Re: questions on swapping

Re: questions on swapping

[Heerappa Hunje]

Hi,

Please let me know what are all standard criteria to be followed when
writing the Bottom Half Interrupt handlers for Device Drivers.

Thanks in Advance

Thanks n Regards
Heerappa



|---------+---------------------------->
|         |           Jan Hudec        |
|         |           <bulb@ucw.cz>    |
|         |           Sent by: Jan     |
|         |           'Bulb' Hudec     |
|         |           <bulb@vagabond.cy|
|         |           bernet.cz>       |
|         |                            |
|         |                            |
|         |           04/29/2003 04:58 |
|         |           PM               |
|         |                            |
|---------+---------------------------->
  >------------------------------------------------------------------------------------------------------------------------------|
  |                                                                                                                              |
  |       To:       Heerappa Hunje <hunjeh@celetron.com>                                                                         |
  |       cc:       kernelnewbies@nl.linux.org, linux-mm@kvack.org, William Lee Irwin III <wli@holomorphy.com>                   |
  |       Subject:  Re: questions on swapping                                                                                    |
  >------------------------------------------------------------------------------------------------------------------------------|




On Tue, Apr 29, 2003 at 04:52:36PM +0530, Heerappa Hunje wrote:
> Thanks for the information, well i have following difficulties.
> 1. How to handle/write the Bottom Half part of Interrupt for Device
Drivers
> 2. If any error, then the messages during the running of Device Driver
> modules where(in which file) they are written by Kernel, or we have to
> specify the location/Pathname of file during the implimentation.

Kernel prints messages using the printk function. It writes them to the
active console and makes them available via a magic file in /proc
filesystem where they are picked by klogd and passed to syslogd.

printk is specially crafted so that it can be called from any point of
kernel (including interrupt context).

-------------------------------------------------------------------------------


Jan 'Bulb' Hudec <bulb@ucw.cz>





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Re: questions on swapping

[Heerappa Hunje]

Dear Jan Hudec.

Thanks for the information, well i have following difficulties.
1. How to handle/write the Bottom Half part of Interrupt for Device Drivers
2. If any error, then the messages during the running of Device Driver
modules where(in which file) they are written by Kernel, or we have to
specify the location/Pathname of file during the implimentation.

Thanks in advance.

Thanks n Regards
Heerappa.



|---------+---------------------------->
|         |           Jan Hudec        |
|         |           <bulb@ucw.cz>    |
|         |           Sent by: Jan     |
|         |           'Bulb' Hudec     |
|         |           <bulb@vagabond.cy|
|         |           bernet.cz>       |
|         |                            |
|         |                            |
|         |           04/29/2003 01:33 |
|         |           PM               |
|         |                            |
|---------+---------------------------->
  >------------------------------------------------------------------------------------------------------------------------------|
  |                                                                                                                              |
  |       To:       Heerappa Hunje <hunjeh@celetron.com>                                                                         |
  |       cc:       William Lee Irwin III <wli@holomorphy.com>, kernelnewbies@nl.linux.org, linux-mm@kvack.org                   |
  |       Subject:  Re: questions on swapping                                                                                    |
  >------------------------------------------------------------------------------------------------------------------------------|




On Mon, Apr 28, 2003 at 03:07:08PM +0530, Heerappa Hunje wrote:
> Let me know how much of memory a system adminstrator can configure for
> buffering mechanism out 128MB/256MB  or it will be choosen by the Linux
> itself.

Buffers are rather transient stuff during IO operations. Kernel will
allocate memory for them as they are needed.

All memory, that is not used by kernel or applications is used for
caching files (page cache). No need to configure that either.

-------------------------------------------------------------------------------


Jan 'Bulb' Hudec <bulb@ucw.cz>





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Re: questions on swapping

[Jan Hudec]

On Tue, Apr 29, 2003 at 04:52:36PM +0530, Heerappa Hunje wrote:
> Thanks for the information, well i have following difficulties.
> 1. How to handle/write the Bottom Half part of Interrupt for Device Drivers
> 2. If any error, then the messages during the running of Device Driver
> modules where(in which file) they are written by Kernel, or we have to
> specify the location/Pathname of file during the implimentation.

Kernel prints messages using the printk function. It writes them to the
active console and makes them available via a magic file in /proc
filesystem where they are picked by klogd and passed to syslogd.

printk is specially crafted so that it can be called from any point of
kernel (including interrupt context).

-------------------------------------------------------------------------------
						 Jan 'Bulb' Hudec <bulb@ucw.cz>
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Re: questions on swapping

[Randy.Dunlap]

On Tue, 29 Apr 2003 13:28:29 +0200 Jan Hudec <bulb@ucw.cz> wrote:

| On Tue, Apr 29, 2003 at 04:52:36PM +0530, Heerappa Hunje wrote:
| > Thanks for the information, well i have following difficulties.
| > 1. How to handle/write the Bottom Half part of Interrupt for Device Drivers
| > 2. If any error, then the messages during the running of Device Driver
| > modules where(in which file) they are written by Kernel, or we have to
| > specify the location/Pathname of file during the implimentation.
| 
| Kernel prints messages using the printk function. It writes them to the
| active console and makes them available via a magic file in /proc
| filesystem where they are picked by klogd and passed to syslogd.

Try this paragraph instead:
Kernel prints messages using the printk function.  printk queues messages
to a ring buffer.  Messages are pulled from the ring buffer by syslog
or klog using the syslog system call.
Console messages are printed to all registered console output methods,
such as ones for the video console, serial console, printer, etc.

(no magic /proc file)

| printk is specially crafted so that it can be called from any point of
| kernel (including interrupt context).

--
~Randy
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Re: questions on swapping

[Heerappa Hunje]

Dear william,

Let me know how much of memory a system adminstrator can configure for
buffering mechanism out 128MB/256MB  or it will be choosen by the Linux
itself.

Thanks n Regards
Heerappa.



|---------+---------------------------->
|         |           William Lee Irwin|
|         |           III              |
|         |           <wli@holomorphy.c|
|         |           om>              |
|         |                            |
|         |           04/28/2003 12:56 |
|         |           PM               |
|         |                            |
|---------+---------------------------->
  >------------------------------------------------------------------------------------------------------------------------------|
  |                                                                                                                              |
  |       To:       Heerappa Hunje <hunjeh@celetron.com>                                                                         |
  |       cc:       linux-mm@kvack.org, kernelnewbies@nl.linux.org                                                               |
  |       Subject:  Re: questions on swapping                                                                                    |
  >------------------------------------------------------------------------------------------------------------------------------|




On Mon, Apr 28, 2003 at 12:46:15PM +0530, Heerappa Hunje wrote:
> 1. I have problem in locating the source code of linux operating system
> because i dont know in which path it is kept. Pls suggest me the
pathname.

ftp://ftp.kernel.org/pub/linux/kernel/v2.5/
             and
ftp://ftp.kernel.org/pub/linux/kernel/v2.4/

for the less adventurous


On Mon, Apr 28, 2003 at 12:46:15PM +0530, Heerappa Hunje wrote:
> 2. let me know the different ways to connect the device drivers module to
> the kernel.

This is a bit too general to answer at all.


On Mon, Apr 28, 2003 at 12:46:15PM +0530, Heerappa Hunje wrote:
> 3. let me know where actually the space for SWAPPING, BUFFERS  are
> allocated. i mean whether they are in RAM Memory or Hard disk drive.

Buffers are in RAM, swap is on-disk.


-- wli





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Re: questions on swapping

[William Lee Irwin III]

On Mon, Apr 28, 2003 at 03:07:08PM +0530, Heerappa Hunje wrote:
> Let me know how much of memory a system adminstrator can configure for
> buffering mechanism out 128MB/256MB  or it will be choosen by the Linux
> itself.

I'd suggest the O'Reilly books on system administration for this kind
of information. A general tour of the manpages (type "man man" to get
started) sounds like something that might be good for you also. There's
a lot of good material in them, and I refer to them routinely.

BTW, the kernelnewbies mailing list is about C language programming in
the kernel, and the linux-mm mailing list about virtual memory
management programming in the kernel. Some of the questions you've
posted are probably best dealt with elsewhere, e.g. on other mailing
lists, as they haven't tended to be very related to kernel programming.

Could someone give him a pointer to a mailing list or other support
forum (newsgroup? anything) that would be of the right flavor? I've not
done much in the way of system administration.

If you're doing kernel programming after all, but are just having a
tough time getting set up, you should probably still try going
elsewhere for the bits about setting up your system properly.


-- wli
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Re: questions on swapping

[Jan Hudec]

On Mon, Apr 28, 2003 at 03:07:08PM +0530, Heerappa Hunje wrote:
> Let me know how much of memory a system adminstrator can configure for
> buffering mechanism out 128MB/256MB  or it will be choosen by the Linux
> itself.

Buffers are rather transient stuff during IO operations. Kernel will
allocate memory for them as they are needed.

All memory, that is not used by kernel or applications is used for
caching files (page cache). No need to configure that either.

-------------------------------------------------------------------------------
						 Jan 'Bulb' Hudec <bulb@ucw.cz>
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Re: questions on swapping

[Heerappa Hunje]

Hi Babu n Anirudh,
Thanks for the reply,

will the driver will get executed if i put my source code of driver in the
path /usr/src/linux/drivers/        or else should i put the makefile in
the same path.


Thanks in advance.


Thanks and Regards
Heerappa.



|---------+---------------------------->
|         |           Babu Dhandapani  |
|         |           <babud@npd.hcltec|
|         |           h.com>           |
|         |                            |
|         |           04/28/2003 01:37 |
|         |           PM               |
|         |                            |
|---------+---------------------------->
  >------------------------------------------------------------------------------------------------------------------------------|
  |                                                                                                                              |
  |       To:       Heerappa Hunje <hunjeh@celetron.com>                                                                         |
  |       cc:                                                                                                                    |
  |       Subject:  Re: questions on swapping                                                                                    |
  >------------------------------------------------------------------------------------------------------------------------------|




Hi  Heerappa,
    I will try to answer to your queries...answers are inline .

      Thanks for the reply and information, well i wanted to know  that how
      can i
      see the source code of linux when iam working on linux being in the
      root,
      what pathname name should i type to get to the source code file of
      linux.
the source code will be in the path /usr/src/linux/


      2. if i have the device driver module's source code written for
      perticular
      device than  where should i store it, so that it will support to my
      device
      whenever any user seeks it.
you can put your driver's code in the path /usr/src/linux/drivers/


      3. During installation of linux, what if i assign the swapping space4
      times
      of my present memory size OR less than the present memory size. I
      mean will
      it have any problems in system performance in both the cases.
if your swap sapce is more means your system may put good performance at
high loads
the vice versa also holds good i think...


      4. what command should i type to know the version of my present OS.
uname -a

Regds,
Babu


      Please Suggest me

      Thanks n Regards
      Heerappa




      |---------+---------------------------->
      |         |           William Lee Irwin|
      |         |           III              |
      |         |           <wli@holomorphy.c|
      |         |           om>              |
      |         |                            |
      |         |           04/28/2003 12:56 |
      |         |           PM               |
      |         |                            |
      |---------+---------------------------->
        >
      ------------------------------------------------------------------------------------------------------------------------------|

        |
      |
        |       To:       Heerappa Hunje <hunjeh@celetron.com>
      |
        |       cc:       linux-mm@kvack.org, kernelnewbies@nl.linux.org
      |
        |       Subject:  Re: questions on swapping
      |
        >
      ------------------------------------------------------------------------------------------------------------------------------|





      On Mon, Apr 28, 2003 at 12:46:15PM +0530, Heerappa Hunje wrote:
            1. I have problem in locating the source code of linux
            operating system
            because i dont know in which path it is kept. Pls suggest me
            the
      pathname.

      ftp://ftp.kernel.org/pub/linux/kernel/v2.5/
                   and
      ftp://ftp.kernel.org/pub/linux/kernel/v2.4/

      for the less adventurous


      On Mon, Apr 28, 2003 at 12:46:15PM +0530, Heerappa Hunje wrote:
            2. let me know the different ways to connect the device drivers
            module to
            the kernel.

      This is a bit too general to answer at all.


      On Mon, Apr 28, 2003 at 12:46:15PM +0530, Heerappa Hunje wrote:
            3. let me know where actually the space for SWAPPING, BUFFERS
            are
            allocated. i mean whether they are in RAM Memory or Hard disk
            drive.

      Buffers are in RAM, swap is on-disk.


      -- wli





      --
      To unsubscribe, send a message with 'unsubscribe linux-mm' in
      the body to majordomo@kvack.org.  For more info on Linux MM,
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Re: questions on swapping

[Heerappa Hunje]

Dear William,

Thanks for the reply and information, well i wanted to know  that how can i
see the source code of linux when iam working on linux being in the root,
what pathname name should i type to get to the source code file of linux.

2. if i have the device driver module's source code written for perticular
device than  where should i store it, so that it will support to my device
whenever any user seeks it.

3. During installation of linux, what if i assign the swapping space4 times
of my present memory size OR less than the present memory size. I mean will
it have any problems in system performance in both the cases.

4. what command should i type to know the version of my present OS.

Please Suggest me

Thanks n Regards
Heerappa




|---------+---------------------------->
|         |           William Lee Irwin|
|         |           III              |
|         |           <wli@holomorphy.c|
|         |           om>              |
|         |                            |
|         |           04/28/2003 12:56 |
|         |           PM               |
|         |                            |
|---------+---------------------------->
  >------------------------------------------------------------------------------------------------------------------------------|
  |                                                                                                                              |
  |       To:       Heerappa Hunje <hunjeh@celetron.com>                                                                         |
  |       cc:       linux-mm@kvack.org, kernelnewbies@nl.linux.org                                                               |
  |       Subject:  Re: questions on swapping                                                                                    |
  >------------------------------------------------------------------------------------------------------------------------------|




On Mon, Apr 28, 2003 at 12:46:15PM +0530, Heerappa Hunje wrote:
> 1. I have problem in locating the source code of linux operating system
> because i dont know in which path it is kept. Pls suggest me the
pathname.

ftp://ftp.kernel.org/pub/linux/kernel/v2.5/
             and
ftp://ftp.kernel.org/pub/linux/kernel/v2.4/

for the less adventurous


On Mon, Apr 28, 2003 at 12:46:15PM +0530, Heerappa Hunje wrote:
> 2. let me know the different ways to connect the device drivers module to
> the kernel.

This is a bit too general to answer at all.


On Mon, Apr 28, 2003 at 12:46:15PM +0530, Heerappa Hunje wrote:
> 3. let me know where actually the space for SWAPPING, BUFFERS  are
> allocated. i mean whether they are in RAM Memory or Hard disk drive.

Buffers are in RAM, swap is on-disk.


-- wli





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Re: questions on swapping

[Jan Hudec]

On Mon, Apr 28, 2003 at 01:24:17PM +0530, Heerappa Hunje wrote:
> 
> Dear William,
> 
> Thanks for the reply and information, well i wanted to know  that how can i
> see the source code of linux when iam working on linux being in the root,
> what pathname name should i type to get to the source code file of linux.

It depends on where you have placed it! If you have installed kernel
from distribution binary package, you have to download it first. If you
have downloaded a source package, query your package manager program. If
you compiled yourself, you should already know.

> 2. if i have the device driver module's source code written for perticular
> device than  where should i store it, so that it will support to my device
> whenever any user seeks it.

If you have it in a form of patch, you apply it using
  patch -p1 <the-patch-file
command in the top-level directory of kernel sources (unless the driver
states otherwise)

If you have sources that already have makefile to compile off-tree, you
can place it anywhere. You just need to tell it where kernel headers
reside (you may or may not need the whole tree - depends on the
particular driver).

If you have just a source without makefile, you may either place them in
kernel (besides other drivers of the same type), modify the Makefiles
and config and compile in kernel tree, or you can write makefile to make
it compile separately.

> 3. During installation of linux, what if i assign the swapping space4 times
> of my present memory size OR less than the present memory size. I mean will
> it have any problems in system performance in both the cases.

Too much swap can not hurt except by wasting your precious disk space.
Linux does not rely on swap space being present at all, so too little
swap won't principialy hurt either. It's just your applications may not
have enough space.

In linux, each page is either in swap or in memory, so you have size of
ram + swap available as virtual memory (part of that is used by kernel
itself)

> 4. what command should i type to know the version of my present OS.

uname -r

-------------------------------------------------------------------------------
						 Jan 'Bulb' Hudec <bulb@ucw.cz>
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RE: questions on swapping

[Patwardhan, Aniruddha]

Hi Heerappa,

I will suggest you try googling before you put question on the list.
anyway find comments in <<...>>

Thanks & Regards,
Aniruddha
 -------------------------------------
| Aniruddha S. Patwardhan             |
| BMC Software India Pvt. Ltd.        |
| Email: aniruddha_patwardhan@bmc.com |
| Phone: +91-20-4035129               |
| www : http://aniruddha.talk.to      |
 -------------------------------------

-----Original Message-----
From: Heerappa Hunje [mailto:hunjeh@celetron.com]
Sent: Monday, April 28, 2003 12:46 PM
To: linux-mm@kvack.org; kernelnewbies@nl.linux.org
Subject: questions on swapping


Dear sir,

1. I have problem in locating the source code of linux operating system
because i dont know in which path it is kept. Pls suggest me the pathname.
<<
Linux source code is generally located in /usr/src/linux<version>
>>

2. let me know the different ways to connect the device drivers module to
the kernel.
<<
You need to compile the device driver module with required flags and need to
insert the module in kernel using insmod
>>

3. let me know where actually the space for SWAPPING, BUFFERS  are
allocated. i mean whether they are in RAM Memory or Hard disk drive.
<<
While configuring the system you generally create a separate partition for
swap device. We can also configure some file as a swap space. Generally swap
space is located on disk bcoz the entire purpose of swap is to extend
physical memory.

Any way technically you can even configure ramdisk and make it swap
partition.
>>

Thanks in advance for the help.


Thanks and regards
Heerappa.





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questions on swapping

[Heerappa Hunje]

Dear sir,

1. I have problem in locating the source code of linux operating system
because i dont know in which path it is kept. Pls suggest me the pathname.

2. let me know the different ways to connect the device drivers module to
the kernel.

3. let me know where actually the space for SWAPPING, BUFFERS  are
allocated. i mean whether they are in RAM Memory or Hard disk drive.

Thanks in advance for the help.


Thanks and regards
Heerappa.





--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
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Re: questions on swapping

[William Lee Irwin III]

On Mon, Apr 28, 2003 at 12:46:15PM +0530, Heerappa Hunje wrote:
> 1. I have problem in locating the source code of linux operating system
> because i dont know in which path it is kept. Pls suggest me the pathname.

ftp://ftp.kernel.org/pub/linux/kernel/v2.5/
	and
ftp://ftp.kernel.org/pub/linux/kernel/v2.4/

for the less adventurous


On Mon, Apr 28, 2003 at 12:46:15PM +0530, Heerappa Hunje wrote:
> 2. let me know the different ways to connect the device drivers module to
> the kernel.

This is a bit too general to answer at all.


On Mon, Apr 28, 2003 at 12:46:15PM +0530, Heerappa Hunje wrote:
> 3. let me know where actually the space for SWAPPING, BUFFERS  are
> allocated. i mean whether they are in RAM Memory or Hard disk drive.

Buffers are in RAM, swap is on-disk.


-- wli
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
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