Convert kernel/rcupdate's rcu_barrier_sema to mutex.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Acked-by: N"Paul E. McKenney" <paulmck@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

convert cpuset.c's callback_sem and manage_sem to mutexes.
Build and boot tested by Ingo.
Build, boot, unit and stress tested by pj.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NPaul Jackson <pj@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Avoid taking the global tasklist_lock when possible, if a process is single
threaded during getrusage().  Any avoidance of tasklist_lock is good for
NUMA boxes (and possibly for large SMPs).  Thanks to Oleg Nesterov for
review and suggestions.
Signed-off-by: NNippun Goel <nippung@calsoftinc.com>
Signed-off-by: NRavikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: NShai Fultheim <shai@scalex86.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

1) Reduce the size of (struct fdtable) to exactly 64 bytes on 32bits
   platforms, lowering kmalloc() allocated space by 50%.

2) Reduce the size of (files_struct), using a special 32 bits (or
   64bits) embedded_fd_set, instead of a 1024 bits fd_set for the
   close_on_exec_init and open_fds_init fields.  This save some ram (248
   bytes per task) as most tasks dont open more than 32 files.  D-Cache
   footprint for such tasks is also reduced to the minimum.

3) Reduce size of allocated fdset.  Currently two full pages are
   allocated, that is 32768 bits on x86 for example, and way too much.  The
   minimum is now L1_CACHE_BYTES.

UP and SMP should benefit from this patch, because most tasks will touch
only one cache line when open()/close() stdin/stdout/stderr (0/1/2),
(next_fd, close_on_exec_init, open_fds_init, fd_array[0 ..  2] being in the
same cache line)
Signed-off-by: NEric Dumazet <dada1@cosmosbay.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Add the SNAPSHOT_S2RAM ioctl to the snapshot device.

This ioctl allows a userland application to make the system (previously frozen
with the SNAPSHOT_FREE ioctl) enter the S3 state without freezing processes
and disabling nonboot CPUs for the second time.

This will allow us to implement the suspend-to-disk-and-RAM (STDR)
functionality in the userland suspend tools.
Signed-off-by: NLuca Tettamanti <kronos.it@gmail.com>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Remove the console-switching code from the suspend part of the swsusp userland
interface and let the userland tools switch the console.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Acked-by: NPavel Machek <pavel@suse.cz>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Highmem could be in pcp list as well.

Signed-off-by: Shaohua Li<shaohua.li@intel.com>
Acked-by: NPavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch from Pavel moves userland freeze signals handling into more logical
place.  It now hits even with mysqld running.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: NPavel Machek <pavel@suse.cz>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Combination of printk/pr_debug led to <7> in the middle of the line, and we
printed way too many dots.
Signed-off-by: NPavel Machek <pavel@suse.cz>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Allow swsusp to freeze processes successfully under heavy load by freezing
userspace processes before kernel threads.

[Thanks to Nigel Cunningham <nigel@suspend2.net> for suggesting the
way to go.]
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Acked-by: NPavel Machek <pavel@suse.cz>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch introduces a user space interface for swsusp.

The interface is based on a special character device, called the snapshot
device, that allows user space processes to perform suspend and resume-related
operations with the help of some ioctls and the read()/write() functions.
 Additionally it allows these processes to allocate free swap pages from a
selected swap partition, called the resume partition, so that they know which
sectors of the resume partition are available to them.

The interface uses the same low-level system memory snapshot-handling
functions that are used by the built-it swap-writing/reading code of swsusp.

The interface documentation is included in the patch.

The patch assumes that the major and minor numbers of the snapshot device will
be 10 (ie.  misc device) and 231, the registration of which has already been
requested.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Acked-by: NPavel Machek <pavel@ucw.cz>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Update suspend-to-RAM documentation with new machines, and makes message
when processes can't be stopped little clearer.  (In one case, waiting
longer actually did help).

From: "Rafael J. Wysocki" <rjw@sisk.pl>

  Warn in the documentation that data may be lost if there are some
  filesystems mounted from USB devices before suspend.

  [Thanks to Alan Stern for providing the answer to the question in the
  Q:-A: part.]
Signed-off-by: NPavel Machek <pavel@suse.cz>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Move externs from C source files to header files.
Signed-off-by: NRandy Dunlap <rdunlap@xenotime.net>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Move the swap-writing/reading code of swsusp to a separate file.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Acked-by: NPavel Machek <pavel@ucw.cz>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Introduce the low level interface that can be used for handling the
snapshot of the system memory by the in-kernel swap-writing/reading code of
swsusp and the userland interface code (to be introduced shortly).

Also change the way in which swsusp records the allocated swap pages and,
consequently, simplifies the in-kernel swap-writing/reading code (this is
necessary for the userland interface too).  To this end, it introduces two
helper functions in mm/swapfile.c, so that the swsusp code does not refer
directly to the swap internals.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Acked-by: NPavel Machek <pavel@ucw.cz>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This was a temporary thing for 2.6.16.

Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

We have noticed lockups during boot when stress testing kexec on ppc64.
Two cpus would deadlock in scheduler code trying to grab already taken
spinlocks.

The double_rq_lock code uses the address of the runqueue to order the
taking of multiple locks.  This address is a per cpu variable:

	if (rq1 < rq2) {
		spin_lock(&rq1->lock);
		spin_lock(&rq2->lock);
	} else {
		spin_lock(&rq2->lock);
		spin_lock(&rq1->lock);
	}

On the other hand, the code in wake_sleeping_dependent uses the cpu id
order to grab locks:

	for_each_cpu_mask(i, sibling_map)
		spin_lock(&cpu_rq(i)->lock);

This means we rely on the address of per cpu data increasing as cpu ids
increase.  While this will be true for the generic percpu implementation it
may not be true for arch specific implementations.

One way to solve this is to always take runqueues in cpu id order. To do
this we add a cpu variable to the runqueue and check it in the
double runqueue locking functions.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Acked-by: NIngo Molnar <mingo@elte.hu>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

When on_each_cpu() runs the callback on other CPUs, it runs with local
interrupts disabled.  So we should run the function with local interrupts
disabled on this CPU, too.

And do the same for UP, so the callback is run in the same environment on both
UP and SMP.  (strictly it should do preempt_disable() too, but I think
local_irq_disable is sufficiently equivalent).

Also uninlines on_each_cpu().  softirq.c was the most appropriate file I could
find, but it doesn't seem to justify creating a new file.

Oh, and fix up that comment over (under?) x86's smp_call_function().  It
drives me nuts.
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

A bare bones trivial patch to ensure we always get -EINVAL on the
unsupported cases for sys_unshare.  If this goes in before 2.6.16 it allows
us to forward compatible with future applications using sys_unshare.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Cc: JANAK DESAI <janak@us.ibm.com>
Cc: <stable@kerenl.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Remove the sleep_avg multiplier.  This multiplier was necessary back when
we had 10 seconds of dynamic range in sleep_avg, but now that we only have
one second, it causes that one second to be compressed down to 100ms in
some cases.  This is particularly noticeable when compiling a kernel in a
slow NFS mount, and I believe it to be a very likely candidate for other
recently reported network related interactivity problems.

In testing, I can detect no negative impact of this removal.
Signed-off-by: NMike Galbraith <efault@gmx.de>
Acked-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The module files, refcnt, version, and srcversion did not properly
increment the owner's module reference count, allowing the modules to
be removed while the files were open, causing oopses.

This patch fixes this, and also fixes the problem that the version and
srcversion files were not showing up, unless CONFIG_MODULE_UNLOAD was
enabled, which is not correct.

Cc: Nathan Lynch <ntl@pobox.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

As the RCU symbols are going to be changed to GPL in the near future,
lets warn users that this is going to happen.

Cc: Paul McKenney <paulmck@us.ibm.com>
Acked-by: NDipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch adds the ability to mark symbols that will be changed in the
future, so that kernel modules that don't include MODULE_LICENSE("GPL")
and use the symbols, will be flagged and printed out to the system log.
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Moving uevent_seqnum and uevent_helper to kobject_uevent.c
because they are used even if CONFIG_SYSFS=n
while kernel/ksysfs.c is built only if CONFIG_SYSFS=y,
Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

testcase:

mount /dev/sdb10 /mnt
touch /mnt/tmp/b
umount /mnt
mount /dev/sdb10 /mnt
rm /mnt/tmp/b </mnt/tmp/b
umount /mnt

and watch blkdev_ioc line in /proc/slabinfo.  Vanilla kernel leaks.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

sys_unshare() does mmput(new_mm).  This is not enough if we have
mm->core_waiters.

This patch is a temporary fix for soon to be released 2.6.16.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
[ Checked with Uli: "I'm not planning to use unshare(CLONE_VM).  It's
  not needed for any functionality planned so far.  What we (as in Red
  Hat) need unshare() for now is the filesystem side." ]
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

When the posix-timer signal is ignored then the timer is rearmed by the
callback function.  The requeue pending accounting has to be fixed up else
the state might be wrong.
Signed-off-by: NRoman Zippel <zippel@linux-m68k.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The pointer to the current time interpolator and the current list of time
interpolators are typically only changed during bootup.  Adding
__read_mostly takes them away from possibly hot cachelines.
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The sighand pointer only needs the rcu_read_lock on the
read side.  So only depending on task_lock protection
when setting this pointer is not enough.  We also need
a memory barrier to ensure the initialization is seen first.

Use rcu_assign_pointer as it does this for us, and clearly
documents that we are setting an rcu readable pointer.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Acked-by: NPaul E. McKenney <paulmck@us.ibm.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch fixes alternate signal stack corruption among cloned threads
with CLONE_SIGHAND (and CLONE_VM) for linux-2.6.16-rc6.

The value of alternate signal stack is currently inherited after a call of
clone(...  CLONE_SIGHAND | CLONE_VM).  But if sigaltstack is set by a
parent thread, and then if multiple cloned child threads (+ parent threads)
call signal handler at the same time, some threads may be conflicted -
because they share to use the same alternative signal stack region.
Finally they get sigsegv.  It's an undesirable race condition.  Note that
child threads created from NPTL pthread_create() also hit this conflict
when the parent thread uses sigaltstack, without my patch.

To fix this problem, this patch clears the child threads' sigaltstack
information like exec().  This behavior follows the SUSv3 specification.
In SUSv3, pthread_create() says "The alternate stack shall not be inherited
(when new threads are initialized)".  It means that sigaltstack should be
cleared when sigaltstack memory space is shared by cloned threads with
CLONE_SIGHAND.

Note that I chose "if (clone_flags & CLONE_SIGHAND)" line because:
  - If clone_flags line is not existed, fork() does not inherit sigaltstack.
  - CLONE_VM is another choice, but vfork() does not inherit sigaltstack.
  - CLONE_SIGHAND implies CLONE_VM, and it looks suitable.
  - CLONE_THREAD is another candidate, and includes CLONE_SIGHAND + CLONE_VM,
    but this flag has a bit different semantics.
I decided to use CLONE_SIGHAND.

[ Changed to test for CLONE_VM && !CLONE_VFORK after discussion --Linus ]
Signed-off-by: NGOTO Masanori <gotom@sanori.org>
Cc: Roland McGrath <roland@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: NLinus Torvalds <torvalds@osdl.org>
Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Jakub Jelinek <jakub@redhat.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The patch '[PATCH] RCU signal handling' [1] added an export for
__put_task_struct_cb, a put_task_struct helper newly introduced in that
patch.  But the put_task_struct couldn't be used modular previously as
__put_task_struct wasn't exported.  There are not callers of it in modular
code, and it shouldn't be exported because we don't want drivers to hold
references to task_structs.

This patch removes the export and folds __put_task_struct into
__put_task_struct_cb as there's no other caller.

[1] http://www2.kernel.org/git/gitweb.cgi?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=e56d090310d7625ecb43a1eeebd479f04affb48bSigned-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NPaul E. McKenney <paulmck@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

I have benchmarked this on an x86_64 NUMA system and see no significant
performance difference on kernbench.  Tested on both x86_64 and powerpc.

The way we do file struct accounting is not very suitable for batched
freeing.  For scalability reasons, file accounting was
constructor/destructor based.  This meant that nr_files was decremented
only when the object was removed from the slab cache.  This is susceptible
to slab fragmentation.  With RCU based file structure, consequent batched
freeing and a test program like Serge's, we just speed this up and end up
with a very fragmented slab -

llm22:~ # cat /proc/sys/fs/file-nr
587730  0       758844

At the same time, I see only a 2000+ objects in filp cache.  The following
patch I fixes this problem.

This patch changes the file counting by removing the filp_count_lock.
Instead we use a separate percpu counter, nr_files, for now and all
accesses to it are through get_nr_files() api.  In the sysctl handler for
nr_files, we populate files_stat.nr_files before returning to user.

Counting files as an when they are created and destroyed (as opposed to
inside slab) allows us to correctly count open files with RCU.
Signed-off-by: NDipankar Sarma <dipankar@in.ibm.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch adds new tunables for RCU queue and finished batches.  There are
two types of controls - number of completed RCU updates invoked in a batch
(blimit) and monitoring for high rate of incoming RCUs on a cpu (qhimark,
qlowmark).

By default, the per-cpu batch limit is set to a small value.  If the input
RCU rate exceeds the high watermark, we do two things - force quiescent
state on all cpus and set the batch limit of the CPU to INTMAX.  Setting
batch limit to INTMAX forces all finished RCUs to be processed in one shot.
 If we have more than INTMAX RCUs queued up, then we have bigger problems
anyway.  Once the incoming queued RCUs fall below the low watermark, the
batch limit is set to the default.
Signed-off-by: NDipankar Sarma <dipankar@in.ibm.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Idle threads should have a sane ->timestamp value, to avoid init kernel
thread(s) from inheriting it and causing miscalculations in
try_to_wake_up().

Reported-by: Mike Galbraith <efault@gmx.de>.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Add a compiler barrier so that we don't read jiffies before updating
jiffies_64.
Signed-off-by: NAtsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Also from Thomas Gleixner <tglx@linutronix.de>

Function next_timer_interrupt() got broken with a recent patch
6ba1b912 as sys_nanosleep() was moved to
hrtimer.  This broke things as next_timer_interrupt() did not check hrtimer
tree for next event.

Function next_timer_interrupt() is needed with dyntick (CONFIG_NO_IDLE_HZ,
VST) implementations, as the system can be in idle when next hrtimer event
was supposed to happen.  At least ARM and S390 currently use
next_timer_interrupt().
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Just to be safe, we should not trigger a conditional reschedule during
the early boot sequence.  We've historically done some questionable
early on, and the safety warnings in __might_sleep() are generally
turned off during that period, so there might be problems lurking.

This affects CONFIG_PREEMPT_VOLUNTARY, which takes over might_sleep() to
cause a voluntary conditional reschedule.
Acked-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

On some platforms readq performs additional work to make sure I/O is done
in a coherent way.  This is not needed for time retrieval as done by the
time interpolator.  So we can use readq_relaxed instead which will improve
performance.

It affects sparc64 and ia64 only.  Apparently it makes a significant
difference on ia64.
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Cc: john stultz <johnstul@us.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

acpi_video_flags variable is unsigned long, so it should be set as such.
This actually matters on x86-64.
Signed-off-by: NStefan Seyfried <seife@suse.de>
Signed-off-by: NPavel Machek <pavel@suse.cz>
Cc: "Brown, Len" <len.brown@intel.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>