February 2013 - kernelnewbies@kernelnewbies.org

Any way to do time keeping during kernel uncompression[ARM architecture]
by sandeep kumar Feb. 7, 2013

Feb. 7, 2013

Hi All On ARM, Just for learning i am working on booting with uncompressed kernel. I am meddling with arch/arm/boot/compressed/head.S, and understand the relocation/decompression stuff through putting some logs. I want to check how much time it takes for kernel to relocate itself and how much time it takes to decompress etc., Is there any possibility of seeing the current time stamp here, like a register which keeps on counting immediately after boot.. With regards, Sandeep Kumar Anantapalli,

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Re: Creating scheduler
by jeshkumar555＠gmail.com Feb. 7, 2013

Feb. 7, 2013

Hey Peter, Think First link is useful for scheduler, thanks :). Sent from my HTC Excuse for typo. ----- Reply message ----- From: "Peter Teoh" <htmldeveloper(a)gmail.com> Date: Thu, Feb 7, 2013 9:38 am Subject: Creating scheduler To: "jeshkumar555(a)gmail.com" <jeshkumar555(a)gmail.com> Cc: "kernelnewbies" <Kernelnewbies(a)kernelnewbies.org> well...u asked for it: http://abstract.cs.washington.edu/~shwetak/classes/ee472/assignments/lab2/l… http://www.cs.cmu.edu/~410-s07/p3/kernel.pdf http://web.stonehill.edu/compsci/CS314/Assignments/Assignment0.pdf http://www.cs.amherst.edu/~sfkaplan/courses/2012/spring/cs261/assignments/p… etc...googling returned me 27000 links.... On Thu, Feb 7, 2013 at 1:49 AM, jeshkumar555(a)gmail.com < jeshkumar555(a)gmail.com> wrote: > Hi all :), > > Can anyone suggest a good tutorial to create our own scheduler ? > > > Sent from my HTC > Excuse for typo. > > > _______________________________________________ > Kernelnewbies mailing list > Kernelnewbies(a)kernelnewbies.org > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > > -- Regards, Peter Teoh

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Creating scheduler
by jeshkumar555＠gmail.com Feb. 7, 2013

Feb. 7, 2013

Hi all :), Can anyone suggest a good tutorial to create our own scheduler ? Sent from my HTC Excuse for typo.

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thread concurrent file operation
by Karaoui mohamed lamine Feb. 7, 2013

Feb. 7, 2013

Hello, I was looking at how a syscall read/write was done, and i found this : .... loff_t pos = file_pos_read(f.file); ret = vfs_read(f.file, buf, count, &pos); file_pos_write(f.file, pos); fdput(f); ... My questions are : Where did the locking go? I would have imaginated something like : .... *lock(f);* loff_t pos = file_pos_read(f.file); ret = vfs_read(f.file, buf, count, &pos); file_pos_write(f.file, pos); fdput(f); *unlock(f);* ... If multiple threads try to read/write at the same time, they could read/write at the same offset ? If my understanding are correct, is this POSIX compliant ? thanks.

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Re: hard disk dirver
by horseriver Feb. 7, 2013

Feb. 7, 2013

hi:) I have a newbie question about hard ware. At booting stage,kernel need to detect the hard device before mount it, does this work need pci's surport? At loading stage ,boot loader need to move binaries from hard disk partition to ram,does this work need pci's surport? thanks!

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Qestion about page->_count and page reclaim
by Li Haifeng Feb. 6, 2013

Feb. 6, 2013

Hi, all in kernel. The page->_count is the page frame's usage count. When page is allocated, the page->_cout will be set 1. After be allocated from buddy system, the page will be used by process. get_page and put_page/put_page_testzero will used in pairs. is it right? When the page is reclaimed to buddy system, the page->_count should be 0. However, Because the initialization of page->_count is 1, get_page() and put_page() is called in pairs, I coufused how page->_count will be 0? Thanks.

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(no subject)
by Jimmy Pan Feb. 6, 2013

Feb. 6, 2013

unsuscribe

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hard disk dirver
by horseriver Feb. 6, 2013

Feb. 6, 2013

hi:) At booting time ,bootloader loads kernel from hard disk too memory. During this period,does it need hd driver's support . thanks!

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Priority the init call will follow in kernel
by Ranganath T.M Feb. 6, 2013

Feb. 6, 2013

Hi Dave, Thanks a lot, I understand that *core_init* call for *CPU*, *subsys_initcall<http://lxr.linux.no/linux+v3.7.6/+code=subsys_initcall> *for core module like *I2c* core and *module_init *for driver built on the core. When will the need arises to call other init calls, kindly provide a pointer to it. Thanks And Regards, Ranganath.T.M On Wed, Feb 6, 2013 at 12:13 PM, Dave Hylands <dhylands(a)gmail.com> wrote: > Hi, > > > On Tue, Feb 5, 2013 at 8:50 PM, Ranganath T.M <ranganathtm88(a)gmail.com> > wrote: > > > > Hi Peter, > > > > Thanks for your information, > > > > And can you kindly suggest me, > > 1)How the probe will be called by comparing the name in driver and name > given in board-files, or it will called based id_table which we fill for > particular bus of that driver. > > When both a device and a driver have been registered, then the probe > routine will be called. > > Normally, the devices are registered in your board files. > > > 2)How the priority will be followed to call the drivers files like BT > first and then HDMI driver. > > The order is determined by how they're registered (i.e. which initcall is > used: > http://lxr.linux.no/#linux+v3.7.6/include/linux/init.h#L209<http://lxr.linux.no/#linux+v3.7.6/include/linux/init.h%23L209> > > module_init maps to device_initcall > > Within the same level, the order is determined by the order that the files > appear in the Makefiles. > > -- > Dave Hylands > Shuswap, BC, Canada > http://www.davehylands.com >

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When does the /dev/sda1 node comes into being ?
by horseriver Feb. 6, 2013

Feb. 6, 2013

hi:) During booting period .every device will have a node at /dev/ folder. what is the detail of ths procedure? thanks!

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