To date, we've tried hard to confine filesystem support for capabilities
to the security modules. This has left a lot of the code in
kernel/capability.c in a state where it looks like it supports something
that filesystem support for capabilities actually suppresses when the LSM
security/commmoncap.c code runs. What is left is a lot of code that uses
sub-optimal locking in the main kernel
With this change we refactor the main kernel code and make it explicit
which locks are needed and that the only remaining kernel races in this
area are associated with non-filesystem capability code.
Signed-off-by: Andrew G. Morgan <morgan@kernel.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add basic support for more than one hstate in hugetlbfs. This is the key
to supporting multiple hugetlbfs page sizes at once.
- Rather than a single hstate, we now have an array, with an iterator
- default_hstate continues to be the struct hstate which we use by default
- Add functions for architectures to register new hstates
[akpm@linux-foundation.org: coding-style fixes]
Acked-by: Adam Litke <agl@us.ibm.com>
Acked-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch reserves huge pages at mmap() time for MAP_PRIVATE mappings in
a similar manner to the reservations taken for MAP_SHARED mappings. The
reserve count is accounted both globally and on a per-VMA basis for
private mappings. This guarantees that a process that successfully calls
mmap() will successfully fault all pages in the future unless fork() is
called.
The characteristics of private mappings of hugetlbfs files behaviour after
this patch are;
1. The process calling mmap() is guaranteed to succeed all future faults until
it forks().
2. On fork(), the parent may die due to SIGKILL on writes to the private
mapping if enough pages are not available for the COW. For reasonably
reliable behaviour in the face of a small huge page pool, children of
hugepage-aware processes should not reference the mappings; such as
might occur when fork()ing to exec().
3. On fork(), the child VMAs inherit no reserves. Reads on pages already
faulted by the parent will succeed. Successful writes will depend on enough
huge pages being free in the pool.
4. Quotas of the hugetlbfs mount are checked at reserve time for the mapper
and at fault time otherwise.
Before this patch, all reads or writes in the child potentially needs page
allocations that can later lead to the death of the parent. This applies
to reads and writes of uninstantiated pages as well as COW. After the
patch it is only a write to an instantiated page that causes problems.
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Adam Litke <agl@us.ibm.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch adds proper extern declarations for five variables in
include/linux/vmstat.h
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'sched/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
sched: hrtick_enabled() should use cpu_active()
sched, x86: clean up hrtick implementation
sched: fix build error, provide partition_sched_domains() unconditionally
sched: fix warning in inc_rt_tasks() to not declare variable 'rq' if it's not needed
cpu hotplug: Make cpu_active_map synchronization dependency clear
cpu hotplug, sched: Introduce cpu_active_map and redo sched domain managment (take 2)
sched: rework of "prioritize non-migratable tasks over migratable ones"
sched: reduce stack size in isolated_cpu_setup()
Revert parts of "ftrace: do not trace scheduler functions"
Fixed up conflicts in include/asm-x86/thread_info.h (due to the
TIF_SINGLESTEP unification vs TIF_HRTICK_RESCHED removal) and
kernel/sched_fair.c (due to cpu_active_map vs for_each_cpu_mask_nr()
introduction).
* 'cpus4096-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (31 commits)
NR_CPUS: Replace NR_CPUS in speedstep-centrino.c
cpumask: Provide a generic set of CPUMASK_ALLOC macros, FIXUP
NR_CPUS: Replace NR_CPUS in cpufreq userspace routines
NR_CPUS: Replace per_cpu(..., smp_processor_id()) with __get_cpu_var
NR_CPUS: Replace NR_CPUS in arch/x86/kernel/genapic_flat_64.c
NR_CPUS: Replace NR_CPUS in arch/x86/kernel/genx2apic_uv_x.c
NR_CPUS: Replace NR_CPUS in arch/x86/kernel/cpu/proc.c
NR_CPUS: Replace NR_CPUS in arch/x86/kernel/cpu/mcheck/mce_64.c
cpumask: Optimize cpumask_of_cpu in lib/smp_processor_id.c, fix
cpumask: Use optimized CPUMASK_ALLOC macros in the centrino_target
cpumask: Provide a generic set of CPUMASK_ALLOC macros
cpumask: Optimize cpumask_of_cpu in lib/smp_processor_id.c
cpumask: Optimize cpumask_of_cpu in kernel/time/tick-common.c
cpumask: Optimize cpumask_of_cpu in drivers/misc/sgi-xp/xpc_main.c
cpumask: Optimize cpumask_of_cpu in arch/x86/kernel/ldt.c
cpumask: Optimize cpumask_of_cpu in arch/x86/kernel/io_apic_64.c
cpumask: Replace cpumask_of_cpu with cpumask_of_cpu_ptr
Revert "cpumask: introduce new APIs"
cpumask: make for_each_cpu_mask a bit smaller
net: Pass reference to cpumask variable in net/sunrpc/svc.c
...
Fix up trivial conflicts in drivers/cpufreq/cpufreq.c manually
* 'core/softlockup-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
softlockup: fix invalid proc_handler for softlockup_panic
softlockup: fix watchdog task wakeup frequency
softlockup: fix watchdog task wakeup frequency
softlockup: show irqtrace
softlockup: print a module list on being stuck
softlockup: fix NMI hangs due to lock race - 2.6.26-rc regression
softlockup: fix false positives on nohz if CPU is 100% idle for more than 60 seconds
softlockup: fix softlockup_thresh fix
softlockup: fix softlockup_thresh unaligned access and disable detection at runtime
softlockup: allow panic on lockup
This adds a fast path for 64-bit syscall entry and exit when
TIF_SYSCALL_AUDIT is set, but no other kind of syscall tracing.
This path does not need to save and restore all registers as
the general case of tracing does. Avoiding the iret return path
when syscall audit is enabled helps performance a lot.
Signed-off-by: Roland McGrath <roland@redhat.com>
Since 15a647eba9 set_irq_wake returned -ENXIO
if another device had it already enabled. Zero is the right value to
return in this case. Moreover the change to desc->status was not reverted
if desc->chip->set_wake returned an error.
Signed-off-by: Uwe Kleine-König <Uwe.Kleine-Koenig@digi.com>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andrew Morton reported this s390 allmodconfig build failure:
kernel/built-in.o: In function `hrtick_start_fair':
sched.c:(.text+0x69c6): undefined reference to `__smp_call_function_single'
the reason is that s390 is not a generic-ipi SMP platform yet, while
the hrtick code relies on it. Fix the dependency.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
remove CONFIG_KMOD from core kernel code
remove CONFIG_KMOD from lib
remove CONFIG_KMOD from sparc64
rework try_then_request_module to do less in non-modular kernels
remove mention of CONFIG_KMOD from documentation
make CONFIG_KMOD invisible
modules: Take a shortcut for checking if an address is in a module
module: turn longs into ints for module sizes
Shrink struct module: CONFIG_UNUSED_SYMBOLS ifdefs
module: reorder struct module to save space on 64 bit builds
module: generic each_symbol iterator function
module: don't use stop_machine for waiting rmmod
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6: (79 commits)
arm: bus_id -> dev_name() and dev_set_name() conversions
sparc64: fix up bus_id changes in sparc core code
3c59x: handle pci_name() being const
MTD: handle pci_name() being const
HP iLO driver
sysdev: Convert the x86 mce tolerant sysdev attribute to generic attribute
sysdev: Add utility functions for simple int/ulong variable sysdev attributes
sysdev: Pass the attribute to the low level sysdev show/store function
driver core: Suppress sysfs warnings for device_rename().
kobject: Transmit return value of call_usermodehelper() to caller
sysfs-rules.txt: reword API stability statement
debugfs: Implement debugfs_remove_recursive()
HOWTO: change email addresses of James in HOWTO
always enable FW_LOADER unless EMBEDDED=y
uio-howto.tmpl: use unique output names
uio-howto.tmpl: use standard copyright/legal markings
sysfs: don't call notify_change
sysdev: fix debugging statements in registration code.
kobject: should use kobject_put() in kset-example
kobject: reorder kobject to save space on 64 bit builds
...
Always compile request_module when the kernel allows modules.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This patch keeps track of the boundaries of module allocation, in
order to speed up module_text_address().
Inspired by Arjan's version, which required arch-specific defines:
Various pieces of the kernel (lockdep, latencytop, etc) tend
to store backtraces, sometimes at a relatively high
frequency. In itself this isn't a big performance deal (after
all you're using diagnostics features), but there have been
some complaints from people who have over 100 modules loaded
that this is a tad too slow.
This is due to the new backtracer code which looks at every
slot on the stack to see if it's a kernel/module text address,
so that's 1024 slots. 1024 times 100 modules... that's a lot
of list walking.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This shrinks module.o and each *.ko file.
And finally, structure members which hold length of module
code (four such members there) and count of symbols
are converted from longs to ints.
We cannot possibly have a module where 32 bits won't
be enough to hold such counts.
For one, module loading checks module size for sanity
before loading, so such insanely big module will fail
that test first.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
module.c and module.h conatains code for finding
exported symbols which are declared with EXPORT_UNUSED_SYMBOL,
and this code is compiled in even if CONFIG_UNUSED_SYMBOLS is not set
and thus there can be no EXPORT_UNUSED_SYMBOLs in modules anyway
(because EXPORT_UNUSED_SYMBOL(x) are compiled out to nothing then).
This patch adds required #ifdefs.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Introduce an each_symbol() iterator to avoid duplicating the knowledge
about the 5 different sections containing symbols. Currently only
used by find_symbol(), but will be used by symbol_put_addr() too.
(Includes NULL ptr deref fix by Jiri Kosina <jkosina@suse.cz>)
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jiri Kosina <jkosina@suse.cz>
rmmod has a little-used "-w" option, meaning that instead of failing if the
module is in use, it should block until the module becomes unused.
In this case, we don't need to use stop_machine: Max Krasnyansky
indicated that would be useful for SystemTap which loads/unloads new
modules frequently.
Cc: Max Krasnyansky <maxk@qualcomm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This allow to dynamically generate attributes and share show/store
functions between attributes. Right now most attributes are generated
by special macros and lots of duplicated code. With the attribute
passed it's instead possible to attach some data to the attribute
and then use that in shared low level functions to do different things.
I need this for the dynamically generated bank attributes in the x86
machine check code, but it'll allow some further cleanups.
I converted all users in tree to the new show/store prototype. It's a single
huge patch to avoid unbisectable sections.
Runtime tested: x86-32, x86-64
Compiled only: ia64, powerpc
Not compile tested/only grep converted: sh, arm, avr32
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
random uvesafb failures were reported against Gentoo:
http://bugs.gentoo.org/show_bug.cgi?id=222799
and Mihai Moldovan bisected it back to:
> 8f4d37ec07 is first bad commit
> commit 8f4d37ec07
> Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Date: Fri Jan 25 21:08:29 2008 +0100
>
> sched: high-res preemption tick
Linus suspected it to be hrtick + vm86 interaction and observed:
> Btw, Peter, Ingo: I think that commit is doing bad things. They aren't
> _incorrect_ per se, but they are definitely bad.
>
> Why?
>
> Using random _TIF_WORK_MASK flags is really impolite for doing
> "scheduling" work. There's a reason that arch/x86/kernel/entry_32.S
> special-cases the _TIF_NEED_RESCHED flag: we don't want to exit out of
> vm86 mode unnecessarily.
>
> See the "work_notifysig_v86" label, and how it does that
> "save_v86_state()" thing etc etc.
Right, I never liked having to fiddle with those TIF flags. Initially I
needed it because the hrtimer base lock could not nest in the rq lock.
That however is fixed these days.
Currently the only reason left to fiddle with the TIF flags is remote
wakeups. We cannot program a remote cpu's hrtimer. I've been thinking
about using the new and improved IPI function call stuff to implement
hrtimer_start_on().
However that does require that smp_call_function_single(.wait=0) works
from interrupt context - /me looks at the latest series from Jens - Yes
that does seem to be supported, good.
Here's a stab at cleaning this stuff up ...
Mihai reported test success as well.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: Mihai Moldovan <ionic@ionic.de>
Cc: Michal Januszewski <spock@gentoo.org>
Cc: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Optimize various places where a pointer to the cpumask_of_cpu value
will result in reducing stack pressure.
Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* This patch replaces the dangerous lvalue version of cpumask_of_cpu
with new cpumask_of_cpu_ptr macros. These are patterned after the
node_to_cpumask_ptr macros.
In general terms, if there is a cpumask_of_cpu_map[] then a pointer to
the cpumask_of_cpu_map[cpu] entry is used. The cpumask_of_cpu_map
is provided when there is a large NR_CPUS count, reducing
greatly the amount of code generated and stack space used for
cpumask_of_cpu(). The pointer to the cpumask_t value is needed for
calling set_cpus_allowed_ptr() to reduce the amount of stack space
needed to pass the cpumask_t value.
If there isn't a cpumask_of_cpu_map[], then a temporary variable is
declared and filled in with value from cpumask_of_cpu(cpu) as well as
a pointer variable pointing to this temporary variable. Afterwards,
the pointer is used to reference the cpumask value. The compiler
will optimize out the extra dereference through the pointer as well
as the stack space used for the pointer, resulting in identical code.
A good example of the orthogonal usages is in net/sunrpc/svc.c:
case SVC_POOL_PERCPU:
{
unsigned int cpu = m->pool_to[pidx];
cpumask_of_cpu_ptr(cpumask, cpu);
*oldmask = current->cpus_allowed;
set_cpus_allowed_ptr(current, cpumask);
return 1;
}
case SVC_POOL_PERNODE:
{
unsigned int node = m->pool_to[pidx];
node_to_cpumask_ptr(nodecpumask, node);
*oldmask = current->cpus_allowed;
set_cpus_allowed_ptr(current, nodecpumask);
return 1;
}
Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The type of softlockup_panic is int, but the proc_handler is
proc_doulongvec_minmax(). This handler is for unsigned long.
This handler should be proc_dointvec_minmax().
Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Jack Ren and Eric Miao tracked down the following long standing
problem in the NOHZ code:
scheduler switch to idle task
enable interrupts
Window starts here
----> interrupt happens (does not set NEED_RESCHED)
irq_exit() stops the tick
----> interrupt happens (does set NEED_RESCHED)
return from schedule()
cpu_idle(): preempt_disable();
Window ends here
The interrupts can happen at any point inside the race window. The
first interrupt stops the tick, the second one causes the scheduler to
rerun and switch away from idle again and we end up with the tick
disabled.
The fact that it needs two interrupts where the first one does not set
NEED_RESCHED and the second one does made the bug obscure and extremly
hard to reproduce and analyse. Kudos to Jack and Eric.
Solution: Limit the NOHZ functionality to the idle loop to make sure
that we can not run into such a situation ever again.
cpu_idle()
{
preempt_disable();
while(1) {
tick_nohz_stop_sched_tick(1); <- tell NOHZ code that we
are in the idle loop
while (!need_resched())
halt();
tick_nohz_restart_sched_tick(); <- disables NOHZ mode
preempt_enable_no_resched();
schedule();
preempt_disable();
}
}
In hindsight we should have done this forever, but ...
/me grabs a large brown paperbag.
Debugged-by: Jack Ren <jack.ren@marvell.com>,
Debugged-by: eric miao <eric.y.miao@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Fix inc_rt_tasks() to not declare variable 'rq' if it's not needed. It is
declared if CONFIG_SMP or CONFIG_RT_GROUP_SCHED, but only used if CONFIG_SMP.
This is a consequence of patch 1f11eb6a8b plus
patch 1100ac91b6.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This goes on top of the cpu_active_map (take 2) patch.
Currently we depend on the stop_machine to provide nescessesary
synchronization for the cpu_active_map updates.
As Dmitry Adamushko pointed this is fragile and is not much clearer
than the previous scheme. In other words we do not want to depend on
the internal stop machine operation here.
So make the synchronization rules clear by doing synchronize_sched()
after clearing out cpu active bit.
Tested on quad-Core2 with:
while true; do
for i in 1 2 3; do
echo 0 > /sys/devices/system/cpu/cpu$i/online
done
for i in 1 2 3; do
echo 1 > /sys/devices/system/cpu/cpu$i/online
done
done
and
stress -c 200
No lockdep, preempt or other complaints.
Signed-off-by: Max Krasnyansky <maxk@qualcomm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This is based on Linus' idea of creating cpu_active_map that prevents
scheduler load balancer from migrating tasks to the cpu that is going
down.
It allows us to simplify domain management code and avoid unecessary
domain rebuilds during cpu hotplug event handling.
Please ignore the cpusets part for now. It needs some more work in order
to avoid crazy lock nesting. Although I did simplfy and unify domain
reinitialization logic. We now simply call partition_sched_domains() in
all the cases. This means that we're using exact same code paths as in
cpusets case and hence the test below cover cpusets too.
Cpuset changes to make rebuild_sched_domains() callable from various
contexts are in the separate patch (right next after this one).
This not only boots but also easily handles
while true; do make clean; make -j 8; done
and
while true; do on-off-cpu 1; done
at the same time.
(on-off-cpu 1 simple does echo 0/1 > /sys/.../cpu1/online thing).
Suprisingly the box (dual-core Core2) is quite usable. In fact I'm typing
this on right now in gnome-terminal and things are moving just fine.
Also this is running with most of the debug features enabled (lockdep,
mutex, etc) no BUG_ONs or lockdep complaints so far.
I believe I addressed all of the Dmitry's comments for original Linus'
version. I changed both fair and rt balancer to mask out non-active cpus.
And replaced cpu_is_offline() with !cpu_active() in the main scheduler
code where it made sense (to me).
Signed-off-by: Max Krasnyanskiy <maxk@qualcomm.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Gregory Haskins <ghaskins@novell.com>
Cc: dmitry.adamushko@gmail.com
Cc: pj@sgi.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
(1) handle in a generic way all cases when a newly woken-up task is
not migratable (not just a corner case when "rt_se->nr_cpus_allowed ==
1")
(2) if current is to be preempted, then make sure "p" will be picked
up by pick_next_task_rt().
i.e. move task's group at the head of its list as well.
currently, it's not a case for the group-scheduling case as described
here: http://www.ussg.iu.edu/hypermail/linux/kernel/0807.0/0134.html
Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Gregory Haskins <ghaskins@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
ftrace: do not trace library functions
ftrace: do not trace scheduler functions
ftrace: fix lockup with MAXSMP
ftrace: fix merge buglet
Xen save/restore needs bits of code enabled by PM_SLEEP, and PM_SLEEP
depends on PM. So make XEN_SAVE_RESTORE depend on PM and PM_SLEEP
depend on XEN_SAVE_RESTORE.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This fixes an arcane bug that we think was a regression introduced
by commit b2b2cbc4b2. When a parent
ignores SIGCHLD (or uses SA_NOCLDWAIT), its children would self-reap
but they don't if it's using ptrace on them. When the parent thread
later exits and ceases to ptrace a child but leaves other live
threads in the parent's thread group, any zombie children are left
dangling. The fix makes them self-reap then, as they would have
done earlier if ptrace had not been in use.
Signed-off-by: Roland McGrath <roland@redhat.com>
This reverts the effect of commit f2cc3eb133
"do_wait: fix security checks". That change reverted the effect of commit
7324328446. The rationale for the original
commit still stands. The inconsistent treatment of children hidden by
ptrace was an unintended omission in the original change and in no way
invalidates its purpose.
This makes do_wait return the error returned by security_task_wait()
(usually -EACCES) in place of -ECHILD when there are some children the
caller would be able to wait for if not for the permission failure. A
permission error will give the user a clue to look for security policy
problems, rather than for mysterious wait bugs.
Signed-off-by: Roland McGrath <roland@redhat.com>
ptrace no longer fiddles with the children/sibling links, and the
old ptrace_children list is gone. Now ptrace, whether of one's own
children or another's via PTRACE_ATTACH, just uses the new ptraced
list instead.
There should be no user-visible difference that matters. The only
change is the order in which do_wait() sees multiple stopped
children and stopped ptrace attachees. Since wait_task_stopped()
was changed earlier so it no longer reorders the children list, we
already know this won't cause any new problems.
Signed-off-by: Roland McGrath <roland@redhat.com>
This breaks out the guts of do_wait into three subfunctions.
The control flow is less nonobvious without so much goto.
do_wait_thread and ptrace_do_wait contain the main work of the outer loop.
wait_consider_task contains the main work of the inner loop.
Signed-off-by: Roland McGrath <roland@redhat.com>
* 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6: (72 commits)
Revert "x86/PCI: ACPI based PCI gap calculation"
PCI: remove unnecessary volatile in PCIe hotplug struct controller
x86/PCI: ACPI based PCI gap calculation
PCI: include linux/pm_wakeup.h for device_set_wakeup_capable
PCI PM: Fix pci_prepare_to_sleep
x86/PCI: Fix PCI config space for domains > 0
Fix acpi_pm_device_sleep_wake() by providing a stub for CONFIG_PM_SLEEP=n
PCI: Simplify PCI device PM code
PCI PM: Introduce pci_prepare_to_sleep and pci_back_from_sleep
PCI ACPI: Rework PCI handling of wake-up
ACPI: Introduce new device wakeup flag 'prepared'
ACPI: Introduce acpi_device_sleep_wake function
PCI: rework pci_set_power_state function to call platform first
PCI: Introduce platform_pci_power_manageable function
ACPI: Introduce acpi_bus_power_manageable function
PCI: make pci_name use dev_name
PCI: handle pci_name() being const
PCI: add stub for pci_set_consistent_dma_mask()
PCI: remove unused arch pcibios_update_resource() functions
PCI: fix pci_setup_device()'s sprinting into a const buffer
...
Fixed up conflicts in various files (arch/x86/kernel/setup_64.c,
arch/x86/pci/irq.c, arch/x86/pci/pci.h, drivers/acpi/sleep/main.c,
drivers/pci/pci.c, drivers/pci/pci.h, include/acpi/acpi_bus.h) from x86
and ACPI updates manually.
We can avoid taking the BKL in snapshot_ioctl() if pm_mutex is used to prevent
the ioctls from being executed concurrently.
In addition, although it is only possible to open /dev/snapshot once, the task
which has done that may spawn a child that will inherit the open descriptor,
so in theory they can call snapshot_write(), snapshot_read() and
snapshot_release() concurrently. pm_mutex can also be used for mutual
exclusion in such cases.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Len Brown <len.brown@intel.com>
Push BKL down into ioctl handlers - snapshot device.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
The freezer currently attempts to distinguish kernel threads from
user space tasks by checking if their mm pointer is unset and it
does not send fake signals to kernel threads. However, there are
kernel threads, mostly related to networking, that behave like
user space tasks and may want to be sent a fake signal to be frozen.
Introduce the new process flag PF_FREEZER_NOSIG that will be set
by default for all kernel threads and make the freezer only send
fake signals to the tasks having PF_FREEZER_NOSIG unset. Provide
the set_freezable_with_signal() function to be called by the kernel
threads that want to be sent a fake signal for freezing.
This patch should not change the freezer's observable behavior.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Len Brown <len.brown@intel.com>
The ACPI device node for the cpu has already been unregistered
when acpi_processor_handle_eject is called.
Thus we should offline the cpu and continue, rather than a failure here.
http://bugzilla.kernel.org/show_bug.cgi?id=9772
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
This reverts commit 6fbbec428c8e7bb617da2e8a589af2e97bcf3bc4.
Rafael doesnt like it - it breaks various assumptions.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Xen save/restore requires PM_SLEEP to be set without requiring
SUSPEND or HIBERNATION.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When a GFP_ATOMIC allocation fails, it falls back to allocating the
data on the stack and converting it to a waiting call.
Make sure we actually wait in this case.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'generic-ipi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (22 commits)
generic-ipi: more merge fallout
generic-ipi: merge fix
x86, visws: use mach-default/entry_arch.h
x86, visws: fix generic-ipi build
generic-ipi: fixlet
generic-ipi: fix s390 build bug
generic-ipi: fix linux-next tree build failure
fix: "smp_call_function: get rid of the unused nonatomic/retry argument"
fix: "smp_call_function: get rid of the unused nonatomic/retry argument"
fix "smp_call_function: get rid of the unused nonatomic/retry argument"
on_each_cpu(): kill unused 'retry' parameter
smp_call_function: get rid of the unused nonatomic/retry argument
sh: convert to generic helpers for IPI function calls
parisc: convert to generic helpers for IPI function calls
mips: convert to generic helpers for IPI function calls
m32r: convert to generic helpers for IPI function calls
arm: convert to generic helpers for IPI function calls
alpha: convert to generic helpers for IPI function calls
ia64: convert to generic helpers for IPI function calls
powerpc: convert to generic helpers for IPI function calls
...
Fix trivial conflicts due to rcu updates in kernel/rcupdate.c manually
* 'timers/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: add PCI ID for 6300ESB force hpet
x86: add another PCI ID for ICH6 force-hpet
kernel-paramaters: document pmtmr= command line option
acpi_pm clccksource: fix printk format warning
nohz: don't stop idle tick if softirqs are pending.
pmtmr: allow command line override of ioport
nohz: reduce jiffies polling overhead
hrtimer: Remove unused variables in ktime_divns()
hrtimer: remove warning in hres_timers_resume
posix-timers: print RT watchdog message
* 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm: (241 commits)
[ARM] 5171/1: ep93xx: fix compilation of modules using clocks
[ARM] 5133/2: at91sam9g20 defconfig file
[ARM] 5130/4: Support for the at91sam9g20
[ARM] 5160/1: IOP3XX: gpio/gpiolib support
[ARM] at91: Fix NAND FLASH timings for at91sam9x evaluation kits.
[ARM] 5084/1: zylonite: Register AC97 device
[ARM] 5085/2: PXA: Move AC97 over to the new central device declaration model
[ARM] 5120/1: pxa: correct platform driver names for PXA25x and PXA27x UDC drivers
[ARM] 5147/1: pxaficp_ir: drop pxa_gpio_mode calls, as pin setting
[ARM] 5145/1: PXA2xx: provide api to control IrDA pins state
[ARM] 5144/1: pxaficp_ir: cleanup includes
[ARM] pxa: remove pxa_set_cken()
[ARM] pxa: allow clk aliases
[ARM] Feroceon: don't disable BPU on boot
[ARM] Orion: LED support for HP mv2120
[ARM] Orion: add RD88F5181L-FXO support
[ARM] Orion: add RD88F5181L-GE support
[ARM] Orion: add Netgear WNR854T support
[ARM] s3c2410_defconfig: update for current build
[ARM] Acer n30: Minor style and indentation fixes.
...
* 'core/softirq' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
softirq: remove irqs_disabled warning from local_bh_enable
softirq: remove initialization of static per-cpu variable
Remove argument from open_softirq which is always NULL
* 'core/printk' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, generic: mark early_printk as asmlinkage
printk: export console_drivers
printk: remember the message level for multi-line output
printk: refactor processing of line severity tokens
printk: don't prefer unsuited consoles on registration
printk: clean up recursion check related static variables
namespacecheck: more kernel/printk.c fixes
namespacecheck: fix kernel printk.c
* 'core/locking' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
lockdep: fix kernel/fork.c warning
lockdep: fix ftrace irq tracing false positive
lockdep: remove duplicate definition of STATIC_LOCKDEP_MAP_INIT
lockdep: add lock_class information to lock_chain and output it
lockdep: add lock_class information to lock_chain and output it
lockdep: output lock_class key instead of address for forward dependency output
__mutex_lock_common: use signal_pending_state()
mutex-debug: check mutex magic before owner
Fixed up conflict in kernel/fork.c manually
* 'sched/new-API-sched_setscheduler' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
sched: add new API sched_setscheduler_nocheck: add a flag to control access checks
* 'tracing/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (228 commits)
ftrace: build fix for ftraced_suspend
ftrace: separate out the function enabled variable
ftrace: add ftrace_kill_atomic
ftrace: use current CPU for function startup
ftrace: start wakeup tracing after setting function tracer
ftrace: check proper config for preempt type
ftrace: trace schedule
ftrace: define function trace nop
ftrace: move sched_switch enable after markers
ftrace: prevent ftrace modifications while being kprobe'd, v2
fix "ftrace: store mcount address in rec->ip"
mmiotrace broken in linux-next (8-bit writes only)
ftrace: avoid modifying kprobe'd records
ftrace: freeze kprobe'd records
kprobes: enable clean usage of get_kprobe
ftrace: store mcount address in rec->ip
ftrace: build fix with gcc 4.3
namespacecheck: fixes
ftrace: fix "notrace" filtering priority
ftrace: fix printout
...
* 'sched/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (76 commits)
sched_clock: and multiplier for TSC to gtod drift
sched_clock: record TSC after gtod
sched_clock: only update deltas with local reads.
sched_clock: fix calculation of other CPU
sched_clock: stop maximum check on NO HZ
sched_clock: widen the max and min time
sched_clock: record from last tick
sched: fix accounting in task delay accounting & migration
sched: add avg-overlap support to RT tasks
sched: terminate newidle balancing once at least one task has moved over
sched: fix warning
sched: build fix
sched: sched_clock_cpu() based cpu_clock(), lockdep fix
sched: export cpu_clock
sched: make sched_{rt,fair}.c ifdefs more readable
sched: bias effective_load() error towards failing wake_affine().
sched: incremental effective_load()
sched: correct wakeup weight calculations
sched: fix mult overflow
sched: update shares on wakeup
...
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6: (25 commits)
security: remove register_security hook
security: remove dummy module fix
security: remove dummy module
security: remove unused sb_get_mnt_opts hook
LSM/SELinux: show LSM mount options in /proc/mounts
SELinux: allow fstype unknown to policy to use xattrs if present
security: fix return of void-valued expressions
SELinux: use do_each_thread as a proper do/while block
SELinux: remove unused and shadowed addrlen variable
SELinux: more user friendly unknown handling printk
selinux: change handling of invalid classes (Was: Re: 2.6.26-rc5-mm1 selinux whine)
SELinux: drop load_mutex in security_load_policy
SELinux: fix off by 1 reference of class_to_string in context_struct_compute_av
SELinux: open code sidtab lock
SELinux: open code load_mutex
SELinux: open code policy_rwlock
selinux: fix endianness bug in network node address handling
selinux: simplify ioctl checking
SELinux: enable processes with mac_admin to get the raw inode contexts
Security: split proc ptrace checking into read vs. attach
...
* 'for-linus' of git://git.kernel.dk/linux-2.6-block: (37 commits)
splice: fix generic_file_splice_read() race with page invalidation
ramfs: enable splice write
drivers/block/pktcdvd.c: avoid useless memset
cdrom: revert commit 22a9189 (cdrom: use kmalloced buffers instead of buffers on stack)
scsi: sr avoids useless buffer allocation
block: blk_rq_map_kern uses the bounce buffers for stack buffers
block: add blk_queue_update_dma_pad
DAC960: push down BKL
pktcdvd: push BKL down into driver
paride: push ioctl down into driver
block: use get_unaligned_* helpers
block: extend queue_flag bitops
block: request_module(): use format string
Add bvec_merge_data to handle stacked devices and ->merge_bvec()
block: integrity flags can't use bit ops on unsigned short
cmdfilter: extend default read filter
sg: fix odd style (extra parenthesis) introduced by cmd filter patch
block: add bounce support to blk_rq_map_user_iov
cfq-iosched: get rid of enable_idle being unused warning
allow userspace to modify scsi command filter on per device basis
...
Enable security modules to distinguish reading of process state via
proc from full ptrace access by renaming ptrace_may_attach to
ptrace_may_access and adding a mode argument indicating whether only
read access or full attach access is requested. This allows security
modules to permit access to reading process state without granting
full ptrace access. The base DAC/capability checking remains unchanged.
Read access to /proc/pid/mem continues to apply a full ptrace attach
check since check_mem_permission() already requires the current task
to already be ptracing the target. The other ptrace checks within
proc for elements like environ, maps, and fds are changed to pass the
read mode instead of attach.
In the SELinux case, we model such reading of process state as a
reading of a proc file labeled with the target process' label. This
enables SELinux policy to permit such reading of process state without
permitting control or manipulation of the target process, as there are
a number of cases where programs probe for such information via proc
but do not need to be able to control the target (e.g. procps,
lsof, PolicyKit, ConsoleKit). At present we have to choose between
allowing full ptrace in policy (more permissive than required/desired)
or breaking functionality (or in some cases just silencing the denials
via dontaudit rules but this can hide genuine attacks).
This version of the patch incorporates comments from Casey Schaufler
(change/replace existing ptrace_may_attach interface, pass access
mode), and Chris Wright (provide greater consistency in the checking).
Note that like their predecessors __ptrace_may_attach and
ptrace_may_attach, the __ptrace_may_access and ptrace_may_access
interfaces use different return value conventions from each other (0
or -errno vs. 1 or 0). I retained this difference to avoid any
changes to the caller logic but made the difference clearer by
changing the latter interface to return a bool rather than an int and
by adding a comment about it to ptrace.h for any future callers.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: James Morris <jmorris@namei.org>
When callbacks are moved from offline cpu to this cpu,
the qlen field of this rdp should be updated.
[ Paul E. McKenney: ]
The effect of this bug would be for force_quiescent_state() to be invoked
when it should not and vice versa -- wasting cycles in the first case
and letting RCU callbacks remain piled up in the second case. The bug
is thus "benign" in that it does not result in premature grace-period
termination, but should of course be fixed nonetheless.
Preemption is disabled by the caller's get_cpu_var(), so we are guaranteed
to remain on the same CPU, as required. The local_irq_disable() is indeed
needed, otherwise, an interrupt might invoke call_rcu() or call_rcu_bh(),
which could cause that interrupt's increment of ->qlen to be lost.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Commit f18f982ab ("sched: CPU hotplug events must not destroy scheduler
domains created by the cpusets") introduced a hotplug-related problem as
described below:
Upon CPU_DOWN_PREPARE,
update_sched_domains() -> detach_destroy_domains(&cpu_online_map)
does the following:
/*
* Force a reinitialization of the sched domains hierarchy. The domains
* and groups cannot be updated in place without racing with the balancing
* code, so we temporarily attach all running cpus to the NULL domain
* which will prevent rebalancing while the sched domains are recalculated.
*/
The sched-domains should be rebuilt when a CPU_DOWN ops. has been
completed, effectively either upon CPU_DEAD{_FROZEN} (upon success) or
CPU_DOWN_FAILED{_FROZEN} (upon failure -- restore the things to their
initial state). That's what update_sched_domains() also does but only
for !CPUSETS case.
With f18f982ab, sched-domains' reinitialization is delegated to
CPUSETS code:
cpuset_handle_cpuhp() -> common_cpu_mem_hotplug_unplug() ->
rebuild_sched_domains()
Being called for CPU_UP_PREPARE and if its callback is called after
update_sched_domains()), it just negates all the work done by
update_sched_domains() -- i.e. a soon-to-be-offline cpu is included in
the sched-domains and that makes it visible for the load-balancer
while the CPU_DOWN ops. is in progress.
__migrate_live_tasks() moves the tasks off a 'dead' cpu (it's already
"offline" when this function is called).
try_to_wake_up() is called for one of these tasks from another CPU ->
the load-balancer (wake_idle()) picks up a "dead" CPU and places the
task on it. Then e.g. BUG_ON(rq->nr_running) detects this a bit later
-> oops.
Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Tested-by: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Paul Menage <menage@google.com>
Cc: Max Krasnyansky <maxk@qualcomm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: miaox@cn.fujitsu.com
Cc: rostedt@goodmis.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
fix:
kernel/trace/ftrace.c:1615: error: 'ftraced_suspend' undeclared (first use in this function)
kernel/trace/ftrace.c:1615: error: (Each undeclared identifier is reported only once
kernel/trace/ftrace.c:1615: error: for each function it appears in.)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The sched_clock code currently tries to keep all CPU clocks of all CPUS
somewhat in sync. At every clock tick it records the gtod clock and
uses that and jiffies and the TSC to calculate a CPU clock that tries to
stay in sync with all the other CPUs.
ftrace depends heavily on this timer and it detects when this timer
"jumps". One problem is that the TSC and the gtod also drift.
When the TSC is 0.1% faster or slower than the gtod it is very noticeable
in ftrace. To help compensate for this, I've added a multiplier that
tries to keep the CPU clock updating at the same rate as the gtod.
I've tried various ways to get it to be in sync and this ended up being
the most reliable. At every scheduler tick we calculate the new multiplier:
multi = delta_gtod / delta_TSC
This means we perform a 64 bit divide at the tick (once a HZ). A shift
is used to handle the accuracy.
Other methods that failed due to dynamic HZ are:
(not used) multi += (gtod - tsc) / delta_gtod
(not used) multi += (gtod - (last_tsc + delta_tsc)) / delta_gtod
as well as other variants.
This code still allows for a slight drift between TSC and gtod, but
it keeps the damage down to a minimum.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
To read the gtod we need to grab the xtime lock for read. Reading the gtod
before the TSC can cause a bigger gab if the xtime lock is contended.
This patch simply reverses the order to read the TSC after the gtod.
The locking in the reading of the gtod handles any barriers one might
think is needed.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Reading the CPU clock should try to stay accurate within the CPU.
By reading the CPU clock from another CPU and updating the deltas can
cause unneeded jumps when reading from the local CPU.
This patch changes the code to update the last read TSC only when read
from the local CPU.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The algorithm to calculate the 'now' of another CPU is not correct.
At each scheduler tick, each CPU records the last sched_clock and
gtod (tick_raw and tick_gtod respectively). If the TSC is somewhat the
same in speed between two clocks the algorithm would be:
tick_gtod1 + (now1 - tick_raw1) = tick_gtod2 + (now2 - tick_raw2)
To calculate now2 we would have:
now2 = (tick_gtod1 - tick_gtod2) + (tick_raw2 - tick_raw1) + now1
Currently the algorithm is:
now2 = (tick_gtod1 - tick_gtod2) + (tick_raw1 - tick_raw2) + now1
This solves most of the rest of the issues I've had with timestamps in
ftace.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Working with ftrace I would get large jumps of 11 millisecs or more with
the clock tracer. This killed the latencing timings of ftrace and also
caused the irqoff self tests to fail.
What was happening is with NO_HZ the idle would stop the jiffy counter and
before the jiffy counter was updated the sched_clock would have a bad
delta jiffies to compare with the gtod with the maximum.
The jiffies would stop and the last sched_tick would record the last gtod.
On wakeup, the sched clock update would compare the gtod + delta jiffies
(which would be zero) and compare it to the TSC. The TSC would have
correctly (with a stable TSC) moved forward several jiffies. But because the
jiffies has not been updated yet the clock would be prevented from moving
forward because it would appear that the TSC jumped too far ahead.
The clock would then virtually stop, until the jiffies are updated. Then
the next sched clock update would see that the clock was very much behind
since the delta jiffies is now correct. This would then jump the clock
forward by several jiffies.
This caused ftrace to report several milliseconds of interrupts off
latency at every resume from NO_HZ idle.
This patch adds hooks into the nohz code to disable the checking of the
maximum clock update when nohz is in effect. It resumes the max check
when nohz has updated the jiffies again.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
With keeping the max and min sched time within one jiffy of the gtod clock
was too tight. Just before a schedule tick the max could easily be hit, as
well as just after a schedule_tick the min could be hit. This caused the
clock to jump around by a jiffy.
This patch widens the minimum to
last gtod + (delta_jiffies ? delta_jiffies - 1 : 0) * TICK_NSECS
and the maximum to
last gtod + (2 + delta_jiffies) * TICK_NSECS
This keeps the minum to gtod or if one jiffy less than delta jiffies
and the maxim 2 jiffies ahead of gtod. This may cause unstable TSCs to be
a bit more sporadic, but it helps keep a clock with a stable TSC working well.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The sched_clock code tries to keep within the gtod time by one tick (jiffy).
The current code mistakenly keeps track of the delta jiffies between
updates of the clock, where the the delta is used to compare with the
number of jiffies that have past since an update of the gtod. The gtod is
updated at each schedule tick not each sched_clock update. After one
jiffy passes the clock is updated fine. But the delta is taken from the
last update so if the next update happens before the next tick the delta
jiffies used will be incorrect.
This patch changes the code to check the delta of jiffies between ticks
and not updates to match the comparison of the updates with the gtod.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Currently the function tracer uses the global tracer_enabled variable that
is used to keep track if the tracer is enabled or not. The function tracing
startup needs to be separated out, otherwise the internal happenings of
the tracer startup is also recorded.
This patch creates a ftrace_function_enabled variable to all the starting
of the function traces to happen after everything has been started.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
