November 2006 - Darwin-kernel

Re: Call function on all processors
by Michael Smith 17 Nov '06

17 Nov '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com User-agent: Thunderbird 1.5.0.8 (Macintosh/20061025) I'm curious; why would you want to do this? = 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.… Paul Litvak wrote: How would you call a function on all cpus from a kernel extension? The only reasons I can think of have to do with changing per-CPU (vs. per context) state, and the OS owns all of that state. This email sent to site_archiver(a)lists.apple.com

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Re: Call function on all processors
by Brian Bechtel 16 Nov '06

16 Nov '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Domainkey-signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=kCXcOcke7hspyCBTNesgFx0u800+vGl7kCk/Id+uKYs+Yh95zzB17Ah6KQeho0qXX2IuzTxzRsYAksFuA1NBSihPkJJtpnWspg26fpwxcKAsqfheYFAB9rRWeGsBfM4e/AKVJIQIhPt4k5W8OnqkNeTmx53KTXPIDiT/3PGrisY= Look in the darwin source for more details: /* * All-CPU rendezvous: * - CPUs are signalled, * - all execute the setup function (if specified), * - rendezvous (i.e. all cpus reach a barrier), * - all execute the action function (if specified), * - rendezvous again, * - execute the teardown function (if specified), and then * - resume. * * Note that the supplied external functions _must_ be reentrant and aware * that they are running in parallel and in an unknown lock context. */ void mp_rendezvous(void (*setup_func)(void *), void (*action_func)(void *), void (*teardown_func)(void *), void *arg) _______________________________________________ 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.… On 11/16/06, Paul Litvak <paullitvak(a)gmail.com> wrote: How would you call a function on all cpus from a kernel extension? This email sent to site_archiver(a)lists.apple.com

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Call function on all processors
by Paul Litvak 16 Nov '06

16 Nov '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Domainkey-signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:mime-version:content-transfer-encoding:message-id:content-type:to:from:subject:date:x-mailer; b=SlfqdE+ceD0fiCiJhdDpy1CxhxLBO8AVCSeQQxA4VwZuwe4hZJyaXBad+nbfJQupXSpj1CKo5LZ5/fTlzKp0AOZmTU5jiPrDge+Wt9Z8ZdIFakqZe/UDaRF6FRsXPxY1tXNExQkC66efxkIJwP/nR58cg5sbNfohH5nytERK6KE= How would you call a function on all cpus from a kernel extension? One way I can think of is to: - Paul Litvak _______________________________________________ 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.… 1. disable preemption through IOSimpleLockLock 2. call function on other cpus by generating an interprocessor interrupt (can this be done through IOKit or another API?) 3. call the function on this cpu 4. enable preemption through IOSimpleLockUnlock This email sent to site_archiver(a)lists.apple.com

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Re: waiting queue
by Michael Smith 16 Nov '06

16 Nov '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com User-agent: Thunderbird 1.5.0.8 (Macintosh/20061025) class foo : public IOService { ... public: IOReturn clientCommand(..); private: IOCommandGate *_commandGate; IOCommandGate::Action _commandAction; IOReturn _clientCommand(...); bool _busyFlag; ... }; foo::_clientCommand(...) { while (_busyFlag) _commandGate->commandSleep(&busyFlag, THREAD_UNINT); ... _busyFlag = false; _commandGate->commandWakeup(&busyFlag, true /* wakeup one only */); } = 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.… devmaillists wrote: we are to implement waiting queues for scheduling threads generated from a UserClient interface in our kext. As I learned from the documentation I should use wait_queue_alloc , wait_queue_free, wait_queue_member and so on to implement wait queues. Unfortunately I do not find the symbols in the 10.4 SDK only in 10.39 SDK but I think this is not an option for Intel based developments. What is the preferred way to do wait queues with 10.4 SDK. If by "wait queues" you mean that you want to queue incoming threads, then you should use a CommandGate with your workloop. Something like this: foo::start() { ... _commandGate = IOCommandGate::(this); getWorkLoop()->addEventSource(_commandGate); _commandAction = OSMemberFunctionCast(IOCommandGate::Action, this, &foo::_clientCommand); _busyFlag = false; ... } foo::clientCommand(...) { _commandGate->runAction(_commandAction, ...) } The busy flag acts as the semaphore indicating that there's a thread in the critical region. The workloop lock is used to provide concurrency protection against your interrupt thread, and making it possible to sleep waiting for that thread without having to deal with other threads coming into the critical region. Caching the result of OSMemberFunctionCast is advisable, as it is somewhat expensive. This email sent to site_archiver(a)lists.apple.com

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waiting queue
by devmaillists 16 Nov '06

16 Nov '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Hello, What is the preferred way to do wait queues with 10.4 SDK. Thanks. Jürgen _______________________________________________ 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.… we are to implement waiting queues for scheduling threads generated from a UserClient interface in our kext. As I learned from the documentation I should use wait_queue_alloc , wait_queue_free, wait_queue_member and so on to implement wait queues. Unfortunately I do not find the symbols in the 10.4 SDK only in 10.39 SDK but I think this is not an option for Intel based developments. This email sent to site_archiver(a)lists.apple.com

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Re: OT: Re: UDF file system driver
by Michael Smith 16 Nov '06

16 Nov '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com User-agent: Thunderbird 1.5.0.8 (Macintosh/20061025) (BTW, I had recently applied for a job at Apple, but they wouldn't even consider me, being from outside the US without a HB-1 visa. Now I'll consider New Zealand... :) Not true. Also, very off-topic. = 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.… Andrei E. Warkentin wrote: That's awful. So basically either you get here yourself or you don't work for them at all? :( This email sent to site_archiver(a)lists.apple.com

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Problem with RunAtLoad Daemon.
by Ravi 16 Nov '06

16 Nov '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com ":exited abnormally: Bus error" Thanks ~ _______________________________________________ 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.… Hi, I have an application which writes logs to a file. I converted my application to a launch-on-demand process and it worked fine, Now I want to make it RunAtLoad process. Am able to checkin but it fails showing following in system log :- *Can I write logs to files from a "RunAtLoad" daemons? Can the file descriptor be initialized at that time. *Can I get to know the exact problem by any other means? This email sent to site_archiver(a)lists.apple.com

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seeking MacOS individuals
by Javier Diaz 16 Nov '06

16 Nov '06

site_archiver(a)lists.apple.com Delivered-To: Darwin-kernel(a)lists.apple.com Thread-index: AccJJJAhbAi630XiQ9maAEX3jhm9QQ== Thread-topic: seeking MacOS individuals _______________________________________________ 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: OSIncrementAtomic(), lck_mtx_lock() interoperability.
by Terry Lambert 16 Nov '06

16 Nov '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On Nov 15, 2006, at 2:04 PM, Matt Darland wrote: For the most part, no. -- Terry _______________________________________________ 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.… If I have an integer value X that is usually incremented through OSIncrementAtomic, but in occasional cases I'm holding a mutex (via lck_mtx_lock) to a structure that contains X, and I want to increment X: Can I just ++X while holding the mutex and avoid also having to call OSIncrementAtomic in those rare cases? i.e. Do OSxxxAtomic and lck_mtx_xxx enforce the same memory coherency with respect to an integer? The value is not guaranteed to be updated in other CPU caches until after a memory barrier, if the operation is not itself an atomic one, and on x86, there is no guarantee that an unlock will result in a memory barrier (it depends on strong write ordering, and the fact that no one else is permitted to write a lock that's locked in order to do the unlock operation). Unless your operation is protected by the same lock in all cases, there's no reliable guarantee. There's ways to order code to usefully use a barrier only on a 1->0 on a release (for example), and use Atomic operations everywhere, but the converse is not true. This email sent to site_archiver(a)lists.apple.com

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OSIncrementAtomic(), lck_mtx_lock() interoperability.
by Matt Darland 15 Nov '06

15 Nov '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com ---- Thanks, Matt Darland _______________________________________________ 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.… If I have an integer value X that is usually incremented through OSIncrementAtomic, but in occasional cases I'm holding a mutex (via lck_mtx_lock) to a structure that contains X, and I want to increment X: Can I just ++X while holding the mutex and avoid also having to call OSIncrementAtomic in those rare cases? i.e. Do OSxxxAtomic and lck_mtx_xxx enforce the same memory coherency with respect to an integer? This email sent to site_archiver(a)lists.apple.com

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