July 2014 - kernelnewbies@kernelnewbies.org - Kernelnewbies Mailing Lists

Re: Add Data to packet header
by Denis Kirjanov July 16, 2014

July 16, 2014

CCing the list On 7/16/14, Denis Kirjanov <kirjanov(a)gmail.com> wrote: > On 7/16/14, Robert Clove <cloverobert(a)gmail.com> wrote: > > Please don't reply privately > >> skb is the new skb >> and >> size is the size of the variable that i will push in new header >> For eg: >> struct my_head_struct { >> int a; >> }; >> unsigned int hook_func(unsigned int hooknum, >> struct sk_buff *skb, >> const struct net_device *in, >> const struct net_device *out, >> int (*okfn)(struct sk_buff *)) >> { >> >> unsigned int length,truesize; >> printk("Inside the hook function\n"); >> >> >> struct my_head_struct * my_head= NULL; >> >> struct sk_buff *newskb; >> newskb = skb_copy_expand(skb, sizeof(struct my_head_struct), 0, >> GFP_ATOMIC); >> if(newskb==NULL) >> { >> printk("Failed to allocate mem\n"); >> //return SEND_FAIL_MEMORY; >> } >> else >> { >> // /* need add check of newskb value for error control */ >> >> skb_push(newskb, sizeof(struct my_head_struct)); > > my_head = (struct my_head_struct *) skb_push(skb, sizeof (*my_head)); > my_head->a = cpu_to_be32(<your be32 value>); > >> >> // /* use network byte order */ >> my_head->a = 21; *//want to push this in new skb* >> >> } >> printk("Dropped packet on %s...\n", drop_if); >> return NF_ACCEPT; >> } else { >> return NF_ACCEPT; >> } >> } >> >> Please guide on above >> >> >> On Wed, Jul 16, 2014 at 4:57 PM, Denis Kirjanov <kirjanov(a)gmail.com> >> wrote: >> >>> On 7/16/14, Robert Clove <cloverobert(a)gmail.com> wrote: >>> > Hi All, >>> > >>> > >>> > I want to add data to the packet header. >>> > >>> > I used the skb_copy_expand to make the copy of the skb and data. >>> > Now in the headroom i want to add some data. >>> > How can i do that,please suggest . >>> >>> __skb_push(skb, <your size>) to adjust the skb->data pointer >>> >>> > >>> > Regards >>> > >>> >>> >>> -- >>> Regards, >>> Denis >>> >> > > > -- > Regards, > Denis > -- Regards, Denis

1 0

Add Data to packet header
by Robert Clove July 16, 2014

July 16, 2014

Hi All, I want to add data to the packet header. I used the skb_copy_expand to make the copy of the skb and data. Now in the headroom i want to add some data. How can i do that,please suggest . Regards

2 1

Re: Problems with Linux next tree
by 黄钦佳 July 15, 2014

July 15, 2014

> Due to the way the linux-next tree is built, 'git pull' won't work. > > You want to 'git clone' Linus's master tree, then 'git remote add' > the Linux-next tree. Then use 'git remote update' instead of 'git pull' > when you want to refresh the tree. I use 'git remote update', and then try 'git checkout master', it tells that my branch has diverged. But I do not have modifies on that branch. So I have to try 'git reset 20140707', and then checkout successed. I don't know why, any help?

4 3

Problems with Linux next tree
by Lucas Tanure July 15, 2014

July 15, 2014

Hi, My local clone of linux-tree always fails to update. When I run git pull origin master, I got a : Automatic merge failed; fix conflicts and then commit the result. So, How I can keep my local tree updated ? Thanks -- Lucas A. Tanure Alves +55 (19) 988176559

3 2

Problems with Linux next tree
by Lucas Tanure July 15, 2014

July 15, 2014

Hi, My local clone of linux-tree always fails to update. When I run git pull origin master, I got a : Automatic merge failed; fix conflicts and then commit the result. So, How I can keep my local tree updated ? No matter what. Thanks -- Lucas Tanure +55 (19) 988176559

6 9

Re: what does nr_iowait_cpu() do?
by Andev July 15, 2014

July 15, 2014

On Mon, Jul 14, 2014 at 10:21 PM, Mohammad Merajul Islam Molla <meraj.enigma(a)gmail.com> wrote: > Hi Andev, > > Thanks for reply. I got the definition too. What I really want to know > is what this variable nr_iowait stands for? > Is it counting pending input/output on a cpu? > > > -- > - Meraj > > > > On Tue, Jul 15, 2014 at 8:07 AM, Andev <debiandev(a)gmail.com> wrote: >> On Mon, Jul 14, 2014 at 10:10 AM, Mohammad Merajul Islam Molla >> <meraj.enigma(a)gmail.com> wrote: >>> Hello, >>> >>> I was looking into the code of cpuidle menu governor and it uses a >>> function nr_iowait_cpu(int cpu). >>> I could not find out what this function does. >>> >>> Can someone please explain what nr_iowait_cpu(int cpu) and variant >>> nr_iowait() do? >>> >>> -- Now that is a better question. Try looking up what nr_iowait is. >> >> In all its glory: >> >> unsigned long nr_iowait_cpu(int cpu) >> { >> struct rq *this = cpu_rq(cpu); >> return atomic_read(&this->nr_iowait); >> } >> >> >>> Thanks, >>> -Meraj >>> >>> _______________________________________________ >>> Kernelnewbies mailing list >>> Kernelnewbies(a)kernelnewbies.org >>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies >> >> >> >> -- >> Andev -- Andev

3 2

what does nr_iowait_cpu() do?
by Mohammad Merajul Islam Molla July 15, 2014

July 15, 2014

Hello, I was looking into the code of cpuidle menu governor and it uses a function nr_iowait_cpu(int cpu). I could not find out what this function does. Can someone please explain what nr_iowait_cpu(int cpu) and variant nr_iowait() do? -- Thanks, -Meraj

2 2

Using /tmp for temprory storage
by sagar hu July 14, 2014

July 14, 2014

Hi, I am trying to log huge data into SD card(class-10), doing this operation is causing frequent loss of data, is there any way in which I can use /tmp for temporary storage and frequently move the data to SD card ? Any pointers on this would be helpful. Thanks, --S

2 1

Re: [PATCH] title: no lookup_page for if statement
by Andev July 14, 2014

July 14, 2014

Hi Nicholas, On Mon, Jul 14, 2014 at 2:59 PM, Paul Bolle <pebolle(a)tiscali.nl> wrote: > > Nicholas, stop! Just stop. > You have been trying to send patches fixing FIX ME for the past few days. A lot of maintainers are really upset with you since you do not follow the proper procedures while submitting patches. Lots of maintainers have asked you to stop sending in patches. If you do not listen, they will start redirecting your mail to /dev/null. (many have already done that) Please read Documentation/SubmittingPatches atleast once. Please test your patches by _atleast_ compiling the kernel ensuring that your changes are compiling. There are other tasks to do than sending in code patches. Like documentation patches. Read the documentation and try to understand them. Fix spelling/grammar mistakes there. Once you are comfortable with programming in C, you can send it code patches. Frankly, your build testing is great and might be helping. Just report that builds fail, you don't need to send in code patches which you are not sure are fixes for the failures. Finally, join kernelnewbies mailing list and learn by asking/answering questions. Regards, -- Andev

1 0

Memory allocation problems on RHEL 6.3 kernel version 2.6.32-279.el6.x86_64
by Amit Agarwal July 14, 2014

July 14, 2014

Hi All, We are running a 32 bit application on RHEL6.3-64 bit OS with kernel version 2.6.32-279.el6.x86_64. While running this application we see the following when running under strace: mmap(offset=33230848, len=2068480) failed with errno=12 for the file <so file name> The system has enough RAM, total 16GB and about 12 GB free. We checked buddyinfo on the system, when the application is running and see the below trend: Node 0, zone Normal 5200 21396 21389 21516 16202 12770 9054 4459 1430 168 313 Node 0, zone Normal 5231 21395 21389 21516 16202 12770 9054 4459 1430 168 313 Node 0, zone Normal 5128 21401 21389 21516 16202 12770 9054 4459 1430 168 313 Node 0, zone Normal 5060 21405 21391 21516 16202 12770 9054 4459 1430 168 313 .............. Node 0, zone Normal 483 17946 21342 21516 16202 12770 9054 4459 1430 168 313 Node 0, zone Normal 315 17937 21342 21516 16202 12770 9054 4459 1430 168 313 Node 0, zone Normal 345 17891 21352 21516 16202 12770 9054 4459 1430 168 313 Node 0, zone Normal 278 17785 21352 21516 16202 12770 9054 4459 1430 168 313 At this point the application crashes with mmap error. Page Type information on the system: Page block order: 9 Pages per block: 512 Free pages count per migrate type at order 0 1 2 3 4 5 6 7 8 9 10 Node 0, zone DMA, type Unmovable 1 0 0 1 0 0 1 0 0 0 0 Node 0, zone DMA, type Reclaimable 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone DMA, type Movable 0 0 0 0 0 0 0 0 0 0 3 Node 0, zone DMA, type Reserve 0 0 0 0 0 0 0 0 0 1 0 Node 0, zone DMA, type Isolate 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone DMA32, type Unmovable 410 261 133 51 24 14 7 2 0 0 0 Node 0, zone DMA32, type Reclaimable 2573 1806 1108 889 522 175 31 0 0 0 0 Node 0, zone DMA32, type Movable 408 352 345 341 328 312 310 260 216 180 356 Node 0, zone DMA32, type Reserve 0 0 0 0 0 0 0 0 0 2 0 Node 0, zone DMA32, type Isolate 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone Normal, type Unmovable 434 788 518 137 58 24 13 4 5 0 0 Node 0, zone Normal, type Reclaimable 1 110 2136 3212 414 25 8 7 8 0 0 Node 0, zone Normal, type Movable 8135 20535 17946 18171 15732 12719 9033 4448 1417 169 312 Node 0, zone Normal, type Reserve 0 0 0 0 0 0 0 0 0 0 1 Node 0, zone Normal, type Isolate 0 0 0 0 0 0 0 0 0 0 0 Number of blocks type Unmovable Reclaimable Movable Reserve Isolate Node 0, zone DMA 1 0 6 1 0 Node 0, zone DMA32 11 79 1436 2 0 Node 0, zone Normal 188 337 6129 2 0 When we are running the same application on other system, it comes up. So, it has to do with memory allocation setting of some sort. So, Is there some setting that we can use to allow the kernel to allocate the 313 - 4M pages that are free for 4k memory allocations? If so, what should we change on the system? Will setting vm.zone_reclaim_mode to 1 help here? Do I need to provide more information, if yes, what? -- Thanks, -aka http://blog.amit-agarwal.co.in

5 16