Commit graph

399522 commits

Author SHA1 Message Date
Paul E. McKenney
4102adab91 rcu: Move RCU-related source code to kernel/rcu directory
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
2013-10-15 12:53:31 -07:00
Paul E. McKenney
2529973309 Merge branch 'idle.2013.09.25a' into HEAD
idle.2013.09.25a: Topic branch for idle entry-/exit-related changes.
2013-10-15 12:49:59 -07:00
Paul E. McKenney
25e03a74e4 Merge branch 'gp.2013.09.25a' into HEAD
gp.2013.09.25a: Topic branch for grace-period updates.
2013-10-15 12:47:04 -07:00
Paul E. McKenney
460aebac73 Merge branches 'doc.2013.09.25b' and 'fixes.2013.09.23b' into HEAD
doc.2013.09.25b: Topic branch for documentation updates.
fixes.2013.09.23b: Topic branch for miscellaneous fixes.
2013-10-15 12:44:33 -07:00
Michael Opdenacker
4b0d3f0fde rcu: Fix occurrence of "the the" in checklist.txt
Signed-off-by: Michael Opdenacker <michael.opdenacker@free-electrons.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
[ paulmck: Add "then" as suggested by Josh Triplett. ]
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2013-09-25 10:07:02 -07:00
Paul E. McKenney
64f26e5c86 kthread: Add pointer to vmstat-avoidance patch
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2013-09-25 06:49:46 -07:00
Paul E. McKenney
64d3b7a1d5 rcu: Update stall-warning documentation
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2013-09-25 06:49:37 -07:00
Paul E. McKenney
5c173eb8bc rcu: Consistent rcu_is_watching() naming
The old rcu_is_cpu_idle() function is just __rcu_is_watching() with
preemption disabled.  This commit therefore renames rcu_is_cpu_idle()
to rcu_is_watching.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2013-09-25 06:45:06 -07:00
Paul E. McKenney
f9ffc31ebd rcu: Change EXPORT_SYMBOL() to EXPORT_SYMBOL_GPL()
Commit e6b80a3b (rcu: Detect illegal rcu dereference in extended
quiescent state) exported the pre-existing rcu_is_cpu_idle() function
using EXPORT_SYMBOL().  However, this is inconsistent with the remaining
exports from RCU, which are all EXPORT_SYMBOL_GPL().  The current state
of affairs means that a non-GPL module could use rcu_is_cpu_idle(),
but in a CONFIG_TREE_PREEMPT_RCU=y kernel would be unable to invoke
rcu_read_lock() and rcu_read_unlock().

This commit therefore makes rcu_is_cpu_idle()'s export be consistent
with the rest of RCU, namely EXPORT_SYMBOL_GPL().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2013-09-25 06:44:56 -07:00
Paul E. McKenney
cc6783f788 rcu: Is it safe to enter an RCU read-side critical section?
There is currently no way for kernel code to determine whether it
is safe to enter an RCU read-side critical section, in other words,
whether or not RCU is paying attention to the currently running CPU.
Given the large and increasing quantity of code shared by the idle loop
and non-idle code, the this shortcoming is becoming increasingly painful.

This commit therefore adds __rcu_is_watching(), which returns true if
it is safe to enter an RCU read-side critical section on the currently
running CPU.  This function is quite fast, using only a __this_cpu_read().
However, the caller must disable preemption.

Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2013-09-25 06:44:41 -07:00
Paul E. McKenney
c337f8f58e rcu: Throttle invoke_rcu_core() invocations due to non-lazy callbacks
If a non-lazy callback arrives on a CPU that has previously gone idle
with no non-lazy callbacks, invoke_rcu_core() forces the RCU core to
run.  However, it does not update the conditions, which could result
in several closely spaced invocations of the RCU core, which in turn
could result in an excessively high context-switch rate and resulting
high overhead.

This commit therefore updates the ->all_lazy and ->nonlazy_posted_snap
fields to prevent closely spaced invocations.

Reported-by: Tibor Billes <tbilles@gmx.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Tibor Billes <tbilles@gmx.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2013-09-25 06:44:33 -07:00
Paul E. McKenney
c229828ca6 rcu: Throttle rcu_try_advance_all_cbs() execution
The rcu_try_advance_all_cbs() function is invoked on each attempted
entry to and every exit from idle.  If this function determines that
there are callbacks ready to invoke, the caller will invoke the RCU
core, which in turn will result in a pair of context switches.  If a
CPU enters and exits idle extremely frequently, this can result in
an excessive number of context switches and high CPU overhead.

This commit therefore causes rcu_try_advance_all_cbs() to throttle
itself, refusing to do work more than once per jiffy.

Reported-by: Tibor Billes <tbilles@gmx.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Tibor Billes <tbilles@gmx.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2013-09-25 06:44:25 -07:00
Paul E. McKenney
7a497c963e rcu: Remove redundant code from rcu_cleanup_after_idle()
The rcu_try_advance_all_cbs() function returns a bool saying whether or
not there are callbacks ready to invoke, but rcu_cleanup_after_idle()
rechecks this regardless.  This commit therefore uses the value returned
by rcu_try_advance_all_cbs() instead of making rcu_cleanup_after_idle()
do this recheck.

Reported-by: Tibor Billes <tbilles@gmx.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Tibor Billes <tbilles@gmx.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2013-09-25 06:44:03 -07:00
Kirill Tkhai
5d5a08003d rcu: Fix CONFIG_RCU_NOCB_CPU_ALL panic on machines with sparse CPU mask
Some architectures have sparse cpu mask. UltraSparc's cpuinfo for example:

CPU0: online
CPU2: online

So, set only possible CPUs when CONFIG_RCU_NOCB_CPU_ALL is enabled.

Also, check that user passes right 'rcu_nocbs=' option.

Signed-off-by: Kirill Tkhai <tkhai@yandex.ru>
CC: Dipankar Sarma <dipankar@in.ibm.com>
[ paulmck: Fix pr_info() issue noted by scripts/checkpatch.pl. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-09-23 14:11:11 -07:00
Paul E. McKenney
15f5191b6a rcu: Avoid sparse warnings in rcu_nocb_wake trace event
The event-tracing macros do not like bool tracing arguments, so this
commit makes them be of type char.  This change has the knock-on effect
of making it illegal to pass a pointer into one of these arguments, so
also change rcutiny's first call to trace_rcu_batch_end() to convert
from pointer to boolean, prefixing with "!!".

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-09-23 09:18:17 -07:00
Paul E. McKenney
69a79bb12a rcu: Track rcu_nocb_kthread()'s sleeping and awakening
This commit adds event traces to track all of rcu_nocb_kthread()'s
blocking and awakening.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-09-23 09:18:16 -07:00
Paul E. McKenney
756cbf6bef rcu: Distinguish between NOCB and non-NOCB rcu_callback trace events
One way to distinguish between NOCB and non-NOCB rcu_callback trace
events is that the former always print zero for the lazy and non-lazy
queue lengths.  Unfortunately, this also means that we cannot see the NOCB
queue lengths.  This commit therefore accesses the NOCB queue lengths,
but negates them.  NOCB rcu_callback trace events should therefore have
negative queue lengths.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
[ paulmck: Match operand size per kbuild test robot's advice. ]
2013-09-23 09:18:14 -07:00
Paul E. McKenney
9261dd0da6 rcu: Add tracing for rcuo no-CBs CPU wakeup handshake
Lost wakeups from call_rcu() to the rcuo kthreads can result in hangs
that are difficult to diagnose.  This commit therefore adds tracing to
help pin down the cause of these hangs.

Reported-by: Clark Williams <williams@redhat.com>
Reported-by: Carsten Emde <C.Emde@osadl.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
[ paulmck: Add const per kbuild test robot's advice. ]
2013-09-23 09:18:13 -07:00
Paul E. McKenney
bb311eccbd rcu: Add tracing of normal (non-NOCB) grace-period requests
This commit adds tracing to the normal grace-period request points.
These are rcu_gp_cleanup(), which checks for the need for another
grace period at the end of the previous grace period, and
rcu_start_gp_advanced(), which restarts RCU's state machine after
an idle period.  These trace events are intended to help track down
bugs where RCU remains idle despite there being work for it to do.

Reported-by: Clark Williams <williams@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-09-23 09:18:08 -07:00
Paul E. McKenney
63c4db78e8 rcu: Add tracing to rcu_gp_kthread()
This commit adds tracing to the rcu_gp_kthread() function in order to
help trace down hangs potentially involving this kthread.

Reported-by: Clark Williams <williams@redhat.com>
Reported-by: Carsten Emde <C.Emde@osadl.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-09-23 09:16:14 -07:00
Paul E. McKenney
591c6d1710 rcu: Flag lockless access to ->gp_flags with ACCESS_ONCE()
This commit applies ACCESS_ONCE() to an outside-of-lock access to
->gp_flags.  Although it is hard to imagine any sane compiler messing
this particular case up, the documentation benefits are substantial.
Plus the definition of "sane compiler" grows ever looser.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-09-23 09:16:13 -07:00
Paul E. McKenney
88d6df612c rcu: Prevent spurious-wakeup DoS attack on rcu_gp_kthread()
Spurious wakeups in the force-quiescent-state loop in rcu_gp_kthread()
cause the timeout to be recalculated, which would prevent rcu_gp_fqs()
from ever being called.  This would in turn would prevent the grace period
from ever ending for as long as there was at least one CPU in an extended
quiescent state that had not yet passed through a quiescent state.

This commit therefore avoids recalculating the timeout unless the
previous pass's call to wait_event_interruptible_timeout() actually
did time out, thus preventing the above scenario.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-09-23 09:16:11 -07:00
Paul E. McKenney
f7be820939 rcu: Improve grace-period start logic
This commit improves grace-period start logic by checking ->gp_flags
under the lock and by issuing a warning if a grace period is already
in progress.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-09-23 09:16:10 -07:00
Paul E. McKenney
0d75292467 rcu: Have rcutiny tracepoints use tracepoint_string()
This commit extends the work done in f7f7bac9 (rcu: Have the RCU
tracepoints use the tracepoint_string infrastructure) to cover rcutiny.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
2013-09-23 09:15:31 -07:00
Paul E. McKenney
26cdfedf6a rcu: Reject memory-order-induced stall-warning false positives
If a system is idle from an RCU perspective for longer than specified
by CONFIG_RCU_CPU_STALL_TIMEOUT, and if one CPU starts a grace period
just as a second checks for CPU stalls, and if this second CPU happens
to see the old value of rsp->jiffies_stall, it will incorrectly report a
CPU stall.  This is quite rare, but apparently occurs deterministically
on systems with about 6TB of memory.

This commit therefore orders accesses to the data used to determine
whether or not a CPU stall is in progress.  Grace-period initialization
and cleanup first increments rsp->completed to mark the end of the
previous grace period, then records the current jiffies in rsp->gp_start,
then records the jiffies at which a stall can be expected to occur in
rsp->jiffies_stall, and finally increments rsp->gpnum to mark the start
of the new grace period.  Now, this ordering by itself does not prevent
false positives.  For example, if grace-period initialization was delayed
between recording rsp->gp_start and rsp->jiffies_stall, the CPU stall
warning code might still see an old value of rsp->jiffies_stall.

Therefore, this commit also orders the CPU stall warning accesses as
well, loading rsp->gpnum and jiffies, then rsp->jiffies_stall, then
rsp->gp_start, and finally rsp->completed.  This ordering means that
the false-positive scenario in the previous paragraph would result
in rsp->completed being greater than or equal to rsp->gpnum, which is
never valid for a CPU stall, allowing the false positive to be rejected.
Furthermore, any fetch that gets an old value of rsp->jiffies_stall
must also get an old value of rsp->gpnum, which will again be rejected
by the comparison of rsp->gpnum and rsp->completed.  Situations where
rsp->gp_start is later than rsp->jiffies_stall are also rejected, as
are situations where jiffies is less than rsp->jiffies_stall.

Although use of unsynchronized accesses means that there are likely
still some false-positive scenarios (synchronization has proven to be
a very bad idea on large systems), this should get rid of a large class
of these scenarios.

Reported-by: Fabian Herschel <fabian.herschel@suse.com>
Reported-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Tested-by: Jochen Striepe <jochen@tolot.escape.de>
2013-09-23 09:15:30 -07:00
Paul E. McKenney
69c8d28c96 rcu: Micro-optimize rcu_cpu_has_callbacks()
The for_each_rcu_flavor() loop unconditionally scans all flavors, even
when the first flavor might have some non-lazy callbacks.  Once the
loop has seen a non-lazy callback, further passes through the loop
cannot change the state.  This is not a huge problem, given that there
can be at most three RCU flavors (RCU-bh, RCU-preempt, and RCU-sched),
but this code is on the path to idle, so speeding it up even a small
amount would have some benefit.

This commit therefore does two things:

1.	Rearranges the order of the list of RCU flavors in order to
	place the most active flavor first in the list.  The most active
	RCU flavor is RCU-preempt, or, if there is no RCU-preempt,
	RCU-sched.

2.	Reworks the for_each_rcu_flavor() to exit early when the first
	non-lazy callback is seen, or, in the case where the caller
	does not care about non-lazy callbacks (RCU_FAST_NO_HZ=n),
	when the first callback is seen.

Reported-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-09-23 09:15:28 -07:00
Paul E. McKenney
289828e62d rcu: Silence unused-variable warnings
The "idle" variable in both rcu_eqs_enter_common() and
rcu_eqs_exit_common() is only used in a WARN_ON_ONCE().  If the kernel
is built disabling WARN_ON_ONCE(), the compiler will complain (rightly)
that "idle" is unused.  This commit therefore adds a __maybe_unused to
the declaration of both variables.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-09-23 09:15:27 -07:00
Christoph Lameter
c9d4b0af9e rcu: Replace __get_cpu_var() uses
__get_cpu_var() is used for multiple purposes in the kernel source. One
of them is address calculation via the form &__get_cpu_var(x). This
calculates the address for the instance of the percpu variable of the
current processor based on an offset.

Other use cases are for storing and retrieving data from the current
processors percpu area.  __get_cpu_var() can be used as an lvalue when
writing data or on the right side of an assignment.

__get_cpu_var() is defined as :

__get_cpu_var() always only does an address determination. However,
store and retrieve operations could use a segment prefix (or global
register on other platforms) to avoid the address calculation.

this_cpu_write() and this_cpu_read() can directly take an offset into
a percpu area and use optimized assembly code to read and write per
cpu variables.

This patch converts __get_cpu_var into either an explicit address
calculation using this_cpu_ptr() or into a use of this_cpu operations
that use the offset. Thereby address calcualtions are avoided and less
registers are used when code is generated.

At the end of the patchset all uses of __get_cpu_var have been removed
so the macro is removed too.

The patchset includes passes over all arches as well. Once these
operations are used throughout then specialized macros can be defined in
non -x86 arches as well in order to optimize per cpu access by f.e. using
a global register that may be set to the per cpu base.

Transformations done to __get_cpu_var()

1. Determine the address of the percpu instance of the current processor.

	DEFINE_PER_CPU(int, y);
	int *x = &__get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(&y);

2. Same as #1 but this time an array structure is involved.

	DEFINE_PER_CPU(int, y[20]);
	int *x = __get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(y);

3. Retrieve the content of the current processors instance of a per cpu
   variable.

	DEFINE_PER_CPU(int, u);
	int x = __get_cpu_var(y)

   Converts to

	int x = __this_cpu_read(y);

4. Retrieve the content of a percpu struct

	DEFINE_PER_CPU(struct mystruct, y);
	struct mystruct x = __get_cpu_var(y);

   Converts to

	memcpy(this_cpu_ptr(&x), y, sizeof(x));

5. Assignment to a per cpu variable

	DEFINE_PER_CPU(int, y)
	__get_cpu_var(y) = x;

   Converts to

	this_cpu_write(y, x);

6. Increment/Decrement etc of a per cpu variable

	DEFINE_PER_CPU(int, y);
	__get_cpu_var(y)++

   Converts to

	this_cpu_inc(y)

Signed-off-by: Christoph Lameter <cl@linux.com>
[ paulmck: Address conflicts. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-09-23 09:15:22 -07:00
Paul E. McKenney
2a855b644c rcu: Make list_splice_init_rcu() account for RCU readers
The list_splice_init_rcu() function allows a list visible to RCU readers
to be spliced into another list visible to RCU readers.  This is OK,
except for the use of INIT_LIST_HEAD(), which does pointer updates
without doing anything to make those updates safe for concurrent readers.

Of course, most of the time INIT_LIST_HEAD() is being used in reader-free
contexts, such as initialization or cleanup, so it is OK for it to update
pointers in an unsafe-for-RCU-readers manner.  This commit therefore
creates an INIT_LIST_HEAD_RCU() that uses ACCESS_ONCE() to make the updates
reader-safe.  The reason that we can use ACCESS_ONCE() instead of the more
typical rcu_assign_pointer() is that list_splice_init_rcu() is updating the
pointers to reference something that is already visible to readers, so
that there is no problem with pre-initialized values.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-09-23 09:13:49 -07:00
Paul E. McKenney
829511d8aa rcu: Fix dubious "if" condition in __call_rcu_nocb_enqueue()
This commit replaces an incorrect (but fortunately functional)
bitwise OR ("|") operator with the correct logical OR ("||").

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-09-23 09:13:44 -07:00
Paul E. McKenney
01896f7e0a rcu: Convert local functions to static
The rcu_cpu_stall_timeout kernel parameter, the rcu_dynticks per-CPU
variable, and the rcu_gp_fqs() function are used only locally.  This
commit therefore marks them as static.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-09-23 09:12:31 -07:00
Paul E. McKenney
b3f2d02598 rcu: Use proper cpp macro for ->gp_flags
One of the ->gp_flags assignments used a raw number rather than the
cpp macro that was intended for this purpose, which this commit fixes.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-09-20 09:43:06 -07:00
Paul E. McKenney
5c889690aa mm: Place preemption point in do_mlockall() loop
There is a loop in do_mlockall() that lacks a preemption point, which
means that the following can happen on non-preemptible builds of the
kernel:

> My fuzz tester keeps hitting this. Every instance shows the non-irq stack
> came in from mlockall.  I'm only seeing this on one box, but that has more
> ram (8gb) than my other machines, which might explain it.
>
> 	Dave
>
> INFO: rcu_preempt self-detected stall on CPU { 3}  (t=6500 jiffies g=470344 c=470343 q=0)
> sending NMI to all CPUs:
> NMI backtrace for cpu 3
> CPU: 3 PID: 29664 Comm: trinity-child2 Not tainted 3.11.0-rc1+ #32
> task: ffff88023e743fc0 ti: ffff88022f6f2000 task.ti: ffff88022f6f2000
> RIP: 0010:[<ffffffff810bf7d1>]  [<ffffffff810bf7d1>] trace_hardirqs_off_caller+0x21/0xb0
> RSP: 0018:ffff880244e03c30  EFLAGS: 00000046
> RAX: ffff88023e743fc0 RBX: 0000000000000001 RCX: 000000000000003c
> RDX: 000000000000000f RSI: 0000000000000004 RDI: ffffffff81033cab
> RBP: ffff880244e03c38 R08: ffff880243288a80 R09: 0000000000000001
> R10: 0000000000000000 R11: 0000000000000001 R12: ffff880243288a80
> R13: ffff8802437eda40 R14: 0000000000080000 R15: 000000000000d010
> FS:  00007f50ae33b740(0000) GS:ffff880244e00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 000000000097f000 CR3: 0000000240fa0000 CR4: 00000000001407e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
> Stack:
>  ffffffff810bf86d ffff880244e03c98 ffffffff81033cab 0000000000000096
>  000000000000d008 0000000300000002 0000000000000004 0000000000000003
>  0000000000002710 ffffffff81c50d00 ffffffff81c50d00 ffff880244fcde00
> Call Trace:
>  <IRQ>
>  [<ffffffff810bf86d>] ? trace_hardirqs_off+0xd/0x10
>  [<ffffffff81033cab>] __x2apic_send_IPI_mask+0x1ab/0x1c0
>  [<ffffffff81033cdc>] x2apic_send_IPI_all+0x1c/0x20
>  [<ffffffff81030115>] arch_trigger_all_cpu_backtrace+0x65/0xa0
>  [<ffffffff811144b1>] rcu_check_callbacks+0x331/0x8e0
>  [<ffffffff8108bfa0>] ? hrtimer_run_queues+0x20/0x180
>  [<ffffffff8109e905>] ? sched_clock_cpu+0xb5/0x100
>  [<ffffffff81069557>] update_process_times+0x47/0x80
>  [<ffffffff810bd115>] tick_sched_handle.isra.16+0x25/0x60
>  [<ffffffff810bd231>] tick_sched_timer+0x41/0x60
>  [<ffffffff8108ace1>] __run_hrtimer+0x81/0x4e0
>  [<ffffffff810bd1f0>] ? tick_sched_do_timer+0x60/0x60
>  [<ffffffff8108b93f>] hrtimer_interrupt+0xff/0x240
>  [<ffffffff8102de84>] local_apic_timer_interrupt+0x34/0x60
>  [<ffffffff81718c5f>] smp_apic_timer_interrupt+0x3f/0x60
>  [<ffffffff817178ef>] apic_timer_interrupt+0x6f/0x80
>  [<ffffffff8170e8e0>] ? retint_restore_args+0xe/0xe
>  [<ffffffff8105f101>] ? __do_softirq+0xb1/0x440
>  [<ffffffff8105f64d>] irq_exit+0xcd/0xe0
>  [<ffffffff81718c65>] smp_apic_timer_interrupt+0x45/0x60
>  [<ffffffff817178ef>] apic_timer_interrupt+0x6f/0x80
>  <EOI>
>  [<ffffffff8170e8e0>] ? retint_restore_args+0xe/0xe
>  [<ffffffff8170b830>] ? wait_for_completion_killable+0x170/0x170
>  [<ffffffff8170c853>] ? preempt_schedule_irq+0x53/0x90
>  [<ffffffff8170e9f6>] retint_kernel+0x26/0x30
>  [<ffffffff8107a523>] ? queue_work_on+0x43/0x90
>  [<ffffffff8107c369>] schedule_on_each_cpu+0xc9/0x1a0
>  [<ffffffff81167770>] ? lru_add_drain+0x50/0x50
>  [<ffffffff811677c5>] lru_add_drain_all+0x15/0x20
>  [<ffffffff81186965>] SyS_mlockall+0xa5/0x1a0
>  [<ffffffff81716e94>] tracesys+0xdd/0xe2

This commit addresses this problem by inserting the required preemption
point.

Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-20 09:43:05 -07:00
Linus Torvalds
272b98c645 Linux 3.12-rc1 2013-09-16 16:17:51 -04:00
Linus Torvalds
a4ae54f90e Merge branch 'timers/core' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer code update from Thomas Gleixner:
 - armada SoC clocksource overhaul with a trivial merge conflict
 - Minor improvements to various SoC clocksource drivers

* 'timers/core' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  clocksource: armada-370-xp: Add detailed clock requirements in devicetree binding
  clocksource: armada-370-xp: Get reference fixed-clock by name
  clocksource: armada-370-xp: Replace WARN_ON with BUG_ON
  clocksource: armada-370-xp: Fix device-tree binding
  clocksource: armada-370-xp: Introduce new compatibles
  clocksource: armada-370-xp: Use CLOCKSOURCE_OF_DECLARE
  clocksource: armada-370-xp: Simplify TIMER_CTRL register access
  clocksource: armada-370-xp: Use BIT()
  ARM: timer-sp: Set dynamic irq affinity
  ARM: nomadik: add dynamic irq flag to the timer
  clocksource: sh_cmt: 32-bit control register support
  clocksource: em_sti: Convert to devm_* managed helpers
2013-09-16 16:10:26 -04:00
Linus Torvalds
3369d11693 Merge branch 'for-next' of git://git.samba.org/sfrench/cifs-2.6
Pull CIFS fixes from Steve French:
 "Two minor cifs fixes and a minor documentation cleanup for cifs.txt"

* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: update cifs.txt and remove some outdated infos
  cifs: Avoid calling unlock_page() twice in cifs_readpage() when using fscache
  cifs: Do not take a reference to the page in cifs_readpage_worker()
2013-09-16 15:39:21 -04:00
Linus Torvalds
f1da3458e9 Just a single fastmap fix plus a regression fix.
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Merge tag 'upstream-3.12-rc1' of git://git.infradead.org/linux-ubi

Pull UBI fixes from Artem Bityutskiy:
 "Just a single fastmap fix plus a regression fix"

* tag 'upstream-3.12-rc1' of git://git.infradead.org/linux-ubi:
  UBI: Fix invalidate_fastmap()
  UBI: Fix PEB leak in wear_leveling_worker()
2013-09-16 15:37:52 -04:00
Linus Torvalds
098e7f1665 Just one patch which fixes the power-cut recovery testing mode.
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Merge tag 'upstream-3.12-rc1' of git://git.infradead.org/linux-ubifs

Pull ubifs fix from Artem Bityutskiy:
 "Just one patch which fixes the power-cut recovery testing mode.

  I'll start using a single UBI/UBIFS tree instead of 2 trees from now
  on.  So in the future you'll get 1 small pull request instead of 2
  tiny ones"

* tag 'upstream-3.12-rc1' of git://git.infradead.org/linux-ubifs:
  UBIFS: remove invalid warn msg with tst_recovery enabled
2013-09-16 15:36:55 -04:00
Linus Torvalds
d8efd82eec Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus
Pull MIPS fixes from Ralf Baechle:
 "These are four patches for three construction sites:

   - Fix register decoding for the combination of multi-core processors
     and multi-threading.

   - Two more fixes that are part of the ongoing DECstation resurrection
     work.  One of these touches a DECstation-only network driver.

   - Finally Markos' trivial build fix for the AP/SP support.

  (With this applied now all MIPS defconfigs are building again)"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: kernel: vpe: Make vpe_attrs an array of pointers.
  MIPS: Fix SMP core calculations when using MT support.
  MIPS: DECstation I/O ASIC DMA interrupt handling fix
  MIPS: DECstation HRT initialization rearrangement
2013-09-15 17:45:52 -04:00
Linus Torvalds
cd619e21ea Merge branch 'for_linus' of git://cavan.codon.org.uk/platform-drivers-x86
Pull x86 platform updates from Matthew Garrett:
 "Nothing amazing here, almost entirely cleanups and minor bugfixes and
  one bit of hardware enablement in the amilo-rfkill driver"

* 'for_linus' of git://cavan.codon.org.uk/platform-drivers-x86:
  platform/x86: panasonic-laptop: reuse module_acpi_driver
  samsung-laptop: fix config build error
  platform: x86: remove unnecessary platform_set_drvdata()
  amilo-rfkill: Enable using amilo-rfkill with the FSC Amilo L1310.
  wmi: parse_wdg() should return kernel error codes
  hp_wmi: Fix unregister order in hp_wmi_rfkill_setup()
  platform: replace strict_strto*() with kstrto*()
  x86: irst: use module_acpi_driver to simplify the code
  x86: smartconnect: use module_acpi_driver to simplify the code
  platform samsung-q10: use ACPI instead of direct EC calls
  thinkpad_acpi: add the ability setting TPACPI_LED_NONE by quirk
  thinkpad_acpi: return -NODEV while operating uninitialized LEDs
2013-09-15 17:42:59 -04:00
Linus Torvalds
0375ec5899 SCSI misc on 20130915
This patch set is a set of driver updates (megaraid_sas, fnic, lpfc, ufs,
 hpsa) we also have a couple of bug fixes (sd out of bounds and ibmvfc error
 handling) and the first round of esas2r checker fixes and finally the much
 anticipated big endian additions for megaraid_sas.
 
 Signed-off-by: James Bottomley <JBottomley@Parallels.com>
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Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi

Pull misc SCSI driver updates from James Bottomley:
 "This patch set is a set of driver updates (megaraid_sas, fnic, lpfc,
  ufs, hpsa) we also have a couple of bug fixes (sd out of bounds and
  ibmvfc error handling) and the first round of esas2r checker fixes and
  finally the much anticipated big endian additions for megaraid_sas"

* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (47 commits)
  [SCSI] fnic: fnic Driver Tuneables Exposed through CLI
  [SCSI] fnic: Kernel panic while running sh/nosh with max lun cfg
  [SCSI] fnic: Hitting BUG_ON(io_req->abts_done) in fnic_rport_exch_reset
  [SCSI] fnic: Remove QUEUE_FULL handling code
  [SCSI] fnic: On system with >1.1TB RAM, VIC fails multipath after boot up
  [SCSI] fnic: FC stat param seconds_since_last_reset not getting updated
  [SCSI] sd: Fix potential out-of-bounds access
  [SCSI] lpfc 8.3.42: Update lpfc version to driver version 8.3.42
  [SCSI] lpfc 8.3.42: Fixed issue of task management commands having a fixed timeout
  [SCSI] lpfc 8.3.42: Fixed inconsistent spin lock usage.
  [SCSI] lpfc 8.3.42: Fix driver's abort loop functionality to skip IOs already getting aborted
  [SCSI] lpfc 8.3.42: Fixed failure to allocate SCSI buffer on PPC64 platform for SLI4 devices
  [SCSI] lpfc 8.3.42: Fix WARN_ON when driver unloads
  [SCSI] lpfc 8.3.42: Avoided making pci bar ioremap call during dual-chute WQ/RQ pci bar selection
  [SCSI] lpfc 8.3.42: Fixed driver iocbq structure's iocb_flag field running out of space
  [SCSI] lpfc 8.3.42: Fix crash on driver load due to cpu affinity logic
  [SCSI] lpfc 8.3.42: Fixed logging format of setting driver sysfs attributes hard to interpret
  [SCSI] lpfc 8.3.42: Fixed back to back RSCNs discovery failure.
  [SCSI] lpfc 8.3.42: Fixed race condition between BSG I/O dispatch and timeout handling
  [SCSI] lpfc 8.3.42: Fixed function mode field defined too small for not recognizing dual-chute mode
  ...
2013-09-15 17:41:30 -04:00
Linus Torvalds
bff157b3ad Merge branch 'slab/next' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux
Pull SLAB update from Pekka Enberg:
 "Nothing terribly exciting here apart from Christoph's kmalloc
  unification patches that brings sl[aou]b implementations closer to
  each other"

* 'slab/next' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux:
  slab: Use correct GFP_DMA constant
  slub: remove verify_mem_not_deleted()
  mm/sl[aou]b: Move kmallocXXX functions to common code
  mm, slab_common: add 'unlikely' to size check of kmalloc_slab()
  mm/slub.c: beautify code for removing redundancy 'break' statement.
  slub: Remove unnecessary page NULL check
  slub: don't use cpu partial pages on UP
  mm/slub: beautify code for 80 column limitation and tab alignment
  mm/slub: remove 'per_cpu' which is useless variable
2013-09-15 07:15:06 -04:00
Linus Torvalds
8bf5e36d04 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
Pull input update from Dmitry Torokhov:
 "The only change is David Hermann's new EVIOCREVOKE evdev ioctl that
  allows safely passing file descriptors to input devices to session
  processes and later being able to stop delivery of events through
  these fds so that inactive sessions will no longer receive user input
  that does not belong to them"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: evdev - add EVIOCREVOKE ioctl
2013-09-15 07:13:39 -04:00
Linus Torvalds
05a8252bde vfs: fix typo in comment in recent dentry work
Sedat points out that I transposed some letters in "LRU" and wrote "RLU"
instead in one of the new comments explaining the flow.  Let's just fix
it.

Reported-by: Sedat Dilek <sedat.dilek@jpberlin.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-15 07:11:01 -04:00
Davidlohr Bueso
6b02fa59a7 partitions/efi: loosen check fot pmbr size in lba
Matt found that commit 27a7c64217 ("partitions/efi: account for pmbr
size in lba") caused his GPT formatted eMMC device not to boot.  The
reason is that this commit enforced Linux to always check the lesser of
the whole disk or 2Tib for the pMBR size in LBA.  While most disk
partitioning tools out there create a pMBR with these characteristics,
Microsoft does not, as it always sets the entry to the maximum 32-bit
limitation - even though a drive may be smaller than that[1].

Loosen this check and only verify that the size is either the whole disk
or 0xFFFFFFFF.  No tool in its right mind would set it to any value
other than these.

[1] http://thestarman.pcministry.com/asm/mbr/GPT.htm#GPTPT

Reported-and-tested-by: Matt Porter <matt.porter@linaro.org>
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-15 07:10:16 -04:00
Linus Torvalds
3711d86a2d a trivial writeback fix
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Merge tag 'writeback-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux

Pull writeback fix from Wu Fengguang:
 "A trivial writeback fix"

* tag 'writeback-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux:
  writeback: Do not sort b_io list only because of block device inode
2013-09-13 23:06:40 -04:00
Linus Torvalds
89dc77bcda vfs: fix dentry LRU list handling and nr_dentry_unused accounting
The LRU list changes interacted badly with our nr_dentry_unused
accounting, and even worse with the new DCACHE_LRU_LIST bit logic.

This introduces helper functions to make sure everything follows the
proper dcache d_lru list rules: the dentry cache is complicated by the
fact that some of the hotpaths don't even want to look at the LRU list
at all, and the fact that we use the same list entry in the dentry for
both the LRU list and for our temporary shrinking lists when removing
things from the LRU.

The helper functions temporarily have some extra sanity checking for the
flag bits that have to match the current LRU state of the dentry.  We'll
remove that before the final 3.12 release, but considering how easy it
is to get wrong, this first cleanup version has some very particular
sanity checking.

Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-13 22:55:10 -04:00
Björn Jacke
81b66220a9 cifs: update cifs.txt and remove some outdated infos
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Björn JACKE <bj@sernet.de>
Signed-off-by: Steve French <smfrench@gmail.com>
2013-09-13 16:29:58 -05:00
Sachin Prabhu
466bd31bbd cifs: Avoid calling unlock_page() twice in cifs_readpage() when using fscache
When reading a single page with cifs_readpage(), we make a call to
fscache_read_or_alloc_page() which once done, asynchronously calls
the completion function cifs_readpage_from_fscache_complete(). This
completion function unlocks the page once it has been populated from
cache. The module then attempts to unlock the page a second time in
cifs_readpage() which leads to warning messages.

In case of a successful call to fscache_read_or_alloc_page() we should skip
the second unlock_page() since this will be called by the
cifs_readpage_from_fscache_complete() once the page has been populated by
fscache.

With the modifications to cifs_readpage_worker(), we will need to re-grab the
page lock in cifs_write_begin().

The problem was first noticed when testing new fscache patches for cifs.
https://bugzilla.redhat.com/show_bug.cgi?id=1005737

Signed-off-by: Sachin Prabhu <sprabhu@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
2013-09-13 16:24:49 -05:00
Sachin Prabhu
a9e9b7bc15 cifs: Do not take a reference to the page in cifs_readpage_worker()
We do not need to take a reference to the pagecache in
cifs_readpage_worker() since the calling function will have already
taken one before passing the pointer to the page as an argument to the
function.

Signed-off-by: Sachin Prabhu <sprabhu@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
2013-09-13 16:24:43 -05:00