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* scheduler: adjust internal locking interfaceJan Beulich2013-10-141-11/+18
| | | | | | | | | | | | | | | Make the locking functions return the lock pointers, so they can be passed to the unlocking functions (which in turn can check that the lock is still actually providing the intended protection, i.e. the parameters determining which lock is the right one didn't change). Further use proper spin lock primitives rather than open coded local_irq_...() constructs, so that interrupts can be re-enabled as appropriate while spinning. Signed-off-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com> Acked-by: Keir Fraser <keir@xen.org>
* SEDF: avoid gathering vCPU-s on pCPU0Jan Beulich2013-03-041-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The introduction of vcpu_force_reschedule() in 14320:215b799fa181 was incompatible with the SEDF scheduler: Any vCPU using VCPUOP_stop_periodic_timer (e.g. any vCPU of half way modern PV Linux guests) ends up on pCPU0 after that call. Obviously, running all PV guests' (and namely Dom0's) vCPU-s on pCPU0 causes problems for those guests rather sooner than later. So the main thing that was clearly wrong (and bogus from the beginning) was the use of cpumask_first() in sedf_pick_cpu(). It is being replaced by a construct that prefers to put back the vCPU on the pCPU that it got launched on. However, there's one more glitch: When reducing the affinity of a vCPU temporarily, and then widening it again to a set that includes the pCPU that the vCPU was last running on, the generic scheduler code would not force a migration of that vCPU, and hence it would forever stay on the pCPU it last ran on. Since that can again create a load imbalance, the SEDF scheduler wants a migration to happen regardless of it being apparently unnecessary. Of course, an alternative to checking for SEDF explicitly in vcpu_set_affinity() would be to introduce a flags field in struct scheduler, and have SEDF set a "always-migrate-on-affinity-change" flag. Signed-off-by: Jan Beulich <jbeulich@suse.com> Acked-by: Keir Fraser <keir@xen.org>
* Fix emacs local variable block to use correct C style variable.David Vrabel2013-02-211-1/+1
| | | | | | | The emacs variable to set the C style from a local variable block is c-file-style, not c-set-style. Signed-off-by: David Vrabel <david.vrabel@citrix.com
* xen: sched_sedf: remove an unused stat in SEDFDario Faggioli2012-10-231-5/+2
| | | | | | | | Namely, `short_cont' which is not updated anywhere in the code. Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com> Acked-by: George Dunlap <george.dunlap@eu.citrix.com> Committed-by: Keir Fraser <keir@xen.org>
* xen: sched: introduce a couple of counters in credit2 and SEDFDario Faggioli2012-10-231-0/+4
| | | | | | | | | | Mainly for consistency with credit, at least for the events that are general enough, like vCPU initialization/destruction and calls to the specific scheduling function. Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com> Acked-by: George Dunlap <george.dunlap@eu.citrix.com> Committed-by: Keir Fraser <keir@xen.org>
* build: Fix build when using -fno-inlineAndrew Cooper2012-10-091-1/+1
| | | | | | | | | | | | | | | struct task_slice.migrated is not initialised by this function, and subsequently returned by value, leading to the error: sched_sedf.c: In function ‘sedf_do_extra_schedule’: sched_sedf.c:711: error: ‘ret.migrated’ may be used uninitialised in this function for both gcc 4.1.2 and 4.4.3 (which are the two I have easily to hand) when combined with the -fno-inline compile option. Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Committed-by: Keir Fraser <keir@xen.org>
* introduce and use common macros for selecting cpupool based cpumasksJuergen Gross2012-01-241-5/+3
| | | | | | | | There are several instances of the same construct finding the cpumask for a cpupool. Use macros instead. Signed-off-by: juergen.gross@ts.fujitsu.com Committed-by: Keir Fraser <keir@xen.org>
* sedf: remove useless tracing printk and harmonize comments style.Dario Faggioli2012-01-151-274/+229
| | | | | | | | | | | | | | | | | | sched_sedf.c used o have its own mechanism for producing tracing-alike kind of information (domain block, wakeup, etc.). Nowadays, with an even not so high number of pCPUs/vCPUs, just trying to enable this makes the serial console completely unusable, produces tons of very hard to parse and interpreet logging and can easily livelock Dom0. Moreover, pretty much the same result this is struggling to get to, is better achieved by enabling the scheduler-related tracing events, as it is for the other schedulers (say, credit or credit2). For all these reasons, this removes that machinery completely. While at it, check in some cosmetics that harmonize the comments withim themself and with the rest of the code base. Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com> Acked-by: George Dunlap <george.dunlap@eu.citrix.com>
* Rework locking for sched_adjust.Dario Faggioli2012-01-041-36/+120
| | | | | | | | | | | | | | | | | The main idea is to move (as much as possible) locking logic from generic code to the various pluggable schedulers. While at it, the following is also accomplished: - pausing all the non-current VCPUs of a domain while changing its scheduling parameters is not effective in avoiding races and it is prone to deadlock, so that is removed. - sedf needs a global lock for preventing races while adjusting domains' scheduling parameters (as it is for credit and credit2), so that is added. Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com> Acked-by: George Dunlap <george.dunlap@eu.citrix.com> Committed-by: Keir Fraser <keir@xen.org>
* All domains (including dom0) should be best effort on creationDario Faggioli2012-01-041-13/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | In the sedf scheduler, while trying to guarantee to dom0 the proper amount of CPU time for being able to do its job, we end up allocating 75% CPU-share to each and every of its VCPUs. This, combined with the fact that such a scheduler has no load balancing logic at all (and thus *all* dom0's VCPUs just rise and stay on physical CPU #0), means that for example on a 12-cores system we're trying to exploit 75x12=3D900% of what we have on a PCPU, which is definitely too much! Moreover, even if a cleverer mechanism for distributing VCPUs among the available PCPUs (if not a proper load balancer) will be put in place some day, it will still be difficult to decide how much guaranteed CPU bandwidth each of the dom0's VCPUs should be provided with, without posing the system at risk of livelock or starvation, even during boot time. Therefore, since sedf is capable of some form of best-effort scheduling, the best thing we can do is ask for this behaviour for dom0, as it is for all other domains, right upon creation. It will then be the sysadmin's job to modify dom0's scheduling parameters to better fit his particular needs, maybe after spreading the load a bit by pinning VCPUs on PCPUs, or using cpupools, etc. Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com> Acked-by: George Dunlap <george.dunlap@eu.citrix.com> Committed-by: Keir Fraser <keir@xen.org>
* sched_sedf: Avoid panic when adjusting sedf parametersJuergen Gross2011-11-181-4/+4
| | | | | | | | | | When using sedf scheduler in a cpupool the system might panic when setting sedf scheduling parameters for a domain. Introduces for_each_domain_in_cpupool macro as it is usable 4 times now. Add appropriate locking in cpupool_unassign_cpu(). Signed-off-by: Juergen Gross <juergen.gross@ts.fujitsu.com> Committed-by: Keir Fraser <keir@xen.org>
* eliminate first_cpu() etcJan Beulich2011-11-081-2/+2
| | | | | | | | This includes the conversion from for_each_cpu_mask() to for_each-cpu(). Signed-off-by: Jan Beulich <jbeulich@suse.com> Acked-by: Keir Fraser <keir@xen.org> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
* eliminate cpu_test_xyz()Jan Beulich2011-11-081-1/+1
| | | | | | Signed-off-by: Jan Beulich <jbeulich@suse.com> Acked-by: Keir Fraser <keir@xen.org> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
* cpupools: allocate CPU masks dynamicallyJan Beulich2011-10-211-1/+1
| | | | | Signed-off-by: Jan Beulich <jbeulich@suse.com> Acked-by: Keir Fraser <keir@xen.org>
* introduce and use nr_cpu_ids and nr_cpumask_bitsJan Beulich2011-10-211-1/+1
| | | | | | | | | | | | | | | The former is the runtime equivalent of NR_CPUS (and users of NR_CPUS, where necessary, get adjusted accordingly), while the latter is for the sole use of determining the allocation size when dynamically allocating CPU masks (done later in this series). Adjust accessors to use either of the two to bound their bitmap operations - which one gets used depends on whether accessing the bits in the gap between nr_cpu_ids and nr_cpumask_bits is benign but more efficient. Signed-off-by: Jan Beulich <jbeulich@suse.com> Acked-by: Keir Fraser <keir@xen.org>
* use xzalloc in common codeJan Beulich2011-10-041-17/+5
| | | | | Signed-off-by: Jan Beulich <jbeulich@suse.com> Acked-by: Keir Fraser <keir@xen.org>
* xen: Fix sedf schedulerGeorge Dunlap2011-07-211-10/+15
| | | | | | | Update the sedf scheduler to be compatible with the most recent generic scheduler interface changes. Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com>
* Remove direct cpumask_t members from struct vcpu and struct domainJan Beulich2011-04-051-1/+1
| | | | | | | | | | | | | | | The CPU masks embedded in these structures prevent NR_CPUS-independent sizing of these structures. Basic concept (in xen/include/cpumask.h) taken from recent Linux. For scalability purposes, many other uses of cpumask_t should be replaced by cpumask_var_t, particularly local variables of functions. This implies that no functions should have by-value cpumask_t parameters, and that the whole old cpumask interface (cpus_...()) should go away in favor of the new (cpumask_...()) one. Signed-off-by: Jan Beulich <jbeulich@novell.com>
* x86: mpparse and cstate need to use 32bit apic idKeir Fraser2010-12-151-1/+0
| | | | | | | | | | | | | | | | | Instead of going with mpc_config_processor struct. that field ony have 8 bits. We should not change that struct, because it is shared with mptable. Also need to increase MAX_APICS. Signed-off-by: Yinghai Lu <yinghai@kernel.org> Rather than using a fixed value of 512, make this scale with NR_CPUS (which obviously still doesn't cover all theoretically possible systems, but at least allows some build time control). Signed-off-by: Jan Beulich <jbeulich@novell.com>
* cpupools: Make interface more consistentKeir Fraser2010-10-241-7/+0
| | | | | | | | | | | | | | | | | | | | The current cpupools code interface is a bit inconsistent. This patch addresses this by making the interaction for each vcpu in a pool look like this: alloc_vdata() -- allocates and sets up vcpu data insert_vcpu() -- the vcpu is ready to run in this pool remove_vcpu() -- take the vcpu out of the pool free_vdata() -- delete allocated vcpu data (Previously, remove_vcpu and free_vdata were combined into a "destroy vcpu", and insert_vcpu was only called for idle vcpus.) This also addresses a bug in credit2 which was caused by a misunderstanding of the cpupools interface. Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com> Acked-by: Juergen Gross <juergen.gross@ts.fujitsu.com>
* x86: IRQ affinity should track vCPU affinityKeir Fraser2010-06-171-0/+2
| | | | | | | | | | | | | | With IRQs getting bound to the CPU the binding vCPU currently runs on there can result quite a bit of extra cross CPU traffic as soon as that vCPU moves to a different pCPU. Likewise, when a domain re-binds an event channel associated with a pIRQ, that IRQ's affinity should also be adjusted. The open issue is how to break ties for interrupts shared by multiple domains - currently, the last request (at any point in time) is being honored. Signed-off-by: Jan Beulich <jbeulich@novell.com>
* Fix CPU hotplug after percpu data handling changes.Keir Fraser2010-05-191-1/+1
| | | | Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
* Remove many uses of cpu_possible_map and iterators over NR_CPUS.Keir Fraser2010-05-141-5/+9
| | | | | | | The significant remaining culprits for x86 are credit2, hpet, and percpu-area subsystems. To be dealt with in a separate patch. Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
* tasklet: Improve scheduler interaction.Keir Fraser2010-05-111-10/+5
| | | | Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
* scheduler: const-ify references to 'struct scheduler' where possible.Keir Fraser2010-05-041-17/+17
| | | | Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
* cpupools [1/6]: hypervisor changesKeir Fraser2010-04-211-46/+98
| | | | Signed-off-by: Juergen Gross <juergen.gross@ts.fujitsu.com>
* Implement tasklets as running in VCPU context (sepcifically, idle-VCPU context)Keir Fraser2010-04-191-15/+8
| | | | | | | | ...rather than in softirq context. This is expected to avoid a lot of subtle deadlocks relating to the fact that softirqs can interrupt a scheduled vcpu. Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
* Miscellaneous data placement adjustmentsKeir Fraser2009-10-281-1/+1
| | | | | | | Make various data items const or __read_mostly where possible/reasonable. Signed-off-by: Jan Beulich <jbeulich@novell.com>
* x86_64: allow more vCPU-s per guestKeir Fraser2009-06-181-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | Since the shared info layout is fixed, guests are required to use VCPUOP_register_vcpu_info prior to booting any vCPU beyond the traditional limit of 32. MAX_VIRT_CPUS, being an implemetation detail of the hypervisor, is no longer being exposed in the public headers. The tools changes are clearly incomplete (and done only so things would build again), and the current state of the tools (using scalar variables all over the place to represent vCPU bitmaps) very likely doesn't permit booting DomU-s with more than the traditional number of vCPU-s. Testing of the extended functionality was done with Dom0 (96 vCPU-s, as well as 128 vCPU-s out of which the kernel elected - by way of a simple kernel side patch - to use only some, resulting in a sparse bitmap). ia64 changes only to make things build, and build-tested only (and the tools part only as far as the build would go without encountering unrelated problems in the blktap code). Signed-off-by: Jan Beulich <jbeulich@novell.com>
* Fix misc issues related to allowing support of more CPUsKeir Fraser2008-09-221-4/+19
| | | | | | | | | | This mainly means removing stack variables that (should) depend on NR_CPUS (other than cpumask_t ones) and adjusting certain array sizes. There's at least one open tools issue: The 'xm vcpu-pin' path assumes a maximum of 64 CPU-s in many places. Signed-off-by: Jan Beulich <jbeulich@novell.com>
* xen: Small cleanups towards allowing stricter compile warnings.Keir Fraser2008-07-151-13/+13
| | | | Signed-off-by: Christoph Egger <Christoph.Egger@amd.com>
* xen: Get rid of some VCPUF_* flags and move into their own byte fields.kfraser@localhost.localdomain2007-03-291-1/+1
| | | | Signed-off-by: Keir Fraser <keir@xensource.com>
* Use RCU for domain_list and domain_hash.kfraser@localhost.localdomain2007-02-211-1/+7
| | | | | Signed-off-by: Jose Renato Santos <jsantos@hpl.hp.com> Signed-off-by: Keir Fraser <keir@xensource.com>
* [XEN] Initial support for multi-core and multi-threaded CPU scheduling.Emmanuel Ackaouy2006-11-061-0/+9
| | | | | | | In multi-core and multi-threaded systems, not all idling "CPUs" are equal: When there are idling execution vehicles, it's better to spread VCPUs across sockets and cores before co-scheduling cores and threads. Signed-off-by: Emmanuel Ackaouy <ack@xensource.com>
* [XEN] Re-jig VCPU initialisation -- VMX init requires generic VCPUkfraser@localhost.localdomain2006-11-061-15/+20
| | | | | | fields to already be allocated. This has led to a general cleanup of domain and vcpu initialisation and destruction. Signed-off-by: Keir Fraser <keir@xensource.com>
* [XEN] Remove definition of printf. All users are switched to printk.kfraser@localhost.localdomain2006-10-231-3/+3
| | | | Signed-off-by: Keir Fraser <keir@xensource.com>
* [XEN] Fix domctl for changing VCPU affinity.kfraser@localhost.localdomain2006-09-211-15/+0
| | | | | | | | | Now works for any VCPU, including the caller's VCPU. By not synchronously pausing the affected VCPU we avoid any risk of deadlock. Signed-off-by: Keir Fraser <keir@xensource.com>
* Replace dom0_ops hypercall with three new hypercalls:kfraser@localhost.localdomain2006-08-251-31/+30
| | | | | | | | | | | | | | | | | | | | | | 1. platform_op -- used by dom0 kernel to perform actions on the hardware platform (e.g., MTRR access, microcode update, platform quirks, ...) 2. domctl -- used by management tools to control a specified domain 3. sysctl -- used by management tools for system-wide actions Benefits include more sensible factoring of actions to hypercalls. Also allows tool compatibility to be tracked separately from the dom0 kernel. The assumption is that it will be easier to replace libxenctrl, libxenguest and Xen as a matched set if the dom0 kernel does not need to be replaced too (e.g., because that would require vendor revalidation). From here on we hope to maintain dom0 kernel compatibility. This promise is not extended to tool compatibility beyond the existing guarantee that compatibility will not be broken within a three-level stable release [3.0.2, 3.0.3, etc.]. Signed-off-by: Keir Fraser <keir@xensource.com>
* [XEN] Clean up some x86 bootstrap code. Replace some CPU iteratorskfraser@localhost.localdomain2006-08-221-9/+2
| | | | | | with for_each_cpu() -- we want to ensure that per_cpu areas are accessed only for cpus in cpu_possible_map. Signed-off-by: Keir Fraser <keir@xensource.com>
* [XEN] Make some implicit header includes explicit.kaf24@localhost.localdomain2006-08-191-0/+1
| | | | Signed-off-by: Tristan Gingold <tristan.gingold@bull.net>
* Whitespace clean-ups. shand@kneesaa.uk.xensource.com2006-08-161-4/+4
| | | | | Signed-off-by: Steven Hand <steven@xensource.com>
* [XEN] Make per-cpu schedule data explicitly PER_CPU.kaf24@firebug.cl.cam.ac.uk2006-08-081-8/+9
| | | | | Signed-off-by: Keir Fraser <keir@xensource.com>
* [XEN] Separate domain creation from vcpu creation.kfraser@localhost.localdomain2006-07-051-0/+2
| | | | | | | Creating a domain no longer creates vcpu0 -- that is now done later. Signed-off-by: Keir Fraser <keir@xensource.com>
* [SEDF] Fix SEDF defaults to make domain0 take only a fairkaf24@firebug.cl.cam.ac.uk2006-06-171-9/+17
| | | | | | | | equally-weighted share of extratime. Also, hack the short- blocking logic as otherwise domain0 steals all CPU time for several seconds after waking from a long sleep. Signed-off-by: Keir Fraser <keir@xensource.com>
* Domain creation/destruction cleanups.kaf24@firebug.cl.cam.ac.uk2006-06-011-24/+9
| | | | | | | | | 1. Move alloc/dealloc routines to domain.[ch] 2. Merge alloc_task/add_vcpu schedops -> init_vcpu 3. Merge free_task/remove_vcpu schedops -> destroy_domain Signed-off-by: Keir Fraser <keir@xensource.com>
* Remove various compile-time options from SEDF scheduler andkaf24@firebug.cl.cam.ac.uk2006-04-091-465/+262
| | | | | | | | clean up formatting. Signed-off-by: Keir Fraser <keir@xensource.com>
* Fix sched_sedf adjdom to properly clamp the period max value.kaf24@firebug.cl.cam.ac.uk2006-03-171-13/+5
| | | | | | | | Remove temporary debug tracing. Signed-off-by: Keir Fraser <keir@xensource.com>
* Fix 64-bit build.kaf24@firebug.cl.cam.ac.uk2006-03-151-1/+2
| | | | | | Signed-off-by: Keir Fraser <keir@xensource.com>
* Add extra tracing near a commonly-failing scheduler assertion.kaf24@firebug.cl.cam.ac.uk2006-03-151-0/+4
| | | | | | Signed-off-by: Keir Fraser <keir@xensource.com>
* Fix broken assertion in SEDF scheduler.kaf24@firebug.cl.cam.ac.uk2006-03-131-1/+1
| | | | | | Signed-off-by: Keir Fraser <keir@xensource.com>
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