Re: pthread_lock
On Tue, Mar 5, 2013 at 11:32 AM, valdis.kletni...@vt.edu wrote: On Tue, 05 Mar 2013 11:02:45 +0530, Mandeep Sandhu said: next schedule. I think the waiting threads (processes) will moved from the wait queue to the run queue from where they will be scheduled to run. For bonus points, read source code and/or comments and figure out what Linux does to prevent the 'thundering herd' problem (consider 100 threads all waiting on the same mutex - if you blindly wake all 100 up, you'll schedule them all, the first will find the mutex available and then re-take it, and then the next 99 will get run only to find it contended and go back to sleep. So figure out what Linux does in that case. :) Googling around, I found the 'thundering herd' being mentioned in relation to threads waiting on sockets using the accept() sys call. Are wait's on mutex's also plagued by the same issue? I guess it is, though what sys call would be used in this case? Thanks, -mandeep ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: pthread_lock
On Tue, Mar 05, 2013 at 01:39:54PM +0530, Mandeep Sandhu wrote: On Tue, Mar 5, 2013 at 11:32 AM, valdis.kletni...@vt.edu wrote: On Tue, 05 Mar 2013 11:02:45 +0530, Mandeep Sandhu said: next schedule. I think the waiting threads (processes) will moved from the wait queue to the run queue from where they will be scheduled to run. For bonus points, read source code and/or comments and figure out what Linux does to prevent the 'thundering herd' problem (consider 100 threads all waiting on the same mutex - if you blindly wake all 100 up, you'll schedule them all, the first will find the mutex available and then re-take it, and then the next 99 will get run only to find it contended and go back to sleep. So figure out what Linux does in that case. :) Googling around, I found the 'thundering herd' being mentioned in relation to threads waiting on sockets using the accept() sys call. Are wait's on mutex's also plagued by the same issue? I guess it is, though what sys call would be used in this case? the threads waiting on sockets will be waked up by net event. similarly,the waiters on mutex's can be wake up by signal.I guess it is pthread_cont_signal Thanks, -mandeep ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Some Links for Easy Understanding of Linux of Kernel Source code
Hello all I am a collage student and i need some link so to under stand kernel source code easily and also how to do IPC programming thank you ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Some Links for Easy Understanding of Linux of Kernel Source code
you dont need to look into kernel code to know how to do ipc stuff... to learn abt ipc get a copy of richard stevens book and go over it. if you want to browse thru the kernel code the easiest way is http://lxr.linux.no/linux On Tue, Mar 5, 2013 at 10:41 AM, praveen kumar spkr...@gmail.com wrote: Hello all I am a collage student and i need some link so to under stand kernel source code easily and also how to do IPC programming thank you ___ 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: Major/minor numbers
-Original Message- From: kernelnewbies-boun...@kernelnewbies.org [mailto:kernelnewbies- boun...@kernelnewbies.org] On Behalf Of kernelnewbies- requ...@kernelnewbies.org Sent: Tuesday, March 05, 2013 5:53 PM To: kernelnewbies@kernelnewbies.org Subject: Kernelnewbies Digest, Vol 28, Issue 9 Send Kernelnewbies mailing list submissions to kernelnewbies@kernelnewbies.org To subscribe or unsubscribe via the World Wide Web, visit http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies or, via email, send a message with subject or body 'help' to kernelnewbies-requ...@kernelnewbies.org You can reach the person managing the list at kernelnewbies-ow...@kernelnewbies.org When replying, please edit your Subject line so it is more specific than Re: Contents of Kernelnewbies digest... Today's Topics: 1. Module compilation error (Pietro Paolini) 2. Re: Module compilation error (Mulyadi Santosa) 3. Re: Module compilation error (valdis.kletni...@vt.edu) 4. pthread_lock (ishare) 5. Re: pthread_lock (Mandeep Sandhu) 6. Re: pthread_lock (valdis.kletni...@vt.edu) 7. Major/minor numbers (Shraddha Kamat) 8. Re: pthread_lock (Mandeep Sandhu) 9. Re: pthread_lock (ishare) 10. Re: Major/minor numbers (Anuz Pratap Singh Tomar) -- Message: 1 Date: Mon, 4 Mar 2013 19:48:33 -0500 (EST) From: Pietro Paolini pulsarpie...@aol.com Subject: Module compilation error To: kernelnewbies@kernelnewbies.org Message-ID: 8CFE7524C1296F0-1764-9EDF@webmail- m235.sysops.aol.com Content-Type: text/plain; charset=us-ascii; format=flowed Hi all, I tried, as beginner, to compile a simple module downloaded by internet, hello_printk, I am using ArchLinux and I followed the simplest way for compile a new kernel tree from here : https://wiki.archlinux.org/index.php/Kernels/Compilation/Arch_Build_Syste m But when I try to compile I catch these errors: echo 2 ERROR: Kernel configuration is invalid.; \ echo 2 include/generated/autoconf.h or include/config/auto.conf are missing.;\ echo 2 Run 'make oldconfig make prepare' on kernel src to fix it.; \ echo 2 ; \ /bin/false) Of course I checked the path of the kernel and under the directory wrote on the error messages I can find the files autoconf.h and auto.conf that I really don't understand what could be wrong, the makefile is really really simple then I can post it: obj-m := hello_printk.o KDIR ?= mypersonalpath/core/linux/src/linux-3.7 PWD := $(shell pwd) default: $(MAKE) -C $(KDIR) M=$(PWD) modules Someone can help me ? Pietro Paolini pulsarpie...@aol.com -- Message: 2 Date: Tue, 5 Mar 2013 09:07:51 +0700 From: Mulyadi Santosa mulyadi.sant...@gmail.com Subject: Re: Module compilation error To: Pietro Paolini pulsarpie...@aol.com Cc: kernelnewbies@kernelnewbies.org Message-ID: CAGdaadZ=eziBhY6zTFzSC5PZ_yTzgnVjQ0rgbk_SQQCjyt6ZBA@mail. gmail.com Content-Type: text/plain; charset=ISO-8859-1 On Tue, Mar 5, 2013 at 7:48 AM, Pietro Paolini pulsarpie...@aol.com wrote: Hi all, I tried, as beginner, to compile a simple module downloaded by internet, hello_printk, I am using ArchLinux and I followed the simplest way for compile a new kernel tree from here : https://wiki.archlinux.org/index.php/Kernels/Compilation/Arch_Build_Sy stem But when I try to compile I catch these errors: echo 2 ERROR: Kernel configuration is invalid.; \ echo 2 include/generated/autoconf.h or include/config/auto.conf are missing.;\ echo 2 Run 'make oldconfig make prepare' on kernel src try the suggested above step. IIRC, those commands will do things like preparing the neccessary object files, headers and so on, so it is ready for you to be used on your kernel programming. Apologize since I can't provide deeper details about this. -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com -- Message: 3 Date: Mon, 04 Mar 2013 21:47:46 -0500 From: valdis.kletni...@vt.edu Subject: Re: Module compilation error To: Mulyadi Santosa mulyadi.sant...@gmail.com Cc: Pietro Paolini pulsarpie...@aol.com, kernelnewbies@kernelnewbies.org Message-ID: 6607.1362451...@turing-police.cc.vt.edu Content-Type: text/plain; charset=us-ascii On Tue, 05 Mar 2013 09:07:51 +0700, Mulyadi Santosa said: On Tue, Mar 5, 2013 at 7:48 AM, Pietro Paolini pulsarpie...@aol.com wrote: echo 2 Run 'make oldconfig make prepare' on kernel src try the suggested above step. IIRC, those commands will do things like preparing the neccessary object files, headers and so
RE: Major/minor numbers
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Regarding GPIO driver module
Hi all , I was trying to write a GPIO driver module for Hawkboard , in order to toggle the LEDs connected to the GPIOs . I am using a OMAP L138 processor , and am trying to do a ioremap of the physical address space to the Kernel's virtual address space . But I guess I am not able to figure out the exact base address of the GPIO bank . I am basically trying to toggle the GPIO Bank 6 . I went through the OMAP L138 reference manual , but am unable to find the base address . Afterwards I plan to use the ioctl function to toggle the LEDs . Attaching herewith the link to the OMAP L138 reference manual . Reference manual : www.ti.com/lit/ug/spruh77a/spruh77a.pdf Could anyone kindly guide me , on the procedure to decipher the Baseaddress of the GPIO Bank 6 from the Reference manual ? Thanks in advance ! Cheers , ~RCB~ ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Regarding GPIO driver module
Hi, On Wed, Mar 6, 2013 at 12:23 PM, Rajesh Bhaskaran cb.rajesh...@gmail.com wrote: Hi all , I was trying to write a GPIO driver module for Hawkboard , in order to toggle the LEDs connected to the GPIOs . I am using a OMAP L138 processor , and am trying to do a ioremap of the physical address space to the Kernel's virtual address space . But I guess I am not able to figure out the exact base address of the GPIO bank . I am basically trying to toggle the GPIO Bank 6 . I went through the OMAP L138 reference manual , but am unable to find the base address . Afterwards I plan to use the ioctl function to toggle the LEDs . Attaching herewith the link to the OMAP L138 reference manual . Reference manual : www.ti.com/lit/ug/spruh77a/spruh77a.pdf Could anyone kindly guide me , on the procedure to decipher the Baseaddress of the GPIO Bank 6 from the Reference manual ? You need to go through the memory map of the device refer[1] for this. In [1] refer table 2-4 you will find the entire memory map including GPIO. For GPIO refer this [2] too. Regards, --Prabhakar Lad http://in.linkedin.com/pub/prabhakar-lad/19/92b/955 [1] http://www.ti.com/lit/ds/sprs586d/sprs586d.pdf [2] http://www.ti.com/lit/ug/sprufl8b/sprufl8b.pdf Thanks in advance ! Cheers , ~RCB~ ___ 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
