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2017-01-13Documentation: Update CPU hotplug and move it to core-apiSebastian Andrzej Siewior1-452/+0
The current CPU hotplug is outdated. During the update to what we currently have I rewrote it partly and moved to sphinx format. Cc: Jonathan Corbet <corbet@lwn.net> Cc: Mauro Carvalho Chehab <mchehab@kernel.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com> Cc: Ashok Raj <ashok.raj@intel.com> Cc: Joel Schopp <jschopp@austin.ibm.com> Cc: linux-doc@vger.kernel.org Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2016-10-25Documentation: cpu-hotplug: Fix typosIgor Vuk1-16/+16
Fix some minor spelling errors and capitalization issues. Signed-off-by: Igor Vuk <parcijala@gmail.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2015-12-10Documentation: cpu-hotplug: Fix sysfs mount instructionsSoren Brinkmann1-1/+1
The instructions for mounting sysfs are inconsistent in instructing to create the directory '/sysfs' but then mounting sysfs to /sys. Also, indentation is slightly off. Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2015-03-05cpumask: fix cpu-hotplug documentationRusty Russell1-1/+1
It refers to an obsolete function. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Jonathan Corbet <corbet@lwn.net> Cc: linux-doc@vger.kernel.org
2014-03-20Doc/cpu-hotplug: Specify race-free way to register CPU hotplug callbacksSrivatsa S. Bhat1-0/+45
Recommend the usage of the new CPU hotplug callback registration APIs (__register_cpu_notifier() etc), when subsystems need to also perform initialization for already online CPUs. Provide examples of correct and race-free ways of achieving this, and point out the kinds of code that are error-prone. Cc: Rob Landley <rob@landley.net> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-01-23Documentation/cpu-hotplug.txt: fix a typo in example codeSangjung Woo1-1/+1
As the notifier_block name (i.e. foobar_cpu_notifer) is different from the parameter (i.e.foobar_cpu_notifier) of register function, that is definitely error and it also makes readers confused. Signed-off-by: Sangjung Woo <sangjung.woo@samsung.com> Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-13MAINTAINERS: update Zwane Mwaikambo's e-mail addressJean Delvare1-1/+1
Zwane Mwaikambo's @arm.linux.org.uk address no longer works. In February 2013 he asked for his gmail address to be used instead [1] so let's just do that. [1] http://marc.info/?l=linux-kernel&m=136079068903214&w=2 Signed-off-by: Jean Delvare <jdelvare@suse.de> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: Zwane Mwaikambo <zwanem@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-14kernel: delete __cpuinit usage from all core kernel filesPaul Gortmaker1-3/+3
The __cpuinit type of throwaway sections might have made sense some time ago when RAM was more constrained, but now the savings do not offset the cost and complications. For example, the fix in commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time") is a good example of the nasty type of bugs that can be created with improper use of the various __init prefixes. After a discussion on LKML[1] it was decided that cpuinit should go the way of devinit and be phased out. Once all the users are gone, we can then finally remove the macros themselves from linux/init.h. This removes all the uses of the __cpuinit macros from C files in the core kernel directories (kernel, init, lib, mm, and include) that don't really have a specific maintainer. [1] https://lkml.org/lkml/2013/5/20/589 Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2013-07-03Merge tag 'pm+acpi-3.11-rc1' of ↵Linus Torvalds1-2/+4
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull power management and ACPI updates from Rafael Wysocki: "This time the total number of ACPI commits is slightly greater than the number of cpufreq commits, but Viresh Kumar (who works on cpufreq) remains the most active patch submitter. To me, the most significant change is the addition of offline/online device operations to the driver core (with the Greg's blessing) and the related modifications of the ACPI core hotplug code. Next are the freezer updates from Colin Cross that should make the freezing of tasks a bit less heavy weight. We also have a couple of regression fixes, a number of fixes for issues that have not been identified as regressions, two new drivers and a bunch of cleanups all over. Highlights: - Hotplug changes to support graceful hot-removal failures. It sometimes is necessary to fail device hot-removal operations gracefully if they cannot be carried out completely. For example, if memory from a memory module being hot-removed has been allocated for the kernel's own use and cannot be moved elsewhere, it's desirable to fail the hot-removal operation in a graceful way rather than to crash the kernel, but currenty a success or a kernel crash are the only possible outcomes of an attempted memory hot-removal. Needless to say, that is not a very attractive alternative and it had to be addressed. However, in order to make it work for memory, I first had to make it work for CPUs and for this purpose I needed to modify the ACPI processor driver. It's been split into two parts, a resident one handling the low-level initialization/cleanup and a modular one playing the actual driver's role (but it binds to the CPU system device objects rather than to the ACPI device objects representing processors). That's been sort of like a live brain surgery on a patient who's riding a bike. So this is a little scary, but since we found and fixed a couple of regressions it caused to happen during the early linux-next testing (a month ago), nobody has complained. As a bonus we remove some duplicated ACPI hotplug code, because the ACPI-based CPU hotplug is now going to use the common ACPI hotplug code. - Lighter weight freezing of tasks. These changes from Colin Cross and Mandeep Singh Baines are targeted at making the freezing of tasks a bit less heavy weight operation. They reduce the number of tasks woken up every time during the freezing, by using the observation that the freezer simply doesn't need to wake up some of them and wait for them all to call refrigerator(). The time needed for the freezer to decide to report a failure is reduced too. Also reintroduced is the check causing a lockdep warining to trigger when try_to_freeze() is called with locks held (which is generally unsafe and shouldn't happen). - cpufreq updates First off, a commit from Srivatsa S Bhat fixes a resume regression introduced during the 3.10 cycle causing some cpufreq sysfs attributes to return wrong values to user space after resume. The fix is kind of fresh, but also it's pretty obvious once Srivatsa has identified the root cause. Second, we have a new freqdomain_cpus sysfs attribute for the acpi-cpufreq driver to provide information previously available via related_cpus. From Lan Tianyu. Finally, we fix a number of issues, mostly related to the CPUFREQ_POSTCHANGE notifier and cpufreq Kconfig options and clean up some code. The majority of changes from Viresh Kumar with bits from Jacob Shin, Heiko Stübner, Xiaoguang Chen, Ezequiel Garcia, Arnd Bergmann, and Tang Yuantian. - ACPICA update A usual bunch of updates from the ACPICA upstream. During the 3.4 cycle we introduced support for ACPI 5 extended sleep registers, but they are only supposed to be used if the HW-reduced mode bit is set in the FADT flags and the code attempted to use them without checking that bit. That caused suspend/resume regressions to happen on some systems. Fix from Lv Zheng causes those registers to be used only if the HW-reduced mode bit is set. Apart from this some other ACPICA bugs are fixed and code cleanups are made by Bob Moore, Tomasz Nowicki, Lv Zheng, Chao Guan, and Zhang Rui. - cpuidle updates New driver for Xilinx Zynq processors is added by Michal Simek. Multidriver support simplification, addition of some missing kerneldoc comments and Kconfig-related fixes come from Daniel Lezcano. - ACPI power management updates Changes to make suspend/resume work correctly in Xen guests from Konrad Rzeszutek Wilk, sparse warning fix from Fengguang Wu and cleanups and fixes of the ACPI device power state selection routine. - ACPI documentation updates Some previously missing pieces of ACPI documentation are added by Lv Zheng and Aaron Lu (hopefully, that will help people to uderstand how the ACPI subsystem works) and one outdated doc is updated by Hanjun Guo. - Assorted ACPI updates We finally nailed down the IA-64 issue that was the reason for reverting commit 9f29ab11ddbf ("ACPI / scan: do not match drivers against objects having scan handlers"), so we can fix it and move the ACPI scan handler check added to the ACPI video driver back to the core. A mechanism for adding CMOS RTC address space handlers is introduced by Lan Tianyu to allow some EC-related breakage to be fixed on some systems. A spec-compliant implementation of acpi_os_get_timer() is added by Mika Westerberg. The evaluation of _STA is added to do_acpi_find_child() to avoid situations in which a pointer to a disabled device object is returned instead of an enabled one with the same _ADR value. From Jeff Wu. Intel BayTrail PCH (Platform Controller Hub) support is added to the ACPI driver for Intel Low-Power Subsystems (LPSS) and that driver is modified to work around a couple of known BIOS issues. Changes from Mika Westerberg and Heikki Krogerus. The EC driver is fixed by Vasiliy Kulikov to use get_user() and put_user() instead of dereferencing user space pointers blindly. Code cleanups are made by Bjorn Helgaas, Nicholas Mazzuca and Toshi Kani. - Assorted power management updates The "runtime idle" helper routine is changed to take the return values of the callbacks executed by it into account and to call rpm_suspend() if they return 0, which allows us to reduce the overall code bloat a bit (by dropping some code that's not necessary any more after that modification). The runtime PM documentation is updated by Alan Stern (to reflect the "runtime idle" behavior change). New trace points for PM QoS are added by Sahara (<keun-o.park@windriver.com>). PM QoS documentation is updated by Lan Tianyu. Code cleanups are made and minor issues are addressed by Bernie Thompson, Bjorn Helgaas, Julius Werner, and Shuah Khan. - devfreq updates New driver for the Exynos5-bus device from Abhilash Kesavan. Minor cleanups, fixes and MAINTAINERS update from MyungJoo Ham, Abhilash Kesavan, Paul Bolle, Rajagopal Venkat, and Wei Yongjun. - OMAP power management updates Adaptive Voltage Scaling (AVS) SmartReflex voltage control driver updates from Andrii Tseglytskyi and Nishanth Menon." * tag 'pm+acpi-3.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (162 commits) cpufreq: Fix cpufreq regression after suspend/resume ACPI / PM: Fix possible NULL pointer deref in acpi_pm_device_sleep_state() PM / Sleep: Warn about system time after resume with pm_trace cpufreq: don't leave stale policy pointer in cdbs->cur_policy acpi-cpufreq: Add new sysfs attribute freqdomain_cpus cpufreq: make sure frequency transitions are serialized ACPI: implement acpi_os_get_timer() according the spec ACPI / EC: Add HP Folio 13 to ec_dmi_table in order to skip DSDT scan ACPI: Add CMOS RTC Operation Region handler support ACPI / processor: Drop unused variable from processor_perflib.c cpufreq: tegra: call CPUFREQ_POSTCHANGE notfier in error cases cpufreq: s3c64xx: call CPUFREQ_POSTCHANGE notfier in error cases cpufreq: omap: call CPUFREQ_POSTCHANGE notfier in error cases cpufreq: imx6q: call CPUFREQ_POSTCHANGE notfier in error cases cpufreq: exynos: call CPUFREQ_POSTCHANGE notfier in error cases cpufreq: dbx500: call CPUFREQ_POSTCHANGE notfier in error cases cpufreq: davinci: call CPUFREQ_POSTCHANGE notfier in error cases cpufreq: arm-big-little: call CPUFREQ_POSTCHANGE notfier in error cases cpufreq: powernow-k8: call CPUFREQ_POSTCHANGE notfier in error cases cpufreq: pcc: call CPUFREQ_POSTCHANGE notfier in error cases ...
2013-06-21Documentation / CPU hotplug: Rephrase the outdated description for MADT entriesHanjun Guo1-2/+4
More than 256 entries in ACPI MADT is supported from ACPI 3.0, so the information in should be Documentation/cpu-hotplug.txt updated. [rjw: Changelog] Suggested-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-06-03Finally eradicate CONFIG_HOTPLUGStephen Rothwell1-1/+1
Ever since commit 45f035ab9b8f ("CONFIG_HOTPLUG should be always on"), it has been basically impossible to build a kernel with CONFIG_HOTPLUG turned off. Remove all the remaining references to it. Cc: Russell King <linux@arm.linux.org.uk> Cc: Doug Thompson <dougthompson@xmission.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-11-14doc: Add x86 CPU0 online/offline featureFenghua Yu1-0/+24
If CONFIG_BOOTPARAM_HOTPLUG_CPU0 is turned on, CPU0 is hotpluggable. Otherwise, by default CPU0 is not hotpluggable and kernel parameter cpu0_hotplug enables CPU0 online/offline feature. The documentations point out two known CPU0 dependencies. First, resume from hibernate or suspend always starts from CPU0. So hibernate and suspend are prevented if CPU0 is offline. Another dependency is PIC interrupts always go to CPU0. It's said that some machines may depend on CPU0 to poweroff/reboot. But I haven't seen such dependency on a few tested machines. Please let me know if you see any CPU0 dependencies on your machine. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Link: http://lkml.kernel.org/r/1352835171-3958-2-git-send-email-fenghua.yu@intel.com Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2012-03-29documentation: remove references to cpu_*_map.Rusty Russell1-11/+11
This has been obsolescent for a while, fix documentation and misc comments. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-03-31Fix common misspellingsLucas De Marchi1-1/+1
Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2010-08-11documentation: fix erroneous email address.Rusty Russell1-1/+1
Hey, at least it has both l's. Reported-by: Marin Mitov <mitov@issp.bas.bg> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2009-12-17cpumask: don't recommend set_cpus_allowed hack in Documentation/cpu-hotplug.txtRusty Russell1-32/+17
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: Ashok Raj <ashok.raj@intel.com>
2009-11-24powerpc/pseries: Add hooks to put the CPU into an appropriate offline stateGautham R Shenoy1-0/+6
When a CPU is offlined on POWER currently, we call rtas_stop_self() and hand the CPU back to the resource pool. This path is used for DLPAR which will cause a change in the LPAR configuration which will be visible outside. This patch changes the default state a CPU is put into when it is offlined. On platforms which support ceding the processor to the hypervisor with latency hint specifier value, during a cpu offline operation, instead of calling rtas_stop_self(), we cede the vCPU to the hypervisor while passing a latency hint specifier value. The Hypervisor can use this hint to provide better energy savings. Also, during the offline operation, the control of the vCPU remains with the LPAR as oppposed to returning it to the resource pool. The patch achieves this by creating an infrastructure to set the preferred_offline_state() which can be either - CPU_STATE_OFFLINE: which is the current behaviour of calling rtas_stop_self() - CPU_STATE_INACTIVE: which cedes the vCPU to the hypervisor with the latency hint specifier. The codepath which wants to perform a DLPAR operation can set the preferred_offline_state() of a CPU to CPU_STATE_OFFLINE before invoking cpu_down(). The patch also provides a boot-time command line argument to disable/enable CPU_STATE_INACTIVE. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2008-12-18x86: use possible_cpus=NUM to extend the possible cpus allowedMike Travis1-8/+9
Impact: add new boot parameter Use possible_cpus=NUM kernel parameter to extend the number of possible cpus. The ability to HOTPLUG ON cpus that are "possible" but not "present" is dealt with in a later patch. Signed-off-by: Mike Travis <travis@sgi.com>
2008-08-12cpu hotplug: s390 doesn't support additional_cpus anymore.Heiko Carstens1-5/+0
s390 doesn't support the additional_cpus kernel parameter anymore since a long time. So we better update the code and documentation to reflect that. Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-01-26[S390] Get rid of additional_cpus kernel parameter.Heiko Carstens1-1/+1
It caused only a lot of confusion. From now on cpu hotplug of up to NR_CPUS will work by default. If somebody wants to limit that then the possible_cpus parameter can be used. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-01-25cpu-hotplug: replace lock_cpu_hotplug() with get_online_cpus()Gautham R Shenoy1-5/+6
Replace all lock_cpu_hotplug/unlock_cpu_hotplug from the kernel and use get_online_cpus and put_online_cpus instead as it highlights the refcount semantics in these operations. The new API guarantees protection against the cpu-hotplug operation, but it doesn't guarantee serialized access to any of the local data structures. Hence the changes needs to be reviewed. In case of pseries_add_processor/pseries_remove_processor, use cpu_maps_update_begin()/cpu_maps_update_done() as we're modifying the cpu_present_map there. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-10-19hotplug cpu: migrate a task within its cpusetCliff Wickman1-1/+3
When a cpu is disabled, move_task_off_dead_cpu() is called for tasks that have been running on that cpu. Currently, such a task is migrated: 1) to any cpu on the same node as the disabled cpu, which is both online and among that task's cpus_allowed 2) to any cpu which is both online and among that task's cpus_allowed It is typical of a multithreaded application running on a large NUMA system to have its tasks confined to a cpuset so as to cluster them near the memory that they share. Furthermore, it is typical to explicitly place such a task on a specific cpu in that cpuset. And in that case the task's cpus_allowed includes only a single cpu. This patch would insert a preference to migrate such a task to some cpu within its cpuset (and set its cpus_allowed to its entire cpuset). With this patch, migrate the task to: 1) to any cpu on the same node as the disabled cpu, which is both online and among that task's cpus_allowed 2) to any online cpu within the task's cpuset 3) to any cpu which is both online and among that task's cpus_allowed In order to do this, move_task_off_dead_cpu() must make a call to cpuset_cpus_allowed_locked(), a new subset of cpuset_cpus_allowed(), that will not block. (name change - per Oleg's suggestion) Calls are made to cpuset_lock() and cpuset_unlock() in migration_call() to set the cpuset mutex during the whole migrate_live_tasks() and migrate_dead_tasks() procedure. [akpm@linux-foundation.org: build fix] [pj@sgi.com: Fix indentation and spacing] Signed-off-by: Cliff Wickman <cpw@sgi.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Christoph Lameter <clameter@sgi.com> Cc: Paul Jackson <pj@sgi.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09Add suspend-related notifications for CPU hotplugRafael J. Wysocki1-2/+7
Since nonboot CPUs are now disabled after tasks and devices have been frozen and the CPU hotplug infrastructure is used for this purpose, we need special CPU hotplug notifications that will help the CPU-hotplug-aware subsystems distinguish normal CPU hotplug events from CPU hotplug events related to a system-wide suspend or resume operation in progress. This patch introduces such notifications and causes them to be used during suspend and resume transitions. It also changes all of the CPU-hotplug-aware subsystems to take these notifications into consideration (for now they are handled in the same way as the corresponding "normal" ones). [oleg@tv-sign.ru: cleanups] Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2006-11-30Fix typos in /Documentation : MiscMatt LaPlante1-2/+2
This patch fixes typos in various Documentation txts. The patch addresses some misc words. Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com> Acked-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-10-20[PATCH] doc: fixing cpu-hotplug documentationSatoru Takeuchi1-74/+74
Fixing cpu-hotplug documentation as follows: - moving confusing asterisk on additional_cpus descrition - fixing some typos - unifying indentation for source code and command line example Signed-off-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com> Cc: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-31[PATCH] cpu hotplug: fix hotplug cpu documentation for proper usageChandra Seetharaman1-2/+10
Update hotplug cpu documentation to clearly state when to use register_cpu_notifier() and register_hotcpu_notifier. Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-28[PATCH] for_each_possible_cpu: documentaionKAMEZAWA Hiroyuki1-2/+2
Replace for_each_cpu with for_each_possible_cpu. Modifies occurences in documentaion. for_each_cpu in whatisRCU.txt should be for_each_online_cpu ??? (I'm not sure..) Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-20[PATCH] cpu hotplug documentation fixHeiko Carstens1-2/+7
Looks like there was a merge conflict when patches 8f8b1138fc9f65e3591aac83a4ee394fef34ac1d and 255acee706b333b79f593dd366f16e1f107cccc3 were applied which wasn't properly resolved. Fix this and add some additional description. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-17[PATCH] s390: possible_cpus parameterHeiko Carstens1-0/+6
Introduce possible_cpus command line option. Hard sets the number of bits set in cpu_possible_map. Unlike the additional_cpus parameter this one guarantees that num_possible_cpus() will stay constant even if the system gets rebooted and a different number of cpus are present at startup. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-17[PATCH] s390: additional_cpus parameterHeiko Carstens1-5/+5
Introduce additional_cpus command line option. By default no additional cpu can be attached to the system anymore. Only the cpus present at IPL time can be switched on/off. If it is desired that additional cpus can be attached to the system the maximum number of additional cpus needs to be specified with this option. This change is necessary in order to limit the waste of per_cpu data structures. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-16[IA64] Count disabled cpus as potential hot-pluggable CPUsAshok Raj1-2/+12
Minor updates to earlier patch. - Added to documentation to add ia64 as well. - Minor clarification on how to use disabled cpus - used plain max instead of max_t per Andew Morton. Signed-off-by: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-01-08[PATCH] Updated CPU hotplug documentationAshok Raj1-0/+357
Thanks to Nathan Lynch for the review and comments. Thanks to Joel Schopp for the pointer to add user space scipts. Signed-off-by: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Nathan Lynch <nathanl@austin.ibm.com> Signed-off-by: Joel Schopp <jschopp@austin.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>