Re: How much control does a block driver have over the buffer cache?
On Wed, Jul 13, 2011 at 07:30, Neil Baylis neil.bay...@gmail.com wrote: For example, would it be possible to create a block driver that does not use the buffer cache? I think the answer must be 'no' because the caching happens before the block driver gets any requests to move data. something like dd iflag=direct or oflag=direct does? btw, you are still under effect of hardware cache installed in the hard disk itself...so what you see is actually IMHO a cumulative effect of caching happen in the entire system -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
how to apply patches from git ?
Hi all, Sorry if this is a basic question. How do i take patches from e-mail? for example git send mail sends patches as e-mail if someone wants to apply that patch to his branch then how do i get that in . patch format and then use patch -p1 *.patch or is there something im missing here? thanks. -- Warm Regards, Ravi . ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Need help understanding memory models, cpu modes and address translation
Hi, I am eager to understand the basics of Memory models (flat, segmented etc) , CPU modes (real,protected) and address translation (physical to logical etc.) and how all of them work together. I am very confused about this and would really appreciate if someone could provide good references to these topics. Thanks Vaibhav Jain ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Need help: How to set .RECIPEPREFIX variable to whitespaces
Hi, How to set .RECIPEPREFIX variable to whitespace(say 4 whitespces) , so that make uses this particular set of characters to identify the recipe for a particular target. In my $HOME/.vimrc file, for code indentation purpose, I've put the following entries to replace tabs with 4 whitespaces: snip from my $HOME/.vimrc file replace tabs with spaces set expandtab set shiftwidth=4 set tabstop=4 snip from my $HOME/.vimrc file but the above will cause problem in case you write your own makefile for a kernel module, because now the tab stroke will be replaced by 4 whitespaces which 'make' will not understand. Quoting from 'make' manual, Please note: you need to put a tab character at the beginning of every recipe line! Seems .RECIPEPREFIX will come for resuce, but as of now I don't know how to use it to fix my problem. Regards, Amit -- Life is elsewhere. Cross Frontiers. Fly away. - Salman Rushdie ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Need help understanding memory models, cpu modes and address translation
Hi, Thanks for the link.I really appreciate but I need something more basic and something that explains these concepts from a broader perspective and not in the context of a particular cpu architecture.Please send me more such links if you come across any. Thanks Vaibhav Jain On Wed, Jul 13, 2011 at 1:14 AM, Daniel Baluta daniel.bal...@gmail.comwrote: Hi, I am eager to understand the basics of Memory models (flat, segmented etc) , CPU modes (real,protected) and address translation (physical to logical etc.) and how all of them work together. I am very confused about this and would really appreciate if someone could provide good references to these topics. You may find useful information inside i366 Programmers Manual. Anyhow, reading materials is the first step in understanding these concepts. You will have to actually read/write/debug pieces of code related to them. thanks, Daniel. [1] pdos.csail.mit.edu/6.828/2010/readings/i386.pdf ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
RE: flush_cache_all API
Hi : The SCU can solve all the cache coherency problems? From: kernelnewbies-boun...@kernelnewbies.org [mailto:kernelnewbies-boun...@kernelnewbies.org] On Behalf Of Vladimir Murzin Sent: 2011年7月11日 17:51 To: naveen yadav Cc: kernelnewbies@kernelnewbies.org Subject: Re: flush_cache_all API On 7/11/11, naveen yadav yad.nav...@gmail.com wrote: Hi All, I am using Multi-core ARM machine. If I use flush_cache_all() API, will it flush only current CPU cache ?, or flush all cache's of all core's. Thanks ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies Hi! I think, it doesn't matter as soon as SCU is involved. ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Need help understanding memory models, cpu modes and address translation
Tons of resource http://wiki.osdev.org/ On Wed, Jul 13, 2011 at 2:07 PM, Vaibhav Jain vjoss...@gmail.com wrote: Hi, Thanks for the link.I really appreciate but I need something more basic and something that explains these concepts from a broader perspective and not in the context of a particular cpu architecture.Please send me more such links if you come across any. Thanks Vaibhav Jain On Wed, Jul 13, 2011 at 1:14 AM, Daniel Baluta daniel.bal...@gmail.com wrote: Hi, I am eager to understand the basics of Memory models (flat, segmented etc) , CPU modes (real,protected) and address translation (physical to logical etc.) and how all of them work together. I am very confused about this and would really appreciate if someone could provide good references to these topics. You may find useful information inside i366 Programmers Manual. Anyhow, reading materials is the first step in understanding these concepts. You will have to actually read/write/debug pieces of code related to them. thanks, Daniel. [1] pdos.csail.mit.edu/6.828/2010/readings/i386.pdf ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies -- Life is elsewhere. Cross Frontiers. Fly away. - Salman Rushdie ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: how to apply patches from git ?
On Wed, Jul 13, 2011 at 00:22, RKK kulkarni.ra...@gmail.com wrote: Hi all, Sorry if this is a basic question. How do i take patches from e-mail? for example git send mail sends patches as e-mail if someone wants to apply that patch to his branch then how do i get that in . patch format and then use patch -p1 *.patch or is there something im missing here? thanks. -- Warm Regards, Ravi . Save the email message in mbox format and then you can use git am /path/to/mbox/file to apply the email patch to your tree. -- Cheers, Jeff ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Query about a PCI device error detection.
Resending the email to kernelnewbies list as well (have sent the same to
edac mailing list). Appreciate any pointers on below query, if any one
has worked on edac.
On Wednesday 06 July 2011 03:56 PM, nilesh wrote:
Hi,
I am fairly new to the edac driver and have some basic query regarding
the error detection in case of PCI devices. I could see the module for
memory controller's error detection is done s.t. UE/CE/controller
specific errors are scanned and detected, also the PCI errors are also
scanned.
E.g. in case of i5400 :
i5400_edac.c :
i5400_probe1()
{
1285 /* Set the function pointer to an actual operation function
*/
1286 mci-edac_check = i5400_check_error;
...
1312 /* allocating generic PCI control info */
1313 i5400_pci = edac_pci_create_generic_ctl(pdev-dev,
EDAC_MOD_STR);
}
And we check the PCI status registers for the errors.
edac_pci_generic_check() -- edac_pci_do_parity_check() --
edac_pci_dev_parity_test()
So, i5400_check_error - detect UE/CE.
edac_pci_generic_check - detect PCI errors.
Query:
--
* If one wants to get the errors harvested for non-MC device (e.g.
ethernet controller etc.) is it going to be done through
edac_pci_generic_check() automatically - as we already scan through all
PCI devices in a loop? Is it required to add the separate module for
that device?
--
Thanks,
Nilesh
___
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xx_initcall ( ) in kernel
Dear friends, I want to know the basics xx_initcall ( ) in linux kernel. How this function works ? Observed in kernel code, many places late_initcall ( ), early_initcall ( ), arch_initcall ( ), core_initcall ( ) gets called. When did all these functions gets call during kernel initialization ? I am more interested in what is the sequence of these functions gets called one after another. Thank you. Regards, Sumeet ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Need help understanding memory models, cpu modes and address translation
The document and osdev are very good and useful. Thanks a lot. - Paraneetharan C On 13 July 2011 14:23, amit mehta gmate.a...@gmail.com wrote: Tons of resource http://wiki.osdev.org/ On Wed, Jul 13, 2011 at 2:07 PM, Vaibhav Jain vjoss...@gmail.com wrote: Hi, Thanks for the link.I really appreciate but I need something more basic and something that explains these concepts from a broader perspective and not in the context of a particular cpu architecture.Please send me more such links if you come across any. Thanks Vaibhav Jain On Wed, Jul 13, 2011 at 1:14 AM, Daniel Baluta daniel.bal...@gmail.com wrote: Hi, I am eager to understand the basics of Memory models (flat, segmented etc) , CPU modes (real,protected) and address translation (physical to logical etc.) and how all of them work together. I am very confused about this and would really appreciate if someone could provide good references to these topics. You may find useful information inside i366 Programmers Manual. Anyhow, reading materials is the first step in understanding these concepts. You will have to actually read/write/debug pieces of code related to them. thanks, Daniel. [1] pdos.csail.mit.edu/6.828/2010/readings/i386.pdf ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies -- Life is elsewhere. Cross Frontiers. Fly away. - Salman Rushdie ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies -- Regards, Paraneetharan C ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: xx_initcall ( ) in kernel
Hi Sumeet, On Wednesday 13 July 2011 04:12 PM, sumeet linux wrote: Dear friends, I want to know the basics xx_initcall ( ) in linux kernel. How this function works ? Observed in kernel code, many places late_initcall ( ), early_initcall ( ), arch_initcall ( ), core_initcall ( ) gets called. When did all these functions gets call during kernel initialization ? I am more interested in what is the sequence of these functions gets called one after another. I could get a nice link explaining about *_initcall(). Refer: http://book.opensourceproject.org.cn/embedded/embeddedprime/opensource/0136130550/ch05lev1sec4.html *_initcall() are macros which set the function pointers for subsystem initialization (typedef int (*initcall_t)(void) : typedef of all such function pointers). Also if we look at the source code, the functions are called in below sequence: http://lxr.linux.no/#linux+v2.6.39/init/main.c#L695 do_basic_setup(void) - do_initcalls(void) - do_one_initcall(*fn); do_one_initcall(*fn) - calls each function. And do_basic_setup() is called inside the initialization sequence (kernel_init()). Thank you. Regards, Sumeet -- Thanks, Nilesh ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Questions regarding console drivers..
Hi all, I have gone through the kernel/kernel/printk.c file. And i have the following questions.. I have some rough idea of several things, but i need to conform them 1) What is a console driver? -- My idea is it allows the kernel to input or output the characters to or from a particular device. 2) Why so many command-line consoles are needed? -- (if first qn is right...why cant u use single console to several devices) 3) What is a boot console real console? 4) How to know how many number of consoles are running at a time? 5) In the boot command line we will pass one console name console=ttyXXX, other than that where the remaining consoles are being registered? Please answer these questions so that i can have furthur understanding Thank you all.. -- With regards, Sandeep Kumar Anantapalli, ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Need basics of booting process
On Wed, Jul 13, 2011 at 1:11 AM, Pavan Kandepet pava...@gmail.com wrote: Check this one out: http://milindchoudhary.wordpress.com/2009/03/30/linux-boot-process/ Another one: http://duartes.org/gustavo/blog/post/kernel-boot-process Hope this helps, Pavan On Tue, Jul 12, 2011 at 11:07 AM, Mulyadi Santosa mulyadi.sant...@gmail.com wrote: On Tue, Jul 12, 2011 at 21:04, Niamathullah sharief newbie...@gmail.com wrote: Its getting confusion for me..I am telling what i understood BIOS---POST-MBR---Bootloader--Kernel. Roughly, yeah something like thatmind you, POST is a procedure that is part of BIOS initialization -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com Can any one share the process of Xen bootstrapping.It is hypervisor which starts.Any link etc. ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: how to apply patches from git ?
On Wed, 13 Jul 2011 02:16:09 -0700, Jeff Kirsher wrote: On Wed, Jul 13, 2011 at 00:22, RKK kulkarni.ra...@gmail.com wrote: Hi all, Sorry if this is a basic question. How do i take patches from e-mail? for example git send mail sends patches as e-mail if someone wants to apply that patch to his branch then how do i get that in . patch format and then use patch -p1 *.patch or is there something im missing here? thanks. -- Warm Regards, Ravi . Save the email message in mbox format and then you can use git am /path/to/mbox/file to apply the email patch to your tree. well, actually you don't need to do the whole mbox thing with git. You only need to get the patches into .patch files in a directory. I believe you can then use git am /path/to/patches and it will apply the patches in the order the ls command displays them. I'm assuming that would be helpful since most people who don't know how to apply patches from mail also don't have an mbox. ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: how to apply patches from git ?
Take a look at 'git apply' and 'git format-patch' commands. On Wed, Jul 13, 2011 at 3:22 AM, RKK kulkarni.ra...@gmail.com wrote: Hi all, Sorry if this is a basic question. How do i take patches from e-mail? for example git send mail sends patches as e-mail if someone wants to apply that patch to his branch then how do i get that in . patch format and then use patch -p1 *.patch or is there something im missing here? thanks. -- Warm Regards, Ravi . ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: how to apply patches from git ?
On Wed, Jul 13, 2011 at 9:40 AM, Anand Arumugam anand.aru...@gmail.comwrote: Take a look at 'git apply' and 'git format-patch' commands. On Wed, Jul 13, 2011 at 3:22 AM, RKK kulkarni.ra...@gmail.com wrote: Hi all, Sorry if this is a basic question. How do i take patches from e-mail? for example git send mail sends patches as e-mail if someone wants to apply that patch to his branch then how do i get that in . patch format and then use patch -p1 *.patch or is there something im missing here? thanks. -- Warm Regards, Ravi . ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies Hi you can see greg video about write and submit your first kernel patch it's really good. It can help you very much. the link is www.youtube.com/watch?v=LLBrBBImJt4 best samuel PS: apologize in advance to weak english and multi times send. ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Need help: How to set .RECIPEPREFIX variable to whitespaces
On Wed, Jul 13, 2011 at 1:52 AM, amit mehta gmate.a...@gmail.com wrote: Hi, How to set .RECIPEPREFIX variable to whitespace(say 4 whitespces) , so that make uses this particular set of characters to identify the recipe for a particular target. In my $HOME/.vimrc file, for code indentation purpose, I've put the following entries to replace tabs with 4 whitespaces: snip from my $HOME/.vimrc file replace tabs with spaces set expandtab set shiftwidth=4 set tabstop=4 snip from my $HOME/.vimrc file but the above will cause problem in case you write your own makefile for a kernel module, because now the tab stroke will be replaced by 4 whitespaces which 'make' will not understand. Quoting from 'make' manual, Please note: you need to put a tab character at the beginning of every recipe line! Seems .RECIPEPREFIX will come for resuce, but as of now I don't know how to use it to fix my problem. Regards, Amit -- Life is elsewhere. Cross Frontiers. Fly away. - Salman Rushdie ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies I have my vimrc file setup to use different tabs/spacing depending on the filetype. 8-width tab in C, 4-space indent in Python, etc... Here's a snippet from my vimrc: C - function! LANG_C() setlocal noexpandtab setlocal shiftwidth=8 setlocal tabstop=8 setlocal softtabstop=8 setlocal formatoptions=tcroq endfunction autocmd FileType c call LANG_C() --- Python function! LANG_PYTHON() setlocal shiftwidth=4 setlocal tabstop=4 setlocal softtabstop=4 setlocal expandtab --- python indent keywords setlocal cinwords=if,elif,else,for,while,try,except,finally,def,class,with endfunction autocmd FileType python call LANG_PYTHON() --- Makefile -- function! LANG_MAKEFILE() setlocal noexpandtab makefiles only work with tab-indents setlocal shiftwidth=8 setlocal tabstop=8 setlocal softtabstop=8 endfunction autocmd FileType make call LANG_MAKEFILE() There may be other/better ways to do this, but it works well for me. ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Regarding the basic use of perf top command
Hi, My question is regarding the basic use of perf top command in linux. The following is the snap shot of running a *perf top -e cache-misses* command from console: -- PerfTop: 76* irqs/sec* kernel:14.5% exact: 0.0% [1000Hz cache-misses], (all, 12 CPUs) -- *samples* *pcnt* functionDSO ___ _ ___ 48.00 36.9% get_page_from_freelist [kernel.kallsyms] 12.00 9.2% JS_CallTracer /usr/lib/xulrunner-1.9.2/libmozjs.so 12.00 9.2% JS_TraceChildren /usr/lib/xulrunner-1.9.2/libmozjs.so 8.00 6.2% dso__find_symbol /usr/bin/perf 7.00 5.4% native_flush_tlb_single [kernel.kallsyms] 6.00 4.6% _int_malloc /lib/libc-2.12.90.so What i want to know is the significance of different parameters here which are the following: 1. irqs/sec 2. samples 3. pcnt It also shows a value of 1000Hz. what is the meaning of that. I searched regarding these in the internet, but was unable to find a good explanation Thanks Ankur ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Kernel development process questions
Hi, I went over the development process Documentation/ in the kernel tree, and had the following question: With respect to Linux Kernel development process, what does the word stage mean? It is the process of getting patches into Greg's staging tree, or is it linux-next? Or depends on the context? Also, is there a standard way to track the status and location of a patch (i.e. some information about which maintainer's tree it is currently applied to, and which tree it is sent for applying to by which maintainer etc). I guess one way is to read the mailing lists, but is there a general preferred technique to get this information? Regards, Joel ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Regarding the basic use of perf top command
Hi, I think this should suffice https://perf.wiki.kernel.org/index.php/Tutorial#Live_analysis_with_perf_top Rest of the information is archived here http://lxr.linux.no/linux+v2.6.39/tools/perf/Documentation/ The value of 1000Hz means the frequency at which the system's timer is programmed to interrupt the kernel. It is a kernel configurable option. Thanks Vipin On 07/13/2011 10:59 AM, ankur dwivedi wrote: Hi, My question is regarding the basic use of perf top command in linux. The following is the snap shot of running a *perf top -e cache-misses* command from console: -- PerfTop: 76*irqs/sec* kernel:14.5% exact: 0.0% [1000Hz cache-misses], (all, 12 CPUs) -- *samples* *pcnt* functionDSO ___ _ ___ 48.00 36.9% get_page_from_freelist [kernel.kallsyms] 12.00 9.2% JS_CallTracer /usr/lib/xulrunner-1.9.2/libmozjs.so 12.00 9.2% JS_TraceChildren /usr/lib/xulrunner-1.9.2/libmozjs.so 8.00 6.2% dso__find_symbol/usr/bin/perf 7.00 5.4% native_flush_tlb_single [kernel.kallsyms] 6.00 4.6% _int_malloc /lib/libc-2.12.90.so http://libc-2.12.90.so What i want to know is the significance of different parameters here which are the following: 1. irqs/sec 2. samples 3. pcnt It also shows a value of 1000Hz. what is the meaning of that. I searched regarding these in the internet, but was unable to find a good explanation Thanks Ankur ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: File System concept
On Tue, Jul 12, 2011 at 9:44 AM, Ajay kumar a2008...@gmail.com wrote: Where can I read about different file system features ?? snapshots, journaling etc.. Regards, Onkar I find wikipedia surprisingly good as a starting point for questions like that. eg. http://en.wikipedia.org/wiki/Snapshot_%28computer_storage%29 Then look at the reference links at the bottom. Greg ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
query regarding inode pages
I am trying to write a memory based file system. The file system is intended to create files/directories and write their contents only on pages. For this I have used the function grab_cache_page() function to get a new locked page in case the page does not exists in the radix tree of the inode. As the filesystem is memory based and all the data exists only on the memory, so I don't release the lock on the page as I fear that the pdflush daemon can swap out the pages on which I have written data and I may never see that data again. I unlock all the pages of all the inodes of the file system in the kill_sb function once the file system is being unmounted. But the problem I am facing is that if I open a file in which I have already written something (and its pages are locked), the open system call in turn calls the __lock_page() function which waits for the pages belonging to the inode to get unlocked. Hence the system call stalls indefinitely. I want to know if there is a mechanism by which I can prevent the pdflush daemon from swapping the pages that my filesystem refers to?? What limited knowledge I have on pdflush daemon, I guess that the daemon searches for the dirty inodes in the list maintained per super block. So if I remove all the inodes from this list (or not add any of my inodes I create in the list), will I be able to prevent the daemon from flushing data from my file system? ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: query regarding inode pages
[CC'ing list] Hi Shubham, I am not very familiar with the code for pdflush. But wasn't it superseded by bdflush (or similar) in recent kernels? On Wed, Jul 13, 2011 at 10:45 AM, shubham sharma shubham20...@gmail.com wrote: I am trying to write a memory based file system. The file system is intended to create files/directories and write their contents only on pages. For this I have used the function grab_cache_page() function to get a new locked page in case the page does not exists in the radix tree of the inode. As the filesystem is memory based and all the data exists only on the memory, so I don't release the lock on the page as I fear that the pdflush daemon can swap out the pages on which I have written data and I may never see that data again. I unlock all the pages of all the inodes of the file system in the kill_sb function once the file system is being unmounted. But the problem I am facing is that if I open a file in which I have already written something (and its pages are locked), the open system call in turn calls the __lock_page() function which waits for the pages belonging to the inode to get unlocked. Hence the system call stalls indefinitely. I want to know if there is a mechanism by which I can prevent the pdflush daemon from swapping the pages that my filesystem refers to?? I'm not sure if pdflush is what swaps pages? Isn't that the role of kswapd? pdflush AFAIK just writes dirty pages back to the backing device. I think what you're referring to is a certain page replacement behavior in low memory conditions that you want to protect your filesystem against. I will be interested in responses from others about this, and will dig into the code during off office hours. Maybe tmpfs is a good reference for your work? Thanks, Joel ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: query regarding inode pages
Hi Joel, On Wed, Jul 13, 2011 at 9:28 PM, Joel A Fernandes agnel.j...@gmail.com wrote: [CC'ing list] Hi Shubham, I am not very familiar with the code for pdflush. But wasn't it superseded by bdflush (or similar) in recent kernels? I don't know about the bdflush daemon, but I guess that pdflush daemon has been superseded in recent kernel. I am working on 2.6.18 kernel. On Wed, Jul 13, 2011 at 10:45 AM, shubham sharma shubham20...@gmail.com wrote: I am trying to write a memory based file system. The file system is intended to create files/directories and write their contents only on pages. For this I have used the function grab_cache_page() function to get a new locked page in case the page does not exists in the radix tree of the inode. As the filesystem is memory based and all the data exists only on the memory, so I don't release the lock on the page as I fear that the pdflush daemon can swap out the pages on which I have written data and I may never see that data again. I unlock all the pages of all the inodes of the file system in the kill_sb function once the file system is being unmounted. But the problem I am facing is that if I open a file in which I have already written something (and its pages are locked), the open system call in turn calls the __lock_page() function which waits for the pages belonging to the inode to get unlocked. Hence the system call stalls indefinitely. I want to know if there is a mechanism by which I can prevent the pdflush daemon from swapping the pages that my filesystem refers to?? I'm not sure if pdflush is what swaps pages? Isn't that the role of kswapd? pdflush AFAIK just writes dirty pages back to the backing device. I think what you're referring to is a certain page replacement behavior in low memory conditions that you want to protect your filesystem against. Yes you got it correct. I want to protect my filesystem against low memory conditions. I will be interested in responses from others about this, and will dig into the code during off office hours. Maybe tmpfs is a good reference for your work? Thanks for the lead. I will dig in that now. Thanks, Joel Thanks, Shubham ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
RE: Need help understanding memory models, cpu modes and address translation
From: kernelnewbies-boun...@kernelnewbies.org [mailto:kernelnewbies-boun...@kernelnewbies.org] On Behalf Of Vaibhav Jain Sent: Wednesday, July 13, 2011 1:38 AM To: Daniel Baluta Cc: kernelnewbies@kernelnewbies.org Subject: Re: Need help understanding memory models,cpu modes and address translation Hi, Thanks for the link.I really appreciate but I need something more basic and something that explains these concepts from a broader perspective and not in the context of a particular cpu architecture.Please send me more such links if you come across any. Thanks Vaibhav Jain On Wed, Jul 13, 2011 at 1:14 AM, Daniel Baluta daniel.bal...@gmail.com wrote: Hi, I am eager to understand the basics of Memory models (flat, segmented etc) , CPU modes (real,protected) and address translation (physical to logical etc.) and how all of them work together. I am very confused about this and would really appreciate if someone could provide good references to these topics. You may find useful information inside i366 Programmers Manual. Anyhow, reading materials is the first step in understanding these concepts. You will have to actually read/write/debug pieces of code related to them. thanks, Daniel. [1] pdos.csail.mit.edu/6.828/2010/readings/i386.pdf You might want to try Understanding the Linux Virtual Memory Manager by Mel Gorman. It's freely available on the web. It's Linux specific, but since Linux needs to run on a multitude of different processors with different memory management hardware, the approach it takes to doing so in inherently broad. ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Need help understanding memory models, cpu modes and address translation
On Wed, Jul 13, 2011 at 6:29 PM, Jeff Haran jha...@bytemobile.com wrote: ** ** ** ** *From:* kernelnewbies-boun...@kernelnewbies.org [mailto: kernelnewbies-boun...@kernelnewbies.org] *On Behalf Of *Vaibhav Jain *Sent:* Wednesday, July 13, 2011 1:38 AM *To:* Daniel Baluta *Cc:* kernelnewbies@kernelnewbies.org *Subject:* Re: Need help understanding memory models,cpu modes and address translation ** ** Hi, Thanks for the link.I really appreciate but I need something more basic and something that explains these concepts from a broader perspective and not in the context of a particular cpu architecture.Please send me more such links if you come across any. Thanks Vaibhav Jain On Wed, Jul 13, 2011 at 1:14 AM, Daniel Baluta daniel.bal...@gmail.com wrote: Hi, I am eager to understand the basics of Memory models (flat, segmented etc) , CPU modes (real,protected) and address translation (physical to logical etc.) and how all of them work together. I am very confused about this and would really appreciate if someone could provide good references to these topics. You may find useful information inside i366 Programmers Manual. Anyhow, reading materials is the first step in understanding these concepts. You will have to actually read/write/debug pieces of code related to them. thanks, Daniel. [1] pdos.csail.mit.edu/6.828/2010/readings/i386.pdf ** ** You might want to try “Understanding the Linux Virtual Memory Manager” by Mel Gorman. It’s freely available on the web. ** ** It’s Linux specific, but since Linux needs to run on a multitude of different processors with different memory management hardware, the approach it takes to doing so in inherently broad. ** ** A lot of basic concepts can be learnt from JIm Turley's book on 8086 Other book is modern operating systems by Tanenbaum which explains everything in much detail with code snippets. ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Device mapper header file error
Hi List, ** ** I am trying to compile a kernel module which uses the device mapper header files (dm.h and dm-bio-list.h). I checked in the stock kernel source that these files are present under drivers/md directory. When I try to build the module, it gives error for these header files as missing. I checked the Makefile and found that it includes the path (-I$(TOPDIR)/ drivers/md) ** ** But when I check the content of this directory on my machine it doesn’t include the header files: [root@localhost redhat]# ls /usr/src/kernels/2.6.18-8.el5-i686/drivers/md*** * Kconfig Makefile raid6test [root@localhost redhat]# ** ** While the other header files referred by the kernel module under include/linux directory exists. ** ** My machine detail: [adil@localhost ~]$ uname -a Linux localhost.localdomain 2.6.18-8.el5 #1 SMP Fri Jan 26 14:15:21 EST 2007 i686 i686 i386 GNU/Linux [adil@localhost ~]$ ** ** Thanks in advance. ** Regards, Adil Mujeeb ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Need help understanding memory models, cpu modes and address translation
Hi, Thanks a lot for the resources! I just had a cursory look at them and could see that they explain virtual memory and address translation in depth. Just wanted to ask if they explain the concepts Memory models (flat, segmented ) and cpu modes (real,protected) equally well. I am more confused about these concepts. Thanks Vaibhav Jain On Wed, Jul 13, 2011 at 10:40 AM, Anuz Pratap Singh Tomar chambilketha...@gmail.com wrote: On Wed, Jul 13, 2011 at 6:29 PM, Jeff Haran jha...@bytemobile.comwrote: ** ** ** ** *From:* kernelnewbies-boun...@kernelnewbies.org [mailto: kernelnewbies-boun...@kernelnewbies.org] *On Behalf Of *Vaibhav Jain *Sent:* Wednesday, July 13, 2011 1:38 AM *To:* Daniel Baluta *Cc:* kernelnewbies@kernelnewbies.org *Subject:* Re: Need help understanding memory models,cpu modes and address translation ** ** Hi, Thanks for the link.I really appreciate but I need something more basic and something that explains these concepts from a broader perspective and not in the context of a particular cpu architecture.Please send me more such links if you come across any. Thanks Vaibhav Jain On Wed, Jul 13, 2011 at 1:14 AM, Daniel Baluta daniel.bal...@gmail.com wrote: Hi, I am eager to understand the basics of Memory models (flat, segmented etc) , CPU modes (real,protected) and address translation (physical to logical etc.) and how all of them work together. I am very confused about this and would really appreciate if someone could provide good references to these topics. You may find useful information inside i366 Programmers Manual. Anyhow, reading materials is the first step in understanding these concepts. You will have to actually read/write/debug pieces of code related to them. thanks, Daniel. [1] pdos.csail.mit.edu/6.828/2010/readings/i386.pdf ** ** You might want to try “Understanding the Linux Virtual Memory Manager” by Mel Gorman. It’s freely available on the web. ** ** It’s Linux specific, but since Linux needs to run on a multitude of different processors with different memory management hardware, the approach it takes to doing so in inherently broad. ** ** A lot of basic concepts can be learnt from JIm Turley's book on 8086 Other book is modern operating systems by Tanenbaum which explains everything in much detail with code snippets. ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: how to apply patches from git ?
Hi Hi all, Sorry if this is a basic question. How do i take patches from e-mail? for example git send mail sends patches as e-mail if someone wants to apply that patch to his branch then how do i get that in . patch format and then use patch -p1 *.patch or is there something im missing here? thanks. -- Warm Regards, Ravi . Save the email message in mbox format and then you can use git am /path/to/mbox/file to apply the email patch to your tree. well, actually you don't need to do the whole mbox thing with git. You only need to get the patches into .patch files in a directory. I believe you can then use git am /path/to/patches and it will apply the patches in the order the ls command displays them. are there any git tools to set up this so that i can use them ? I'm assuming that would be helpful since most people who don't know how to apply patches from mail also don't have an mbox. makes sense -- Warm Regards, Ravi Kulkarni. ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
