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* [NET]: Remove the empty net_tablePavel Emelyanov2008-01-281-8/+0
| | | | | | | | I have removed all the entries from this table (core_table, ipv4_table and tr_table), so now we can safely drop it. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* sysctl: Infrastructure for per namespace sysctlsEric W. Biederman2008-01-282-22/+96
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch implements the basic infrastructure for per namespace sysctls. A list of lists of sysctl headers is added, allowing each namespace to have it's own list of sysctl headers. Each list of sysctl headers has a lookup function to find the first sysctl header in the list, allowing the lists to have a per namespace instance. register_sysct_root is added to tell sysctl.c about additional lists of sysctl_headers. As all of the users are expected to be in kernel no unregister function is provided. sysctl_head_next is updated to walk through the list of lists. __register_sysctl_paths is added to add a new sysctl table on a non-default sysctl list. The only intrusive part of this patch is propagating the information to decided which list of sysctls to use for sysctl_check_table. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Serge Hallyn <serue@us.ibm.com> Cc: Daniel Lezcano <dlezcano@fr.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* sysctl: Remember the ctl_table we passed to register_sysctl_pathsEric W. Biederman2008-01-281-0/+1
| | | | | | | | | | | | | | | | | By doing this we allow users of register_sysctl_paths that build and dynamically allocate their ctl_table to be simpler. This allows them to just remember the ctl_table_header returned from register_sysctl_paths from which they can now find the ctl_table array they need to free. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Serge Hallyn <serue@us.ibm.com> Cc: Daniel Lezcano <dlezcano@fr.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* sysctl: Add register_sysctl_paths functionEric W. Biederman2008-01-281-15/+74
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are a number of modules that register a sysctl table somewhere deeply nested in the sysctl hierarchy, such as fs/nfs, fs/xfs, dev/cdrom, etc. They all specify several dummy ctl_tables for the path name. This patch implements register_sysctl_path that takes an additional path name, and makes up dummy sysctl nodes for each component. This patch was originally written by Olaf Kirch and brought to my attention and reworked some by Olaf Hering. I have changed a few additional things so the bugs are mine. After converting all of the easy callers Olaf Hering observed allyesconfig ARCH=i386, the patch reduces the final binary size by 9369 bytes. .text +897 .data -7008 text data bss dec hex filename 26959310 4045899 4718592 35723801 2211a19 ../vmlinux-vanilla 26960207 4038891 4718592 35717690 221023a ../O-allyesconfig/vmlinux So this change is both a space savings and a code simplification. CC: Olaf Kirch <okir@suse.de> CC: Olaf Hering <olaf@aepfle.de> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Serge Hallyn <serue@us.ibm.com> Cc: Daniel Lezcano <dlezcano@fr.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* kernel: add CLONE_IO to specifically request sharing of IO contextsJens Axboe2008-01-281-4/+10
| | | | | | | syslets (or other threads/processes that want io context sharing) can set this to enforce sharing of io context. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* io context sharing: preliminary supportJens Axboe2008-01-281-1/+0
| | | | | | | Detach task state from ioc, instead keep track of how many processes are accessing the ioc. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* ioprio: move io priority from task_struct to io_contextJens Axboe2008-01-281-5/+27
| | | | | | | This is where it belongs and then it doesn't take up space for a process that doesn't do IO. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* printk: revert ktime_get() timestampsIngo Molnar2008-01-271-3/+1
| | | | | | | | | | revert 19ef9309273d26cb005cb23e6a370353dca91099. Kevin Winchester reported a lockup during X startup an bisected it to this commit. Reported-by: Kevin Winchester <kjwinchester@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* [S390] Remove appldata include from sysctl_check.cHeiko Carstens2008-01-261-1/+0
| | | | | | | Forgot to remove this when removing the appldata binary sysctls. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6Linus Torvalds2008-01-261-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6: (200 commits) [SCSI] usbstorage: use last_sector_bug flag universally [SCSI] libsas: abstract STP task status into a function [SCSI] ultrastor: clean up inline asm warnings [SCSI] aic7xxx: fix firmware build [SCSI] aacraid: fib context lock for management ioctls [SCSI] ch: remove forward declarations [SCSI] ch: fix device minor number management bug [SCSI] ch: handle class_device_create failure properly [SCSI] NCR5380: fix section mismatch [SCSI] sg: fix /proc/scsi/sg/devices when no SCSI devices [SCSI] IB/iSER: add logical unit reset support [SCSI] don't use __GFP_DMA for sense buffers if not required [SCSI] use dynamically allocated sense buffer [SCSI] scsi.h: add macro for enclosure bit of inquiry data [SCSI] sd: add fix for devices with last sector access problems [SCSI] fix pcmcia compile problem [SCSI] aacraid: add Voodoo Lite class of cards. [SCSI] aacraid: add new driver features flags [SCSI] qla2xxx: Update version number to 8.02.00-k7. [SCSI] qla2xxx: Issue correct MBC_INITIALIZE_FIRMWARE command. ...
| * [SCSI] sysfs: add filter function to groupsJames Bottomley2008-01-231-1/+1
| | | | | | | | | | | | | | | | | | | | This patch allows the various users of attribute_groups to selectively allow the appearance of group attributes. The primary consumer of this will be the transport classes in which we currently have elaborate attribute selection algorithms to do this same thing. Acked-by: Greg KH <greg@kroah.com> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
* | sched: keep total / count stats in addition to the max forArjan van de Ven2008-01-252-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | Right now, the linux kernel (with scheduler statistics enabled) keeps track of the maximum time a process is waiting to be scheduled. While the maximum is a very useful metric, tracking average and total is equally useful (at least for latencytop) to figure out the accumulated effect of scheduler delays. The accumulated effect is important to judge the performance impact of scheduler tuning/behavior. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched: fix: don't take a mutex from interrupt contextPeter Zijlstra2008-01-251-2/+2
| | | | | | | | | | | | | | | | | | print_cfs_stats is callable from interrupt context (sysrq), hence it should not take mutexes. Change it to use RCU since the task group data is RCU freed anyway. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched: print backtrace of running tasks tooNick Piggin2008-01-251-2/+1
| | | | | | | | | | | | | | The attached patch is something really simple that can sometimes help in getting more info out of a hung system. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | printk: use ktime_get()Ingo Molnar2008-01-251-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | printk timestamps: use ktime_get(). Some platforms have a functioning clocksource function only after they are done with early bootup, so delay this until out of SYSTEM_BOOTING state. it's also inherently safe now, as any bugs in this area will be caught by the printk recursion checks. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | softlockup: fix signednessIngo Molnar2008-01-252-13/+13
| | | | | | | | | | | | | | | | fix softlockup tunables signedness. mark tunables read-mostly. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched: latencytop supportArjan van de Ven2008-01-255-1/+258
| | | | | | | | | | | | | | | | LatencyTOP kernel infrastructure; it measures latencies in the scheduler and tracks it system wide and per process. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched: fix goto retry in pick_next_task_rt()Dmitry Adamushko2008-01-251-7/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | looking at it one more time: (1) it looks to me that there is no need to call sched_rt_ratio_exceeded() from pick_next_rt_entity() - [ for CONFIG_FAIR_GROUP_SCHED ] queues with rt_rq->rt_throttled are not within this 'tree-like hierarchy' (or whatever we should call it :-) - there is also no need to re-check 'rt_rq->rt_time > ratio' at this point as 'rt_rq->rt_time' couldn't have been increased since the last call to update_curr_rt() (which obviously calls sched_rt_ratio_esceeded()) well, it might be that 'ratio' for this rt_rq has been re-configured (and the period over which this rt_rq was active has not yet been finished)... but I don't think we should really take this into account. (2) now pick_next_rt_entity() must never return NULL, so let's change pick_next_task_rt() accordingly. Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched: monitor clock underflows in /proc/sched_debugGuillaume Chazarain2008-01-252-2/+5
| | | | | | | | | | | | | | We monitor clock overflows, let's also monitor clock underflows. Signed-off-by: Guillaume Chazarain <guichaz@yahoo.fr> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched: fix rq->clock warps on frequency changesGuillaume Chazarain2008-01-251-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | sched: fix rq->clock warps on frequency changes Fix 2bacec8c318ca0418c0ee9ac662ee44207765dd4 (sched: touch softlockup watchdog after idling) that reintroduced warps on frequency changes. touch_softlockup_watchdog() calls __update_rq_clock that checks rq->clock for warps, so call it after adjusting rq->clock. Signed-off-by: Guillaume Chazarain <guichaz@yahoo.fr> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched: fix, always create kernel threads with normal priorityMichal Schmidt2008-01-251-1/+11
| | | | | | | | | | | | | | | | | | Ensure that the kernel threads are created with the usual nice level and affinity even if kthreadd's properties were changed from the default by root. Signed-off-by: Michal Schmidt <mschmidt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | debug: clean up kernel/profile.cPaolo Ciarrocchi2008-01-251-50/+49
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Before: total: 25 errors, 13 warnings, 602 lines checked After: total: 0 errors, 2 warnings, 601 lines checked No code changed: kernel/profile.o: text data bss dec hex filename 3048 236 24 3308 cec profile.o.before 3048 236 24 3308 cec profile.o.after md5: 2501d64748a4d350dffb11203e2a5182 profile.o.before.asm 2501d64748a4d350dffb11203e2a5182 profile.o.after.asm Signed-off-by: Paolo Ciarrocchi <paolo.ciarrocchi@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched: remove the !PREEMPT_BKL codeIngo Molnar2008-01-252-20/+3
| | | | | | | | | | | | | | | | remove the !PREEMPT_BKL code. this removes 160 lines of legacy code. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched: make PREEMPT_BKL the defaultIngo Molnar2008-01-251-8/+1
| | | | | | | | | | | | | | | | make PREEMPT_BKL the default. precursor to removal of the !PREEMPT_BKL code. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | debug: track and print last unloaded module in the oops traceArjan van de Ven2008-01-251-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Based on a suggestion from Andi: In various cases, the unload of a module may leave some bad state around that causes a kernel crash AFTER a module is unloaded; and it's then hard to find which module caused that. This patch tracks the last unloaded module, and prints this as part of the module list in the oops trace. Right now, only the last 1 module is tracked; I expect that this is enough for the vast majority of cases where this information matters; if it turns out that tracking more is important, we can always extend it to that. [ mingo@elte.hu: build fix ] Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | debug: show being-loaded/being-unloaded indicator for modulesArjan van de Ven2008-01-251-6/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It's rather common that an oops/WARN_ON/BUG happens during the load or unload of a module. Unfortunatly, it's not always easy to see directly which module is being loaded/unloaded from the oops itself. Worse, it's not even always possible to ask the bug reporter, since there are so many components (udev etc) that auto-load modules that there's a good chance that even the reporter doesn't know which module this is. This patch extends the existing "show if it's tainting" print code, which is used as part of printing the modules in the oops/BUG/WARN_ON to include a "+" for "being loaded" and a "-" for "being unloaded". As a result this extension, the "taint_flags()" function gets renamed to "module_flags()" (and takes a module struct as argument, not a taint flags int). Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched: rt-watchdog: fix .rlim_max = RLIM_INFINITYPeter Zijlstra2008-01-252-8/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | Remove the curious logic to set it_sched_expires in the future. It useless because rt.timeout wouldn't be incremented anyway. Explicity check for RLIM_INFINITY as a test programm that had a 1s soft limit and a inf hard limit would SIGKILL at 1s. This is because RLIM_INFINITY+d-1 is d-2. Signed-off-by: Peter Zijlsta <a.p.zijlstra@chello.nl> CC: Michal Schmidt <mschmidt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched: rt-group: reduce reschedulingPeter Zijlstra2008-01-251-1/+4
| | | | | | | | | | | | | | Only reschedule if the new group has a higher prio task. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | hrtimer: unlock hrtimer_wakeupPeter Zijlstra2008-01-251-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | hrtimer_wakeup creates a base->lock rq->lock lock dependancy. Avoid this by switching to HRTIMER_CB_IRQSAFE_NO_SOFTIRQ which doesn't hold base->lock. This fully untangles hrtimer locks from the scheduler locks, and allows hrtimer usage in the scheduler proper. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | hrtimer: fixup the HRTIMER_CB_IRQSAFE_NO_SOFTIRQ fallbackPeter Zijlstra2008-01-252-132/+141
| | | | | | | | | | | | | | | | | | | | Currently all highres=off timers are run from softirq context, but HRTIMER_CB_IRQSAFE_NO_SOFTIRQ timers expect to run from irq context. Fix this up by splitting it similar to the highres=on case. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | hrtimer: clean up cpu->base locking tricksPeter Zijlstra2008-01-252-9/+19
| | | | | | | | | | | | | | | | In order to more easily allow for the scheduler to use timers, clean up the locking a bit. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched: rt throttling vs no_hzPeter Zijlstra2008-01-253-15/+43
| | | | | | | | | | | | | | We need to teach no_hz about the rt throttling because its tick driven. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched: pull_rt_task() cleanupMike Galbraith2008-01-251-6/+4
| | | | | | | | | | | | | | "goto out" is an odd way to spell "skip". Signed-off-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched: rt group schedulingPeter Zijlstra2008-01-253-203/+537
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Extend group scheduling to also cover the realtime classes. It uses the time limiting introduced by the previous patch to allow multiple realtime groups. The hard time limit is required to keep behaviour deterministic. The algorithms used make the realtime scheduler O(tg), linear scaling wrt the number of task groups. This is the worst case behaviour I can't seem to get out of, the avg. case of the algorithms can be improved, I focused on correctness and worst case. [ akpm@linux-foundation.org: move side-effects out of BUG_ON(). ] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched: rt time limitPeter Zijlstra2008-01-253-21/+120
| | | | | | | | | | | | | | | | | | | | Very simple time limit on the realtime scheduling classes. Allow the rq's realtime class to consume sched_rt_ratio of every sched_rt_period slice. If the class exceeds this quota the fair class will preempt the realtime class. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched: high-res preemption tickPeter Zijlstra2008-01-255-17/+268
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use HR-timers (when available) to deliver an accurate preemption tick. The regular scheduler tick that runs at 1/HZ can be too coarse when nice level are used. The fairness system will still keep the cpu utilisation 'fair' by then delaying the task that got an excessive amount of CPU time but try to minimize this by delivering preemption points spot-on. The average frequency of this extra interrupt is sched_latency / nr_latency. Which need not be higher than 1/HZ, its just that the distribution within the sched_latency period is important. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched: do not do cond_resched() when CONFIG_PREEMPTHerbert Xu2008-01-251-2/+4
| | | | | | | | | | | | | | | | | | Why do we even have cond_resched when real preemption is on? It seems to be a waste of space and time. remove cond_resched with CONFIG_PREEMPT on. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched: documentation, whitespace fixesIngo Molnar2008-01-251-4/+4
| | | | | | | | | | | | whitespace fixes. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched: SCHED_FIFO/SCHED_RR watchdog timerPeter Zijlstra2008-01-252-0/+59
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce a new rlimit that allows the user to set a runtime timeout on real-time tasks their slice. Once this limit is exceeded the task will receive SIGXCPU. So it measures runtime since the last sleep. Input and ideas by Thomas Gleixner and Lennart Poettering. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> CC: Lennart Poettering <mzxreary@0pointer.de> CC: Michael Kerrisk <mtk.manpages@googlemail.com> CC: Ulrich Drepper <drepper@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched: sched_rt_entityPeter Zijlstra2008-01-252-11/+11
| | | | | | | | | | | | | | | | | | | | Move the task_struct members specific to rt scheduling together. A future optimization could be to put sched_entity and sched_rt_entity into a union. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> CC: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | uids: merge multiple error paths in alloc_uid() into onePavel Emelyanov2008-01-251-27/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | There are already 4 error paths in alloc_uid() that do incremental rollbacks. I think it's time to merge them. This costs us 8 lines of code :) Maybe it would be better to merge this patch with the previous one, but I remember that some time ago I sent a similar patch (fixing the error path and cleaning it), but I was told to make two patches in such cases. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: Dhaval Giani <dhaval@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched: dynamically update the root-domain span/online mapsGregory Haskins2008-01-251-12/+19
| | | | | | | | | | | | | | | | | | | | The baseline code statically builds the span maps when the domain is formed. Previous attempts at dynamically updating the maps caused a suspend-to-ram regression, which should now be fixed. Signed-off-by: Gregory Haskins <ghaskins@novell.com> CC: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | Preempt-RCU: CPU Hotplug handlingPaul E. McKenney2008-01-251-5/+142
| | | | | | | | | | | | | | | | | | | | | | This patch allows preemptible RCU to tolerate CPU-hotplug operations. It accomplishes this by maintaining a local copy of a map of online CPUs, which it accesses under its own lock. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | Preempt-RCU: implementationPaul E. McKenney2008-01-256-2/+1166
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch implements a new version of RCU which allows its read-side critical sections to be preempted. It uses a set of counter pairs to keep track of the read-side critical sections and flips them when all tasks exit read-side critical section. The details of this implementation can be found in this paper - http://www.rdrop.com/users/paulmck/RCU/OLSrtRCU.2006.08.11a.pdf and the article- http://lwn.net/Articles/253651/ This patch was developed as a part of the -rt kernel development and meant to provide better latencies when read-side critical sections of RCU don't disable preemption. As a consequence of keeping track of RCU readers, the readers have a slight overhead (optimizations in the paper). This implementation co-exists with the "classic" RCU implementations and can be switched to at compiler. Also includes RCU tracing summarized in debugfs. [ akpm@linux-foundation.org: build fixes on non-preempt architectures ] Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com> Signed-off-by: Paul E. McKenney <paulmck@us.ibm.com> Reviewed-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | Preempt-RCU: fix rcu_barrier for preemptive environment.Paul E. McKenney2008-01-252-1/+11
| | | | | | | | | | | | | | | | | | | | | | | | Fix rcu_barrier() to work properly in preemptive kernel environment. Also, the ordering of callback must be preserved while moving callbacks to another CPU during CPU hotplug. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | Preempt-RCU: reorganize RCU code into rcuclassic.c and rcupdate.cPaul E. McKenney2008-01-253-551/+602
| | | | | | | | | | | | | | | | | | | | | | | | | | This patch re-organizes the RCU code to enable multiple implementations of RCU. Users of RCU continues to include rcupdate.h and the RCU interfaces remain the same. This is in preparation for subsequently merging the preemptible RCU implementation. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | Preempt-RCU: Use softirq instead of tasklets forDipankar Sarma2008-01-251-8/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch makes RCU use softirq instead of tasklets. It also adds a memory barrier after raising the softirq inorder to ensure that the cpu sees the most recently updated value of rcu->cur while processing callbacks. The discussion of the related theoretical race pointed out by James Huang can be found here --> http://lkml.org/lkml/2007/11/20/603 Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com> Reviewed-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched: remove some old cpuset logicGregory Haskins2008-01-251-33/+0
| | | | | | | | | | | | | | | | | | We had support for overlapping cpuset based rto logic in early prototypes that is no longer used, so remove it. Signed-off-by: Gregory Haskins <ghaskins@novell.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched: RT-balance, only adjust overload state when changingGregory Haskins2008-01-251-3/+5
| | | | | | | | | | | | | | | | | | | | | | | | The overload set/clears were originally idempotent when this logic was first implemented. But that is no longer true due to the addition of the atomic counter and this logic was never updated to work properly with that change. So only adjust the overload state if it is actually changing to avoid getting out of sync. Signed-off-by: Gregory Haskins <ghaskins@novell.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched: RT-balance, add new methods to sched_classSteven Rostedt2008-01-254-22/+179
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Dmitry Adamushko found that the current implementation of the RT balancing code left out changes to the sched_setscheduler and rt_mutex_setprio. This patch addresses this issue by adding methods to the schedule classes to handle being switched out of (switched_from) and being switched into (switched_to) a sched_class. Also a method for changing of priorities is also added (prio_changed). This patch also removes some duplicate logic between rt_mutex_setprio and sched_setscheduler. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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