- 27 May, 2015 9 commits
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Bartosz Golaszewski authored
The former duplicate the functionalities of the latter but are neither documented nor arch-independent. Signed-off-by:
Bartosz Golaszewski <bgolaszewski@baylibre.com> Reviewed-by:
Thomas Gleixner <tglx@linutronix.de> Cc: Benoit Cousson <bcousson@baylibre.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Jean Delvare <jdelvare@suse.de> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Drokin <oleg.drokin@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> Cc: Russell King <linux@arm.linux.org.uk> Cc: Viresh Kumar <viresh.kumar@linaro.org> Link: http://lkml.kernel.org/r/1432645896-12588-9-git-send-email-bgolaszewski@baylibre.comSigned-off-by:
Ingo Molnar <mingo@kernel.org>
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Bartosz Golaszewski authored
The former duplicates the functionality of the latter but is neither documented nor arch-independent. Signed-off-by:
Viresh Kumar <viresh.kumar@linaro.org> Acked-by:
Rafael J. Wysocki <rjw@rjwysocki.net> Cc: Benoit Cousson <bcousson@baylibre.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Jean Delvare <jdelvare@suse.de> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Drokin <oleg.drokin@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1432645896-12588-8-git-send-email-bgolaszewski@baylibre.comSigned-off-by:
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Bartosz Golaszewski authored
The former duplicate the functionalities of the latter but are neither documented nor arch-independent. Signed-off-by:
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Bartosz Golaszewski authored
The former duplicates the functionality of the latter but is neither documented nor arch-independent. Signed-off-by:
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Bartosz Golaszewski authored
The former duplicates the functionality of the latter but is neither documented nor arch-independent. Signed-off-by:
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Bartosz Golaszewski authored
The former duplicates the functionality of the latter but is neither documented nor arch-independent. Signed-off-by:
Guenter Roeck <linux@roeck-us.net> Cc: Benoit Cousson <bcousson@baylibre.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Jean Delvare <jdelvare@suse.de> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Drokin <oleg.drokin@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> Cc: Russell King <linux@arm.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Link: http://lkml.kernel.org/r/1432645896-12588-4-git-send-email-bgolaszewski@baylibre.comSigned-off-by:
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Bartosz Golaszewski authored
The documentation on cpu topology seems to be a bit out-of-date. It doesn't mention the **_siblings_list attributes and uses old names for topology_**_cpumask() macros. Add information on missing attributes plus some additional clarifications. Signed-off-by:
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Bartosz Golaszewski authored
Rename topology_thread_cpumask() to topology_sibling_cpumask() for more consistency with scheduler code. Signed-off-by:
Russell King <rmk+kernel@arm.linux.org.uk> Acked-by:
Catalin Marinas <catalin.marinas@arm.com> Cc: Benoit Cousson <bcousson@baylibre.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Jean Delvare <jdelvare@suse.de> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Drokin <oleg.drokin@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> Cc: Russell King <linux@arm.linux.org.uk> Cc: Viresh Kumar <viresh.kumar@linaro.org> Link: http://lkml.kernel.org/r/1432645896-12588-2-git-send-email-bgolaszewski@baylibre.comSigned-off-by:
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Huang Rui authored
A single "default" is fine. Signed-off-by:
Huang Rui <ray.huang@amd.com> [ Fix another typo and reflow comment. ] Signed-off-by:
Borislav Petkov <bp@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1432022472-2224-5-git-send-email-ray.huang@amd.com Link: http://lkml.kernel.org/r/1432628901-18044-7-git-send-email-bp@alien8.deSigned-off-by:
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- 19 May, 2015 31 commits
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Peter Zijlstra authored
A missing include file caused build fail. Reported-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Cc: David Hildenbrand <dahi@linux.vnet.ibm.com> Cc: David.Laight@ACULAB.COM Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Zijlstra (Intel) <peterz@infradead.org> Cc: airlied@linux.ie Cc: akpm@linux-foundation.org Cc: benh@kernel.crashing.org Cc: bigeasy@linutronix.de Cc: borntraeger@de.ibm.com Cc: daniel.vetter@intel.com Cc: heiko.carstens@de.ibm.com Cc: herbert@gondor.apana.org.au Cc: hocko@suse.cz Cc: hughd@google.com Cc: mst@redhat.com Cc: paulus@samba.org Cc: ralf@linux-mips.org Cc: schwidefsky@de.ibm.com Cc: yang.shi@windriver.com Fixes: 70ffdb93 ("mm/fault, arch: Use pagefault_disable() to check for disabled pagefaults in the handler") Signed-off-by:
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Luca Abeni authored
Introduce 4 subsections to make Section 3 more readable. Signed-off-by:
Luca Abeni <luca.abeni@unitn.it> Signed-off-by:
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Luca Abeni authored
sched/dl/Documentation: Clarify the relationship between tasks' deadlines and absolute scheduling deadlines Clarify what is the relationship between tasks' parameters and scheduling parameters, explaining how to set the scheduling parameters so that all the absolute deadlines of a task are respected. Signed-off-by:
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Luca Abeni authored
Add a description of the Dhall's effect, some discussion about schedulability tests for global EDF, and references to real-time literature. Signed-off-by:
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Luca Abeni authored
Add a short discussion about sufficient and necessary schedulability tests, and add a simple example showing that if D_i != P_i then density based tests are only sufficient. Also add some references to scientific papers on schedulability tests for EDF that are both necessary and sufficient, and on their computational complexity. Signed-off-by:
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Luca Abeni authored
The "_i" index is used in this document to to denote a particular task, so "sum_i", "max_i" and "min_i" might be confusing. Signed-off-by:
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Luca Abeni authored
The name "C_i" was used (without previously defining it) instead of "WCET_i". Signed-off-by:
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Luca Abeni authored
Signed-off-by:
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Luca Abeni authored
This file previously mixed American and British English; switch to American for consistency. Signed-off-by:
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Zhiqiang Zhang authored
C_i/min{D_i,T_i}, where T_i is not referred before, should be substituted with C_i/min{D_i,P_i}. Signed-off-by:Zhiqiang Zhang <zhangzhiqiang.zhang@huawei.com> Signed-off-by:
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Rik van Riel authored
It is possible for fbq_classify_rq() to indicate that a CPU has tasks that should be moved to another NUMA node, but for migrate_improves_locality and migrate_degrades_locality to not identify those tasks. This patch always gives preference to preferred node evaluations, and only checks the number of faults when evaluating moves between two non-preferred nodes on a larger NUMA system. On a two node system, the number of faults is never evaluated. Either a task is about to be pulled off its preferred node, or migrated onto it. Signed-off-by:
Rik van Riel <riel@redhat.com> Signed-off-by:
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Peter Zijlstra authored
Currently people use TASK_INTERRUPTIBLE to idle kthreads and wait for 'work' because TASK_UNINTERRUPTIBLE contributes to the loadavg. Having all idle kthreads contribute to the loadavg is somewhat silly. Now mostly this works OK, because kthreads have all their signals masked. However there's a few sites where this is causing problems and TASK_UNINTERRUPTIBLE should be used, except for that loadavg issue. This patch adds TASK_NOLOAD which, when combined with TASK_UNINTERRUPTIBLE avoids the loadavg accounting. As most of imagined usage sites are loops where a thread wants to idle, waiting for work, a helper TASK_IDLE is introduced. Signed-off-by:
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David Hildenbrand authored
As the fault handlers now all rely on the pagefault_disabled() checks and implicit preempt_disable() calls by pagefault_disable() have been made explicit, we can completely rely on the pagefault_disableD counter. So let's no longer touch the preempt count when disabling/enabling pagefaults. After a call to pagefault_disable(), pagefault_disabled() will return true, but in_atomic() won't. Reviewed-and-tested-by:
David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by:
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David Hildenbrand authored
Let's always disable preemption and pagefaults when locking the fpu, so we can be sure that the owner won't change in between. This is a preparation for pagefault_disable() not touching preemption anymore. Reviewed-and-tested-by:
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David Hildenbrand authored
enable_kernel_altivec() has to be called with disabled preemption. Let's make this explicit, to prepare for pagefault_disable() not touching preemption anymore. Reviewed-and-tested-by:
Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David.Laight@ACULAB.COM Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: airlied@linux.ie Cc: akpm@linux-foundation.org Cc: bigeasy@linutronix.de Cc: borntraeger@de.ibm.com Cc: daniel.vetter@intel.com Cc: heiko.carstens@de.ibm.com Cc: herbert@gondor.apana.org.au Cc: hocko@suse.cz Cc: hughd@google.com Cc: mst@redhat.com Cc: paulus@samba.org Cc: ralf@linux-mips.org Cc: schwidefsky@de.ibm.com Cc: yang.shi@windriver.com Link: http://lkml.kernel.org/r/1431359540-32227-14-git-send-email-dahi@linux.vnet.ibm.comSigned-off-by:
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David Hildenbrand authored
As arm64 and arc have no special implementations for !CONFIG_SMP, mutual exclusion doesn't seem to rely on preemption. Let's make it clear in the comments that preemption doesn't have to be disabled when accessing user space in the futex code, so we can remove preempt_disable() from pagefault_disable(). Reviewed-and-tested-by:
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David Hildenbrand authored
The !CONFIG_SMP implementation of futex_atomic_op_inuser() seems to rely on disabled preemption to guarantee mutual exclusion. From commit e589ed23 ("[ARM] 5218/1: arm: improved futex support"): "For UP it's enough to disable preemption to ensure mutual exclusion..." From the code itself: "!SMP, we can work around lack of atomic ops by disabling preemption" Let's make this explicit, to prepare for pagefault_disable() not touching preemption anymore. Reviewed-and-tested-by:
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David Hildenbrand authored
The !CONFIG_SMP implementation of futex_atomic_cmpxchg_inatomic() requires preemption to be disabled to guarantee mutual exclusion. Let's make this explicit. This patch is based on a patch by Sebastian Andrzej Siewior on the -rt branch. Reviewed-and-tested-by:
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David Hildenbrand authored
Let's explicitly disable/enable preemption in the !CONFIG_SMP version of futex_atomic_cmpxchg_inatomic(), to prepare for pagefault_disable() not touching preemption anymore. This is needed for this function to be callable from both, atomic and non-atomic context. Otherwise we might break mutual exclusion when relying on a get_user()/ put_user() implementation. Reviewed-and-tested-by:
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David Hildenbrand authored
Let's explicitly disable/enable preemption in the !CONFIG_SMP version of futex_atomic_op_inuser, to prepare for pagefault_disable() not touching preemption anymore. Otherwise we might break mutual exclusion when relying on a get_user()/ put_user() implementation. Reviewed-and-tested-by:
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David Hildenbrand authored
Now that the pagefault disabled counter is in place, we can replace the in_atomic() check by a pagefault_disabled() checks. Reviewed-and-tested-by:
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David Hildenbrand authored
Introduce faulthandler_disabled() and use it to check for irq context and disabled pagefaults (via pagefault_disable()) in the pagefault handlers. Please note that we keep the in_atomic() checks in place - to detect whether in irq context (in which case preemption is always properly disabled). In contrast, preempt_disable() should never be used to disable pagefaults. With !CONFIG_PREEMPT_COUNT, preempt_disable() doesn't modify the preempt counter, and therefore the result of in_atomic() differs. We validate that condition by using might_fault() checks when calling might_sleep(). Therefore, add a comment to faulthandler_disabled(), describing why this is needed. faulthandler_disabled() and pagefault_disable() are defined in linux/uaccess.h, so let's properly add that include to all relevant files. This patch is based on a patch from Thomas Gleixner. Reviewed-and-tested-by:
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David Hildenbrand authored
k(un)map_coherent relies on pagefault_disable() to also disable preemption. Let's make this explicit, to prepare for pagefault_disable() not touching preemption anymore. This patch is based on a patch by Yang Shi on the -rt tree: "k{un}map_coherent are just called when cpu_has_dc_aliases == 1 with VIPT cache. However, actually, the most modern MIPS processors have PIPT dcache without dcache alias issue. In such case, k{un}map_atomic will be called with preempt enabled." Reviewed-and-tested-by: -
David Hildenbrand authored
The existing code relies on pagefault_disable() implicitly disabling preemption, so that no schedule will happen between kmap_atomic() and kunmap_atomic(). Let's make this explicit, to prepare for pagefault_disable() not touching preemption anymore. Reviewed-and-tested-by:
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David Hildenbrand authored
In general, non-atomic variants of user access functions must not sleep if pagefaults are disabled. Let's update all relevant comments in uaccess code. This also reflects the might_sleep() checks in might_fault(). Reviewed-and-tested-by:
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David Hildenbrand authored
Commit 662bbcb2 ("mm, sched: Allow uaccess in atomic with pagefault_disable()") removed might_sleep() checks for all user access code (that uses might_fault()). The reason was to disable wrong "sleep in atomic" warnings in the following scenario: pagefault_disable() rc = copy_to_user(...) pagefault_enable() Which is valid, as pagefault_disable() increments the preempt counter and therefore disables the pagefault handler. copy_to_user() will not sleep and return an error code if a page is not available. However, as all might_sleep() checks are removed, CONFIG_DEBUG_ATOMIC_SLEEP would no longer detect the following scenario: spin_lock(&lock); rc = copy_to_user(...) spin_unlock(&lock) If the kernel is compiled with preemption turned on, preempt_disable() will make in_atomic() detect disabled preemption. The fault handler would correctly never sleep on user access. However, with preemption turned off, preempt_disable() is usually a NOP (with !CONFIG_PREEMPT_COUNT), therefore in_atomic() will not be able to detect disabled preemption nor disabled pagefaults. The fault handler could sleep. We really want to enable CONFIG_DEBUG_ATOMIC_SLEEP checks for user access functions again, otherwise we can end up with horrible deadlocks. Root of all evil is that pagefault_disable() acts almost as preempt_disable(), depending on preemption being turned on/off. As we now have pagefault_disabled(), we can use it to distinguish whether user acces functions might sleep. Convert might_fault() into a makro that calls __might_fault(), to allow proper file + line messages in case of a might_sleep() warning. Reviewed-and-tested-by:
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David Hildenbrand authored
Until now, pagefault_disable()/pagefault_enabled() used the preempt count to track whether in an environment with pagefaults disabled (can be queried via in_atomic()). This patch introduces a separate counter in task_struct to count the level of pagefault_disable() calls. We'll keep manipulating the preempt count to retain compatibility to existing pagefault handlers. It is now possible to verify whether in a pagefault_disable() envionment by calling pagefault_disabled(). In contrast to in_atomic() it will not be influenced by preempt_enable()/preempt_disable(). This patch is based on a patch from Ingo Molnar. Reviewed-and-tested-by:
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Frederic Weisbecker authored
Now that PREEMPT_ACTIVE implies PREEMPT_DISABLE_OFFSET, ignoring PREEMPT_ACTIVE from in_atomic() check isn't useful anymore. Signed-off-by:
Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by:
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Frederic Weisbecker authored
Signed-off-by:
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Frederic Weisbecker authored
__schedule() disables preemption and some of its callers (the preempt_schedule*() family) also set PREEMPT_ACTIVE. So we have two preempt_count() modifications that could be performed at once. Lets remove the preemption disablement from __schedule() and pull this responsibility to its callers in order to optimize preempt_count() operations in a single place. Suggested-by:
Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by:
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Frederic Weisbecker authored
"CHECK" suggests it's only used as a comparison mask. But now it's used further as a config-conditional preempt disabler offset. Lets disambiguate this name. Signed-off-by:
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