Backlight class attributes are currently easy to implement incorrectly.
Moving certain handling into the backlight core prevents this whilst at the
same time makes the drivers simpler and consistent. The following changes are
included:
The brightness attribute only sets and reads the brightness variable in the
backlight_properties structure.
The power attribute only sets and reads the power variable in the
backlight_properties structure.
Any framebuffer blanking events change a variable fb_blank in the
backlight_properties structure.
The backlight driver has only two functions to implement. One function is
called when any of the above properties change (to update the backlight
brightness), the second is called to return the current backlight brightness
value. A new attribute "actual_brightness" is added to return this brightness
as determined by the driver having combined all the above factors (and any
driver/device specific factors).
Additionally, the backlight core takes care of checking the maximum brightness
is not exceeded and of turning off the backlight before device removal.
The corgi backlight driver is updated to reflect these changes.
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add acceleration support in w100fb.c (i.e. ATI Imageons) for the copyarea and
fillrect operations.
Signed-off-by: Alberto Mardegan <mardy@users.sourceforge.net>
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The current display was not saved during initialization. This leads to hard
to track console corruption, such as a misplaced cursor, which is correctible
by switching consoles. Fix this minor bug.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
It is very common to hash a dentry and then to call lookup. If we take fs
specific hash functions into account the full hash logic can get ugly.
Further full_name_hash as an inline function is almost 100 bytes on x86 so
having a non-inline choice in some cases can measurably decrease code size.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Simplifies the code, reduces the need for 4 pid hash tables, and makes the
code more capable.
In the discussions I had with Oleg it was felt that to a large extent the
cleanup itself justified the work. With struct pid being dynamically
allocated meant we could create the hash table entry when the pid was
allocated and free the hash table entry when the pid was freed. Instead of
playing with the hash lists when ever a process would attach or detach to a
process.
For myself the fact that it gave what my previous task_ref patch gave for free
with simpler code was a big win. The problem is that if you hold a reference
to struct task_struct you lock in 10K of low memory. If you do that in a user
controllable way like /proc does, with an unprivileged but hostile user space
application with typical resource limits of 1000 fds and 100 processes I can
trigger the OOM killer by consuming all of low memory with task structs, on a
machine wight 1GB of low memory.
If I instead hold a reference to struct pid which holds a pointer to my
task_struct, I don't suffer from that problem because struct pid is 2 orders
of magnitude smaller. In fact struct pid is small enough that most other
kernel data structures dwarf it, so simply limiting the number of referring
data structures is enough to prevent exhaustion of low memory.
This splits the current struct pid into two structures, struct pid and struct
pid_link, and reduces our number of hash tables from PIDTYPE_MAX to just one.
struct pid_link is the per process linkage into the hash tables and lives in
struct task_struct. struct pid is given an indepedent lifetime, and holds
pointers to each of the pid types.
The independent life of struct pid simplifies attach_pid, and detach_pid,
because we are always manipulating the list of pids and not the hash table.
In addition in giving struct pid an indpendent life it makes the concept much
more powerful.
Kernel data structures can now embed a struct pid * instead of a pid_t and
not suffer from pid wrap around problems or from keeping unnecessarily
large amounts of memory allocated.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
A big problem with rcu protected data structures that are also reference
counted is that you must jump through several hoops to increase the reference
count. I think someone finally implemented atomic_inc_not_zero(&count) to
automate the common case. Unfortunately this means you must special case the
rcu access case.
When data structures are only visible via rcu in a manner that is not
determined by the reference count on the object (i.e. tasks are visible until
their zombies are reaped) there is a much simpler technique we can employ.
Simply delaying the decrement of the reference count until the rcu interval is
over.
What that means is that the proc code that looks up a task and later
wants to sleep can now do:
rcu_read_lock();
task = find_task_by_pid(some_pid);
if (task) {
get_task_struct(task);
}
rcu_read_unlock();
The effect on the rest of the kernel is that put_task_struct becomes cheaper
and immediate, and in the case where the task has been reaped it frees the
task immediate instead of unnecessarily waiting an until the rcu interval is
over.
Cleanup of task_struct does not happen when its reference count drops to
zero, instead cleanup happens when release_task is called. Tasks can only
be looked up via rcu before release_task is called. All rcu protected
members of task_struct are freed by release_task.
Therefore we can move call_rcu from put_task_struct into release_task. And
we can modify release_task to not immediately release the reference count
but instead have it call put_task_struct from the function it gives to
call_rcu.
The end result:
- get_task_struct is safe in an rcu context where we have just looked
up the task.
- put_task_struct() simplifies into its old pre rcu self.
This reorganization also makes put_task_struct uncallable from modules as
it is not exported but it does not appear to be called from any modules so
this should not be an issue, and is trivially fixed.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
proc_check_chroot() does the check in a very unintuitive way (keeping a
copy of the argument, then modifying the argument), and has uncommented
sideeffects.
Signed-off-by: Herbert Poetzl <herbert@13thfloor.at>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This just got nuked in mainline. Bring it back because Eric's patches use it.
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The core problem: setsid fails if it is called by init. The effect in 2.6.16
and the earlier kernels that have this problem is that if you do a "ps -j 1 or
ps -ej 1" you will see that init and several of it's children have process
group and session == 0. Instead of process group == session == 1. Despite
init calling setsid.
The reason it fails is that daemonize calls set_special_pids(1,1) on kernel
threads that are launched before /sbin/init is called.
The only remaining effect in that current->signal->leader == 0 for init
instead of 1. And the setsid call fails. No one has noticed because
/sbin/init does not check the return value of setsid.
In 2.4 where we don't have the pidhash table, and daemonize doesn't exist
setsid actually works for init.
I care a lot about pid == 1 not being a special case that we leave broken,
because of the container/jail work that I am doing.
- Carefully allow init (pid == 1) to call setsid despite the kernel using
its session.
- Use find_task_by_pid instead of find_pid because find_pid taking a
pidtype is going away.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The futex timeval is not checked for correctness. The change does not
break existing applications as the timeval is supplied by glibc (and glibc
always passes a correct value), but the glibc-internal tests for this
functionality fail.
Signed-off-by: Thomas Gleixner <tglx@tglx.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
To increase the strength of SCHED_BATCH as a scheduling hint we can
activate batch tasks on the expired array since by definition they are
latency insensitive tasks.
Signed-off-by: Con Kolivas <kernel@kolivas.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
On runqueue time is used to elevate priority in schedule().
In the code it currently requeues tasks even if their priority is not
elevated, which would end up placing them at the end of their runqueue
array effectively delaying them instead of improving their priority.
Bug spotted by Mike Galbraith <efault@gmx.de>
This patch removes this requeueing.
Signed-off-by: Con Kolivas <kernel@kolivas.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Tasks waiting in SLEEP_NONINTERACTIVE state can now get to best priority so
they need to be included in the idle detection code.
Signed-off-by: Con Kolivas <kernel@kolivas.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
We watch for tasks that sleep extended periods and don't allow one single
prolonged sleep period from elevating priority to maximum bonus to prevent cpu
bound tasks from getting high priority with single long sleeps. There is a
bug in the current code that also penalises tasks that already have high
priority. Correct that bug.
Signed-off-by: Con Kolivas <kernel@kolivas.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Alterations to the pipe code in the kernel made it possible for relative
starvation to occur with tasks that slept waiting on a pipe getting unfair
priority bonuses even if they were otherwise fully cpu bound so the
TASK_NONINTERACTIVE flag was introduced which prevented any change to
sleep_avg while sleeping waiting on a pipe. This change also leads to the
converse though, preventing any priority boost from occurring in truly
interactive tasks that wait on pipes.
Convert the TASK_NONINTERACTIVE flag to set sleep_type to SLEEP_NONINTERACTIVE
which will allow a linear bonus to priority based on sleep time thus allowing
interactive tasks to get high priority if they sleep enough.
Signed-off-by: Con Kolivas <kernel@kolivas.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The activated flag in task_struct is used to track different sleep types and
its usage is somewhat obfuscated. Convert the variable to an enum with more
descriptive names without altering the function.
Signed-off-by: Con Kolivas <kernel@kolivas.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Currently, count_active_tasks() calls both nr_running() &
nr_interruptible(). Each of these functions does a "for_each_cpu" & reads
values from the runqueue of each cpu. Although this is not a lot of
instructions, each runqueue may be located on different node. Depending on
the architecture, a unique TLB entry may be required to access each
runqueue.
Since there may be more runqueues than cpu TLB entries, a scan of all
runqueues can trash the TLB. Each memory reference incurs a TLB miss &
refill.
In addition, the runqueue cacheline that contains nr_running &
nr_uninterruptible may be evicted from the cache between the two passes.
This causes unnecessary cache misses.
Combining nr_running() & nr_interruptible() into a single function
substantially reduces the TLB & cache misses on large systems. This should
have no measureable effect on smaller systems.
On a 128p IA64 system running a memory stress workload, the new function
reduced the overhead of calc_load() from 605 usec/call to 324 usec/call.
Signed-off-by: Jack Steiner <steiner@sgi.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
It seems that run_hrtimer_queue() is calling get_softirq_time() more
often than it needs to.
With this patch, it only calls get_softirq_time() if there's a
pending timer.
Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The removal of the data field in the hrtimer structure enforces the
embedding of the timer into another data structure. nanosleep now uses a
private implementation of the most common used timer callback function
(simple task wakeup).
In order to avoid the reimplentation of such functionality all over the
place a generic hrtimer_sleeper functionality is created.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
NEW_LEDS support for ixp4xx boards where LEDs are connected to the GPIO lines.
This includes a new generic ixp4xx driver (leds-ixp4xx-gpio.c name
"IXP4XX-GPIO-LED")
Signed-off-by: John Bowler <jbowler@acm.org>
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Richard Purdie
Alberto Mardegan
Antonino A. Daplas
Eric W. Biederman
Herbert Poetzl
Andrew Morton
Thomas Gleixner
Con Kolivas
Jack Steiner
Dimitri Sivanich
Dirk Opfer
John Bowler