February 2004 - Darwin-kernel

dynamic_pager and context switching
by Brian Tabone 08 Feb '04

08 Feb '04

I was digging through the darwin kernel lists, and did some cursory searches on developer.apple.com, but I didn't find the answer. My question is , does the kernel turn to dynamic_pager every time it swaps pages in and out, or does dynamic_pager simply manage the swap file(s) and grow/shrink them based on usage by the kernel? The reason I ask is that it would seem a large performance penalty to have to context switch out to a user-space daemon for every page in/out request. Not only would you be contesting with page swaps, but you would further be slowed down by expensive context switching from kernel to user space. Thanks in advance, -Brian T _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.

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Re: SYSCTL
by Mike Smith 08 Feb '04

08 Feb '04

On Feb 7, 2004, at 3:45 PM, Matt Jaffa wrote: I am planning on having my Daemon in userspace pass in the socket it creates so that I can use unp_connect and bind the socket from userspace and the one i create in the Kernel together so that I can create a communication channel between my User Daemon and my KEXT, In trying to parse this again, I'm even more confused. What are you trying to do? Create a socket in userspace and then allow your kext to read/write on that socket? Or are you trying to communicate between your process and your kext? If the former, then use descriptor passing (though you will need a process in which to use the descriptors). If the latter, then just use sysctl to communicate. It will work fine for most things; you don't need or want the overhead of a socket in the majority of cases. = Mike _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.

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Re: SYSCTL
by Mike Smith 08 Feb '04

08 Feb '04

On Feb 7, 2004, at 3:45 PM, Matt Jaffa wrote: I can find no other solution to my problem, I have aksed over and over on this list for help with ipc but they reply back making every solution seem stupid, since my KEXT is not an IOKit service I can't use it the way normal IOKits communicate with their KEXTs, Registering a sysctl node is a perfectly OK way to communicate with a non- I/O Kit kext. So by using the above method ( the way webDAV does it) and it works and no crashing I will be satisified, unless there is a much better way of doing things, that someone can point me too very well documented stuff, instead of documentation that only states it exists and does no help. I think you're mistaken, or confused. The MacOS X webdavfs does not try to copy a socket structure into/out of the kernel; it uses the normal BSD file descriptor passing mechanism. Will my above method work theoretically ? No. = Mike (Apologies for the previous From: line. Mail.app insists on using a stupid default.) _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.

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Re: sysctlbyname
by chuck remes 08 Feb '04

08 Feb '04

On Feb 7, 2004, at 11:20 PM, Matt Jaffa wrote: Ok those are confusing words when I read them over, let me explain it better: When I say it fails I mean it returns a -1, I check the SYSCTL_STRUC thing I made in my KEXT and CTLFLAG_ANYBODY and CTLFLAG_RW are set so it shouldn't be complaining when I try to write a new value through sysctlbyname On Feb 7, 2004, at 9:45 PM, Matt Jaffa wrote: Sorry, I mean it returns a -1, when i do the one when it just reads it returns a 0 and i get the value from my KEXT, but when I try to do it this way result = sysctlbyname(name, &si, &len, &pass, leng); result = sysctlbyname(name2, &getvalue, &length, &finalvalue, length2); it returns a -1, meaning it couldn't change the value, but I check the SYSCTL_STRUCT i made and it does have CTLFLAG_RW and CTLFLAG_ANYBODY so I don't know why it won't let me change the values in my KEXT % man 3 sysctl [snip] RETURN VALUES Upon successful completion, the value 0 is returned; otherwise the value -1 is returned and the global variable errno is set to indicate the error. Looks like you need to check the value of "errno" to find out what went wrong. cr _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.

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Re: sysctlbyname
by Matt Jaffa 08 Feb '04

08 Feb '04

Sorry, Justin I wasn't aware of the global errno variable, Thanks a bunch for your help in pointing out the obvious to me :) Matt On Feb 7, 2004, at 10:03 PM, Justin Walker wrote: On Saturday, February 7, 2004, at 08:45 PM, Matt Jaffa wrote: Sorry, I mean it returns a -1, when i do the one when it just reads it returns a 0 and i get the value from my KEXT, but when I try to do it this way Ya know, if you did a little thinking you might be able to solve the problem on your own. A check of the man page might help. Hint: look for the section entitled "RETURN VALUES". Regards, Justin -- Justin C. Walker, Curmudgeon-At-Large * Institute for General Semantics | If you're not confused, | You're not paying attention *-------------------------------------- *-------------------------------* _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored. _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.

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Re: sysctlbyname
by Matt Jaffa 08 Feb '04

08 Feb '04

Ok those are confusing words when I read them over, let me explain it better: When I say it fails I mean it returns a -1, I check the SYSCTL_STRUC thing I made in my KEXT and CTLFLAG_ANYBODY and CTLFLAG_RW are set so it shouldn't be complaining when I try to write a new value through sysctlbyname On Feb 7, 2004, at 9:45 PM, Matt Jaffa wrote: Sorry, I mean it returns a -1, when i do the one when it just reads it returns a 0 and i get the value from my KEXT, but when I try to do it this way result = sysctlbyname(name, &si, &len, &pass, leng); result = sysctlbyname(name2, &getvalue, &length, &finalvalue, length2); it returns a -1, meaning it couldn't change the value, but I check the SYSCTL_STRUCT i made and it does have CTLFLAG_RW and CTLFLAG_ANYBODY so I don't know why it won't let me change the values in my KEXT On Feb 7, 2004, at 9:19 PM, Justin Walker wrote: On Saturday, February 7, 2004, at 08:05 PM, Matt Jaffa wrote: [snip] BUT when I do it like this it fails: when i try to set the values: result = sysctlbyname(name, &si, &len, &pass, leng); result = sysctlbyname(name2, &getvalue, &length, &finalvalue, length2); What does "it fails" mean? Regards, Justin -- /~\ The ASCII Justin C. Walker, Curmudgeon-at-Large \ / Ribbon Campaign X Help cure HTML Email / \ _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored. _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored. _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.

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Re: sysctlbyname
by Justin Walker 08 Feb '04

08 Feb '04

On Saturday, February 7, 2004, at 08:45 PM, Matt Jaffa wrote: Sorry, I mean it returns a -1, when i do the one when it just reads it returns a 0 and i get the value from my KEXT, but when I try to do it this way Ya know, if you did a little thinking you might be able to solve the problem on your own. A check of the man page might help. Hint: look for the section entitled "RETURN VALUES". Regards, Justin -- Justin C. Walker, Curmudgeon-At-Large * Institute for General Semantics | If you're not confused, | You're not paying attention *--------------------------------------*-------------------------------* _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.

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Re: sysctlbyname
by Matt Jaffa 08 Feb '04

08 Feb '04

Sorry, I mean it returns a -1, when i do the one when it just reads it returns a 0 and i get the value from my KEXT, but when I try to do it this way result = sysctlbyname(name, &si, &len, &pass, leng); result = sysctlbyname(name2, &getvalue, &length, &finalvalue, length2); it returns a -1, meaning it couldn't change the value, but I check the SYSCTL_STRUCT i made and it does have CTLFLAG_RW and CTLFLAG_ANYBODY so I don't know why it won't let me change the values in my KEXT On Feb 7, 2004, at 9:19 PM, Justin Walker wrote: On Saturday, February 7, 2004, at 08:05 PM, Matt Jaffa wrote: [snip] BUT when I do it like this it fails: when i try to set the values: result = sysctlbyname(name, &si, &len, &pass, leng); result = sysctlbyname(name2, &getvalue, &length, &finalvalue, length2); What does "it fails" mean? Regards, Justin -- /~\ The ASCII Justin C. Walker, Curmudgeon-at-Large \ / Ribbon Campaign X Help cure HTML Email / \ _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored. _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.

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Re: sysctlbyname
by Justin Walker 08 Feb '04

08 Feb '04

On Saturday, February 7, 2004, at 08:05 PM, Matt Jaffa wrote: [snip] BUT when I do it like this it fails: when i try to set the values: result = sysctlbyname(name, &si, &len, &pass, leng); result = sysctlbyname(name2, &getvalue, &length, &finalvalue, length2); What does "it fails" mean? Regards, Justin -- /~\ The ASCII Justin C. Walker, Curmudgeon-at-Large \ / Ribbon Campaign X Help cure HTML Email / \ _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.

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sysctlbyname
by Matt Jaffa 08 Feb '04

08 Feb '04

Hi, I have created a sysctl_struct in my KEXT that extends off (a child) of _kern. I have created these two: SYSCTL_STRUCT(_kern, OID_AUTO, ttttt, CTLFLAG_RW|CTLFLAG_ANYBODY, &somo, testingt, "dfdf"); SYSCTL_INT(_kern,OID_AUTO,tttttt,CTLFLAG_RW|CTLFLAG_ANYBODY, &testing, 0, "dfsd"); testing == to a int testingt, or somo === a struct Now in my Daemon i am using sysctlbyname to read from those values that are in the Kernel, inside my KEXT. It works great, except when i try to set the values by using sysctlbyname it doesn't work, here is my daemon code: These two work just fine result = sysctlbyname(name, &si, &len, NULL, 0); result = sysctlbyname(name2, &getvalue, &length, NULL, 0); BUT when I do it like this it fails: when i try to set the values: result = sysctlbyname(name, &si, &len, &pass, leng); result = sysctlbyname(name2, &getvalue, &length, &finalvalue, length2); Any help would be appreciated, Thanks, Matt _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.

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