe.conf: it tells modprobe to run your command instead of inserting the module in the kernel as normal. The command can be any shell command: this allows you to do any kind of complex processing you might wish. For example, if the module "fred" worked better with the module "barney" already installed (but it didn't depend on it, so modprobe won't automatically load it), you could say "install fred /sbin/modprobe barney; /sbin/modprobe --ignore-install fred", which would do what you wanted. Note the --ignore-install, which stops the second modprobe from re-running the same install command. See also remove below. You can also use install to make up modules which don't otherwise exist. For example: "install probe-ethernet /sbin/modprobe e100 || /sbin/modprobe eepro100", which will try first the e100 driver, then the eepro100 driver, when you do "modprobe probe-ethernet". If you use the string "$CMDLINE_OPTS" in the command, it will be replaced by any options specified on the modprobe command line. This can be useful because users expect "modprobe fred opt=1" to pass the "opt=1" arg to the module, even if there's an install command in the configuration file. So our above example becomes "install fred /sbin/modprobe barney; /sbin/modprobe --ignore-install fred $CMDLINE_OPTS"

iometer & dynamo

problem:

Getting host name for "test" failed

solution:

In /ect/hosts

add one line:

hostIp test

run:

./dynamo -i windonsIp -m linuxIp

set retry for multipath

ex:

no_path_retry 1000

objdump

objdump -l -D test.o

show assembly code and line number of source code

bmap

kernel 重置

Kernel 重製:

流程:

1. 設定 kernel 選項
2. 編譯 kernel
3. 編譯 modules, 安裝 modules
4. 安裝 kernel
5. 設定 boot loader
6. 重新開機

步驟:

1. cd 您解壓後的目錄下的 linux 目錄中
2. make mrproper
3. make xconfig (menuconfig 或 config), 它會存成 .config
4. make dep
5. make bzImage
6. make modules
7. make modules_install
8. cp arch/boot/i386/bzImage /boot
9. 編輯 /etc/lilo.conf 或 /boot/grub/grub.conf
10. 執行 lilo -v -v; 若是使用 grub, 則不必.
11. reboot

scheduler

schedule_timeout
ex:
schedule_timeout(30*HZ);
// sleep for 30 seconds.

linux question website

http://www.linuxquestions.org/questions/programming-9/

linux question website

http://www.linuxquestions.org/questions/programming-9/

kthread

find current kernel threads in the system:
ps -ef
the process with [ ] is kernel thread

is kernel thread preemptive?
1. if CONFIG_PREEMPT is defined, kernel thread is preemptive
2. if CONFIG_PREEMPT is not defined, kernel thread is not preemptive. It will freeze the system if it doesn’t go to sleep.

kthread_create

kernel_thread

resource:
http://svn.openfoundry.org/vwebsdk/Reference/kernel_thread.txt
http://www.jollen.org/blog/2006/11/_scheduler_running_process.html#more

interrupt

in_interrupt():

 to find out whether it's executing in interrupt context.

linux type

linux/types.h

sector_t 

block device driver header

linux/fs.h

struct block_device:

scsi/scsi_device.h

struct scsi_device

linux list

defined in /include/linux/list.h

struct list_head {
struct list_head *next, *prev;
};

#define LIST_HEAD_INIT(name) { &(name), &(name) }

#define LIST_HEAD(name) \
struct list_head name = LIST_HEAD_INIT(name)

INIT_LIST_HEAD: when list_head is first created, its next & prev point to itself
static inline void INIT_LIST_HEAD(struct list_head *list)
{
list->next = list;
list->prev = list;
}

list_add: add new element A to B, if B's next is C, then final sequence is B, A, C
static inline void list_add(struct list_head *new, struct list_head *head)
{
__list_add(new, head, head->next);
}

static inline void __list_add(struct list_head *new,
struct list_head *prev,
struct list_head *next)
{
next->prev = new;
new->next = next;
new->prev = prev;
prev->next = new;
}


#define list_for_each(pos, head) \
for (pos = (head)->next; prefetch(pos->next), pos != (head); \
pos = pos->next)

/* list_entry - get the struct for this entry
@ptr: the &struct list_head pointer.
@type: the type of the struct this is embedded in.
@member: the name of the list_struct within the struct.
*/
#define list_entry(ptr, type, member) \
container_of(ptr, type, member)

/* container_of - cast a member of a structure out to the containing structure
@ptr: the pointer to the member.
@type: the type of the container struct this is embedded in.
@member: the name of the member within the struct.
*/
#define container_of(ptr, type, member) ({ \
const typeof( ((type *)0)->member ) *__mptr = (ptr); \
(type *)( (char *)__mptr - offsetof(type,member) );})

multipath-tools

get source:
http://christophe.varoqui.free.fr/



compile:
(1) install device-mapper-devel-1.02.13-6.14.x86_64.rpm
(2) install readline-devel-5.1-24.19.x86_64.rpm.rpm
(3) cd multipathd
(4) make