This patch adds a check to __rcu_pending() that does a local
set_need_resched() if the current CPU is holding up the current grace
period and if force_quiescent_state() will be called soon. The goal is
to reduce the probability that force_quiescent_state() will need to do
smp_send_reschedule(), which sends an IPI and is therefore more expensive
on most architectures.
Signed-off-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
There is no need to disable lockdep after an RCU lockdep splat,
so remove the debug_lockdeps_off() from lockdep_rcu_dereference().
To avoid repeated lockdep splats, use a static variable in the inlined
rcu_dereference_check() and rcu_dereference_protected() macros so that
a given instance splats only once, but so that multiple instances can
be detected per boot.
This is controlled by a new config variable CONFIG_PROVE_RCU_REPEATEDLY,
which is disabled by default. This provides the normal lockdep behavior
by default, but permits people who want to find multiple RCU-lockdep
splats per boot to easily do so.
Requested-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Tested-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
commit 672917dcc7 ("cpuidle: menu governor: reduce latency on exit")
added an optimization, where the analysis on the past idle period moved
from the end of idle, to the beginning of the new idle.
Unfortunately, this optimization had a bug where it zeroed one key
variable for new use, that is needed for the analysis. The fix is
simple, zero the variable after doing the work from the previous idle.
During the audit of the code that found this issue, another issue was
also found; the ->measured_us data structure member is never set, a
local variable is always used instead.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: Corrado Zoccolo <czoccolo@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://neil.brown.name/md:
md: restore ability of spare drives to spin down.
md/raid6: Fix raid-6 read-error correction in degraded state
* 'urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/brodo/pcmcia-2.6:
pcmcia: fix compilation after 16bit state locking changes
pcmcia: order userspace suspend and resume requests
pcmcia: avoid pccard_validate_cis failure in resume callpath
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
blk-cgroup: Fix an RCU warning in blkiocg_create()
blk-cgroup: Fix RCU correctness warning in cfq_init_queue()
drbd: don't expose failed local READ to upper layers
* 'bugfixes' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6:
NFS: Fix RCU issues in the NFSv4 delegation code
NFSv4: Fix the locking in nfs_inode_reclaim_delegation()
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6:
ACPI: sleep: init_set_sci_en_on_resume for Dell Studio 155x
ACPI: fix acpi_hest_firmware_first_pci() caused oops
sbshc: acpi_device_class "smbus_host_controller" too long
power_meter: acpi_device_class "power_meter_resource" too long
acpi_pad: "processor_aggregator" name too long
PNP: don't check for conflicts with bridge windows
ACPI: DMI init_set_sci_en_on_resume for multiple Lenovo ThinkPads
PNPACPI: compute Address Space length rather than using _LEN
ACPI: silence kmemcheck false positive
* 'v4l_for_2.6.34' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6:
V4L/DVB: pxa_camera: move fifo reset direct before dma start
V4L/DVB: video: testing unsigned for less than 0
V4L/DVB: mx1-camera: compile fix
V4L/DVB: budget: Oops: "BUG: unable to handle kernel NULL pointer dereference"
V4L/DVB: ngene: Workaround for stuck DiSEqC pin
V4L/DVB: saa7146: fix regression of the av7110/budget-av driver
V4L/DVB: v4l: fix config dependencies: mxb and saa7191 are V4L2 drivers, not V4L1
V4L/DVB: feature-removal: announce videotext.h removal
V4L/DVB: V4L - vpfe capture - fix for kernel crash
V4L/DVB: gspca: make usb id 0461:0815 get handled by the right driver
V4L/DVB: gspca - stv06xx: Remove the 046d:08da from the stv06xx driver
V4L/DVB: gspca - sn9c20x: Correct onstack wait_queue_head declaration
V4L/DVB: saa7146: fix up bytesperline if it is an impossible value
V4L/DVB: V4L: vpfe_capture - free ccdc_lock when memory allocation fails
V4L/DVB: V4L - Makfile:Removed duplicate entry of davinci
V4L/DVB: omap24xxcam: potential buffer overflow
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
rcu: create rcu_my_thread_group_empty() wrapper
memcg: css_id() must be called under rcu_read_lock()
cgroup: Check task_lock in task_subsys_state()
sched: Fix an RCU warning in print_task()
cgroup: Fix an RCU warning in alloc_css_id()
cgroup: Fix an RCU warning in cgroup_path()
KEYS: Fix an RCU warning in the reading of user keys
KEYS: Fix an RCU warning
Some time ago we stopped the clean/active metadata updates
from being written to a 'spare' device in most cases so that
it could spin down and say spun down. Device failure/removal
etc are still recorded on spares.
However commit 51d5668cb2 broke this 50% of the time,
depending on whether the event count is even or odd.
The change log entry said:
This means that the alignment between 'odd/even' and
'clean/dirty' might take a little longer to attain,
how ever the code makes no attempt to create that alignment, so it
could take arbitrarily long.
So when we find that clean/dirty is not aligned with odd/even,
force a second metadata-update immediately. There are already cases
where a second metadata-update is needed immediately (e.g. when a
device fails during the metadata update). We just piggy-back on that.
Reported-by: Joe Bryant <tenminjoe@yahoo.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Cc: stable@kernel.org
with CONFIG_PROVE_RCU=y, a warning can be triggered:
# mount -t cgroup -o blkio xxx /mnt
# mkdir /mnt/subgroup
...
kernel/cgroup.c:4442 invoked rcu_dereference_check() without protection!
...
To fix this, we avoid caling css_depth() here, which is a bit simpler
than the original code.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
It's unused and buggy in its current form, since it can place a bo
in the reserved state without removing it from lru lists.
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Bring radeon up to speed with the async event synchronization for
drmWaitVblank. See c9a9c5e02a for
more information. Without this patch event never get delivered
to userspace client.
Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Move the fifo reset from pxa_camera_start_capture to pxa_camera_irq direct
before the dma start after an end of frame interrupt to prevent images from
shifting because of old data at the begin of the frame.
Signed-off-by: Stefan Herbrechtsmeier <hbmeier@hni.uni-paderborn.de>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Tested-by: Antonio Ospite <ospite@studenti.unina.it>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
soc_mbus_bytes_per_line() returns -EINVAL on error but we store it in an
unsigned int so the test for less than zero doesn't work. I think it
always returns "small" positive values so we can just cast it to int
here.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Lai Jiangshan
Paul E. McKenney
Linus Torvalds
Arjan van de Ven
Stijn Tintel
NeilBrown
Gabriele A. Trombetti
Li Zefan
Len Brown
Thomas Hellstrom
Jerome Glisse
Stefan Herbrechtsmeier
Dan Carpenter
Uwe Kleine-König