Re: Implementation of events in Linux Kernel

Re: Implementation of events in Linux Kernel

[mohanlal jangir]

----- Original Message -----
From: "rakesh" <raklfs@yahoo.com>
To: <kernelnewbies@nl.linux.org>
Cc: <linux-kernel@vger.kernel.org>
Sent: Wednesday, April 14, 2004 7:54 PM
Subject: Implementation of events in Linux Kernel


>
> Hi All,
>
> Please excuse me if this is not the right place to post this question.
>
>       I have an application which runs on MIPS with Embedded Linux. Iwant
to write a char driver . I have a Rx Task and an Interrupthandler for the
char driver which will let me know if anything comesat the chip level.

If you receive interrupt from device, you can establish an interrupt handler
for that. See function "request_irq". If you want a sleep/wakeup mechanism,
there are many ways of doing this in Linux kernel. One of them is using
interruptible_sleep_on/wake_up_interruptible.

Regards
Mohanlal

  Assuming its pSOS or other real time operating systems one ofhandling an
interrupt is sending an event to the Rx Task then Rx Taskwill read from the
whatever buffer it may be.       If I want to implement the same thing in
Linux at the kernellevel treating my driver as a module. How ( what system
call ) can Ipass an event to the task such that it receives the event and
readsfrom the buffer ?      One more question in general what are all the
various exceptionsor Traps I have to look while writing a Linux Device
Driver.Thanks in Advance for all your help.ThanksRakesh
>
>
>
>
> ---------------------------------
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lvcreate -- ERROR "Cannot allocate memory" creating VGDA

[Shesha Sreenivasamurthy]

Hi All,
  I am trying the following "lvcreate" command and  I am hit an error. I 
googled for this error, and I can see it being listed in lotz of places, 
but without any solution or workaround.

Configuration:
----------------------
    RH-Linux 2.4.26
    1GB memory.

But the same command works fine, if I have only 512 MB RAM. Any help is 
highly appreciated.

Thanks
Shesha

---------------
[root@mc26300a root]# lvcreate -s -l 4306 -n stest /dev/VG_H41/LV_H41
lvcreate -- WARNING: the snapshot will be automatically disabled once it 
gets full
lvcreate -- INFO: using default snapshot chunk size of 64 KB for 
"/dev/VG_H41/ste1"
lvcreate -- ERROR "Cannot allocate memory" creating VGDA for 
"/dev/VG_H41/ste1" in kernel
----------------