- 04 Oct, 2006 40 commits
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Josh Triplett authored
rcutorture currently has one writer and an arbitrary number of readers. To better exercise some of the code paths in RCU implementations, add fake writer threads which call the synchronize function for the RCU variant in a loop, with a delay between calls to arrange for different numbers of writers running in parallel. [bunk@stusta.de: cleanup] Acked-by:
Paul McKenney <paulmck@us.ibm.com> Cc: Dipkanar Sarma <dipankar@in.ibm.com> Signed-off-by:
Josh Triplett <josh@freedesktop.org> Signed-off-by:
Adrian Bunk <bunk@stusta.de> Signed-off-by:
Andrew Morton <akpm@osdl.org> Signed-off-by:
Linus Torvalds <torvalds@osdl.org>
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Josh Triplett authored
rcu_random uses a counter rrs_count to occasionally mix data from get_random_bytes into the state of its pseudorandom generator. However, the rrs_counter gets declared as an unsigned long, and rcu_random checks for --rrs_count < 0, so this code will never mix any real random data into the state, and will thus always return the same sequence of random numbers. Also, change the return value of rcu_random from long to unsigned long, to avoid potential issues caused by the use of the % operator, which can return negative values for negative left operands. Signed-off-by:
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Josh Triplett authored
rcu_torture_init kmallocs the array of reader threads, then creates each one with kthread_run, cleaning up with rcu_torture_cleanup if this fails. rcu_torture_cleanup calls kthread_stop on any non-NULL pointer in the array; however, any readers after the one that failed to start up will have invalid pointers, not null pointers. Avoid this by using kzalloc instead. Signed-off-by:
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Josh Triplett authored
The comment for rcutorture's torture_type parameter only lists the RCU variants rcu and srcu, but not rcu_bh; add rcu_bh to the list. Signed-off-by:
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Josh Triplett authored
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Alan Stern authored
This patch (as762) changes the cpufreq_transition_notifier_list from a blocking_notifier_head to an srcu_notifier_head. This will prevent errors caused attempting to call down_read() to access the notifier chain at a time when interrupts must remain disabled, during system suspend. It's not clear to me whether this is really necessary; perhaps the chain could be made into an atomic_notifier. However a couple of the callout routines do use blocking operations, so this approach seems safer. The head of the notifier chain needs to be initialized before use; this is done by an __init routine at core_initcall time. If this turns out not to be a good choice, it can easily be changed. Signed-off-by:
Alan Stern <stern@rowland.harvard.edu> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Jesse Brandeburg <jesse.brandeburg@gmail.com> Cc: Dave Jones <davej@codemonkey.org.uk> Signed-off-by:
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Alan Stern authored
Currently the init_srcu_struct() routine has no way to report out-of-memory errors. This patch (as761) makes it return -ENOMEM when the per-cpu data allocation fails. The patch also makes srcu_init_notifier_head() report a BUG if a notifier head can't be initialized. Perhaps it should return -ENOMEM instead, but in the most likely cases where this might occur I don't think any recovery is possible. Notifier chains generally are not created dynamically. [akpm@osdl.org: avoid statement-with-side-effect in macro] Signed-off-by:
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Alan Stern authored
This patch (as751) adds a new type of notifier chain, based on the SRCU (Sleepable Read-Copy Update) primitives recently added to the kernel. An SRCU notifier chain is much like a blocking notifier chain, in that it must be called in process context and its callout routines are allowed to sleep. The difference is that the chain's links are protected by the SRCU mechanism rather than by an rw-semaphore, so calling the chain has extremely low overhead: no memory barriers and no cache-line bouncing. On the other hand, unregistering from the chain is expensive and the chain head requires special runtime initialization (plus cleanup if it is to be deallocated). SRCU notifiers are appropriate for notifiers that will be called very frequently and for which unregistration occurs very seldom. The proposed "task notifier" scheme qualifies, as may some of the network notifiers. Signed-off-by:
Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by:
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Paul E. McKenney authored
Adds SRCU operations to rcutorture and updates rcutorture documentation. Also increases the stress imposed by the rcutorture test. [bunk@stusta.de: make needlessly global code static] Signed-off-by:
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Paul E. McKenney authored
Updated patch adding a variant of RCU that permits sleeping in read-side critical sections. SRCU is as follows: o Each use of SRCU creates its own srcu_struct, and each srcu_struct has its own set of grace periods. This is critical, as it prevents one subsystem with a blocking reader from holding up SRCU grace periods for other subsystems. o The SRCU primitives (srcu_read_lock(), srcu_read_unlock(), and synchronize_srcu()) all take a pointer to a srcu_struct. o The SRCU primitives must be called from process context. o srcu_read_lock() returns an int that must be passed to the matching srcu_read_unlock(). Realtime RCU avoids the need for this by storing the state in the task struct, but SRCU needs to allow a given code path to pass through multiple SRCU domains -- storing state in the task struct would therefore require either arbitrary space in the task struct or arbitrary limits on SRCU nesting. So I kicked the state-storage problem up to the caller. Of course, it is not permitted to call synchronize_srcu() while in an SRCU read-side critical section. o There is no call_srcu(). It would not be hard to implement one, but it seems like too easy a way to OOM the system. (Hey, we have enough trouble with call_rcu(), which does -not- permit readers to sleep!!!) So, if you want it, please tell me why... [josht@us.ibm.com: sparse notation] Signed-off-by:
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Eric W. Biederman authored
This moves the declarations for the architecture helpers into include/linux/htirq.h from the generic include/linux/pci.h. Hopefully this will make this distinction clearer. htirq.h is included where it is needed. The dependency on the msi code is fixed and removed. The Makefile is tidied up. Signed-off-by:
Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Tony Luck <tony.luck@intel.com> Cc: Andi Kleen <ak@suse.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Greg KH <greg@kroah.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by:
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Eric W. Biederman authored
This is just a few makefile tweaks and some file renames. Signed-off-by:
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Eric W. Biederman authored
It turns out msi_ops was simply not enough to abstract the architecture specific details of msi. So I have moved the resposibility of constructing the struct irq_chip to the architectures, and have two architecture specific functions arch_setup_msi_irq, and arch_teardown_msi_irq. For simple architectures those functions can do all of the work. For architectures with platform dependencies they can call into the appropriate platform code. With this msi.c is finally free of assuming you have an apic, and this actually takes less code. The helpers for the architecture specific code are declared in the linux/msi.h to keep them separate from the msi functions used by drivers in linux/pci.h Signed-off-by:
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Eric W. Biederman authored
The logic works like this. Since we no longer track the state logic by hand in msi.c startup and shutdown are no longer needed. By updating msi_set_mask_bit to work on msi devices that do not implement a mask bit we can always call the mask/unmask functions. What we really have are mask and unmask so we use them to implement the .mask and .unmask functions instead of .enable and .disable. By switching to the handle_edge_irq handler we only need an ack function that moves the irq if necessary. Which removes the old end and ack functions and their peculiar logic of sometimes disabling an irq. This removes the reliance on pre genirq irq handling methods. Signed-off-by:
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Eric W. Biederman authored
Currently msi.c is doing sanity checks that make certain before an irq is destroyed it has no more users. By adding irq_has_action I can perform the test is a generic way, instead of relying on a msi specific data structure. By performing the core check in dynamic_irq_cleanup I ensure every user of dynamic irqs has a test present and we don't free resources that are in use. In msi.c this allows me to kill the attrib.state member of msi_desc and all of the assciated code to maintain it. To keep from freeing data structures when irq cleanup code is called to soon changing dyanamic_irq_cleanup is insufficient because there are msi specific data structures that are also not safe to free. Signed-off-by:
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Eric W. Biederman authored
This patch implements two functions ht_create_irq and ht_destroy_irq for use by drivers. Several other functions are implemented as helpers for arch specific irq_chip handlers. The driver for the card I tested this on isn't yet ready to be merged. However this code is and hypertransport irqs are in use in a few other places in the kernel. Not that any of this will get merged before 2.6.19 Because the ipath-ht400 is slightly out of spec this code will need to be generalized to work there. I think all of the powerpc uses are for a plain interrupt controller in a chipset so support for native hypertransport devices is a little less interesting. However I think this is a half way decent model on how to separate arch specific and generic helper code, and I think this is a functional model of how to get the architecture dependencies out of the msi code. [akpm@osdl.org: Kconfig fix] Signed-off-by:
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Eric W. Biederman authored
This adds defines for the hypertransport capability subtypes and starts using them a little. [akpm@osdl.org: fix typo] Signed-off-by:
Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Greg KH <greg@kroah.com> Signed-off-by:
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Eric W. Biederman authored
With more irqs in the system we don't need this. Signed-off-by:
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Eric W. Biederman authored
After raising the number of irqs the system supports this function is no longer necessary. Signed-off-by:
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Eric W. Biederman authored
This refactors the irq handling code to make the vectors a per cpu resource so the same vector number can be simultaneously used on multiple cpus for different irqs. This should make systems that were hitting limits on the total number of irqs much more livable. [akpm@osdl.org: build fix] [akpm@osdl.org: __target_IO_APIC_irq is unneeded on UP] Signed-off-by:
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Eric W. Biederman authored
This is a small pessimization but it paves the way for making this information per cpu. Which allows the the maximum number of IRQS to become NR_CPUS*224. Signed-off-by:
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Eric W. Biederman authored
This patch adds support for systems that cannot receive every interrupt on a single cpu simultaneously, in the check to see if we have enough HARDIRQ_BITS. MAX_HARDIRQS_PER_CPU becomes the count of the maximum number of hardare generated interrupts per cpu. On architectures that support per cpu interrupt delivery this can be a significant space savings and scalability bonus. This patch adds support for systems that cannot receive every interrupt on Signed-off-by:
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Eric W. Biederman authored
Because of the nasty way that CONFIG_PCI_MSI was implemented we wound up with set_irq_info and set_native_irq_info, with move_irq and move_native_irq. Both functions did the same thing but they were built and called under different circumstances. Now that the msi hacks are gone we can kill move_irq and set_irq_info. Signed-off-by:
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Eric W. Biederman authored
This patch removes the change in behavior of the irq allocation code when CONFIG_PCI_MSI is defined. Removing all instances of the assumption that irq == vector. create_irq is rewritten to first allocate a free irq and then to assign that irq a vector. assign_irq_vector is made static and the AUTO_ASSIGN case which allocates an vector not bound to an irq is removed. The ioapic vector methods are removed, and everything now works with irqs. The definition of NR_IRQS no longer depends on CONFIG_PCI_MSI [akpm@osdl.org: cleanup] Signed-off-by:
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Eric W. Biederman authored
This patch removes the change in behavior of the irq allocation code when CONFIG_PCI_MSI is defined. Removing all instances of the assumption that irq == vector. create_irq is rewritten to first allocate a free irq and then to assign that irq a vector. assign_irq_vector is made static and the AUTO_ASSIGN case which allocates an vector not bound to an irq is removed. The ioapic vector methods are removed, and everything now works with irqs. The definition of NR_IRQS no longer depends on CONFIG_PCI_MSI Signed-off-by:
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Eric W. Biederman authored
After the previous changes ia64 is the only architecture useing msi-apic.c [akpm@osdl.org: unbreak MSI on ia64] Signed-off-by:
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Eric W. Biederman authored
This removes the hardcoded assumption that irq == vector in the msi composition code, and it allows the msi message composition to setup logical mode, or lowest priorirty delivery mode as we do for other apic interrupts, and with the same selection criteria. Basically this moves the problem of what is in the msi message into the architecture irq management code where it belongs. Not in a generic layer that doesn't have enough information to compose msi messages properly. Signed-off-by:
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Eric W. Biederman authored
This removes the hardcoded assumption that irq == vector in the msi composition code, and it allows the msi message composition to setup logical mode, or lowest priorirty delivery mode as we do for other apic interrupts, and with the same selection criteria. Basically this moves the problem of what is in the msi message into the architecture irq management code where it belongs. Not in a generic layer that doesn't have enough information to compose msi messages properly. Signed-off-by:
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Eric W. Biederman authored
The msi currently allocates irqs backwards. First it allocates a platform dependent routing value for an interrupt the ``vector'' and then it figures out from the vector which irq you are on. For ia64 this is fine. For x86 and x86_64 this is complete nonsense and makes an enourmous mess of the irq handling code and prevents some pretty significant cleanups in the code for handling large numbers of irqs. This patch refactors msi.c to work in terms of irqs and create_irq/destroy_irq for dynamically managing irqs. Hopefully this is finally a version of msi.c that is useful on more than just x86 derivatives. Signed-off-by:
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Eric W. Biederman authored
The current implementation of create_irq() is a hack but it is the current hack that msi.c uses, and unfortunately the ``generic'' apic msi ops depend on this hack. Thus we are this hack of assuming irq == vector until the depencencies in the generic irq code are removed. Signed-off-by:
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Eric W. Biederman authored
The current implementation of create_irq() is a hack but it is the current hack that msi.c uses, and unfortunately the ``generic'' apic msi ops depend on this hack. Thus we are stuck this hack of assuming irq == vector until the depencencies in the generic msi code are removed. Signed-off-by:
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Eric W. Biederman authored
[akpm@osdl.org: build fix] Signed-off-by:
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Eric W. Biederman authored
With the msi support comes a new concept in irq handling, irqs that are created dynamically at run time. Currently the msi code allocates irqs backwards. First it allocates a platform dependent routing value for an interrupt the ``vector'' and then it figures out from the vector which irq you are on. This msi backwards allocator suffers from two basic problems. The allocator suffers because it is trying to do something that is architecture specific in a generic way making it brittle, inflexible, and tied to tightly to the architecture implementation. The alloctor also suffers from it's very backwards nature as it has tied things together that should have no dependencies. To solve the basic dynamic irq allocation problem two new architecture specific functions are added: create_irq and destroy_irq. create_irq takes no input and returns an unused irq number, that won't be reused until it is returned to the free poll with destroy_irq. The irq then can be used for any purpose although the only initial consumer is the msi code. destroy_irq takes an irq number allocated with create_irq and returns it to the free pool. Making this functionality per architecture increases the simplicity of the irq allocation code and increases it's flexibility. dynamic_irq_init() and dynamic_irq_cleanup() are added to automate the irq_desc initializtion that should happen for dynamic irqs. Signed-off-by:
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Eric W. Biederman authored
Currently we attempt to predict how many irqs we will be able to allocate with msi using pci_vector_resources and some complicated accounting, and then we only allow each device as many irqs as we think are available on average. Only the s2io driver even takes advantage of this feature all other drivers have a fixed number of irqs they need and bail if they can't get them. pci_vector_resources is inaccurate if anyone ever frees an irq. The whole implmentation is racy. The current irq limit policy does not appear to make sense with current drivers. So I have simplified things. We can revisit this we we need a more sophisticated policy. Signed-off-by:
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Eric W. Biederman authored
The current msi_ops are short sighted in a number of ways, this patch attempts to fix the glaring deficiences. - Report in msi_ops if a 64bit address is needed in the msi message, so we can fail 32bit only msi structures. - Send and receive a full struct msi_msg in both setup and target. This is a little cleaner and allows for architectures that need to modify the data to retarget the msi interrupt to a different cpu. - In target pass in the full cpu mask instead of just the first cpu in case we can make use of the full cpu mask. - Operate in terms of irqs and not vectors, currently there is still a 1-1 relationship but on architectures other than ia64 I expect this will change. Signed-off-by:
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Eric W. Biederman authored
In support of this I also add a struct msi_msg that captures the the two address and one data field ina typical msi message, and I remember the pos and if the address is 64bit in struct msi_desc. This makes the code a little more readable and easier to maintain, and paves the way to further simplfications. Signed-off-by:
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Eric W. Biederman authored
This allows the output of the msi tests to be stored directly in a bit field. If you don't do this a value greater than one will be truncated and become 0. Changing true to false with bizare consequences. Signed-off-by:
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Eric W. Biederman authored
The problem. Because the disable routines leave the msi interrupts in all sorts of half enabled states the enable routines become impossible to implement correctly, and almost impossible to understand. Simplifing this allows me to simply kill the buggy reroute_msix_table, and generally makes the code more maintainable. Signed-off-by:
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Eric W. Biederman authored
In the latest changes the code for migrating x86_64 irqs was dropped. This reads it in a fashion that will work even if we change the vector on level triggered irqs when we migrate them. [akpm@osdl.org: build fix] Signed-off-by:
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Eric W. Biederman authored
Currently move_native_irq disables and renables the irq we are migrating to ensure we don't take that irq when we are actually doing the migration operation. Disabling the irq needs to happen but sometimes doing the work is move_native_irq is too late. On x86 with ioapics the irq move sequences needs to be: edge_triggered: mask irq. move irq. unmask irq. ack irq. level_triggered: mask irq. ack irq. move irq. unmask irq. We can easily perform the edge triggered sequence, with the current defintion of move_native_irq. However the level triggered case does not map well. For that I have added move_masked_irq, to allow me to disable the irqs around both the ack and the move. Q: Why have we not seen this problem earlier? A: The only symptom I have been able to reproduce is that if we change the vector before acknowleding an irq the wrong irq is acknowledged. Since we currently are not reprogramming the irq vector during migration no problems show up. We have to mask the irq before we acknowledge the irq or else we could hit a window where an irq is asserted just before we acknowledge it. Edge triggered irqs do not have this problem because acknowledgements do not propogate in the same way. Signed-off-by:
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