Re: How to alloc memory in kernel on a specific numa node
Hi, all, @Krishna Actually, I believe that in sone cases, allocating memory on a specified Numa node can be of interest, especiallly in terms of performance. For example, each PCI device is associated with a Numa node. Projects like DPDK are NUMA aware in the sense that memory is allocated on a specified NUMA node. This contributes to boost performance. Regards, Rami Rosen בתאריך יום ב׳, 27 באוג׳ 2018, 11:30, מאת s.v.krishna reddy < svkr...@gmail.com>: > How does it matter to allocate on specific node? > > Thanks, > Krishna. > > On Tue, Aug 21, 2018 at 5:59 PM bing zhu wrote: > >> Dear Sir / Ma'am: >> Greeting ,Thank you for your time,I'm trying to alloc some memory on a >> specific numa node (like cpu 0) ,but i'm new to linux kernel ,can someone >> help me with some information ?please . >> Thanks anyway >> ___ >> Kernelnewbies mailing list >> Kernelnewbies@kernelnewbies.org >> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies >> > ___ > Kernelnewbies mailing list > Kernelnewbies@kernelnewbies.org > https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Linux Networking Internals Question
Hi Ravi, The path that a packet goes through, from being received by the network driver and up to kernel Layer 3 (IPV4/IPV6) and from there to kernel Layer 4 (UDP/TCP/SCTP/other sockets) and from there to userspace sockets is quite complex. The logic is heavy, on that path there are lookups in routing tables, netfilter hooks, sanity checks, interaction with other subsystems, and more. In order to try to simplify things, and not go into deep technical details, we can say that generally the 5 tuple of the packet (SRC address, DST address, SRC port, DST port and protocol) is what determines to which socket it will go. Regards, Rami Rosen http://ramirose.wixsite.com/ramirosen On 16 June 2018 at 20:16, V.Ravikumar wrote: > Hi All, > > I wanted to know how a packet received will be handovered to a correct user > process. > Basically I want to understand what are the various header parameters in > packet which will help to find the open socket descriptor of respective > user process. I'm not able to find the exact answers in the web. > > Thanks in advance > > Regards, > Ravi > > ___ > Kernelnewbies mailing list > Kernelnewbies@kernelnewbies.org > https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Importance of kobject
Hi, Also sysfs is tied inherently to the kobject infrastructure. So I suggest that you will take a look also in http://elixir.free-electrons.com/linux/latest/source/Documentation/filesystems/sysfs.txt Chapter 14 of Linux Device Drivers, 3rd edition, was written in 2005, so you should take in account that things change a bit since then in terms of implementation details. The principles are for a large extent quite the same, though. Regards, Rami Rosen On 17 May 2017 at 10:21, Alexander Kapshuk <alexander.kaps...@gmail.com> wrote: > -- Forwarded message -- > From: Alexander Kapshuk <alexander.kaps...@gmail.com> > Date: Wed, May 17, 2017 at 10:20 AM > Subject: Re: Importance of kobject > To: Madhu K <madhu.s...@gmail.com> > > > On Wed, May 17, 2017 at 10:08 AM, Madhu K <madhu.s...@gmail.com> wrote: >> Hi All, >> >> I am kernel newbie, I want to know the importance of kobject, can anybody >> explain the importance of kobject with an example. >> >> Thanks in advance. >> Madhu >> >> ___ >> Kernelnewbies mailing list >> Kernelnewbies@kernelnewbies.org >> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies >> > > Kobjects play an essential role in the Device Model. > The documentation below may be a good starting point in learning about > kobjects: > > https://lwn.net/images/pdf/LDD3/ch14.pdf > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/plain/Documentation/kobject.txt?h=v4.12-rc1 > > ___ > Kernelnewbies mailing list > Kernelnewbies@kernelnewbies.org > https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: pls help in veth
Hi Er, First, the veth modules should be in your kernel, as it does exist in 3.14: http://lxr.free-electrons.com/source/drivers/net/veth.c?v=3.14 It could be that the iprotue1 package you have does not support veth. What does the version of iproute2 you have on your machine ? what is the output of "ip -V"? Also do you have man page of "ip link" ? and in case you have, please run "man ip link" and post here what you see in the "TYPE :=" section, you have veth, Also, assuming you have access to the source tree where the kernel was built, what do you get when running, from the root of this tree: more .config | grep VETH And finally - which distro is running on this device ? Regards, Rami Rosen http://ramirose.wix.com/ramirosen On 6 December 2016 at 18:25, Er Krishna <erkris...@gmail.com> wrote: > Hi Rami, > > Thanks, some how I am able to manage all the details you asked : > > root@krishna:~# lsmod | grep veth > root@krishna:~# > root@krishna:~# > root@krishna:~# uname -a > Linux 3.14.55- #1 SMP PREEMPT i686 GNU/Linux > root@krishna:~# > root@krishna:~# > root@krishna:~# modprobe -r veth > modprobe: FATAL: Module veth is builtin. > root@krishna:~# > > Any suggestion from your end to enable this is most welcome. > > BR/Krish > > On Tue, Dec 6, 2016 at 9:18 PM, Er Krishna <erkris...@gmail.com> wrote: >> >> Thanks Rami for all the help. Yes lsmod shows that veth is not there. >> Perhaps the kernel has not been compiled with config_veth option enable in >> .config. Exact kernel version I will let you know tomorrow but most of the >> chances its 4.* kernel. Its customized kernel I got from different team, >> they have build it via yocto and I had to setup one network topology on it. >> >> BR/Krish >> >> On Tue, Dec 6, 2016 at 8:18 PM, Rami Rosen <roszenr...@gmail.com> wrote: >>> >>> Hi Eri, >>> The driver is the veth driver, but it should be loaded automatically >>> when running this >>> command. >>> >>> What do you get when running: >>> >>> modprobe veth >>> >>> And what do you have when running >>> lsmod | grep veth ? >>> >>> Which kernel are you working with ? can you paste the output of >>> "uname -a"? is it a kernel you built from source, or a kernel which is >>> part of a distro? >>> >>> Regards, >>> Rami Rosen >>> http://ramirose.wix.com/ramirosen >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> On 6 December 2016 at 15:15, Er Krishna <erkris...@gmail.com> wrote: >>> > Hi All, >>> > >>> > Can some one pls let me know for below command to run on linux which >>> > driver >>> > and which package I need to install ? I see I have iproute package >>> > installed >>> > on my box, but still I am facing below error. >>> > >>> > root@krishna:~# ip link add ep1 type veth peer name ep2 >>> > RTNETLINK answers: Operation not supported >>> > >>> > BR/Krish >>> > >>> > ___ >>> > Kernelnewbies mailing list >>> > Kernelnewbies@kernelnewbies.org >>> > https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies >>> > >> >> > ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: pls help in veth
Hi Eri, The driver is the veth driver, but it should be loaded automatically when running this command. What do you get when running: modprobe veth And what do you have when running lsmod | grep veth ? Which kernel are you working with ? can you paste the output of "uname -a"? is it a kernel you built from source, or a kernel which is part of a distro? Regards, Rami Rosen http://ramirose.wix.com/ramirosen On 6 December 2016 at 15:15, Er Krishna <erkris...@gmail.com> wrote: > Hi All, > > Can some one pls let me know for below command to run on linux which driver > and which package I need to install ? I see I have iproute package installed > on my box, but still I am facing below error. > > root@krishna:~# ip link add ep1 type veth peer name ep2 > RTNETLINK answers: Operation not supported > > BR/Krish > > ___ > Kernelnewbies mailing list > Kernelnewbies@kernelnewbies.org > https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: an advise how to start
Hi Limor, Regarding your question about bugs: The Linux kernel has a Bugzilla: You can browse it by a subsystem. https://bugzilla.kernel.org/describecomponents.cgi Regards, Rami Rosen http://ramirose.wixsite.com/ramirosen Hi all, i am a senior c,c++ engineer which is used to complex MT systems both in user space and in layer 4. i have read some books on the kernel, wondered around kernel code and understood parts of it subsystems. i am really enthutiastic about writing something within the kernel but i dont know where to start. a good start for me would be list of bugs and small features missing but i dont know where to find such updated list. i have heard about the outreachy project and liked it but next cycle is only at may, and even than i need to dedicate 3 full months without working and it also seems like a students kind of program so i m not sure i will fit. Is any has any idea how can i find list of bugs and small features to begin with ? I m great at understanding code and in sync mechanisms. i truly love the rcu. i also love smp and cpu in general and vm. i have an experience with file systems , some experience with embeded and allot of background in networks but the kernel network internals is not a subsystem i have dived into seriously yet ( even implemented tcp stack from scratch though for some company i worked in. and it worked smoothly with great performance ) Any guidance will be appreciated. Thanks Limor. Sent from Yahoo Mail on Android ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: ip_hdr vs ipip_hdr
Hi Ricky,
ipip in the linux semantics refers usually to IP tunnel, for example:
http://lxr.free-electrons.com/source/net/ipv4/ipip.c
Traffic of ip tunnels is composed from an inner IP header which is
encapsulated within a packet which as the external IP header,
>(1) what is differences between ip_hdr and ipip_hdr? Why we have them? No
>?>documentation whatever to figure it out.
ip_hdr() is the IP header of layer 3, the network
ipip_hdr() is the IP header of layer 4, the transport layer. So this
is the IP header of the internal IP header when you have a tunnel, not
the external IP header.
Hope this helps,
Regards,
Rami Rosen
http://ramirose.wix.com/ramirosen
On 18 August 2016 at 11:47, Ricky <zhangchaow...@gmail.com> wrote:
>
> In include/linux/ip.h,
>
> 23 static inline struct iphdr *ip_hdr(const struct sk_buff *skb)
> 24 {
> 25 return (struct iphdr *)skb_network_header(skb);
> 26 }
> 27
> 28 static inline struct iphdr *inner_ip_hdr(const struct sk_buff *skb)
> 29 {
> 30 return (struct iphdr *)skb_inner_network_header(skb);
> 31 }
> 32
> 33 static inline struct iphdr *ipip_hdr(const struct sk_buff *skb)
> 34 {
> 35 return (struct iphdr *)skb_transport_header(skb);
> 36 }
> 37 #endif /* _LINUX_IP_H */
>
> if I passed in sk_buff to ip_hdr and ipip_hdr
>
> struct iphdr *ip_hdr ip_hdr_net = ip_hdr(skb);
> struct iphdr *ip_hdr ip_hdr_trans = ipip_hdr(skb);
>
> Do ip_hdr_net->saddr and ip_hdr_trans->saddr point to the same thing? I
> tried it on code. It doesn't. It seems that only ip_hdr_net->saddr point to
> source IP address, which make sense. Because network layer has IP but not on
> transport layer.
>
> So questions:
>
> (1) what is differences between ip_hdr and ipip_hdr? Why we have them? No
> documentation whatever to figure it out.
>
> (2) should I use ntohX function to convert ip_hdr member data when accessing
> them? eg, ip_hdr_net->saddr.
>
>
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>
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Re: Is there a way to force probe to be called (etherned driver) ?
Hi, Ran, Do you define the probe as a member is a platform_driver object ? See for example, http://lxr.free-electrons.com/source/drivers/net/ethernet/marvell/mvneta.c#L4219 In this case, maybe something is missing/wrong in platform_device_register(); or do you use a platfom_driver object ? http://lxr.free-electrons.com/source/include/linux/platform_device.h#L180 In this case, maybe something is missing/wrong in platform_driver_register(). Regards, Rami Rosen http://ramirose.wix.com/ramirosen In case you do, probably something is missing in your platform_device_register() method (which may be in arch/arm/plat-...) On 24 July 2016 at 11:51, Ran Shalit <ransha...@gmail.com> wrote: > Hello, > > > I write ethernet driver (mac controller is implemented in fpga connected to > cpu) > > I see that the probe is not called on doing insmod. > > Is there a way to force the probe to be called on doing insmod ? > > I could not find in the board file (omap dart, kernel 3.4.0) any > reference to ethernet. > > > Best Regards, > > Ran > > ___ > Kernelnewbies mailing list > Kernelnewbies@kernelnewbies.org > https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Are these books outdated?
Hi Andrey, >Here is link to Jessica McKellar's (LDD4 co-author) repo with examples >for the next book. >https://github.com/jesstess/ldd4 Thanks for the link, I was not aware of it ! Rami Rosen ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Are these books outdated?
Hi, Since there was a concern about that theses books are outdated, I want to mention here also a book title "Professional Linux Kernel Architecture", by Wolfganag Maurer, Wiley, 2008, 1368 pages. (I read it partially) And also I agree with Robert saying that he wouldn't count on that publication date of LDD4 by Oreilly,, since indeed the publication date was postponed in the past (at least once but maybe more, I am unsure about that) Regards, Rami Rosen http://ramirose.wix.com/ramirosen On 14 July 2016 at 15:26, Robert P. J. Day <rpj...@crashcourse.ca> wrote: > On Thu, 14 Jul 2016, François wrote: > >> On Thu, Jul 14, 2016 at 02:01:55PM +0300, Aleksander Alekseev wrote: >> >> Hello Aleksander, >> >> I only know LDD 3: >> > * Linux Device Drivers, 3rd Edition (2005) >> >> Since this book is freely available in PDF, I would advise you to >> read it. It is out-dated (in sense you won't compile snippets as is) >> but it is well written, and pleasant to read. >> >> The version 4 was scheduled for dec 2015 iirc, but is now annonced >> for nov 2017 on O'Reilly's website. > > i wouldn't count on that publication date. according to sources, > nothing has been finalized. > > rday > > -- > > > Robert P. J. Day Ottawa, Ontario, CANADA > http://crashcourse.ca > > Twitter: http://twitter.com/rpjday > LinkedIn: http://ca.linkedin.com/in/rpjday > > ___ > Kernelnewbies mailing list > Kernelnewbies@kernelnewbies.org > https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: OS Error: 105
Hi, Shilpa, Can you send the code/put it in pastebin and send the link ? Rami Rosen On 13 July 2016 at 15:20, Shilpa Yellapragada <yshilpa.1...@gmail.com> wrote: > Hi, > > Can someone explain me why I am encountering an OS error 105, while > trying to write to a socket? > > Regards, > Shilpa > > -- > Shilpa Yellapragada > Software Engineer > Infinera India Pvt Ltd > > ___ > Kernelnewbies mailing list > Kernelnewbies@kernelnewbies.org > https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Is there any good literature explaining Linux's file system ?
Hi, Ruan,
AFAIK, there is no book which is dedicated to the Linux kernel
implementation of Linux filesystems.
In "Understanding the Linux Kernel, 3rd Edition"
By Daniel P. Bovet, Marco Cesati
rhere is one chapter (chapter 18) of about 40 pages about the
implementation of Ext2 and Ext3.
Please keep in mind that ext3 was removed:
https://lwn.net/Articles/651645/
There is also a chapter about Virtual File System (VFS), even though
you did not asked about it. I believe that learning about VFS is
important in ordet to understand how particular filesystems like
ext2/ext3/btrfs work.
See:http://shop.oreilly.com/product/9780596005658.do
Also in "Professional Linux Kernel Architecture" by Wolfgang Mauerer,
Wiley Publishing, Inc., there is a chapter about the "The Extended
Filesystem Family" (chapter 9), and also a chapter about VFS (Chapter
8).
here is also a book titled "Linux Filesystems Paperback"
by William Von Hagen. I did not read it. However, it is really old
(2002!); 14 years are significant in Linux development.
Good luck!
Regards,
Rami Rosen
http://ramirose.wix.com/ramirosen
On 10 July 2016 at 15:23, Yubin Ruan <ablacktsh...@gmail.com> wrote:
> Hi everybody,
> I'm really curious about whether there is any literature that
> describe Linux's file systems(e.g. ext2{3,4}, btrfs) deeply?
> I can't find much literature about Linux's filesystem. I have read
> some papers about Unix's file system. For example, **A Fast File System
> for UNIX**, which explain things in detail(though not so informative for
> me). I also read **Design and Implementation of the Second Extend
> Filesystem** by Remy, Theodore, et al. But those papers and blogs can't
> make thing clear for me, because there are so many things that they have
> not explained.
> I wonder is there any book that explain one of the Linux
> filesystem(design, implementation) in detail, like what Mal Gorman
> explain about Linux Memory Management in his books **Understand The
> Linux Memory Manager** and **Code Commentary On The Linux Virtual Memory
> Manager** ?
>
> Thanks in advance,
> Ruan.
>
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Re: boot param to change tick
Hi, >You have to rebuild the kernel to change the HZ value. +1 Rami Rosen ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Adding new protocol to linux.
Hi, Header files under include/net are for kernel internal use. Header files under include/uapi are for exposure to userspace: http://lxr.free-electrons.com/source/include/uapi/ Regards, Rami Rosen http://ramirose.wix.com/ramirosen בתאריך 28 במרץ 2016 18:04, "Manoj Nayak" <manojnayak2...@gmail.com> כתב: > > 1) Is it possible to write a new protocol for linux with an out of > > tree module without modifing socket.h file? > > I think this has been already tried in the following code. > > http://lxr.free-electrons.com/source/include/net/bluetooth/bluetooth.h#L36 > > http://lxr.free-electrons.com/source/include/linux/socket.h#L239 > > The challenge is to expose this development specific header file to > userspace. > The following document talks about that. > > http://kernelnewbies.org/KernelHeaders > > Regards > Manoj Nayak > > > ___ > 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: Adding new protocol to linux.
Hi Daniel, Following are answers for several of your questions: Adding a protocol in Linux is done first by defining a protocol, and then registering it with the proto_register() method: http://lxr.free-electrons.com/source/net/core/sock.c#L2815 For that you need to define a proto object; for TCPv4 it is done thus, for example: http://lxr.free-electrons.com/source/net/ipv4/tcp_ipv4.c#L2315 Defining a protocol is not enough, you should also register a protocol handler for this protocol. Defining a protocol handler is done first by defining a packet_type object of this protocol and then defining a callback for this packet_type. So for example, for IPv4, a packet_type object called ip_packet_type is defined in http://lxr.free-electrons.com/source/net/ipv4/af_inet.c#L1677 The protocol handler for this packet type is ip_rcv(): http://lxr.free-electrons.com/source/net/ipv4/ip_input.c#L378 This protocol is registered with dev_add_pack(): http://lxr.free-electrons.com/source/net/core/dev.c#L397 So, for example, for IPv4 it is done in inet_init(): http://lxr.free-electrons.com/source/net/ipv4/af_inet.c#L1791 Apart from the protocol handler, a unique Ethernet type should be defined for this protocol; for IPv4 we have 0x0800 (ETH_P_IP) http://lxr.free-electrons.com/source/include/uapi/linux/if_ether.h#L46 and for the ARP protocol we have 0x0806 (ETH_P_ARP), and so on. The Ethernet type in the Ethernet header represents the protocol assigned to this packet. The net_device_ops structure is not related, it merely represents the interface of the of the kernel representation of network device (a net_device object) to userspace, for userspace operations like setting the MTU, setting the MAC address, bringing the device up and down, putting the device in promiscuous mode, and more. Hope this helps! Regards, Rami Rosen http://ramirose.wix.com/ramirosen On 26 March 2016 at 05:00, Daniel. <danielhi...@gmail.com> wrote: > Hi everybody, > > I'm planing to write a socket API for Nordic's nRF24L01+ and I was > digging on socket code and find all supported protocols at > include/linux/socket.h with all that #define AF_x y. So my questions > are: > > 1) Is it possible to write a new protocol for linux with an out of > tree module without modifing socket.h file? > 2) Could netlink socket be used to solve this? .. and > 3) I saw that there is net_device_ops and proto_ops. How they are tied > together? > > Thanks in advance and > Best regards, > > -- > "Do or do not. There is no try" > Yoda Master > > ___ > 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: kexec not working
Hi Ronit, Can you please tell what happens when you ran the "kexec -p" that you mentioned ? Do you see any message on screen ? Does it hang immediately ? Regards, Rami Rosen בתאריך 6 במרץ 2016 05:23, "Ronit Halder" <ronit.li...@gmail.com> כתב: > When I am doing normal load of kernel using kexec, it works. > > #kexec -l /boot/vmlinuz-4.3.0-crash+ > --initrd=/boot/initramfs-4.3.0-crash+.img > --append="root=/dev/mapper/fedora-root 1 irqpoll maxcpus=1 > reset_devices" > > #kexec -e > > > But, when I am doing load on panic using kexec, it isn't working. > > #kexec -p /boot/vmlinuz-4.3.0-crash+ > --initrd=/boot/initramfs-4.3.0-crash+.img > --append="root=/dev/mapper/fedora-root 1 irqpoll maxcpus=1 > reset_devices" > > #echo "1" >/proc/sys/kernel/sysrq > > #echo c > /proc/sysrq-trigger > > > What am I doing wrong? > > ___ > 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: Reading network connections for processes in a separate net namespaces from /proc/[pid]/net/tcp|tcp6
Hi, Darek, cat /proc/[pid]/net/tcp is handled by http://lxr.free-electrons.com/source/net/ipv4/tcp_ipv4.c#L2230 and cat /proc/[pid]/net/tcp6 is handled by: http://lxr.free-electrons.com/source/net/ipv6/tcp_ipv6.c#L1782 Hope it helps! Regards, Rami Rosen http://ramirose.wix.com/ramirosen On 25 January 2016 at 15:00, dariusz ostolski <dariusz.ostol...@gmail.com> wrote: > Hello, > > > 2016-01-22 10:21 GMT+01:00 Rami Rosen <roszenr...@gmail.com>: >>>I've found >>>functions for global files, maybe they are the same). I'd like to >>>check when these files where introduced (from what kernel version they >>>are available) >> >> Support for kernel network namesapces was added with kernel 2.6.29. >> It is basically based on adding an object called "net_ns" to the >> process descriptor, and instance of struct net, which represents a >> network namesapce. You can think of such object as representing the >> network state of a process, including all stats, sockets, devices, >> tables, and so on. This net_ns is a member of an object called >> nsproxy, which includes pointers to 4 other namesapces (uts, mnt, pid >> and ipc). >> >> >>>and there is no information about network >>>namespaces at all (google, stackoverflow, man pages, kernel docs) >> > > Thank You for your answer it gave me some clues so I was not > completely blind when I checked kernel source code. > Nevertheless, excuse me for not being precise enough, what I meant is > that I couldn't find any docs about those 2 specific files: > 1. /proc/[pid]/net/tcp > 2. /proc/[pid]/net/tcp6 > > And how is their content related to net namespaces? > > I want to read connections for a process that is in a separate net > namespace but I'd like to avoid switching to that namespace, > my experiments showed that reading /proc/[pid]/net/tcp|tcp6 should be > enough, but I'd like to find confirmation of that > either in official docs (which I couldnt find) or in kernel source > code (I failed there too). > > Again thank You in advance for your help. > > Regards, > Darek ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: How to statically build kernel module?
Hi, Assuming that you are talking about a kernel module which is part of the Kernel tree, you simply need to run make menuconfig, navigate to that module, and instead "M" you should choose "Y". The build and install the kernel image. Regards, Rami Rosen http://ramirose.wix.com/ramirosen בתאריך 22 בינו 2016 21:44, "Kenneth Adam Miller" < kennethadammil...@gmail.com> כתב: > Is there a guidance anywhere? I know my question is simple and > straightforward, but I've looked around a bit and I can't find a direct way > to statically build a kernel module into the kernel. > > ___ > 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: Reading network connections for processes in a separate net namespaces from /proc/[pid]/net/tcp|tcp6
Hi,Darek, >I've found >functions for global files, maybe they are the same). I'd like to >check when these files where introduced (from what kernel version they >are available) Support for kernel network namesapces was added with kernel 2.6.29. It is basically based on adding an object called "net_ns" to the process descriptor, and instance of struct net, which represents a network namesapce. You can think of such object as representing the network state of a process, including all stats, sockets, devices, tables, and so on. This net_ns is a member of an object called nsproxy, which includes pointers to 4 other namesapces (uts, mnt, pid and ipc). >and there is no information about network >namespaces at all (google, stackoverflow, man pages, kernel docs) This is not really so. Look for example in the following: Namespaces and Cgroups – the basis of Linux Containers by Rami Rosen http://files.meetup.com/18720713/Namespaces_Cgroups_Conatiners.pdf "Resource management: Linux kernel Namespaces and cgroups by Rami Rosen http://www.haifux.org/lectures/299/netLec7.pdf Namespaces in operation, part 7: Network namespaces by Jake Edge https://lwn.net/Articles/580893/ Introduction to Network Namepaces - David Mahler https://www.youtube.com/watch?v=_WgUwUf1d34 (Shamless plug, I am the owner of the first two links...) Hope this helps, Regards, Rami Rosen http://ramirose.wix.com/ramirosen On 22 January 2016 at 10:34, dariusz ostolski <dariusz.ostol...@gmail.com> wrote: > Hello, > > My name is Darek Ostolski, I'm computer enthusiast and hobbyst (also a > developer). > If this is incorrect mailing list excuse me and please point to > the appropriate place to ask this kind of question. I couldn't find > any other more > appropriate place. > > I have a process that is in the separate net namespace (basically a > container) and I want to check opened connections for that process. I > have a kernel 4.3.3. > My experiments showed that this information is available in > /proc/[pid]/net/tcp|tcp6 files. For example for a global > /proc/net/tcp6 shows following opened ports: > > root@host:~# cat /proc/net/tcp6 > sl local_address remote_address >st tx_queue rx_queue tr tm->when retrnsmt uid timeout > inode >0: :01BD > : 0A : 00: > 00 22882 1 88040de7b240 100 0 0 10 0 >1: :008B > : 0A : 00: > 00 22883 1 88040de7a9c0 100 0 0 10 0 >2: :0050 > : 0A : 00: > 00 1214363 1 880077ed9340 100 0 0 10 0 >3: :0016 > : 0A : 00: > 00 21933 1 880400a33140 100 0 0 10 0 >4: :445C > : 0A : 00: > 10000 29904 1 880400a32040 100 0 0 10 0 > > And for a process running in container I have: > root@host:~# cat /proc/30518/net/tcp6 > sl local_address remote_address >st tx_queue rx_queue tr tm->when retrnsmt uid timeout > inode >0: 017F:1F45 > : 0A : 00: > 00 1211206 1 880364fcb380 100 0 0 10 0 >1: :1F49 > : 0A : 00: > 00 1215425 1 8802befd0200 100 0 0 10 0 >2: :1F90 > : 0A : 00: > 00 1215421 1 880077ed8240 100 0 0 10 0 > > > So I see that there are opened ports that are not visible on host > level but are visible at a container level for example 1F90 -> which > is basically 8080. > > > I'd like to ask following questions: > 1. Where can I find documentation for /proc/[pid]/net/tcp|tcp6 files? > All I could find was documentation about global file(i.e. > /proc/net/tcp|tcp6) and there is no information about network > namespaces at all (google, stackoverflow, man pages, kernel docs) > 2. Could You confirm that in these files I'll see all connections that > are specific for a given process even if this process is in separate > network namespace? (so I dont have to enter target net/pid namespace > to read their global /proc/net/tcp|tcp6 files) > 3. I've grep k
Re: Preceding a method call with (void)
Hi,
Well, there are rare cases in the kernel when you add (void) before calling
the method. For example, if the method returns int or other type and you
want to emphasize that you are aware of that and deliberately not check the
return value.
See for example:
http://lxr.free-electrons.com/source/drivers/acpi/acpica/tbxfload.c#L156
Regards,
Rami Rosen
בתאריך 10 בספט 2015 09:39, <valdis.kletni...@vt.edu> כתב:
> On Thu, 10 Sep 2015 07:52:49 +0300, Kevin Wilson said:
>
> > (void) myFunc(param1);
> >
> > I did not encounter such cases in the kernel code that I read, thus far.
> >
> > On the other hand, I did not saw in the kernel coding style doc
> > anything which prohibits such usage.
> >
> > If I remember, using (void) before the method name is a way to tell
> > explicitly that this method does not return any value,
> > but I am not sure as for the exact reasons it is used (in userspace).
>
> Well, if the function actually returns nothing, in kernel code we usually
> declare it as:
>
> void myFunc( int param1)
> {
> /* yadda yadda yadda *.
> }
>
> Given that, what reason is there for casting the return value with (void)?
>
> (And if the function is actually 'int myFunc ( int param1) {...}',
> why are you calling it and then ignoring the return value? That's a clue
> that you're abusing the API...)
>
> ___
> 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: When to use threaded interrupts?
Kosta, This kernel and older ones include device drivers which use threaded IRQs (call request_threaded_irq(), etc). For example, many of the driver under drivers/input/touchscreen are using threaded IRQs: Following link is from kernel 3.18: http://lxr.free-electrons.com/source/drivers/input/touchscreen/ucb1400_ts.c?v=3.18 How did you came to the conclusion that this kernel does not support threaded IRQs ? could it be that you simply do not use device drivers that use this mechanism ? Regards, Rami Rosen http://ramirose.wix.com/ramirosen On 13 September 2015 at 09:24, Kosta Zertsekel <zertse...@gmail.com> wrote: >>> I think I get the pro of using threaded interrupts - to decrease the >>> maximum >>> interrupt latency on RT workloads and/or RT machines (servers, embedded, >>> etc.). >>> So, I'd like to ask: >>>- Why not **all** of the drivers use the threaded interrupts? >>>- What are the cons of the threaded interrupts? >>> >> Just a wild assumption: maybe the cost of incurring context switches ? >> (comparing to tasklets) > > I get that threaded IRQ is better than softIrqs because threaded IRQ > supports > priorities. On the other hand, added context switches surely get system > slower. > But from the practical point of view - why on relatively new Intel PC there > are > no threaded irqs at all? > > ``` > $ uname -a > Linux kostaz-OptiPlex-7010 3.19.0-26-generic #28-Ubuntu SMP Tue Aug 11 > 14:16:32 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux > ``` > > --- KostaZ > > On Thu, Sep 10, 2015 at 11:09 PM, Rami Rosen <roszenr...@gmail.com> wrote: >> >> Kosta, >> >> Just a wild assumption: maybe the cost of incurring context switches ? >> (comparing to tasklets) >> >> Best Regards, >> Rami Rosen >> http://ramirose.wix.com/ramirosen >> >> >> >> On 10 September 2015 at 20:49, Kosta Zertsekel <zertse...@gmail.com> >> wrote: >> > Hi guys, >> > >> > I hope I'm on right mailing list. :-) >> > I think I get the pro of using threaded interrupts - to decrease the >> > maximum >> > interrupt latency on RT workloads and/or RT machines (servers, embedded, >> > etc.). >> > >> > Also, I see that in 4.2 there are only ~76 drivers that use threaded >> > interrupt: >> > ``` >> > $ git grep -l IRQ_WAKE_THREAD | sort | grep -v "\.h" | wc -l >> > 76 >> > ``` >> > >> > So, I'd like to ask: >> >- Why not **all** of the drivers use the threaded interrupts? >> >- What are the cons of the threaded interrupts? >> > >> > Thanks, >> > --- KostaZ >> > >> > ___ >> > 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: When to use threaded interrupts?
Kosta, Just a wild assumption: maybe the cost of incurring context switches ? (comparing to tasklets) Best Regards, Rami Rosen http://ramirose.wix.com/ramirosen On 10 September 2015 at 20:49, Kosta Zertsekel <zertse...@gmail.com> wrote: > Hi guys, > > I hope I'm on right mailing list. :-) > I think I get the pro of using threaded interrupts - to decrease the maximum > interrupt latency on RT workloads and/or RT machines (servers, embedded, > etc.). > > Also, I see that in 4.2 there are only ~76 drivers that use threaded > interrupt: > ``` > $ git grep -l IRQ_WAKE_THREAD | sort | grep -v "\.h" | wc -l > 76 > ``` > > So, I'd like to ask: >- Why not **all** of the drivers use the threaded interrupts? >- What are the cons of the threaded interrupts? > > Thanks, > --- KostaZ > > ___ > 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: Questions on Netlink sockets
Hi, Bhaskar, Thanks for posting the code. PS: I am humbled to see a reply from you. I read Chapter 2 from your book to understand netlink sockets. I hope you enjoyed it and find it useful! + My code is not creating VLAN interface as executed by the 'ip link ...' command. Can you elaborate a bit about this: which difference do you see between creating a VLAN with ip link add name eth2.200 link eth2 type vlan id 200 And running your program (let's call your executable vlan_nl) in this way: ./vlan_nl eth1.100 eth1 100 Regards, Rami Rosen http://ramirose.wix.com/ramirosen ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Questions on Netlink sockets
Hi, Bhaskar, Indeed the netdev mailing list is too advanced for this. Do you get any error as a result of sending this netlink message ? (I mean error in userspace or in kernel; if there is an error message in the kernel it can be viewed by looking at the end of dmesg output) Further more, I suggest that you will post the code here. The concept itself is right, It should work, you either build the netlink message incorrectly or send it incorrectly, so it seems. Regards, Rami Rosen http://ramirose.wix.com/ramirosen On 18 August 2015 at 01:55, Bhaskar Upadhyayula bu.ker...@gmail.com wrote: Hello, I want to check with the group if this is right mailing list to post my question. Here is what I am doing. + From a user-space program, mimicking the behavior of creating a VLAN interface when we execute the following ip command: $ ip link add name vlan-intf-name link parent-intf-name type vlan id id Example: $ ip link add name dummy.110 link dummy type vlan id 110 + My program open's a netlink socket and sends information to kernel (interface names, vlan tags etc). My code more or less follows the code in iproute2/ip/iplink.c + My code is not creating VLAN interface as executed by the 'ip link ...' command. I have a few questions around this and can post my code, if required. But please let me know if this is right mailing list or should I post on netdev list (which I feel is for advanced network questions). Thx. ___ 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: A flow path for ethernet kernel driver
Hi, Airton, This is simply a matter of setting dmesg to work with the level which you need in your setup. You should set dmesg -n to work with the pr_info() level. Pleas look in man dmesg, for the -n, --console-level level part. If you are in a haste and looking for immediate solution, you can also try pr_err() instead, as most distros do print such messages with dmesg without need for any special setup. Regards, Rami Rosen http://ramirose.wix.com/ramirosen On 18 May 2015 at 22:23, Airton Ishimori nobumasa@gmail.com wrote: Hello, everybody, I'm trying to develop a new Ethernet driver (Realtek) for Linux kernel 4.0.2. [3.612938] r8169 Gigabit Ethernet driver 2.3LK-NAPI loaded As part of my studies, I'm trying to trace the path for functions defined in drivers/net/ethernet/realtek/r8169.c, net/core/dev.c and net/core/dev_ioctl.c. I'm using printks for this purpose. For instance, something like: printk(TEST: __dev_set_promiscuity\n); However, I'm not getting what's going on. I can set/unset the promiscuity behaviour via ifconfig command. [ 131.330091] device eth0 entered promiscuous mode [ 170.619086] device eth0 left promiscuous mode By looking at the dmesg output above, I thought the function that deals with promiscuity was __dev_set_promiscuity() defined in net/core/dev.c, because this function calls a function to print the message above: pr_info(device %s %s promiscuous mode\n, dev-name, dev-flags IFF_PROMISC ? entered : left); But, when I tried to look for my printk message with dmesg after compiling and running the kernel, I couldn't find it. $ cd linux-4.0.2/ $ make net make modules $ sudo make modules_install sudo make install Can somebody help me to understand what's happening? Thanks in advance, -- Airton Ishimori ___ 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: Lxc vs openvz
Hi, In fact, the LXC project itself was not added to the kernel. It is the underlying components, cgroups and namespaces, which were added to the kernel. The work on cgroups started several years ago (by google), and the work on namespaces started event before. The OpenVZ project, on the other hand, is based on a proprietary project (Virtuozzo). The are many heavy features which OpenVZ added, and it will take probably years so that the project will be fully in mainline. If you want to learn more about this fascinating subject, you can read two very detailed documents (pdf) with over 200 pages about Linux Containers, LXC, OpenVZ, Docker, CRIU, Namespaces and cgroups, in my website: http://ramirose.wix.com/ramirosen. Regards, Rami Rosen http://ramirose.wix.com/ramirosen On Mon, Jun 16, 2014 at 5:10 PM, Grzegorz Dwornicki gd1...@gmail.com wrote: Hi Can anyone point me why lxc was added to the kernel instead of openvz? The point in time will be sufficient as I will look in the lkml archives. Grzegorz ___ 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: Problem with inserting nfs module in kernel
Hi, Sivakumar, This should work. Are you sure all your printk are proper ? Can you please pastebin the crash message and send us a link ? Regards, Rami Rosen http://ramirose.wix.com/ramirosen בתאריך 12 במאי 2014 23:09, Sivakumar V sivakumar...@gmail.com כתב: Hi All, I am tried to compile and install (network file system)nfs module to kernel i.e. modified nfs code(inserted printk's in kernel nfs code) without compiling entire kernel . It is inserted but when configuring nfs the mount command crashes. i.e. mount -t nfs 172.16.10.44:/tmp /home/user/ddd can anyone know why it happens? Is there any way to do this Thanks in advance ___ 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: Regarding net_device_ops
Hi, Pranay, First, let's assume that you are talking about IPv4, though you did not mention it explicitly. (The principles in IPv6 are quite similar, though) A packet is sent out in the usual case with the ip_queue_xmit() method. The ip_queue_xmit() method calls the ip_route_output_ports() method in order to perform a lookup in the IPv4 routing tables. see: http://lxr.free-electrons.com/source/net/ipv4/ip_output.c#L352 The results of this IPv4 routing lookup determines on which network device (net_device) the packet will be sent. You should look at the code of ip_route_output_ports() method in net/ipv4/route.c in order to understand the IPv4 routing subsystem and the IPv4 routing lookup. Packets can, under certain circumstances, be sent by the ip_send_skb() method, but this happens when the flow (which consists also of the net_device to be used) is known before. Best Regards, Rami Rosen http://ramirose.wix.com/ramirosen On Sat, May 3, 2014 at 12:43 PM, Pranay Srivastava pran...@gmail.com wrote: Hi Referring to Documentation/networking/netdevices.txt a) ndo-ndo_start_xmit if written as is will be thread safe? [Correct?] NETIF_F_LLTX is not set only then this is true. But dev_queue_xmit(skb) doesn't seem to take any lock, neither does dev_hard_start_xmit. Please let me know if i'm wrong and where is this lock taken before calling dev_queue_xmit/dev_hard_start_xmit. b) Why and when would I want to use rtnl_lock/unlock? Is it like registering multiple device simultaneously? c) ndo-ndo_start_xmit is supposed to start the transmission of the skb. However I've a doubt --- Suppose that there's no room left for the incoming skb in the device buffer, so in that case it would be ideal to call netif_stop_queue. At this the the skb already with the ndo_start_xmit will not be retried again[Correct?] Is ndo_start_xmit required to wait in this case? However if the above spin_lock in a) was taken then this would be a waste. So is it possible that this skb is deffered to whenever there's room and return NETDEV_TX_OK? But if we do this we are telling the application that it's packet was delivered so in case there was a timeout set by the application on a reply it would again send us the same packet. So instead of deferring is it good to drop ? -- ---P.K.S ___ 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: Regarding skb and net_device.
Hi, Pranay, First, let's assume that you are talking about IPv4, though you did not mention it explicitly. (The principles in IPv6 are quite similar, though) A packet is sent out in the usual case with the ip_queue_xmit() method. The ip_queue_xmit() method calls the ip_route_output_ports() method in order to perform a lookup in the IPv4 routing tables. see: http://lxr.free-electrons.com/source/net/ipv4/ip_output.c#L352 The results of this IPv4 routing lookup determines on which network device (net_device) the packet will be sent. You should look at the code of ip_route_output_ports() method in net/ipv4/route.c in order to understand the IPv4 routing subsystem and the IPv4 routing lookup. Packets can, under certain circumstances, be sent by the ip_send_skb() method, but this happens when the flow (which consists also of the net_device to be used) is known before. Best Regards, Rami Rosen http://ramirose.wix.com/ramirosen On Sat, May 3, 2014 at 11:33 AM, Pranay Srivastava pran...@gmail.com wrote: Hi, This is probably a stupid question, but i'm not able to find the answer. How does the networking subsystem decides which device to use for sending the skb. Can some one please guide me to the particular code. I seem to get lost in there :( -- ---P.K.S ___ 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: Regarding net_device_ops
Hi, Sorry, I of course discuss here your previous question about SKB Regards, Rami On Sat, May 3, 2014 at 1:34 PM, Rami Rosen roszenr...@gmail.com wrote: Hi, Pranay, First, let's assume that you are talking about IPv4, though you did not mention it explicitly. (The principles in IPv6 are quite similar, though) A packet is sent out in the usual case with the ip_queue_xmit() method. The ip_queue_xmit() method calls the ip_route_output_ports() method in order to perform a lookup in the IPv4 routing tables. see: http://lxr.free-electrons.com/source/net/ipv4/ip_output.c#L352 The results of this IPv4 routing lookup determines on which network device (net_device) the packet will be sent. You should look at the code of ip_route_output_ports() method in net/ipv4/route.c in order to understand the IPv4 routing subsystem and the IPv4 routing lookup. Packets can, under certain circumstances, be sent by the ip_send_skb() method, but this happens when the flow (which consists also of the net_device to be used) is known before. Best Regards, Rami Rosen http://ramirose.wix.com/ramirosen On Sat, May 3, 2014 at 12:43 PM, Pranay Srivastava pran...@gmail.com wrote: Hi Referring to Documentation/networking/netdevices.txt a) ndo-ndo_start_xmit if written as is will be thread safe? [Correct?] NETIF_F_LLTX is not set only then this is true. But dev_queue_xmit(skb) doesn't seem to take any lock, neither does dev_hard_start_xmit. Please let me know if i'm wrong and where is this lock taken before calling dev_queue_xmit/dev_hard_start_xmit. b) Why and when would I want to use rtnl_lock/unlock? Is it like registering multiple device simultaneously? c) ndo-ndo_start_xmit is supposed to start the transmission of the skb. However I've a doubt --- Suppose that there's no room left for the incoming skb in the device buffer, so in that case it would be ideal to call netif_stop_queue. At this the the skb already with the ndo_start_xmit will not be retried again[Correct?] Is ndo_start_xmit required to wait in this case? However if the above spin_lock in a) was taken then this would be a waste. So is it possible that this skb is deffered to whenever there's room and return NETDEV_TX_OK? But if we do this we are telling the application that it's packet was delivered so in case there was a timeout set by the application on a reply it would again send us the same packet. So instead of deferring is it good to drop ? -- ---P.K.S ___ 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: system call returns -1
Hi, Nada, Return value of -1 could be EPERM, Operation not permitted; see: http://lxr.free-electrons.com/source/include/uapi/asm-generic/errno-base.h Can you paste the code in pastebin or some other public site? regards, Rami Rosen http://ramirose.wix.com/ramirosen On Fri, May 2, 2014 at 9:23 AM, Nada Saif nada.sa...@gmail.com wrote: Hi, I added a new system call to kernel 2.6.32.61 - I used these commands for complication : make oldconfig make make modules install It went ok with few warning messages. When I tried to test the system call , the function _syscall return -1, what that means? Thanks, Nada ___ 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: cgroups: cannot write on file memory.oom_control
Hi Hedi, Well, you can use disabling oom in conjunction with event handler. Thus, you can free memory by changing memory setting of other cgroups when an oom occurs in a specific cgroup, and avoid having an oops in that cgroup. You can see an example of using event handler in conjunction with disabling the oom killer in Namespaces and cgroups in linux, in slides 101/102, see: http://ramirose.wix.com/ramirosen A shameless plug - I wrote this presentation of 121 slides about namespaces and cgroups. Regards, Rami Rosen בתאריך 17 באפר 2014 11:24, Hedi Boufaied hedi.boufa...@amadeus.com כתב: Hi Rami, Thanks a lot for your sequence. I followed it and it does work. I now see my process paused in sleep state instead of getting killed when the cgroup reaches OoO. This being said: * I do not really understand why the use_hierarchy option needs to be disabled in order to allow disabling of the oom killer... * I'm not sure that disabling the OoO killer is safe/reliable enough: in some of the trials I made, I saw other processes (xterms) not part of the OoO cgroup getting completely stuck and I had to reboot my machine... Best Regards, Hedi From:Rami Rosen roszenr...@gmail.com To:Hedi Boufaied hedi.boufa...@amadeus.com, Cc:kernelnewbies kernelnewbies@kernelnewbies.org Date:15/04/2014 15:39 Subject:Re: cgroups: cannot write on file memory.oom_control -- Hi, Hedi, This sequence works for me: echo 0 /sys/fs/cgroup/memory/memory.use_hierarchy mkdir /sys/fs/cgroup/memory/0 Then, the following two commands changes the value of oom_kill_disable: echo 1/sys/fs/cgroup/memory/0/memory.oom_control echo 0/sys/fs/cgroup/memory/0/memory.oom_control For more info, please look for the text about enabling/disabling use_hierarchy in section 6, http://lxr.free-electrons.com/source/Documentation/cgroups/memory.txt. Regards, Rami Rosen http://ramirose.wix.com/ramirosen On Mon, Apr 14, 2014 at 12:22 PM, Hedi Boufaied hedi.boufa...@amadeus.com wrote: Hi everyone, I am working with cgroups on OpenSuse (over VirtualBox) and I cannot disable the OOM killer by writing to the file memory.oom_control: echo 1 memory.oom_control -bash: echo: write error: Invalid argument I can change the memory limit and several other settings by writing to the appropriate files (like memory.limit_in_bytes) but I could never write to file memory.oom_control although I am root. I saw someone posted a similar issue a few days ago but there was no reply... I have copied below the sequence of command I am using. Any idea what could be the issue ? Thanks in advance for your help! Hedi /sys/fs su - root /sys/fs cd cgroup /sys/fs/cgroup cgcreate -g memory:/mygroup /sys/fs/cgroup cd memory/mygroup /sys/fs/cgroup/memory/mygroup echo 32M memory.limit_in_bytes /sys/fs/cgroup/memory/mygroup cat memory.limit_in_bytes 33554432 /sys/fs/cgroup/memory/mygroup echo 1 memory.oom_control -bash: echo: write error: Invalid argument /sys/fs/cgroup/memory/mygroup cat memory.oom_control oom_kill_disable 0 under_oom 0 --- ___ 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: cgroups: cannot write on file memory.oom_control
Hi, Hedi, This sequence works for me: echo 0 /sys/fs/cgroup/memory/memory.use_hierarchy mkdir /sys/fs/cgroup/memory/0 Then, the following two commands changes the value of oom_kill_disable: echo 1/sys/fs/cgroup/memory/0/memory.oom_control echo 0/sys/fs/cgroup/memory/0/memory.oom_control For more info, please look for the text about enabling/disabling use_hierarchy in section 6, http://lxr.free-electrons.com/source/Documentation/cgroups/memory.txt. Regards, Rami Rosen http://ramirose.wix.com/ramirosen On Mon, Apr 14, 2014 at 12:22 PM, Hedi Boufaied hedi.boufa...@amadeus.com wrote: Hi everyone, I am working with cgroups on OpenSuse (over VirtualBox) and I cannot disable the OOM killer by writing to the file memory.oom_control: echo 1 memory.oom_control -bash: echo: write error: Invalid argument I can change the memory limit and several other settings by writing to the appropriate files (like memory.limit_in_bytes) but I could never write to file memory.oom_control although I am root. I saw someone posted a similar issue a few days ago but there was no reply... I have copied below the sequence of command I am using. Any idea what could be the issue ? Thanks in advance for your help! Hedi /sys/fs su - root /sys/fs cd cgroup /sys/fs/cgroup cgcreate -g memory:/mygroup /sys/fs/cgroup cd memory/mygroup /sys/fs/cgroup/memory/mygroup echo 32M memory.limit_in_bytes /sys/fs/cgroup/memory/mygroup cat memory.limit_in_bytes 33554432 /sys/fs/cgroup/memory/mygroup echo 1 memory.oom_control -bash: echo: write error: Invalid argument /sys/fs/cgroup/memory/mygroup cat memory.oom_control oom_kill_disable 0 under_oom 0 --- ___ 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 in enable configuration when compile Kernel module
Hi, 'y' is used for building the module as a built-in in the kernel image. 'm' stands for building the module as a stand alone object (*.ko), which is not part of the kernel image, and should be insmoded or modprobed in order to be used. Regards, Rami Rosen http://ramirose.wix.com/ramirosen On Fri, Jan 10, 2014 at 8:24 AM, m silverstri michael.j.silvers...@gmail.com wrote: And please help me udnerstand what is the difference between 'y' and 'm' in 'CONFIG_VIDEOBUF2_CORE=y instead of CONFIG_VIDEOBUF2_CORE=m'? On Thu, Jan 9, 2014 at 10:23 PM, m silverstri michael.j.silvers...@gmail.com wrote: Thanks. Can you please help me understand what you mean by 'make this to build into kernel instead of static'? On Thu, Jan 9, 2014 at 7:18 PM, Ashokkumar G ashok.sysprogram...@gmail.com wrote: Dear Silverstri, I am not sure for which platform you are compiling Kernel. But for X86(_64) and ARM, CONFIG_VIDEOBUF2_CORE will be selected as a module (will not build into kernel image static), this is the dependency VIDEOBUF2_DMA_CONTIG [=m] MEDIA_SUPPORT [=m] HAS_DMA [=y] || VIDEOBUF2_VMALLOC [=m] MEDIA_SUPPORT [=m] || VIDEOBUF2_DMA_SG [=n] MEDIA_SUPPORT [=m] || SOC_CAMERA [=m] MEDIA_SUPPORT [=m] V4L_PLATFORM_DRIVERS [=y] VIDEO_V4L2 [=m] HAS_DMA [=y] I2C [=y]. select MEDIA_SUPPORT and SOC_CAMERA to build into kernel image static (when you select one of MEDIA_SUPPORT/SOC_CAMERA/VIDEO_V4L2 as build static into kernel, .config will have CONFIG_VIDEOBUF2_CORE=y instead of CONFIG_VIDEOBUF2_CORE=m) For ARM board I used Device Drivers-Multimedia Support (make this to build into kernel instead of static)-V4L platform devices (make this to build into kernel instead of static)-Soc Camera Support(make this to build into kernel instead of static). -- Best Regards Ashokkumar.G 100 Things can not be taken back. 001. A lost opportunity. 010. A spoken word. 011. A sped arrow. 100. Time spent. On Thu, Jan 9, 2014 at 7:16 PM, m silverstri michael.j.silvers...@gmail.com wrote: I am using 3.10.x kernel tree. My kernel module needs config VIDEOBUF2. That is defined in drivers/media/v4l2-core/Kconfig: # Used by drivers that need Videobuf2 modules config VIDEOBUF2_CORE select DMA_SHARED_BUFFER tristate So I put 'CONFIG_VIDEOBUF2_CORE=y' in my Kernel config file and compile. From the Kconfig it has CONFIG_VIDEOBUF2_CORE has no dependency and I think adding CONFIG_VIDEOBUF2_CORE=y to my kernel config should work. I am modify the right kernel config file since I set other flags like CONFIG_VIDEO_DEV=y and that works. The generated .config does not contain 'CONFIG_VIDEOBUF2_CORE=y' and the compilation fails with a bunch of undefined reference to `vb2_buffer_done' undefined reference to `vb2_buffer_done' undefined reference to `vb2_buffer_done' undefined reference to `vb2_buffer_done' I really appreciate if someone can help me with this. 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 ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: how to find kernel patch applied on existing build kernel
Hi, Vipul If you want to know to which kernel release is a specified patch related, you can do it by git describe --contains: git describe --contains e605b36575e896edd8161534550c9ea021b03bc0 v3.13-rc2~6^2 Regards, Rami Rosen http://ramirose.wix.com/ramirosen On Sun, Dec 22, 2013 at 1:26 PM, Alexandru Juncu al...@rosedu.org wrote: On 22 December 2013 06:56, Vipul Jain vipu...@gmail.com wrote: Hi, If I would like to find out if any particular build kernel has a particular patch applied to that kernel how to go about it? Regards, Vipul. Hello! You can do a git log on the kernel's repo and see when it was applied. Or do a git blame if you need a particular line of a file. If you want to match it to a release, track the tags in the repo. You can use the webinterface: https://git.kernel.org/cgit/ Just remember that because of the distributed nature of git and the kernel's development model, a particular patch is merged in many trees before reaching the de facto main linux repo (Linus' repo). ___ 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: create sysfs class attribute and sub directories
Hi, You should use sysfs_create_group() and kobject_create_and_add() and DEVICE_ATTR() macro see net/bridge/br_sysfs_br.c and also see Documentation/kobject.txt and filesystems/sysfs.txt Regards, Rami Rosen http://ramirose.wix.com/ramirosen On Sun, Dec 15, 2013 at 3:52 PM, Jeshwanth Kumar N K jeshkumar...@gmail.com wrote: Hello List :), I have a small question about sysfs. I am creating a kernel module to print some versions in sysfs attributes. So the directory tree would be. /sys/class/versions/main/version /dev/version So, versions is my class directory, inside that two directories main and dev, both directory should contains version attribute. I am little familiar with creating with sysfs class attribute using struct class, but how to create the directory (like main/dev) and create attributes in both directory ? I have one more question, Is sysfs is right place to display version information ? Thanks in Advance :) -- Regards Jeshwanth Kumar N K Bangalore, India ___ 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: A question about ip_options's option type
Hi, Guibin,
Your example with SO_LINGER is not relevant as this is the SO_LINGER
option and not the generic IP_OPTION.
Please take a look at the ping implementation:
http://www.linux-ipv6.org/gitweb/gitweb.cgi?p=gitroot/iputils.git;a=blob;f=ping.c;h=c0366cdacd626dde1669bf2d97588eb7c6ece3fd;hb=HEAD
You have there:
if (options F_TIMESTAMP) {
492 memset(rspace, 0, sizeof(rspace));
493 rspace[0] = IPOPT_TIMESTAMP;
494 rspace[1] = (ts_type==IPOPT_TS_TSONLY ? 40 : 36);
495 rspace[2] = 5;
So for the type, byte 0, you have IPOPT_TIMESTAMP
and for the length, you have 40 or 36 (It depends on ts_type)
Best Regards,
Rami Rosen
http://ramirose.wix.com/ramirosen
On Sat, Dec 14, 2013 at 3:00 AM, Guibin(Bill) Tian gbt...@gmail.com wrote:
Hi, maybe it's a naive question. But I am confused here.
For the options field of an IP header, as for the data in this field,
according to document and the code in the method of ip_options_compile,
the first byte is the options type data and the second byte is the length
of the option. But I traced back the method of ip_options_get_from_user,
there is no place that assign these two values to the __data field.
I checked some example of socket API setsockopt, it also just converts the
target options data pointer into a char * pointer and passes down to
ip_options_get_from_user, still it doesn't set these two values.
Can anyone help me on this? Because I am trying to add my own options to IP
header at the IP layer for some experiment purposes.
struct linger linger = { 0 };
linger.l_onoff = 1;
linger.l_linger = 30;
status = setsockopt(serverSocket,
SOL_SOCKET, SO_LINGER,
(const char *) linger,
sizeof(linger));
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Re: Sending an ICMP packet with ip_local_out
Adel,
You say you have a NULL pointer but you do not specify where.
can you please send the log of the panic ?
Can you send the kernel module full code ?
Regards,
Rami Rosen
http://ramirose.wix.com/ramirosen
On Mon, Jun 17, 2013 at 6:18 AM, Adel Qodmani mpca...@gmail.com wrote:
Hello everyone,
I am trying to send an ICMP message in a kernel module; typically I'd
build the skb, set up the net_device, the ethernet header and then use
dev_queue_xmit.
But right now I want my packet to follow the IP routing rules set in the
system, so I thought I'll use ip_local_out function and let it handle the
routing and setting the rest of the parameters in the skb.
Yet, my code causes the kernel to panic due to a NULL pointer.
The code is as follows:
/* This function assumes source and dest are in NETWORK byte order */
int sendICMPEcho(char *msg, unsigned int length, __be32 source, __be32
dest)
{
struct iphdr *iph;
struct icmphdr *icmph;
struct sk_buff *newPacket;
unsigned char *data;
unsigned int skbSize = length + sizeof(struct icmphdr) * 2
+ sizeof(struct iphdr) * 2
+ sizeof(struct ethhdr) * 2;
/* Allocate the skb */
newPacket = alloc_skb(skbSize, GFP_ATOMIC);
if(newPacket == NULL)
return SEND_FAIL_MEMORY;
/* Reserve the headers area */
skb_reserve(newPacket, sizeof(struct icmphdr)
+ sizeof(struct iphdr)
+ sizeof(struct ethhdr));
/* Extend the data area from 0 to the message length */
data = skb_put(newPacket, length);
/* Copy the data from the message buffer to the newPacket */
memcpy(data, msg, length);
/** ICMP HEADER***/
/* skb_push - pushing the icmp header in the packet data */
icmph = (struct icmphdr *) skb_push(newPacket,
sizeof(struct icmphdr));
/*set ICMP header here */
icmph-type = ICMP_ECHO;
icmph-code = 0;
icmph-un.echo.id = 0;
icmph-un.echo.sequence = htons(sendCounter);
icmph-checksum= 0;
icmph-checksum = in_cksum((unsigned short *)icmph,
sizeof(struct icmphdr) + length);
/** END ICMP HEADER**/
/** IP HEADER ***/
iph = (struct iphdr *) skb_push(newPacket,
sizeof(struct iphdr));
/* set IP header here */
iph-ihl = 5;/* 5 * 32(bits) */
iph-version = 4;
iph-tos = 0; /* The recommended value by IANA for ICMP request */
iph-tot_len = htons( sizeof(struct iphdr)
+ sizeof(struct icmphdr)
+ length);
iph-id = 0;
iph-frag_off = 0; /* No fragementation */
iph-ttl = 65;
iph-protocol = IPPROTO_ICMP;
iph-saddr = source;
iph-daddr = dest;
iph-check = 0;
iph-check = in_cksum((unsigned short *)iph, sizeof(struct iphdr));
/** END IP HEADER ***/
// if(ip_local_out(newPacket) 0) THIS CRASHES WITH A NULL POINTER
// return SEND_FAIL_SEND;
++sendCounter;
return SEND_SUCCESS;
}
/* end sendICMPEcho */
In my attempts when trying to solve this, I've tried to manually set the
net_device in the skb and that didn't work either; I still had the same
kernel panic.
So I am sorry for the trouble, any hint where the error can be?
Regards,
Adel
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Re: which function perform gso
Hi, Varun look in dev_gso_segment(): http://lxr.free-electrons.com/source/net/core/dev.c#L2382 Regards, Rami Rosen http://ramirose.wix.com/ramirosen On Fri, May 31, 2013 at 9:53 AM, Varun Sharma vsd...@gmail.com wrote: Hi, which function perform Generic segmentation offload in kernel. ___ 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: Device mapper api v/s block device driver api
Hi Just of pure curiosity, can you please provide a link to the blog you had mentioned? Regards Rami Rosen http://ramirose.wix.com/ramirosen On May 6, 2013 10:46 PM, neha naik nehanai...@gmail.com wrote: Hi, Reading a blog on device mapper api got me confused about when one should use device mapper api and when to use block device driver api. I was under the impression that even for stackable device drivers (say a customized block device driver on top of lvm or such) we need to use the block device driver api. But, reading about the device mapper api i have started thinking that it may not be the case. May be for stackable device drivers device mapper is the solution. What do you think? What are the pros and cons of device mapper v/s block device driver Regards, Neha ___ 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: Dynamic Sysfs Attribute Files
Hi, Take a look in: http://lxr.free-electrons.com/source/Documentation/filesystems/sysfs.txt You should consider the sysfs API like sysfs_create_dir(), sysfs_create_group(), sysfs_create_file() Best Regards, Rami Rosen http://ramirose.wix.com/ramirosen ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: open_softirq do?
Hi, This is simply a registration of the software interrupt TX method (net_tx_action). The net_tx_action() is invoked in general when transmission was finished: look in : http://lxr.free-electrons.com/source/net/core/dev.c void dev_kfree_skb_irq(struct sk_buff *skb) ... raise_softirq_irqoff(NET_TX_SOFTIRQ); ... whereas the dev_kfree_skb_irq() is called from the driver TX path for freeing the skb. There are other case; look in __netif_reschedule(), and in dev_cpu_callback(), in net/core/dev.c regards, Rami Rosen http://ramirose.wix.com/ramirosen On Wed, Apr 10, 2013 at 3:18 PM, Robert Clove cloverob...@gmail.com wrote: Hello All, I am clear all that the softirq is a software interrupt : Whenever a system call is about to return to the user space or h/w interrupt exit,ant s/w interrupt which are marked pending are run. Now in networking code i found open_softirq(NET_TX_SOFTIRQ, net_tx_action, NULL); What does this do? Thanks ___ 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: Interrupt Handler of Ethernet Device
Hi,
we have in :
http://lxr.free-electrons.com/source/drivers/net/ethernet/intel/e100.c
struct nic {
/* Begin: frequently used values: keep adjacent for cache effect */
u32 msg_enable cacheline_aligned;
struct net_device *netdev;
struct pci_dev *pdev;
...
...
And indeed nic-netdev represents an Ethernet interface, which
is the struct net_device (see: include/linux/netdevice.h)
Regards,
Rami Rosen
http://ramirose.wix.com/ramirosen
On Sun, Apr 7, 2013 at 5:52 AM, ishare june.tune@gmail.com wrote:
On Fri, Apr 05, 2013 at 03:06:37PM +0300, Rami Rosen wrote:
Robert,
You should look for the request_irq() method in the driver.
This method registers an interrupt handler.
For example, you can look in:
http://lxr.free-electrons.com/source/drivers/net/ethernet/intel/e100.c
...
...
if ((err = request_irq(nic-pdev-irq, e100_intr, IRQF_SHARED,
nic-netdev-name, nic-netdev)))
...
This means that e100_intr is registered as an interrupt handler.
Is this nic-netdev represent a Ethernet interface ?
Best,
Rami Rosen
http://ramirose.wix.com/ramirosen
On Fri, Apr 5, 2013 at 11:50 AM, Robert Clove cloverob...@gmail.com wrote:
Hello All,
I am new here.
I want to know the interrupt handler of the ethernet card and where can i
find the definition of it so as i can clear the flow of packet reception.
Thanks
Robert
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Re: Interrupt Handler of Ethernet Device
Robert, You should look for the request_irq() method in the driver. This method registers an interrupt handler. For example, you can look in: http://lxr.free-electrons.com/source/drivers/net/ethernet/intel/e100.c ... ... if ((err = request_irq(nic-pdev-irq, e100_intr, IRQF_SHARED, nic-netdev-name, nic-netdev))) ... This means that e100_intr is registered as an interrupt handler. Best, Rami Rosen http://ramirose.wix.com/ramirosen On Fri, Apr 5, 2013 at 11:50 AM, Robert Clove cloverob...@gmail.com wrote: Hello All, I am new here. I want to know the interrupt handler of the ethernet card and where can i find the definition of it so as i can clear the flow of packet reception. Thanks Robert ___ 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: cgroup.procs versus tasks (cgroups)
Hi, BTW, for a given thread group with a specified TGID, you can view all the threads PIDs in that thread group thus: pstree -p TGID and: pstree TGID will give one line; It visually merges identical branches by putting them in square brackets and prefixing them with the repetition count. Regards, Rami Rosen http://ramirose.wix.com/ramirosen On Tue, Apr 2, 2013 at 9:14 PM, valdis.kletni...@vt.edu wrote: On Tue, 02 Apr 2013 16:46:24 +0300, Kevin Wilson said: Hi, Thanks a lot Vlad. This explains it. - Does anybody know of a ps command (or a filter to ps command) which will display only multithreaded processes (list processes by TGID) ? (I know now about the option of displaying cgroup.procs , but is something parallel can be done with ps ? ) Have you tried 'ps -m' and friends? Though it doesn't do exactly what you wanted and *only* display multithreaded, you need to do some post-processing: $ ps max ... 928 ?- 0:00 /sbin/auditd -n - -Ssl 0:00 - - -Ssl 0:00 - 940 ?- 0:00 /sbin/audispd - -Ssl 0:00 - - -Ssl 0:00 - 951 ?- 0:00 /usr/sbin/abrtd -d -s - -Ss 0:00 - 960 ?- 0:00 /usr/bin/abrt-watch-log -F Backtrace /var/log/Xorg.0.log -- /usr/bin/abrt-dump-xorg -xD - -Ss 0:00 - If there's 2 or more '- -' after the process entry, it's multi=threaded. Note however that as far as the kernel is concerned, a single-threaded process is handled by the code as a multi-threaded that happens to have only one thread at the moment. In other words, thinking that single and multi threaded is different in some mystical way will probably end up causing trouble for 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: relationship between cpu_affinity and Packet RX Processing
Hi, Stay tuned as I intend to put on the web an expanded document, including documentations about kernel internals (besides networking). Regards, Rami Rosen http://ramirose.wix.com/ramirosen On Fri, Mar 29, 2013 at 4:36 PM, Kumar amit mehta gmate.a...@gmail.com wrote: On Tue, Mar 26, 2013 at 09:31:01PM +0200, Rami Rosen wrote: Hi, 1) You can be sure that it does not use more than one rx queue. You can find more info about RX queues in http://media.wix.com/ugd//295986_4ef6dbdf11fd0a7f74f09741b4b5b2ee.pdf Thank you so much for sharing this. ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: what does the kernel does after it is being notified of incoming Frame
Hi, Can you give me more references even linked videos. You might want to take a look in section 6, Receiving a packet, in Linux Kernel Networking (free 189 pages doc). see: http://media.wix.com/ugd//295986_4ef6dbdf11fd0a7f74f09741b4b5b2ee.pdf (A shameless plug as I wrote it...) rgs, Rami Rosen http://ramirose.wix.com/ramirosen ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: relationship between cpu_affinity and Packet RX Processing
Hi, Kumar, 1) Regarding rx queues: what does ls /sys/class/net/eth0/queues show ? 2) can you try setting affinity for working only with CPU3 and see what happens after some traffic is sent by cat /proc/interrupts? regards, Rami Rosen http://ramirose.wix.com/ramirosen On Tue, Mar 26, 2013 at 8:31 PM, Kumar amit mehta gmate.a...@gmail.com wrote: Hi All, I was reading some stuff on interrupts and irq lines today and I thought I'll expermient with the network rx path. To start with, I've a Virtual Machine running 3.8 linux kernel. My machine has 4 CPU cores, network (eth) interface is driven by pcnet_32 AMD driver and is tied to IRQ line #19. I started some network traffic and I notice that out of those 4 CPUs, only one of them is being used and despite changing the CPU affinity, I still don't see the other cores being used for this network traffic. So based on this behavior(please see the logs below), I've these following queries: i) Does it mean that this network card do not have multiple Rx Queues ? ii) I think all the modern NICs must be implementing multiple Rx Queues and hence Can someone please point me to the simplest of such implemenation in any of the in-tree drivers ? iii) I'm just doing a simple 'ping' to google with of big size packets, As I do not have a peer to use packetgen/netperf/iperf utilities. ref: Comments in double quotes. logs $ uname -r 3.8.0-rc6-next-20130208 $ cat /proc/cpuinfo |grep processor processor : 0 processor : 1 processor : 2 processor : 3 Total 4 cpu cores $ cat /proc/interrupts|egrep 'eth0|CPU' CPU0 CPU1 CPU2 CPU3 19: 5103 74 33 5 IO-APIC-fasteoi eth0 IRQ Line #19 for the network device $ lspci|grep -i ethernet 02:01.0 Ethernet controller: Advanced Micro Devices [AMD] 79c970 [PCnet32 LANCE] (rev 10) AMD NIC $ lspci -s 02:01.0 -vvv|grep module Kernel modules: pcnet32 $ lsmod|grep pcnet32 pcnet3240671 0 driver # whoami root # cat /proc/irq/19/smp_affinity 03 # cat /proc/irq/19/affinity_hint 00 I think smp_affinity is a bit map, therefore for all the four cores to be utilized, all 4 bits should be set to 1, which leads to 15(0xf), hence Chaning the cpu affinity # echo 15 /proc/irq/19/smp_affinity # cat /proc/irq/19/smp_affinity 15 started network traffic here and monitoring it # cat /proc/interrupts|grep eth0 19: 5452 78 33 5 IO-APIC-fasteoi eth0 # cat /proc/interrupts|grep eth0 19: 5488 78 35 5 IO-APIC-fasteoi eth0 # cat /proc/interrupts|grep eth0 19: 5492 78 35 5 IO-APIC-fasteoi eth0 # cat /proc/interrupts|grep eth0 19: 5500 78 35 5 IO-APIC-fasteoi eth0 . .after some time. # cat /proc/interrupts|grep eth0 19: 6035 78 42 5 IO-APIC-fasteoi eth0 Most of the packets are still getting routed through CPU0 *Only*. logs -Amit ___ 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: relationship between cpu_affinity and Packet RX Processing
Hi, 1) You can be sure that it does not use more than one rx queue. You can find more info about RX queues in http://media.wix.com/ugd//295986_4ef6dbdf11fd0a7f74f09741b4b5b2ee.pdf (I wrote it, a shameless plug...) 2) Does the irqbalance service, which is common in some distros, is running ? can you try to disable it and run traffic again and check /proc/interrupts afrer some time ? 3) regardless of 2 (meaning not stopping irqbalance if it was active) can you please try taskset 02 ping www.google.com and tell us whether interrupts were incremented on the second CPU ? (please send /proc/interrupts | grep eth0 before and after sending, let's say, 5 pings)? Rgs, Rami Rosen http://ramirose.wix.com/ramirosen On Tue, Mar 26, 2013 at 9:05 PM, Kumar amit mehta gmate.a...@gmail.com wrote: On Tue, Mar 26, 2013 at 08:35:56PM +0200, Rami Rosen wrote: 1) Regarding rx queues: what does ls /sys/class/net/eth0/queues show ? $ ls /sys/class/net/eth0/queues rx-0 tx-0 2) can you try setting affinity for working only with CPU3 and see what happens after some traffic is sent by cat /proc/interrupts? # echo 8 /proc/irq/19/smp_affinity # cat /proc/irq/19/smp_affinity 08 $ cat /proc/interrupts |grep eth0 19: 20635 78387 1857 IO-APIC-fasteoi eth0 $ cat /proc/interrupts |grep eth0 19: 20635 78387 3041 IO-APIC-fasteoi eth0 Now only, CPU3 is processing the packets. So, i think, this driver(pcnet32) is not using multiple Rx Queue. ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Why we Use both mm_users and mm_count in struct mm_struct{ }
Hi,
Regarding your question about the previous thread:
Think of a context switch, let's say between a userspace process and a
kernel thread. A context switch is done between two processes
(processes are represented by struct task_struct). So when you look at
context_switch() prototype, you see:
context_switch(struct rq *rq, struct task_struct *prev,
...)
and prev is the process which ran in the run_queue of the scheduler
previously, before switching
to the new kernel thread. And we borrow memory descriptor from this process.
Rgs,
Rami Rosen
http://ramirose.wix.com/ramirosen
On Mon, Mar 25, 2013 at 8:02 AM, anish singh
anish198519851...@gmail.com wrote:
On Mon, Mar 25, 2013 at 1:35 AM, Rami Rosen roszenr...@gmail.com wrote:
Hi, Niroj,
Please look at the following scenario:
Suppose we create a kernel thread.
With kernel threads, the mm member of the task_struct is NULL.
(We are not permitted to access user space addresses from kernel thread,
so we don't need mm).
Kernel threads use (borrow) the active_mm of the previous thread.
as we know that kernel threads are not associated with any user space
process then why this overheads of active_mm or why we borrow the
active_mm of the previous thread.
Can you explain: what is previous thread here?
But in order to avoid freeing the active_mm if the previous threads
terminates
before the kernel thread terminates, we increment mm_count of the
active_mm of the previous thread
when we create a kernel thread (which borrows the active_mm of the
previous thread).
In such a case, even if the mm_users is 0, mm_count is not 0, and
we do not free that mm_active.
(remember that mm_users is initialized to 1).
To be more specific:
when that previous thread terminates, we call
the mmput() (see exit_mm(), in kernel/exit.c)
mmput() decrements mm_users and calls mmdrop().
Since in mmdrop(), after decrements mm_count it is not 0,
we do not free the mm_struct.
Here are the code snippets:
/*
* Decrement the use count and release all resources for an mm.
*/
void mmput(struct mm_struct *mm)
{
might_sleep();
if (atomic_dec_and_test(mm-mm_users)) {
uprobe_clear_state(mm);
exit_aio(mm);
ksm_exit(mm);
khugepaged_exit(mm); /* must run before exit_mmap */
exit_mmap(mm);
set_mm_exe_file(mm, NULL);
if (!list_empty(mm-mmlist)) {
spin_lock(mmlist_lock);
list_del(mm-mmlist);
spin_unlock(mmlist_lock);
}
if (mm-binfmt)
module_put(mm-binfmt-module);
mmdrop(mm);
}
}
mmdrop() is for freeing a memory descriptor:
static inline void mmdrop(struct mm_struct * mm)
{
if (unlikely(atomic_dec_and_test(mm-mm_count)))
__mmdrop(mm);
}
When the condition if (!mm) is true, this means this is a kernel thread:
static inline void
context_switch(struct rq *rq, struct task_struct *prev,
struct task_struct *next)
{
struct mm_struct *mm, *oldmm;
prepare_task_switch(rq, prev, next);
mm = next-mm;
oldmm = prev-active_mm;
/*
* For paravirt, this is coupled with an exit in switch_to to
* combine the page table reload and the switch backend into
* one hypercall.
*/
arch_start_context_switch(prev);
if (!mm) {
next-active_mm = oldmm;
atomic_inc(oldmm-mm_count);
enter_lazy_tlb(oldmm, next);
} else
...
Regards,
Rami Rosen
http://ramirose.wix.com/ramirosen
On Sat, Mar 23, 2013 at 7:02 AM, Niroj Pokhrel nirojpokh...@gmail.com
wrote:
Hi all,
I have been going through the Address Space in the linux and came across two
variables in the struct mm_struct and I'm a bit confused about the two:
struct mm_struct
{
..
atomic_t mm_users;
atomic_t mm_count;
}
Basically, after reading through I came to understand that mm_users are used
to store the number of processes or threads using the memory so depending
upon the number of users it is going to be set.
But, I am confused with mm_count, it is said the mm_count is increment by
one for all the mm_users and when all the mm_users value is reduced to zero
then mm_count is reduced. So, my question is can the value of mm_count be
ever greater than one because all the mm_users are equivalent to mm_count .
So, if not then why are we using the mm_count as we can simply remove the
memory areas whenever the mm_users count reduce to zero.
May be the explanation is simple but I'm lost. Thanking all of you in
advance.
Regards,
Niroj Pokhrel
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Re: question about
Hi, In init_clocksource_sysfs() method, device_register() adds the folder: /sys/devices/system/clocksource/clocksource0, whereas subsys_system_register() adds the parent folder (/sys/devices/system/clocksource) see: http://lxr.free-electrons.com/source/kernel/time/clocksource.c#L902 rgs, Rami Rosen http://ramirose.wix.com/ramirosen On Mon, Mar 25, 2013 at 4:57 AM, Moritz Fischer moritz.fisc...@ettus.com wrote: On Sun, Mar 24, 2013 at 1:29 PM, Kevin Wilson wkev...@gmail.com wrote: Kevin, Any idea which methods adds the following entries: /sys/devices/system/clocksource/clocksource0 /sys/devices/system/clocksource/clocksource0/available_clocksource I'm not an expert, but a quick grep for 'available_clocksource' led me to the kernel/time/clocksource.c file. Hope that helps you out, - Moritz ___ 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: Why we Use both mm_users and mm_count in struct mm_struct{ }
Hi, Niroj,
Please look at the following scenario:
Suppose we create a kernel thread.
With kernel threads, the mm member of the task_struct is NULL.
(We are not permitted to access user space addresses from kernel thread,
so we don't need mm).
Kernel threads use (borrow) the active_mm of the previous thread.
But in order to avoid freeing the active_mm if the previous threads terminates
before the kernel thread terminates, we increment mm_count of the
active_mm of the previous thread
when we create a kernel thread (which borrows the active_mm of the
previous thread).
In such a case, even if the mm_users is 0, mm_count is not 0, and
we do not free that mm_active.
(remember that mm_users is initialized to 1).
To be more specific:
when that previous thread terminates, we call
the mmput() (see exit_mm(), in kernel/exit.c)
mmput() decrements mm_users and calls mmdrop().
Since in mmdrop(), after decrements mm_count it is not 0,
we do not free the mm_struct.
Here are the code snippets:
/*
* Decrement the use count and release all resources for an mm.
*/
void mmput(struct mm_struct *mm)
{
might_sleep();
if (atomic_dec_and_test(mm-mm_users)) {
uprobe_clear_state(mm);
exit_aio(mm);
ksm_exit(mm);
khugepaged_exit(mm); /* must run before exit_mmap */
exit_mmap(mm);
set_mm_exe_file(mm, NULL);
if (!list_empty(mm-mmlist)) {
spin_lock(mmlist_lock);
list_del(mm-mmlist);
spin_unlock(mmlist_lock);
}
if (mm-binfmt)
module_put(mm-binfmt-module);
mmdrop(mm);
}
}
mmdrop() is for freeing a memory descriptor:
static inline void mmdrop(struct mm_struct * mm)
{
if (unlikely(atomic_dec_and_test(mm-mm_count)))
__mmdrop(mm);
}
When the condition if (!mm) is true, this means this is a kernel thread:
static inline void
context_switch(struct rq *rq, struct task_struct *prev,
struct task_struct *next)
{
struct mm_struct *mm, *oldmm;
prepare_task_switch(rq, prev, next);
mm = next-mm;
oldmm = prev-active_mm;
/*
* For paravirt, this is coupled with an exit in switch_to to
* combine the page table reload and the switch backend into
* one hypercall.
*/
arch_start_context_switch(prev);
if (!mm) {
next-active_mm = oldmm;
atomic_inc(oldmm-mm_count);
enter_lazy_tlb(oldmm, next);
} else
...
Regards,
Rami Rosen
http://ramirose.wix.com/ramirosen
On Sat, Mar 23, 2013 at 7:02 AM, Niroj Pokhrel nirojpokh...@gmail.com wrote:
Hi all,
I have been going through the Address Space in the linux and came across two
variables in the struct mm_struct and I'm a bit confused about the two:
struct mm_struct
{
..
atomic_t mm_users;
atomic_t mm_count;
}
Basically, after reading through I came to understand that mm_users are used
to store the number of processes or threads using the memory so depending
upon the number of users it is going to be set.
But, I am confused with mm_count, it is said the mm_count is increment by
one for all the mm_users and when all the mm_users value is reduced to zero
then mm_count is reduced. So, my question is can the value of mm_count be
ever greater than one because all the mm_users are equivalent to mm_count .
So, if not then why are we using the mm_count as we can simply remove the
memory areas whenever the mm_users count reduce to zero.
May be the explanation is simple but I'm lost. Thanking all of you in
advance.
Regards,
Niroj Pokhrel
___
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Re: networking question
Hi, Can you post your client and server code? rgs, Rami Rosen http://ramirose.wix.com/ramirosen On Thu, Mar 14, 2013 at 12:55 PM, devendra.aaru devendra.a...@gmail.com wrote: Hey all, I have got a strange bug(?) while testing the multicasting server and client. I have done only the INADDR_ANY bind in server and client adds its IP_MULTICAST_IF to 224.0.0.1 , surprisingly i recvd pkts from the client with out joining using IP_ADD_MEMBERSHIP. Is that a bug? or as we listening on INADDR_ANY will make us recv all the mcast/bcast pkts? while if i do tx on 224.0.0.3 , the server is not able to recv the packets. any ideas? ___ 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: Sending an IP packet
Hi, Adel, You should use ip_route_output_flow(). For this you should construct a flowi4 instance. ip_route_output_flow() is exported via EXPORT_SYMBOL_GPL. See for example how this is done in udp_sendmsg(). Good luck! Rami Rosen http://ramirose.wix.com/ramirosen On Fri, Feb 22, 2013 at 2:36 PM, Adel Qodmani mpca...@gmail.com wrote: Hey, My question is quite simple, I have an sk_buff that I want to transmit, the sk_buff is an ICMP message and so far, I've built the headers and set up everything. The problem is, when I want to do such a thing, I typically use a function called: dev_queue_xmit which takes the skb and transmits the packet using the net_device specified in the skb; but time time I can't set the net_device, I need the packet to go through the routing code and get it sent normally; so what function can I use to that? Some notes: *The kernel I am working on is 3.2.0-37 *I am working using Modules, so symbols that are not exported are unreachable for me *I set the IP header using htons, so my header data is already in network byte-order. Regards, Adel ___ 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: Sending an IP packet
Hi, Adel, ip_route_output_flow() calls __ip_route_output_key(). The return value is the routing entry, rtable. the parameters for __ip_route_output_key() do not include sock; only net and flow (flp4). And the __ip_route_output_key() is exported. There is a call for xfrm_lookup() which does need a sock in ip_route_output_flow() The xfrm_lookup() is empty when building without IPsec. So in you case, if you know that your solution does not require IPSec traffic, you can use __ip_route_output_key(). rgs. Rami Rosen http://ramirose.wix.com/ramirosen On Fri, Feb 22, 2013 at 3:53 PM, Adel Qodmani mpca...@gmail.com wrote: On Fri, Feb 22, 2013 at 3:47 PM, Rami Rosen roszenr...@gmail.com wrote: Hi, Adel, You should use ip_route_output_flow(). For this you should construct a flowi4 instance. ip_route_output_flow() is exported via EXPORT_SYMBOL_GPL. See for example how this is done in udp_sendmsg(). Good luck! Rami Rosen http://ramirose.wix.com/ramirosen On Fri, Feb 22, 2013 at 2:36 PM, Adel Qodmani mpca...@gmail.com wrote: Hey, My question is quite simple, I have an sk_buff that I want to transmit, the sk_buff is an ICMP message and so far, I've built the headers and set up everything. The problem is, when I want to do such a thing, I typically use a function called: dev_queue_xmit which takes the skb and transmits the packet using the net_device specified in the skb; but time time I can't set the net_device, I need the packet to go through the routing code and get it sent normally; so what function can I use to that? Some notes: *The kernel I am working on is 3.2.0-37 *I am working using Modules, so symbols that are not exported are unreachable for me *I set the IP header using htons, so my header data is already in network byte-order. Regards, Adel ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies Hi Rami, Using ip_route_output_flow() or using udp_sendmsg() would require not only constructing a flowi4 but also a sock; I am intentionally trying to avoid building a sock at the time being. Is there a way I can deliver my sk_buff to the routing code so that it'd set the net_device in there or at least tell me which interface to use and then I'd set it up myself? Thankful, Adel ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Sending an IP packet
Hi, Adel, - In your first message you said you are using kernel modules. - In case you intend to add code in ICMP for your special requirements from the control protocol, then this seems not a good idea (because this means patching the kernel for using your module; and probably such patches will not go to mainline) I don't know of any usage of ICMP for purposes beyond what is declared in the ICMP RFC. regards, Rami Rosen http://ramirose.wix.com/ramirosen On Fri, Feb 22, 2013 at 5:15 PM, Adel Qodmani mpca...@gmail.com wrote: On Fri, Feb 22, 2013 at 4:54 PM, valdis.kletni...@vt.edu wrote: On Fri, 22 Feb 2013 14:36:17 +0200, Adel Qodmani said: Others have given some details on how. A better question is why. Well, the why is the following: I am trying to implement a new protocol that we've designed which works on top of the IP layer, so I am using ICMP messages to carry control information for the protocol. Why using ICMP, it seemed natural since our protocol is a Network-layer protocol and ICMP is a control messages protocol. Does that make sense? Regards, Adel ___ 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: kernel source code tree
Hi, You can pick a kernel to download from: http://www.kernel.org/pub/linux/kernel/v3.x/ The latest stable kernel is Regarding configuration, you can take the config file of Ubuntu in order to avoid risk of errors in configuration. Regards, Rami Rosen http://ramirose.wix.com/ramirosen On Sat, Feb 9, 2013 at 5:48 PM, sunil sunil.slvp...@gmail.com wrote: Hi all, need help, I am trying to write simple device driver. But before that i need to download kernel source code tree someone please explain how to download this and configure. I am very new to this. I am using ubuntu 12.04 thanks regards sunil A S ___ 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: Linux Kernel Networking document (free, 178 pages doc)
Hi, Have you considered to start with ext4? it seems that ext3, ext2 are a bit out of fashion, Regards, Rami Rosen http://ramirose.wix.com/ramirosen On Thu, Jan 31, 2013 at 8:58 PM, shubham kernel.shub...@gmail.com wrote: Thanks Rami, I am also trying to understand ext3 and write some document for the same. Regards Shubham On 31-Jan-13 12:51 AM, Rami Rosen wrote: HI, I will try to write something for Linux Filesystems (and maybe for other subsystems) but this will probably take a lot of time. Regards, Rami Rosen http://ramirose.wix.com/ramirosen On Wed, Jan 30, 2013 at 5:44 PM, shubham kernel.shub...@gmail.com wrote: Thanks for sharing the document. I hope we could have such documents for other subsystems as well. Regards Shubham On 28-Jan-13 10:23 PM, Rami Rosen wrote: Hi everyone, You can find here an up to date and detailed document in pdf (178 pages) about Linux Kernel Networking; going deep into design and implementation details as well as the theory behind it: http://media.wix.com/ugd//295986_931b8bcf34d93419d46e05b5aa5d0216.pdf I believe that developers/sysadmins/researchers/students may find help with it. regards, Rami Rosen http://ramirose.wix.com/ramirosen ___ 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: Linux Kernel Networking document (free, 178 pages doc)
HI, I will try to write something for Linux Filesystems (and maybe for other subsystems) but this will probably take a lot of time. Regards, Rami Rosen http://ramirose.wix.com/ramirosen On Wed, Jan 30, 2013 at 5:44 PM, shubham kernel.shub...@gmail.com wrote: Thanks for sharing the document. I hope we could have such documents for other subsystems as well. Regards Shubham On 28-Jan-13 10:23 PM, Rami Rosen wrote: Hi everyone, You can find here an up to date and detailed document in pdf (178 pages) about Linux Kernel Networking; going deep into design and implementation details as well as the theory behind it: http://media.wix.com/ugd//295986_931b8bcf34d93419d46e05b5aa5d0216.pdf I believe that developers/sysadmins/researchers/students may find help with it. regards, Rami Rosen http://ramirose.wix.com/ramirosen ___ 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
Linux Kernel Networking document (free, 178 pages doc)
Hi everyone, You can find here an up to date and detailed document in pdf (178 pages) about Linux Kernel Networking; going deep into design and implementation details as well as the theory behind it: http://media.wix.com/ugd//295986_931b8bcf34d93419d46e05b5aa5d0216.pdf I believe that developers/sysadmins/researchers/students may find help with it. regards, Rami Rosen http://ramirose.wix.com/ramirosen ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: sys fs interface
Hi, This is done via: kobject_create_and_add(), which eventually calls sysfs_create_file(), or sysfs_create_group(). Look in Documentation/kobject.txt regards, Rami Rosen http://ramirose.wix.com/ramirosen On Fri, Dec 28, 2012 at 1:22 PM, Rahul Bedarkar rpal...@gmail.com wrote: Hi, When driver provides sys fs interface for user space programs, how we specify name of file to be created ? Thanks, Rahul B. ___ 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: what is tty* in /edv file folder?
Hi, These are character devices for I/O. /dev/tty0 is a special device, representing the current terminal. /dev/tty1 is the first virtual terminal, /dev/tty1 is second virtual terminal (usually there are 6 virtual terminals). The other /dev/tty* are for other purposes. Regards, Rami Rosen http://ramirose.wix.com/ramirosen On Wed, Nov 28, 2012 at 12:11 PM, horse_rivers horse_riv...@126.com wrote: hi： I find in /dev/ file folder ,there are many tty* ， which is like tty0,ty1,tty7,tty9,and son on. I do not know what is this ? my computer may not have so many device thanks! ___ 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
