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Pull RCU changes from Ingo Molnar:
"SRCU changes:
- These include debugging aids, updates that move towards the goal of
permitting srcu_read_lock() and srcu_read_unlock() to be used from
idle and offline CPUs, and a few small fixes.
Changes to rcutorture and to RCU documentation:
- Posted to LKML at https://lkml.org/lkml/2013/1/26/188
Enhancements to uniprocessor handling in tiny RCU:
- Posted to LKML at https://lkml.org/lkml/2013/1/27/2
Tag RCU callbacks with grace-period number to simplify callback
advancement:
- Posted to LKML at https://lkml.org/lkml/2013/1/26/203
Miscellaneous fixes:
- Posted to LKML at https://lkml.org/lkml/2013/1/26/204"
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (27 commits)
srcu: use ACCESS_ONCE() to access sp->completed in srcu_read_lock()
srcu: Update synchronize_srcu_expedited()'s comments
srcu: Update synchronize_srcu()'s comments
srcu: Remove checks preventing idle CPUs from calling srcu_read_lock()
srcu: Remove checks preventing offline CPUs from calling srcu_read_lock()
srcu: Simple cleanup for cleanup_srcu_struct()
srcu: Add might_sleep() annotation to synchronize_srcu()
srcu: Simplify __srcu_read_unlock() via this_cpu_dec()
rcu: Allow rcutorture to be built at low optimization levels
rcu: Make rcutorture's shuffler task shuffle recently added tasks
rcu: Allow TREE_PREEMPT_RCU on UP systems
rcu: Provide RCU CPU stall warnings for tiny RCU
context_tracking: Add comments on interface and internals
rcu: Remove obsolete Kconfig option from comment
rcu: Remove unused code originally used for context tracking
rcu: Consolidate debugging Kconfig options
rcu: Correct 'optimized' to 'optimize' in header comment
rcu: Trace callback acceleration
rcu: Tag callback lists with corresponding grace-period number
rcutorture: Don't compare ptr with 0
...
commit d8e794dfd51c368ed3f686b7f4172830b60ae47b ("workqueue: set
delayed_work->timer function on initialization") exports function
delayed_work_timer_fn() only for GPL modules. This makes delayed-works
unusable for non-GPL modules, because initialization macro now requires
GPL symbol. For example schedule_delayed_work() available for non-GPL.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org # 3.7
This reverts commit ec0c4274e33c0373e476b73e01995c53128f1257.
get_robust_list() is in use and a removal would break existing user
space. With the permission checks in place it's not longer a security
hole. Remove the deprecation warnings.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: akpm@linux-foundation.org
Cc: paul.gortmaker@windriver.com
Cc: davej@redhat.com
Cc: keescook@chromium.org
Cc: stable@vger.kernel.org
Cc: ebiederm@xmission.com
seconds_overflow() is called from hard interrupt context even on
Preempt-RT. This requires the lock to be a raw_spinlock.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The get_timestamp() function is always called with current cpu,
thus using local_clock() would be more appropriate and it makes
the code shorter and cleaner IMHO.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Don Zickus <dzickus@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1356576585-28782-1-git-send-email-namhyung@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The reader side code has no requirement to disable interrupts while
sampling data. The sequence counter is enough to ensure consistency.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull in 'net' to take in the bug fixes that didn't make it into
3.8-final.
Also, deal with the semantic conflict of the change made to
net/ipv6/xfrm6_policy.c A missing rt6->n neighbour release
was added to 'net', but in 'net-next' we no longer cache the
neighbour entries in the ipv6 routes so that change is not
appropriate there.
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit: c1bf08ac "ftrace: Be first to run code modification on modules"
changed ftrace module notifier's priority to INT_MAX in order to
process the ftrace nops before anything else could touch them
(namely kprobes). This was the correct thing to do.
Unfortunately, the ftrace module notifier also contains the ftrace
clean up code. As opposed to the set up code, this code should be
run *after* all the module notifiers have run in case a module is doing
correct clean-up and unregisters its ftrace hooks. Basically, ftrace
needs to do clean up on module removal, as it needs to know about code
being removed so that it doesn't try to modify that code. But after it
removes the module from its records, if a ftrace user tries to remove
a probe, that removal will fail due as the record of that code segment
no longer exists.
Nothing really bad happens if the probe removal is called after ftrace
did the clean up, but the ftrace removal function will return an error.
Correct code (such as kprobes) will produce a WARN_ON() if it fails
to remove the probe. As people get annoyed by frivolous warnings, it's
best to do the ftrace clean up after everything else.
By splitting the ftrace_module_notifier into two notifiers, one that
does the module load setup that is run at high priority, and the other
that is called for module clean up that is run at low priority, the
problem is solved.
Cc: stable@vger.kernel.org
Reported-by: Frank Ch. Eigler <fche@redhat.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
If we pass fd of memory.usage_in_bytes of cgroup A to cgroup.event_control
of cgroup B, then we won't get memory usage notification from A but B!
What's worse, if A and B are in different mount hierarchy, we'll end up
accessing NULL pointer!
Disallow this kind of invalid usage.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Acked-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Tejun Heo <tj@kernel.org>
commit 205a872bd6f9a9a09ef035ef1e90185a8245cc58 ("cgroup: fix lockdep
warning for event_control") solved a deadlock by introducing a new
bug.
Move cgrp->event_list to a temporary list doesn't mean you can traverse
this list locklessly, because at the same time cgroup_event_wake() can
be called and remove the event from the list. The result of this race
is disastrous.
We adopt the way how kvm irqfd code implements race-free event removal,
which is now described in the comments in cgroup_event_wake().
v3:
- call eventfd_signal() no matter it's eventfd close or cgroup removal
that removes the cgroup event.
Acked-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
rename() will change dentry->d_name. The result of this race can
be worse than seeing partially rewritten name, but we might access
a stale pointer because rename() will re-allocate memory to hold
a longer name.
It's safe in the protection of dentry->d_lock.
v2: check NULL dentry before acquiring dentry lock.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org
In cgroup_exit() put_css_set_taskexit() is called without any lock,
which might lead to accessing a freed cgroup:
thread1 thread2
---------------------------------------------
exit()
cgroup_exit()
put_css_set_taskexit()
atomic_dec(cgrp->count);
rmdir();
/* not safe !! */
check_for_release(cgrp);
rcu_read_lock() can be used to make sure the cgroup is alive.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org
bc is the standard tool for multi-precision arithmetic. We switched
to Perl because akpm reported a hard-to-reproduce build hang, which
was very odd because affected and unaffected machines were all running
the same version of GNU bc.
Unfortunately switching to Perl required a really ugly "canning"
mechanism to support Perl < 5.8 installations lacking the Math::BigInt
module.
It was recently pointed out to me that some very old versions of GNU
make had problems with pipes in subshells, which was indeed the
construct used in the Makefile rules in that version of the patch;
Perl didn't need it so switching to Perl fixed the problem for
unrelated reasons. With the problem (hopefully) root-caused, we can
switch back to bc and do the arbitrary-precision arithmetic naturally.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>
PARISC defines /proc/sys/kernel/unaligned-trap to runtime toggle
unaligned access emulation.
The exact mechanics of enablig/disabling are still arch specific, we can
make the sysctl usable by other arches.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
The only difference between wait_for_completion[_timeout]() and
wait_for_completion_io[_timeout]() is that the latter calls
io_schedule_timeout() instead of schedule_timeout() so that the caller
is accounted as waiting for IO, not just sleeping.
These functions can be used for correct iowait time accounting when the
completion struct is actually used for waiting for IO (e.g. completion
of a bio request in the block layer).
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The trinity fuzzer triggered a task_struct reference leak via
clock_nanosleep with CPU_TIMERs. do_cpu_nanosleep() calls
posic_cpu_timer_create(), but misses a corresponding
posix_cpu_timer_del() which leads to the task_struct reference leak.
Reported-and-tested-by: Tommi Rantala <tt.rantala@gmail.com>
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Dave Jones <davej@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20130215100810.GF4392@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Obviously this is a typo and could result in memory leaks if kzalloc
fails on a given cpu.
Signed-off-by: Daniel Baluta <dbaluta@ixiacom.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1360186160-7566-1-git-send-email-dbaluta@ixiacom.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Use the smpboot thread infrastructure. Mark the stopper thread
selfparking and park it after it has finished the take_cpu_down()
work.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Arjan van de Veen <arjan@infradead.org>
Cc: Paul Turner <pjt@google.com>
Cc: Richard Weinberger <rw@linutronix.de>
Cc: Magnus Damm <magnus.damm@gmail.com>
Link: http://lkml.kernel.org/r/20130131120741.686315164@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
To allow the stopper thread being managed by the smpboot thread
infrastructure separate out the task storage from the stopper data
structure.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Arjan van de Veen <arjan@infradead.org>
Cc: Paul Turner <pjt@google.com>
Cc: Richard Weinberger <rw@linutronix.de>
Cc: Magnus Damm <magnus.damm@gmail.com>
Link: http://lkml.kernel.org/r/20130131120741.626690384@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The stop machine threads are still killed when a cpu goes offline. The
reason is that the thread is used to bring the cpu down, so it can't
be parked along with the other per cpu threads.
Allow a per cpu thread to be excluded from automatic parking, so it
can park itself once it's done
Add a create callback function as well.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Arjan van de Veen <arjan@infradead.org>
Cc: Paul Turner <pjt@google.com>
Cc: Richard Weinberger <rw@linutronix.de>
Cc: Magnus Damm <magnus.damm@gmail.com>
Link: http://lkml.kernel.org/r/20130131120741.553993267@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
__ARCH_WANT_SYS_RT_SIGACTION,
__ARCH_WANT_SYS_RT_SIGSUSPEND,
__ARCH_WANT_COMPAT_SYS_RT_SIGSUSPEND,
__ARCH_WANT_COMPAT_SYS_SCHED_RR_GET_INTERVAL - not used anymore
CONFIG_GENERIC_{SIGALTSTACK,COMPAT_RT_SIG{ACTION,QUEUEINFO,PENDING,PROCMASK}} -
can be assumed always set.
workqueue has moved away from global_cwqs to worker_pools and with the
scheduled custom worker pools, wforkqueues will be associated with
pools which don't have anything to do with CPUs. The workqueue code
went through significant amount of changes recently and mass renaming
isn't likely to hurt much additionally. Let's replace 'cpu' with
'pool' so that it reflects the current design.
* s/struct cpu_workqueue_struct/struct pool_workqueue/
* s/cpu_wq/pool_wq/
* s/cwq/pwq/
This patch is purely cosmetic.
Signed-off-by: Tejun Heo <tj@kernel.org>
is_chained_work() was added before current_wq_worker() and implemented
its own ham-fisted way of finding out whether %current is a workqueue
worker - it iterates through all possible workers.
Drop the custom implementation and reimplement using
current_wq_worker().
Signed-off-by: Tejun Heo <tj@kernel.org>
c9e7cf273f ("workqueue: move busy_hash from global_cwq to
worker_pool") incorrectly converted is_chained_work() to use
get_gcwq() inside for_each_gcwq_cpu() while removing get_gcwq().
As cwq might not exist for all possible workqueue CPUs, @cwq can be
NULL and the following cwq deferences can lead to oops.
Fix it by using for_each_cwq_cpu() instead, which is the better one to
use anyway as we only need to check pools that the wq is associated
with.
Signed-off-by: Tejun Heo <tj@kernel.org>
The tracing of ia32 compat system calls has been a bit of a pain as they
use different system call numbers than the 64bit equivalents.
I wrote a simple 'lls' program that lists files. I compiled it as a i686
ELF binary and ran it under a x86_64 box. This is the result:
echo 0 > /debug/tracing/tracing_on
echo 1 > /debug/tracing/events/syscalls/enable
echo 1 > /debug/tracing/tracing_on ; ./lls ; echo 0 > /debug/tracing/tracing_on
grep lls /debug/tracing/trace
[.. skipping calls before TS_COMPAT is set ...]
lls-1127 [005] d... 936.409188: sys_recvfrom(fd: 0, ubuf: 4d560fc4, size: 0, flags: 8048034, addr: 8, addr_len: f7700420)
lls-1127 [005] d... 936.409190: sys_recvfrom -> 0x8a77000
lls-1127 [005] d... 936.409211: sys_lgetxattr(pathname: 0, name: 1000, value: 3, size: 22)
lls-1127 [005] d... 936.409215: sys_lgetxattr -> 0xf76ff000
lls-1127 [005] d... 936.409223: sys_dup2(oldfd: 4d55ae9b, newfd: 4)
lls-1127 [005] d... 936.409228: sys_dup2 -> 0xfffffffffffffffe
lls-1127 [005] d... 936.409236: sys_newfstat(fd: 4d55b085, statbuf: 80000)
lls-1127 [005] d... 936.409242: sys_newfstat -> 0x3
lls-1127 [005] d... 936.409243: sys_removexattr(pathname: 3, name: ffcd0060)
lls-1127 [005] d... 936.409244: sys_removexattr -> 0x0
lls-1127 [005] d... 936.409245: sys_lgetxattr(pathname: 0, name: 19614, value: 1, size: 2)
lls-1127 [005] d... 936.409248: sys_lgetxattr -> 0xf76e5000
lls-1127 [005] d... 936.409248: sys_newlstat(filename: 3, statbuf: 19614)
lls-1127 [005] d... 936.409249: sys_newlstat -> 0x0
lls-1127 [005] d... 936.409262: sys_newfstat(fd: f76fb588, statbuf: 80000)
lls-1127 [005] d... 936.409279: sys_newfstat -> 0x3
lls-1127 [005] d... 936.409279: sys_close(fd: 3)
lls-1127 [005] d... 936.421550: sys_close -> 0x200
lls-1127 [005] d... 936.421558: sys_removexattr(pathname: 3, name: ffcd00d0)
lls-1127 [005] d... 936.421560: sys_removexattr -> 0x0
lls-1127 [005] d... 936.421569: sys_lgetxattr(pathname: 4d564000, name: 1b1abc, value: 5, size: 802)
lls-1127 [005] d... 936.421574: sys_lgetxattr -> 0x4d564000
lls-1127 [005] d... 936.421575: sys_capget(header: 4d70f000, dataptr: 1000)
lls-1127 [005] d... 936.421580: sys_capget -> 0x0
lls-1127 [005] d... 936.421580: sys_lgetxattr(pathname: 4d710000, name: 3000, value: 3, size: 812)
lls-1127 [005] d... 936.421589: sys_lgetxattr -> 0x4d710000
lls-1127 [005] d... 936.426130: sys_lgetxattr(pathname: 4d713000, name: 2abc, value: 3, size: 32)
lls-1127 [005] d... 936.426141: sys_lgetxattr -> 0x4d713000
lls-1127 [005] d... 936.426145: sys_newlstat(filename: 3, statbuf: f76ff3f0)
lls-1127 [005] d... 936.426146: sys_newlstat -> 0x0
lls-1127 [005] d... 936.431748: sys_lgetxattr(pathname: 0, name: 1000, value: 3, size: 22)
Obviously I'm not calling newfstat with a fd of 4d55b085. The calls are
obviously incorrect, and confusing.
Other efforts have been made to fix this:
https://lkml.org/lkml/2012/3/26/367
But the real solution is to rewrite the syscall internals and come up
with a fixed solution. One that doesn't require all the kluge that the
current solution has.
Thus for now, instead of outputting incorrect data, simply ignore them.
With this patch the changes now have:
#> grep lls /debug/tracing/trace
#>
Compat system calls simply are not traced. If users need compat
syscalls, then they should just use the raw syscall tracepoints.
For an architecture to make their compat syscalls ignored, it must
define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS (done in asm/ftrace.h) and also
define an arch_trace_is_compat_syscall() function that will return true
if the current task should ignore tracing the syscall.
I want to stress that this change does not affect actual syscalls in any
way, shape or form. It is only used within the tracing system and
doesn't interfere with the syscall logic at all. The changes are
consolidated nicely into trace_syscalls.c and asm/ftrace.h.
I had to make one small modification to asm/thread_info.h and that was
to remove the include of asm/ftrace.h. As asm/ftrace.h required the
current_thread_info() it was causing include hell. That include was
added back in 2008 when the function graph tracer was added:
commit caf4b323 "tracing, x86: add low level support for ftrace return tracing"
It does not need to be included there.
Link: http://lkml.kernel.org/r/1360703939.21867.99.camel@gandalf.local.home
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
We're forgetting to reenable local interrupts on an error path.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Reported-by: Josh Boyer <jwboyer@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 12ad100046: "clockevents: Add generic timer broadcast function"
made tick_device_uses_broadcast set up the generic broadcast function
for dummy devices (where !tick_device_is_functional(dev)), but neglected
to set up the broadcast function for devices that stop in low power
states (with the CLOCK_EVT_FEAT_C3STOP flag).
When these devices enter low power states they will not have the generic
broadcast function assigned, and will bring down the system when an
attempt is made to broadcast to them.
This patch ensures that the broadcast function is also assigned for
devices which require broadcast in low power states.
Reported-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: nico@linaro.org
Cc: Marc.Zyngier@arm.com
Cc: Will.Deacon@arm.com
Cc: santosh.shilimkar@ti.com
Cc: john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
At present, the value of timeout for freezing is 20s, which is
meaningless in case that one thread is frozen with mutex locked
and another thread is trying to lock the mutex, as this time of
freezing will fail unavoidably.
And if there is no new wakeup event registered, the system will
waste at most 20s for such meaningless trying of freezing.
With this patch, the value of timeout can be configured to smaller
value, so such meaningless trying of freezing will be aborted in
earlier time, and later freezing can be also triggered in earlier
time. And more power will be saved.
In normal case on mobile phone, it costs real little time to freeze
processes. On some platform, it only costs about 20ms to freeze
user space processes and 10ms to freeze kernel freezable threads.
Signed-off-by: Liu Chuansheng <chuansheng.liu@intel.com>
Signed-off-by: Li Fei <fei.li@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
PM_SUSPEND_FREEZE state is a general state that
does not need any platform specific support, it equals
frozen processes + suspended devices + idle processors.
Compared with PM_SUSPEND_MEMORY,
PM_SUSPEND_FREEZE saves less power
because the system is still in a running state.
PM_SUSPEND_FREEZE has less resume latency because it does not
touch BIOS, and the processors are in idle state.
Compared with RTPM/idle,
PM_SUSPEND_FREEZE saves more power as
1. the processor has longer sleep time because processes are frozen.
The deeper c-state the processor supports, more power saving we can get.
2. PM_SUSPEND_FREEZE uses system suspend code path, thus we can get
more power saving from the devices that does not have good RTPM support.
This state is useful for
1) platforms that do not have STR, or have a broken STR.
2) platforms that have an extremely low power idle state,
which can be used to replace STR.
The following describes how PM_SUSPEND_FREEZE state works.
1. echo freeze > /sys/power/state
2. the processes are frozen.
3. all the devices are suspended.
4. all the processors are blocked by a wait queue
5. all the processors idles and enters (Deep) c-state.
6. an interrupt fires.
7. a processor is woken up and handles the irq.
8. if it is a general event,
a) the irq handler runs and quites.
b) goto step 4.
9. if it is a real wake event, say, power button pressing, keyboard touch, mouse moving,
a) the irq handler runs and activate the wakeup source
b) wakeup_source_activate() notifies the wait queue.
c) system starts resuming from PM_SUSPEND_FREEZE
10. all the devices are resumed.
11. all the processes are unfrozen.
12. system is back to working.
Known Issue:
The wakeup of this new PM_SUSPEND_FREEZE state may behave differently
from the previous suspend state.
Take ACPI platform for example, there are some GPEs that only enabled
when the system is in sleep state, to wake the system backk from S3/S4.
But we are not touching these GPEs during transition to PM_SUSPEND_FREEZE.
This means we may lose some wake event.
But on the other hand, as we do not disable all the Interrupts during
PM_SUSPEND_FREEZE, we may get some extra "wakeup" Interrupts, that are
not available for S3/S4.
The patches has been tested on an old Sony laptop, and here are the results:
Average Power:
1. RPTM/idle for half an hour:
14.8W, 12.6W, 14.1W, 12.5W, 14.4W, 13.2W, 12.9W
2. Freeze for half an hour:
11W, 10.4W, 9.4W, 11.3W 10.5W
3. RTPM/idle for three hours:
11.6W
4. Freeze for three hours:
10W
5. Suspend to Memory:
0.5~0.9W
Average Resume Latency:
1. RTPM/idle with a black screen: (From pressing keyboard to screen back)
Less than 0.2s
2. Freeze: (From pressing power button to screen back)
2.50s
3. Suspend to Memory: (From pressing power button to screen back)
4.33s
>From the results, we can see that all the platforms should benefit from
this patch, even if it does not have Low Power S0.
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
wait_for_kprobe_optimizer() seems largely broken. It uses
optimizer_comp which is never re-initialized, so
wait_for_kprobe_optimizer() will never wait for anything once
kprobe_optimizer() finishes all pending jobs for the first time.
Also, aside from completion, delayed_work_pending() is %false once
kprobe_optimizer() starts execution and wait_for_kprobe_optimizer()
won't wait for it.
Reimplement it so that it flushes optimizing_work until
[un]optimizing_lists are empty. Note that this also makes
optimizing_work execute immediately if someone's waiting for it, which
is the nicer behavior.
Only compile tested.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
At init time, if the system time is "warped" forward in warp_clock()
it will differ from the hardware clock by sys_tz.tz_minuteswest. This time
difference is not taken into account when ntp updates the hardware clock,
and this causes the system time to jump forward by this offset every reboot.
The kernel must take this offset into account when writing the system time
to the hardware clock in the ntp code. This patch adds
persistent_clock_is_local which indicates that an offset has been applied
in warp_clock() and accounts for the "warp" before writing the hardware
clock.
x86 does not have this problem as rtc writes are software limited to a
+/-15 minute window relative to the current rtc time. Other arches, such
as powerpc, however do a full synchronization of the system time to the
rtc and will see this problem.
[v2]: generated against tip/timers/core
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Synchronize with 'net' in order to sort out some l2tp, wireless, and
ipv6 GRE fixes that will be built on top of in 'net-next'.
Signed-off-by: David S. Miller <davem@davemloft.net>
uprobe_perf_open/close call the costly uprobe_apply() every time,
we can avoid it if:
- "nr_systemwide != 0" is not changed.
- There is another process/thread with the same ->mm.
- copy_proccess() does inherit_event(). dup_mmap() preserves the
inserted breakpoints.
- event->attr.enable_on_exec == T, we can rely on uprobe_mmap()
called by exec/mmap paths.
- tp_target is exiting. Only _close() checks PF_EXITING, I don't
think TRACE_REG_PERF_OPEN can hit the dying task too often.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Change uprobe_trace_func() and uprobe_perf_func() to return "int". Change
uprobe_dispatcher() to return "trace_ret | perf_ret" although this is not
needed, currently TP_FLAG_TRACE/TP_FLAG_PROFILE are mutually exclusive.
The only functional change is that uprobe_perf_func() checks the filtering
too and returns UPROBE_HANDLER_REMOVE if nobody wants to trace current.
Testing:
# perf probe -x /lib/libc.so.6 syscall
# perf record -e probe_libc:syscall -i perl -e 'fork; syscall -1 for 1..10; wait'
# perf report --show-total-period
100.00% 10 perl libc-2.8.so [.] syscall
Before this patch:
# cat /sys/kernel/debug/tracing/uprobe_profile
/lib/libc.so.6 syscall 20
A child process doesn't have a counter, but still it hits this breakoint
"copied" by dup_mmap().
After the patch:
# cat /sys/kernel/debug/tracing/uprobe_profile
/lib/libc.so.6 syscall 11
The child process hits this int3 only once and does unapply_uprobe().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Finally implement uprobe_perf_filter() which checks ->nr_systemwide or
->perf_events to figure out whether we need to insert the breakpoint.
uprobe_perf_open/close are changed to do uprobe_apply(true/false) when
the new perf event comes or goes away.
Note that currently this is very suboptimal:
- uprobe_register() called by TRACE_REG_PERF_REGISTER becomes a
heavy nop, consumer->filter() always returns F at this stage.
As it was already discussed we need uprobe_register_only() to
avoid the costly register_for_each_vma() when possible.
- uprobe_apply() is oftenly overkill. Unless "nr_systemwide != 0"
changes we need uprobe_apply_mm(), unapply_uprobe() is almost
what we need.
- uprobe_apply() can be simply avoided sometimes, see the next
changes.
Testing:
# perf probe -x /lib/libc.so.6 syscall
# perl -e 'syscall -1 while 1' &
[1] 530
# perf record -e probe_libc:syscall perl -e 'syscall -1 for 1..10; sleep 1'
# perf report --show-total-period
100.00% 10 perl libc-2.8.so [.] syscall
Before this patch:
# cat /sys/kernel/debug/tracing/uprobe_profile
/lib/libc.so.6 syscall 79291
A huge ->nrhit == 79291 reflects the fact that the background process
530 constantly hits this breakpoint too, even if doesn't contribute to
the output.
After the patch:
# cat /sys/kernel/debug/tracing/uprobe_profile
/lib/libc.so.6 syscall 10
This shows that only the target process was punished by int3.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Introduce "struct trace_uprobe_filter" which records the "active"
perf_event's attached to ftrace_event_call. For the start we simply
use list_head, we can optimize this later if needed. For example, we
do not really need to record an event with ->parent != NULL, we can
rely on parent->child_list. And we can certainly do some optimizations
for the case when 2 events have the same ->tp_target or tp_target->mm.
Change trace_uprobe_register() to process TRACE_REG_PERF_OPEN/CLOSE
and add/del this perf_event to the list.
We can probably avoid any locking, but lets start with the "obvioulsy
correct" trace_uprobe_filter->rwlock which protects everything.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Currently it is not possible to change the filtering constraints after
uprobe_register(), so a consumer can not, say, start to trace a task/mm
which was previously filtered out, or remove the no longer needed bp's.
Introduce uprobe_apply() which simply does register_for_each_vma() again
to consult uprobe_consumer->filter() and install/remove the breakpoints.
The only complication is that register_for_each_vma() can no longer
assume that uprobe->consumers should be consulter if is_register == T,
so we change it to accept "struct uprobe_consumer *new" instead.
Unlike uprobe_register(), uprobe_apply(true) doesn't do "unregister" if
register_for_each_vma() fails, it is up to caller to handle the error.
Note: we probably need to cleanup the current interface, it is strange
that uprobe_apply/unregister need inode/offset. We should either change
uprobe_register() to return "struct uprobe *", or add a private ->uprobe
member in uprobe_consumer. And in the long term uprobe_apply() should
take a single argument, uprobe or consumer, even "bool add" should go
away.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
sys_perf_event_open()->perf_init_event(event) is called before
find_get_context(event), this means that event->ctx == NULL when
class->reg(TRACE_REG_PERF_REGISTER/OPEN) is called and thus it
can't know if this event is per-task or system-wide.
This patch adds hw_perf_event->tp_target for PERF_TYPE_TRACEPOINT,
this is analogous to PERF_TYPE_BREAKPOINT/bp_target we already have.
The patch also moves ->bp_target up so that it can overlap with the
new member, this can help the compiler to generate the better code.
trace_uprobe_register() will use it for prefiltering to avoid the
unnecessary breakpoints in mm's we do not want to trace.
->tp_target doesn't have its own reference, but we can rely on the
fact that either sys_perf_event_open() holds a reference, or it is
equal to event->ctx->task. So this pointer is always valid until
free_event().
Also add the "struct list_head tp_list" into this union. It is not
strictly necessary, but it can simplify the next changes and we can
add it for free.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Move tu->nhit++ from uprobe_trace_func() to uprobe_dispatcher().
->nhit counts how many time we hit the breakpoint inserted by this
uprobe, we do not want to loose this info if uprobe was enabled by
sys_perf_event_open().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
trace_uprobe->consumer and "struct uprobe_trace_consumer" add the
unnecessary indirection and complicate the code for no reason.
This patch simply embeds uprobe_consumer into "struct trace_uprobe",
all other changes only fix the compilation errors.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
probe_event_enable/disable() check tu->consumer != NULL to avoid the
wrong uprobe_register/unregister().
We are going to kill this pointer and "struct uprobe_trace_consumer",
so we add the new helper, is_trace_uprobe_enabled(), which can rely
on TP_FLAG_TRACE/TP_FLAG_PROFILE instead.
Note: the current logic doesn't look optimal, it is not clear why
TP_FLAG_TRACE/TP_FLAG_PROFILE are mutually exclusive, we will probably
change this later.
Also kill the unused TP_FLAG_UPROBE.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
probe_event_enable/disable() check tu->inode != NULL at the start.
This is ugly, if igrab() can fail create_trace_uprobe() should not
succeed and "postpone" the failure.
And S_ISREG(inode->i_mode) check added by d24d7dbf is not safe.
Note: alloc_uprobe() should probably check igrab() != NULL as well.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
