27 May, 2015
3 commits
-
The documentation on cpu topology seems to be a bit out-of-date.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: Bartosz Golaszewski
Cc: Benoit Cousson
Cc: Catalin Marinas
Cc: Fenghua Yu
Cc: Guenter Roeck
Cc: Jean Delvare
Cc: Jonathan Corbet
Cc: Linus Torvalds
Cc: Oleg Drokin
Cc: Peter Zijlstra
Cc: Rafael J. Wysocki
Cc: Russell King
Cc: Thomas Gleixner
Cc: Viresh Kumar
Link: http://lkml.kernel.org/r/1432645896-12588-3-git-send-email-bgolaszewski@baylibre.com
Signed-off-by: Ingo Molnar -
Rename topology_thread_cpumask() to topology_sibling_cpumask()
for more consistency with scheduler code.Signed-off-by: Bartosz Golaszewski
Reviewed-by: Thomas Gleixner
Acked-by: Russell King
Acked-by: Catalin Marinas
Cc: Benoit Cousson
Cc: Fenghua Yu
Cc: Guenter Roeck
Cc: Jean Delvare
Cc: Jonathan Corbet
Cc: Linus Torvalds
Cc: Oleg Drokin
Cc: Peter Zijlstra
Cc: Rafael J. Wysocki
Cc: Russell King
Cc: Viresh Kumar
Link: http://lkml.kernel.org/r/1432645896-12588-2-git-send-email-bgolaszewski@baylibre.com
Signed-off-by: Ingo Molnar -
A single "default" is fine.
Signed-off-by: Huang Rui
[ Fix another typo and reflow comment. ]
Signed-off-by: Borislav Petkov
Cc: Andy Lutomirski
Cc: Borislav Petkov
Cc: Brian Gerst
Cc: Denys Vlasenko
Cc: H. Peter Anvin
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
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.de
Signed-off-by: Ingo Molnar
19 May, 2015
37 commits
-
A missing include file caused build fail.
Reported-by: Ingo Molnar
Signed-off-by: Peter Zijlstra (Intel)
Cc: David Hildenbrand
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: Zijlstra (Intel)
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: 70ffdb9393a7 ("mm/fault, arch: Use pagefault_disable() to check for disabled pagefaults in the handler")
Signed-off-by: Ingo Molnar -
Introduce 4 subsections to make Section 3 more readable.
Signed-off-by: Luca Abeni
Signed-off-by: Peter Zijlstra (Intel)
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: henrik@austad.us
Cc: juri.lelli@gmail.com
Cc: raistlin@linux.it
Link: http://lkml.kernel.org/r/1431954032-16473-10-git-send-email-luca.abeni@unitn.it
Signed-off-by: Ingo Molnar -
…solute 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: Luca Abeni <luca.abeni@unitn.it>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: henrik@austad.us
Cc: juri.lelli@gmail.com
Cc: raistlin@linux.it
Link: http://lkml.kernel.org/r/1431954032-16473-9-git-send-email-luca.abeni@unitn.it
Signed-off-by: Ingo Molnar <mingo@kernel.org> -
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: Luca Abeni
Signed-off-by: Peter Zijlstra (Intel)
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: henrik@austad.us
Cc: juri.lelli@gmail.com
Cc: raistlin@linux.it
Link: http://lkml.kernel.org/r/1431954032-16473-8-git-send-email-luca.abeni@unitn.it
Signed-off-by: Ingo Molnar -
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: Luca Abeni
Signed-off-by: Peter Zijlstra (Intel)
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: henrik@austad.us
Cc: juri.lelli@gmail.com
Cc: raistlin@linux.it
Link: http://lkml.kernel.org/r/1431954032-16473-7-git-send-email-luca.abeni@unitn.it
Signed-off-by: Ingo Molnar -
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: Luca Abeni
Signed-off-by: Peter Zijlstra (Intel)
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: henrik@austad.us
Cc: juri.lelli@gmail.com
Cc: raistlin@linux.it
Link: http://lkml.kernel.org/r/1431954032-16473-6-git-send-email-luca.abeni@unitn.it
Signed-off-by: Ingo Molnar -
The name "C_i" was used (without previously defining it)
instead of "WCET_i".Signed-off-by: Luca Abeni
Signed-off-by: Peter Zijlstra (Intel)
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: henrik@austad.us
Cc: juri.lelli@gmail.com
Cc: raistlin@linux.it
Link: http://lkml.kernel.org/r/1431954032-16473-5-git-send-email-luca.abeni@unitn.it
Signed-off-by: Ingo Molnar -
Signed-off-by: Luca Abeni
Signed-off-by: Peter Zijlstra (Intel)
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: henrik@austad.us
Cc: juri.lelli@gmail.com
Cc: raistlin@linux.it
Link: http://lkml.kernel.org/r/1431954032-16473-4-git-send-email-luca.abeni@unitn.it
Signed-off-by: Ingo Molnar -
This file previously mixed American and British English; switch to American
for consistency.Signed-off-by: Luca Abeni
Signed-off-by: Peter Zijlstra (Intel)
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: henrik@austad.us
Cc: juri.lelli@gmail.com
Cc: raistlin@linux.it
Link: http://lkml.kernel.org/r/1431954032-16473-3-git-send-email-luca.abeni@unitn.it
Signed-off-by: Ingo Molnar -
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
Signed-off-by: Peter Zijlstra (Intel)
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: henrik@austad.us
Cc: juri.lelli@gmail.com
Cc: raistlin@linux.it
Link: http://lkml.kernel.org/r/1431954032-16473-2-git-send-email-luca.abeni@unitn.it
Signed-off-by: Ingo Molnar -
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
Signed-off-by: Peter Zijlstra (Intel)
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: mgorman@suse.de
Link: http://lkml.kernel.org/r/20150514225936.35b91717@annuminas.surriel.com
Signed-off-by: Ingo Molnar -
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: Peter Zijlstra (Intel)
Cc: Julian Anastasov
Cc: Linus Torvalds
Cc: NeilBrown
Cc: Oleg Nesterov
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Signed-off-by: Ingo Molnar -
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: Thomas Gleixner
Signed-off-by: David Hildenbrand
Signed-off-by: Peter Zijlstra (Intel)
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
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
Link: http://lkml.kernel.org/r/1431359540-32227-16-git-send-email-dahi@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar -
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: Thomas Gleixner
Signed-off-by: David Hildenbrand
Signed-off-by: Peter Zijlstra (Intel)
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
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
Link: http://lkml.kernel.org/r/1431359540-32227-15-git-send-email-dahi@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar -
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: Thomas Gleixner
Signed-off-by: David Hildenbrand
Signed-off-by: Peter Zijlstra (Intel)
Acked-by: Benjamin Herrenschmidt
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
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.com
Signed-off-by: Ingo Molnar -
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: Thomas Gleixner
Signed-off-by: David Hildenbrand
Signed-off-by: Peter Zijlstra (Intel)
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
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
Link: http://lkml.kernel.org/r/1431359540-32227-13-git-send-email-dahi@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar -
The !CONFIG_SMP implementation of futex_atomic_op_inuser() seems to rely
on disabled preemption to guarantee mutual exclusion.From commit e589ed23dd27 ("[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: Thomas Gleixner
Signed-off-by: David Hildenbrand
Signed-off-by: Peter Zijlstra (Intel)
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
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
Link: http://lkml.kernel.org/r/1431359540-32227-12-git-send-email-dahi@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar -
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: Thomas Gleixner
Signed-off-by: David Hildenbrand
Signed-off-by: Peter Zijlstra (Intel)
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
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
Link: http://lkml.kernel.org/r/1431359540-32227-11-git-send-email-dahi@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar -
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: Thomas Gleixner
Signed-off-by: David Hildenbrand
Signed-off-by: Peter Zijlstra (Intel)
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
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
Link: http://lkml.kernel.org/r/1431359540-32227-10-git-send-email-dahi@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar -
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: Thomas Gleixner
Signed-off-by: David Hildenbrand
Signed-off-by: Peter Zijlstra (Intel)
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
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
Link: http://lkml.kernel.org/r/1431359540-32227-9-git-send-email-dahi@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar -
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: Thomas Gleixner
Signed-off-by: David Hildenbrand
Signed-off-by: Peter Zijlstra (Intel)
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
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
Link: http://lkml.kernel.org/r/1431359540-32227-8-git-send-email-dahi@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar -
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: Thomas Gleixner
Signed-off-by: David Hildenbrand
Signed-off-by: Peter Zijlstra (Intel)
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
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
Link: http://lkml.kernel.org/r/1431359540-32227-7-git-send-email-dahi@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar -
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: Thomas Gleixner
Signed-off-by: David Hildenbrand
Signed-off-by: Peter Zijlstra (Intel)
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
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
Link: http://lkml.kernel.org/r/1431359540-32227-6-git-send-email-dahi@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar -
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: Thomas Gleixner
Signed-off-by: David Hildenbrand
Signed-off-by: Peter Zijlstra (Intel)
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
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
Link: http://lkml.kernel.org/r/1431359540-32227-5-git-send-email-dahi@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar -
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: Thomas Gleixner
Signed-off-by: David Hildenbrand
Signed-off-by: Peter Zijlstra (Intel)
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
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
Link: http://lkml.kernel.org/r/1431359540-32227-4-git-send-email-dahi@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar -
Commit 662bbcb2747c ("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: Thomas Gleixner
Signed-off-by: David Hildenbrand
Signed-off-by: Peter Zijlstra (Intel)
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
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
Link: http://lkml.kernel.org/r/1431359540-32227-3-git-send-email-dahi@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar -
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: Thomas Gleixner
Signed-off-by: David Hildenbrand
Signed-off-by: Peter Zijlstra (Intel)
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
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
Link: http://lkml.kernel.org/r/1431359540-32227-2-git-send-email-dahi@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar -
Now that PREEMPT_ACTIVE implies PREEMPT_DISABLE_OFFSET, ignoring
PREEMPT_ACTIVE from in_atomic() check isn't useful anymore.Signed-off-by: Frederic Weisbecker
Signed-off-by: Peter Zijlstra (Intel)
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Link: http://lkml.kernel.org/r/1431441711-29753-7-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar -
Signed-off-by: Frederic Weisbecker
Signed-off-by: Peter Zijlstra (Intel)
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Link: http://lkml.kernel.org/r/1431441711-29753-6-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar -
__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
Signed-off-by: Frederic Weisbecker
Signed-off-by: Peter Zijlstra (Intel)
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Link: http://lkml.kernel.org/r/1431441711-29753-5-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar -
"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: Frederic Weisbecker
Signed-off-by: Peter Zijlstra (Intel)
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Link: http://lkml.kernel.org/r/1431441711-29753-4-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar -
Adjust a few comments, and further integrate a few definitions after
the dumb headers copy.Signed-off-by: Frederic Weisbecker
Signed-off-by: Peter Zijlstra (Intel)
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Link: http://lkml.kernel.org/r/1431441711-29753-3-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar -
preempt_mask.h defines all the preempt_count semantics and related
symbols: preempt, softirq, hardirq, nmi, preempt active, need resched,
etc...preempt.h defines the accessors and mutators of preempt_count.
But there is a messy dependency game around those two header files:
* preempt_mask.h includes preempt.h in order to access preempt_count()
* preempt_mask.h defines all preempt_count semantic and symbols
except PREEMPT_NEED_RESCHED that is needed by asm/preempt.h
Thus we need to define it from preempt.h, right before including
asm/preempt.h, instead of defining it to preempt_mask.h with the
other preempt_count symbols. Therefore the preempt_count semantics
happen to be spread out.* We plan to introduce preempt_active_[enter,exit]() to consolidate
preempt_schedule*() code. But we'll need to access both preempt_count
mutators (preempt_count_add()) and preempt_count symbols
(PREEMPT_ACTIVE, PREEMPT_OFFSET). The usual place to define preempt
operations is in preempt.h but then we'll need symbols in
preempt_mask.h which already includes preempt.h. So we end up with
a ressource circle dependency.Lets merge preempt_mask.h into preempt.h to solve these dependency issues.
This way we gather semantic symbols and operation definition of
preempt_count in a single file.This is a dumb copy-paste merge. Further merge re-arrangments are
performed in a subsequent patch to ease review.Signed-off-by: Frederic Weisbecker
Signed-off-by: Peter Zijlstra (Intel)
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Link: http://lkml.kernel.org/r/1431441711-29753-2-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar -
Signed-off-by: Ingo Molnar
-
Two watchdog changes that came through different trees had a non
conflicting conflict, that is, one changed the semantics of a variable
but no actual code conflict happened. So the merge appeared fine, but
the resulting code did not behave as expected.Commit 195daf665a62 ("watchdog: enable the new user interface of the
watchdog mechanism") changes the semantics of watchdog_user_enabled,
which thereafter is only used by the functions introduced by
b3738d293233 ("watchdog: Add watchdog enable/disable all functions").There further appears to be a distinct lack of serialization between
setting and using watchdog_enabled, so perhaps we should wrap the
{en,dis}able_all() things in watchdog_proc_mutex.This patch fixes a s2r failure reported by Michal; which I cannot
readily explain. But this does make the code internally consistent
again.Reported-and-tested-by: Michal Hocko
Signed-off-by: Peter Zijlstra (Intel)
Signed-off-by: Linus Torvalds -
Pull MTD fixes from Brian Norris:
"Two MTD fixes for 4.1:- readtest: the signal-handling code was clobbering the error codes
we should be handling/reporting in this test, rendering it useless.
Noticed by Coverity.- the common SPI NOR flash DT binding (merged for 4.1-rc1) is being
revised, so let's change that before 4.1 is minted"* tag 'for-linus-20150516' of git://git.infradead.org/linux-mtd:
Documentation: dt: mtd: replace "nor-jedec" binding with "jedec, spi-nor"
mtd: readtest: don't clobber error reports
