December 2009 - Darwin-kernel

Re: Modifying the mbuf data structure?
by Michael Smith 04 Dec '09

04 Dec '09

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Start by looking at soreceive. And after you've finished cursing at people that think that "refactoring" is something that you do with fractions, you're looking for uiomove calls, not copyout. = Mike On Dec 4, 2009, at 12:54 PM, Godfrey van der Linden wrote: > Hey guys. I think my idea can work and it will be pretty narrow changes. I'll explore the tagging infrastructure to move some data around. > > The ifconfigd/xinted target process doesn't worry me too much, firstly my project is to build developer tools and some developer support will be required, but secondly I don't mind if I mis-attribute a few I/Os as long as I get the primary data paths covered. This simplifies my problem so that shared resource isn't a big problem either. > > I think the place I'm after is where the mbuf does a copyout into the user process. I had hoped that mbuf_copyout would be in kpi_mbuf.c but it doesn't seem to be the case. So a quick question, where does this occur, is it spread out over many different stacks or is there a centralised mbuf copyout somewhere burred in the net stacks. Cscope reports that copyout is called from way to many places in the whole network infrastructure for a newbie like me to understand. > > Cheers > > Godfrey > > On 2009-12-04, at 3:44 AM, Josh Graessley wrote: > >> >> It may be possible to use mbuf tags. Mbuf tags allow you to attach additional information to an mbuf. The downside is that mbuf tags are not as light weight as they ought to be. Internally the stack allocates another mbuf for the tag. >> >> I think you'll need to go in to each protocol at the socket layer and modify the code to add the tag. That may also require modifying the socket to track the current owning process. Some sockets are shared across processes. The most common example are sockets created in launchd for incoming connections and then handed off to another process to handle the socket. If I remember correctly, the new connection is created in the kernels context and placed on the listening queue. The listening socket is shared with another process which is responsible for calling accept. The process of calling accept probably creates the new socket. >> >> One other example if sharing sockets is a helper utility that runs as root to create a socket and bind it to a low numbered port and then hand it off to another process. The stack doesn't currently track the notion of the owning process for a given socket so handling this could be tricky. >> >> Sent from my iPhone >> >> On Dec 3, 2009, at 6:59, Godfrey van der Linden <gvdl(a)mac.com> wrote: >> >>> G'day, Kernel dudes. >>> >>> For my Ph.D. research I wish to collect I/O statistics and then to attribute them to the initiating process. >>> >>> I'm going to be building a new kernel that can track per-process I/O stats. This is reasonably easy to do for raw IOKit memory descriptor I/Os, I can tag the descriptor with a process tag and on completion accumulate it into data. This should be a reasonably narrow change primarily to IOKit. >>> >>> However, the network stats presents a problem, the drivers where I collect the data do not know which process attribute them to until the top of the network stack. I've had an idea that may work but I'd like real networking experts opinion. >>> >>> A natural analog to memory descriptors in networking is the mbuf structure. I'd like to add a new field for my research kernel that points to the data collected by the driver. Then I'll modify the top of the networking stack to accumulate it into per process data. >>> >>> Is this the easiest way of doing this or is their an easier way? Your opinions and advice will be gratefully received. Note the code is very carefully written to be extremely light weight and lock-free (in the sense that no additional locks are required over and above the locks already used by networking. There will be some cache invalidation which appears to be unavoidable). >>> >>> Cheers >>> >>> Godfrey >>> >>> _______________________________________________ >>> Do not post admin requests to the list. They will be ignored. >>> Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) >>> Help/Unsubscribe/Update your Subscription: >>> http://lists.apple.com/mailman/options/darwin-kernel/jgraessley%40apple.com >>> >>> This email sent to jgraessley(a)apple.com > > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) > Help/Unsubscribe/Update your Subscription: > http://lists.apple.com/mailman/options/darwin-kernel/drivers%40mu.org > > This email sent to drivers(a)mu.org _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: Modifying the mbuf data structure?
by Godfrey van der Linden 04 Dec '09

04 Dec '09

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Hey guys. I think my idea can work and it will be pretty narrow changes. I'll explore the tagging infrastructure to move some data around. The ifconfigd/xinted target process doesn't worry me too much, firstly my project is to build developer tools and some developer support will be required, but secondly I don't mind if I mis-attribute a few I/Os as long as I get the primary data paths covered. This simplifies my problem so that shared resource isn't a big problem either. I think the place I'm after is where the mbuf does a copyout into the user process. I had hoped that mbuf_copyout would be in kpi_mbuf.c but it doesn't seem to be the case. So a quick question, where does this occur, is it spread out over many different stacks or is there a centralised mbuf copyout somewhere burred in the net stacks. Cscope reports that copyout is called from way to many places in the whole network infrastructure for a newbie like me to understand. Cheers Godfrey On 2009-12-04, at 3:44 AM, Josh Graessley wrote: > > It may be possible to use mbuf tags. Mbuf tags allow you to attach additional information to an mbuf. The downside is that mbuf tags are not as light weight as they ought to be. Internally the stack allocates another mbuf for the tag. > > I think you'll need to go in to each protocol at the socket layer and modify the code to add the tag. That may also require modifying the socket to track the current owning process. Some sockets are shared across processes. The most common example are sockets created in launchd for incoming connections and then handed off to another process to handle the socket. If I remember correctly, the new connection is created in the kernels context and placed on the listening queue. The listening socket is shared with another process which is responsible for calling accept. The process of calling accept probably creates the new socket. > > One other example if sharing sockets is a helper utility that runs as root to create a socket and bind it to a low numbered port and then hand it off to another process. The stack doesn't currently track the notion of the owning process for a given socket so handling this could be tricky. > > Sent from my iPhone > > On Dec 3, 2009, at 6:59, Godfrey van der Linden <gvdl(a)mac.com> wrote: > >> G'day, Kernel dudes. >> >> For my Ph.D. research I wish to collect I/O statistics and then to attribute them to the initiating process. >> >> I'm going to be building a new kernel that can track per-process I/O stats. This is reasonably easy to do for raw IOKit memory descriptor I/Os, I can tag the descriptor with a process tag and on completion accumulate it into data. This should be a reasonably narrow change primarily to IOKit. >> >> However, the network stats presents a problem, the drivers where I collect the data do not know which process attribute them to until the top of the network stack. I've had an idea that may work but I'd like real networking experts opinion. >> >> A natural analog to memory descriptors in networking is the mbuf structure. I'd like to add a new field for my research kernel that points to the data collected by the driver. Then I'll modify the top of the networking stack to accumulate it into per process data. >> >> Is this the easiest way of doing this or is their an easier way? Your opinions and advice will be gratefully received. Note the code is very carefully written to be extremely light weight and lock-free (in the sense that no additional locks are required over and above the locks already used by networking. There will be some cache invalidation which appears to be unavoidable). >> >> Cheers >> >> Godfrey >> >> _______________________________________________ >> Do not post admin requests to the list. They will be ignored. >> Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) >> Help/Unsubscribe/Update your Subscription: >> http://lists.apple.com/mailman/options/darwin-kernel/jgraessley%40apple.com >> >> This email sent to jgraessley(a)apple.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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undefined symbols: DiskArbInit/DiskArbDiskAppearedWithMountpointPing_auto
by mogambo 03 Dec '09

03 Dec '09

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semget, initial semaphore values
by Alex Sheh 03 Dec '09

03 Dec '09

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Thread-index: Acp0bZxLN5PsT1wtRXWrDcTyGI+CsQ== Thread-topic: semget, initial semaphore values _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: Modifying the mbuf data structure?
by Michael Smith 03 Dec '09

03 Dec '09

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On Dec 4, 2009, at 1:59 AM, Godfrey van der Linden wrote: > For my Ph.D. research I wish to collect I/O statistics and then to attribute them to the initiating process. > > I'm going to be building a new kernel that can track per-process I/O stats. This is reasonably easy to do for raw IOKit memory descriptor I/Os, I can tag the descriptor with a process tag and on completion accumulate it into data. This should be a reasonably narrow change primarily to IOKit. > > However, the network stats presents a problem, the drivers where I collect the data do not know which process attribute them to until the top of the network stack. I've had an idea that may work but I'd like real networking experts opinion. > > A natural analog to memory descriptors in networking is the mbuf structure. I'd like to add a new field for my research kernel that points to the data collected by the driver. Then I'll modify the top of the networking stack to accumulate it into per process data. Note that network buffers can be (and are routinely) split, merged and resized. You may need to ensure that any ancillary data you come up with can be likewise manipulated. > Is this the easiest way of doing this or is their an easier way? There's no easy way to deal with charging work to an unknown consumer. Given that you're already being forced to generalise (e.g. no trivial way to account for work that benefits multiple consumers, no good way to tentatively account for speculative work, etc.) it may be enough just to have the work billing travel with the packet header and bill whichever poor sucker first pulls it out of the socket buffer at the receive end. = Mike _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: Modifying the mbuf data structure?
by Josh Graessley 03 Dec '09

03 Dec '09

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Sent from my iPhone On Dec 3, 2009, at 6:59, Godfrey van der Linden <gvdl(a)mac.com> wrote: G'day, Kernel dudes. Cheers Godfrey _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/jgraessley%40apple.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… It may be possible to use mbuf tags. Mbuf tags allow you to attach additional information to an mbuf. The downside is that mbuf tags are not as light weight as they ought to be. Internally the stack allocates another mbuf for the tag. I think you'll need to go in to each protocol at the socket layer and modify the code to add the tag. That may also require modifying the socket to track the current owning process. Some sockets are shared across processes. The most common example are sockets created in launchd for incoming connections and then handed off to another process to handle the socket. If I remember correctly, the new connection is created in the kernels context and placed on the listening queue. The listening socket is shared with another process which is responsible for calling accept. The process of calling accept probably creates the new socket. One other example if sharing sockets is a helper utility that runs as root to create a socket and bind it to a low numbered port and then hand it off to another process. The stack doesn't currently track the notion of the owning process for a given socket so handling this could be tricky. For my Ph.D. research I wish to collect I/O statistics and then to attribute them to the initiating process. I'm going to be building a new kernel that can track per-process I/O stats. This is reasonably easy to do for raw IOKit memory descriptor I/Os, I can tag the descriptor with a process tag and on completion accumulate it into data. This should be a reasonably narrow change primarily to IOKit. However, the network stats presents a problem, the drivers where I collect the data do not know which process attribute them to until the top of the network stack. I've had an idea that may work but I'd like real networking experts opinion. A natural analog to memory descriptors in networking is the mbuf structure. I'd like to add a new field for my research kernel that points to the data collected by the driver. Then I'll modify the top of the networking stack to accumulate it into per process data. Is this the easiest way of doing this or is their an easier way? Your opinions and advice will be gratefully received. Note the code is very carefully written to be extremely light weight and lock-free (in the sense that no additional locks are required over and above the locks already used by networking. There will be some cache invalidation which appears to be unavoidable). This email sent to jgraessley(a)apple.com This email sent to site_archiver(a)lists.apple.com

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Re: Modifying the mbuf data structure?
by Justin C. Walker 03 Dec '09

03 Dec '09

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Hey, Godfrey, On Dec 3, 2009, at 06:59 , Godfrey van der Linden wrote: HTH Justin -- Justin C. Walker, Curmudgeon-At-Large Director Institute for the Enhancement of the Director's Income -------- "Weaseling out of things is what separates us from the animals. Well, except the weasel." - Homer J Simpson -------- _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… For my Ph.D. research I wish to collect I/O statistics and then to attribute them to the initiating process. Ignoring the deep philosophical issues associated with this goal (that's for your thesis :-}) I'm going to be building a new kernel that can track per-process I/O stats. This is reasonably easy to do for raw IOKit memory descriptor I/Os, I can tag the descriptor with a process tag and on completion accumulate it into data. This should be a reasonably narrow change primarily to IOKit. However, the network stats presents a problem, the drivers where I collect the data do not know which process attribute them to until the top of the network stack. I've had an idea that may work but I'd like real networking experts opinion. A natural analog to memory descriptors in networking is the mbuf structure. I'd like to add a new field for my research kernel that points to the data collected by the driver. Then I'll modify the top of the networking stack to accumulate it into per process data. Is this the easiest way of doing this or is their an easier way? Your opinions and advice will be gratefully received. Note the code is very carefully written to be extremely light weight and lock-free (in the sense that no additional locks are required over and above the locks already used by networking. There will be some cache invalidation which appears to be unavoidable). It's been a while since I have looked at the code, but AIR, except at the very bottom or top of the stack, mbuf users tend to rely on m_data to find out where to put their data. If that be the case, then (since you're at the very bottom [I assume]), you can just "steal" the space you need by fiddling with that value. You would need a marker to tell you when one of "your" mbufs passes by, but there may be flag space available. You'd need to spend some time tracing the use of that value in kernel, NKEs, and drivers to be sure no one is "backing up" the m_data pointer. Modifying the mbuf structure can be tricky, especially in a world of plugins (and don't forget the possibility of the odd skanky user-mode process that wants to paw through the entrails of the kernel, looking for juicy bits of data). Others on the list may have more current understanding of the state of things. This email sent to site_archiver(a)lists.apple.com

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Modifying the mbuf data structure?
by Godfrey van der Linden 03 Dec '09

03 Dec '09

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com G'day, Kernel dudes. For my Ph.D. research I wish to collect I/O statistics and then to attribute them to the initiating process. I'm going to be building a new kernel that can track per-process I/O stats. This is reasonably easy to do for raw IOKit memory descriptor I/Os, I can tag the descriptor with a process tag and on completion accumulate it into data. This should be a reasonably narrow change primarily to IOKit. However, the network stats presents a problem, the drivers where I collect the data do not know which process attribute them to until the top of the network stack. I've had an idea that may work but I'd like real networking experts opinion. A natural analog to memory descriptors in networking is the mbuf structure. I'd like to add a new field for my research kernel that points to the data collected by the driver. Then I'll modify the top of the networking stack to accumulate it into per process data. Is this the easiest way of doing this or is their an easier way? Your opinions and advice will be gratefully received. Note the code is very carefully written to be extremely light weight and lock-free (in the sense that no additional locks are required over and above the locks already used by networking. There will be some cache invalidation which appears to be unavoidable). Cheers Godfrey _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: Kernel stack size and kernel memory debugger
by mogambo 02 Dec '09

02 Dec '09

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Re: Building 10.6 kernel?
by Nix, James L (IS) 01 Dec '09

01 Dec '09

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Thread-index: Acpu0vJAWsuyjxYyR7yEF6pyFWM4XQD64Lmy Thread-topic: Building 10.6 kernel? Thanks for all the help. The advice I received worked great. I no longer see the 10 minute delay at system startup. Below is a summary of the steps I took to build and run a 10.6.2 kernel. However, I would still like to know why the AppleProfileFamily kext needs to be disabled. Could someone shed some light on exactly how the AppleProfileFamily kext is dependent upon the specific kernel that it ships with? Thanks, --Jim Building 10.6.2 kernel: 1. Build xnu kernel using instructions at: http://shantonu.blogspot.com/2009/09/mac-os-x-kernel-source-xnu-has-been.ht… 2. Install new mach_kernel file on test partition. 3. Disable AppleProfileFamily.kext by removing it from the /System/Library/Extensions directory of the test partition. 4. touch /System/Library/Extensions directory of the test partition. 5. Boot up the test partition! --------------------------------------------- After you install the new kernel, on the same partition, touch SystemLibrary/Extensions The first time it reboots it will rebuild the kernel cache. After booting successfully once, it will boot fast again. -- Terry --------------------------------------------- Date: Thu, 26 Nov 2009 14:58:15 -0500 From: nawcom <nawcom(a)nawcom.com> Subject: Re: Building 10.6 kernel? To: darwin-kernel(a)lists.apple.com Message-ID: <4B0EDDD7.7070107(a)nawcom.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed What I have been doing since the first xnu src for darwin 10 came out is using a kernel extension to prevent any of the kexts of and within AppleProfileFamily.kext from loading. If you'd like to see the source code for this kext let me know, but simply removing the kexts and subkexts inside of it does the same thing. Give this a try James, move AppleProfileFamily.kext out from /System/Library/Extensions to some other place and rebuild the Extensions.mkext (can be done with a simple: sudo mv /System/Library/Extensions/AppleProfileFamily.kext /System/Library; sudo touch /System/Library/Extensions) and reboot, launching your compiled kernel. you will see that you won't have to wait 10 minutes and there will be no losses or effects in performance or anything in the OS itself. I still haven't been able to get information from Apple on how to solve this issue, but this is what I have been using as an effective solution to the problem. -nawcom --------------------------------------------- Nix, James L (IS) wrote: > The instructions at: > > http://shantonu.blogspot.com/2009/09/mac-os-x-kernel-source-xnu-has-been.ht… > > work great. I had no problems building the kernel. The problem is that when I > install the new kernel, my test machine takes approx. 10 minutes to boot. > Actually boot works ok, but the machine hangs prior to login -- just after > the SecurityAgent launches. It hangs for about 10 minutes and then proceeds > normally. It's as if some process is timing out. > > When I ssh into the machine and run top, I notice that the hidd process is "stuck". > If I kill the hidd process, it restarts, and the machine immediately becomes responsive. > > Any ideas? Are there some kernel dependencies that I am overlooking? > By the way, this happens with all three versions of the 10.6 source available > at opensource.apple.com. > > Thanks, > > --Jim > > _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com <<winmail.dat>>

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