Peter pointed out that hrtick_enabled() should use cpu_active().
Signed-off-by: Ingo Molnar <mingo@elte.hu>

random uvesafb failures were reported against Gentoo:

  http://bugs.gentoo.org/show_bug.cgi?id=222799

and Mihai Moldovan bisected it back to:

> 8f4d37ec is first bad commit
> commit 8f4d37ec
> Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Date:   Fri Jan 25 21:08:29 2008 +0100
>
>    sched: high-res preemption tick

Linus suspected it to be hrtick + vm86 interaction and observed:

> Btw, Peter, Ingo: I think that commit is doing bad things. They aren't
> _incorrect_ per se, but they are definitely bad.
>
> Why?
>
> Using random _TIF_WORK_MASK flags is really impolite for doing
> "scheduling" work. There's a reason that arch/x86/kernel/entry_32.S
> special-cases the _TIF_NEED_RESCHED flag: we don't want to exit out of
> vm86 mode unnecessarily.
>
> See the "work_notifysig_v86" label, and how it does that
> "save_v86_state()" thing etc etc.

Right, I never liked having to fiddle with those TIF flags. Initially I
needed it because the hrtimer base lock could not nest in the rq lock.
That however is fixed these days.

Currently the only reason left to fiddle with the TIF flags is remote
wakeups. We cannot program a remote cpu's hrtimer. I've been thinking
about using the new and improved IPI function call stuff to implement
hrtimer_start_on().

However that does require that smp_call_function_single(.wait=0) works
from interrupt context - /me looks at the latest series from Jens - Yes
that does seem to be supported, good.

Here's a stab at cleaning this stuff up ...

Mihai reported test success as well.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: Mihai Moldovan <ionic@ionic.de>
Cc: Michal Januszewski <spock@gentoo.org>
Cc: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

provide an empty partition_sched_domains() definition for the UP case:

 include/linux/cpuset.h: In function ‘rebuild_sched_domains':
 include/linux/cpuset.h:163: error: implicit declaration of function ‘partition_sched_domains'
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Fix inc_rt_tasks() to not declare variable 'rq' if it's not needed.  It is
declared if CONFIG_SMP or CONFIG_RT_GROUP_SCHED, but only used if CONFIG_SMP.

This is a consequence of patch 1f11eb6a plus
patch 1100ac91.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

This goes on top of the cpu_active_map (take 2) patch.

Currently we depend on the stop_machine to provide nescessesary
synchronization for the cpu_active_map updates.
As Dmitry Adamushko pointed this is fragile and is not much clearer
than the previous scheme. In other words we do not want to depend on
the internal stop machine operation here.
So make the synchronization rules clear by doing synchronize_sched()
after clearing out cpu active bit.

Tested on quad-Core2 with:

   while true; do
      for i in 1 2 3; do
        echo 0 > /sys/devices/system/cpu/cpu$i/online
      done
      for i in 1 2 3; do
        echo 1 > /sys/devices/system/cpu/cpu$i/online
      done
   done
and
   stress -c 200

No lockdep, preempt or other complaints.
Signed-off-by: Max Krasnyansky <maxk@qualcomm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

This is based on Linus' idea of creating cpu_active_map that prevents
scheduler load balancer from migrating tasks to the cpu that is going
down.

It allows us to simplify domain management code and avoid unecessary
domain rebuilds during cpu hotplug event handling.

Please ignore the cpusets part for now. It needs some more work in order
to avoid crazy lock nesting. Although I did simplfy and unify domain
reinitialization logic. We now simply call partition_sched_domains() in
all the cases. This means that we're using exact same code paths as in
cpusets case and hence the test below cover cpusets too.
Cpuset changes to make rebuild_sched_domains() callable from various
contexts are in the separate patch (right next after this one).

This not only boots but also easily handles
	while true; do make clean; make -j 8; done
and
	while true; do on-off-cpu 1; done
at the same time.
(on-off-cpu 1 simple does echo 0/1 > /sys/.../cpu1/online thing).

Suprisingly the box (dual-core Core2) is quite usable. In fact I'm typing
this on right now in gnome-terminal and things are moving just fine.

Also this is running with most of the debug features enabled (lockdep,
mutex, etc) no BUG_ONs or lockdep complaints so far.

I believe I addressed all of the Dmitry's comments for original Linus'
version. I changed both fair and rt balancer to mask out non-active cpus.
And replaced cpu_is_offline() with !cpu_active() in the main scheduler
code where it made sense (to me).
Signed-off-by: Max Krasnyanskiy <maxk@qualcomm.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Gregory Haskins <ghaskins@novell.com>
Cc: dmitry.adamushko@gmail.com
Cc: pj@sgi.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

(1) handle in a generic way all cases when a newly woken-up task is
not migratable (not just a corner case when "rt_se->nr_cpus_allowed ==
1")

(2) if current is to be preempted, then make sure "p" will be picked
up by pick_next_task_rt().
i.e. move task's group at the head of its list as well.

currently, it's not a case for the group-scheduling case as described
here: http://www.ussg.iu.edu/hypermail/linux/kernel/0807.0/0134.htmlSigned-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Gregory Haskins <ghaskins@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

  * Remove 16k stack requirements in isolated_cpu_setup when NR_CPUS=4096.
Signed-off-by: Mike Travis <travis@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

the removal of -mno-spe in the !ftrace case was not intended.
Signed-off-by: Ingo Molnar <mingo@elte.hu>

* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mfasheh/ocfs2:
  [PATCH] ocfs2: fix oops in mmap_truncate testing
  configfs: call drop_link() to cleanup after create_link() failure
  configfs: Allow ->make_item() and ->make_group() to return detailed errors.
  configfs: Fix failing mkdir() making racing rmdir() fail
  configfs: Fix deadlock with racing rmdir() and rename()
  configfs: Make configfs_new_dirent() return error code instead of NULL
  configfs: Protect configfs_dirent s_links list mutations
  configfs: Introduce configfs_dirent_lock
  ocfs2: Don't snprintf() without a format.
  ocfs2: Fix CONFIG_OCFS2_DEBUG_FS #ifdefs
  ocfs2/net: Silence build warnings on sparc64
  ocfs2: Handle error during journal load
  ocfs2: Silence an error message in ocfs2_file_aio_read()
  ocfs2: use simple_read_from_buffer()
  ocfs2: fix printk format warnings with OCFS2_FS_STATS=n
  [PATCH 2/2] ocfs2: Instrument fs cluster locks
  [PATCH 1/2] ocfs2: Add CONFIG_OCFS2_FS_STATS config option

* git://git.kernel.org/pub/scm/linux/kernel/git/brodo/pcmcia-fixes-2.6:
  pcmcia: ide-cs: Remove outdated comment
  pcmcia: fix cisinfo_t removal
  pcmcia: fix return value in cm4000_cs.c

Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: fix asm/e820.h for userspace inclusion
  x86: fix numaq_tsc_disable
  x86: fix kernel_physical_mapping_init() for large x86 systems

Merge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  ftrace: do not trace library functions
  ftrace: do not trace scheduler functions
  ftrace: fix lockup with MAXSMP
  ftrace: fix merge buglet

asm-x86/e820.h is included from userspace.  'x86: make e820.c to have
common functions' (b79cd8f1) broke it:

	make -C Documentation/lguest
	cc -Wall -Wmissing-declarations -Wmissing-prototypes -O3 -I../../include
lguest.c  -lz -o lguest
	In file included from ../../include/asm-x86/bootparam.h:8,
	                 from lguest.c:45:
	../../include/asm/e820.h:66: error: expected ‘)’ before ‘start’
	../../include/asm/e820.h:67: error: expected ‘)’ before ‘start’
	../../include/asm/e820.h:68: error: expected ‘)’ before ‘start’
	../../include/asm/e820.h:72: error: expected ‘=’, ‘,’, ‘;’, ‘asm’
or ‘__attribute__’ before ‘e820_update_range’
	...
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

fix:

 arch/x86/kernel/numaq_32.c: In function ‘numaq_tsc_disable’:
 arch/x86/kernel/numaq_32.c:99: warning: ‘return’ with a value, in function returning void
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Fix calls of smp_call_function*() in arch/ia64/kvm for recent API
changes.

    CC [M]  arch/ia64/kvm/kvm-ia64.o
  arch/ia64/kvm/kvm-ia64.c: In function 'handle_global_purge':
  arch/ia64/kvm/kvm-ia64.c:398: error: too many arguments to function 'smp_call_function_single'
  arch/ia64/kvm/kvm-ia64.c: In function 'kvm_vcpu_kick':
  arch/ia64/kvm/kvm-ia64.c:1696: error: too many arguments to function 'smp_call_function_single'
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Acked-by Xiantao Zhang <xiantao.zhang@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge branch 'ptrace-cleanup' of git://git.kernel.org/pub/scm/linux/kernel/git/frob/linux-2.6-utrace

* 'ptrace-cleanup' of git://git.kernel.org/pub/scm/linux/kernel/git/frob/linux-2.6-utrace:
  fix dangling zombie when new parent ignores children
  do_wait: return security_task_wait() error code in place of -ECHILD
  ptrace children revamp
  do_wait reorganization

Also fix unwanted rebuilds of the firmware/ihex2fw tool by including
the .ihex2fw.cmd file when present.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Reported-and-tested-by: Wang Chen <wangchen@cn.fujitsu.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

* 'for-linus' of git://git390.osdl.marist.edu/pub/scm/linux-2.6:
  [S390] dasd: use -EOPNOTSUPP instead of -ENOTSUPP
  [S390] qdio: new qdio driver.
  [S390] cio: Export chsc_error_from_response().
  [S390] vmur: Fix return code handling.
  [S390] Fix stacktrace compile bug.
  [S390] Increase default warning stacksize.
  [S390] dasd: Fix cleanup in dasd_{fba,diag}_check_characteristics().
  [S390] chsc headers userspace cleanup
  [S390] dasd: fix unsolicited SIM handling.
  [S390] zfcpdump: Make SCSI disk dump tool recognize storage holes

The patch named "powerpc/mpc5121: Add clock driver", also contained
an unrelated and bogus change to the top-level makefile.  This patch
backs out the bad bit.

SHA1 of offending patch: 137e9590)
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Repented-by: John Rigby <jrigby@freescale.com>
[ Heh. Normally I pick these out from the diffstats, but I guess
  I've grown to trust the ppc tree too much ;)   - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

make function tracing more robust: do not trace library functions.

We've already got a sizable list of exceptions:

 ifdef CONFIG_FTRACE
 # Do not profile string.o, since it may be used in early boot or vdso
 CFLAGS_REMOVE_string.o = -pg
 # Also do not profile any debug utilities
 CFLAGS_REMOVE_spinlock_debug.o = -pg
 CFLAGS_REMOVE_list_debug.o = -pg
 CFLAGS_REMOVE_debugobjects.o = -pg
 CFLAGS_REMOVE_find_next_bit.o = -pg
 CFLAGS_REMOVE_cpumask.o = -pg
 CFLAGS_REMOVE_bitmap.o = -pg
 endif

... and the pattern has been that random library functionality showed
up in ftrace's critical path (outside of its recursion check), causing
hard to debug lockups.

So be a bit defensive about it and exclude all lib/*.o functions by
default. It's not that they are overly interesting for tracing purposes
anyway. Specific ones can still be traced, in an opt-in manner.
Signed-off-by: Ingo Molnar <mingo@elte.hu>

do not trace scheduler functions - it's still a bit fragile
and can lock up with:

  http://redhat.com/~mingo/misc/config-Thu_Jul_17_13_34_52_CEST_2008Signed-off-by: Ingo Molnar <mingo@elte.hu>

MAXSMP brings in lots of use of various bitops in smp_processor_id()
and friends - causing ftrace to lock up during bootup:

  calling  anon_inode_init+0x0/0x130
  initcall anon_inode_init+0x0/0x130 returned 0 after 0 msecs
  calling  acpi_event_init+0x0/0x57
  [ hard hang ]

So exclude the bitops facilities from tracing.
Signed-off-by: Ingo Molnar <mingo@elte.hu>

return value -ENOTSUPP is not valid in userspace context, use
-EOPNOTSUPP instead
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

List of major changes:
- split qdio driver into several files
- seperation of thin interrupt code
- improved handling for multiple thin interrupt devices
- inbound and outbound processing now always runs in tasklet context
- significant less tasklet schedules per interrupt needed
- merged qebsm with non-qebsm handling
- cleanup qdio interface and added kerneldoc
- coding style
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Utz Bacher <utz.bacher@de.ibm.com>
Reviewed-by: Ursula Braun <braunu@de.ibm.com>
Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

Make chsc_error_from_response() available to chsc callers outside
of chsc.c (namely qdio) to avoid duplicating error checking code.
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

Use -EOPNOTSUPP instead of -ENOTSUPP.
Signed-off-by: Frank Munzert <munzert@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>

Add missing module.h include to fix this:

  CC      arch/s390/kernel/stacktrace.o
arch/s390/kernel/stacktrace.c:84: warning: data definition has no type or storage class
arch/s390/kernel/stacktrace.c:84: warning: type defaults to 'int' in declaration of 'EXPORT_SYMBOL_GPL'
arch/s390/kernel/stacktrace.c:84: warning: parameter names (without types) in function declaration
arch/s390/kernel/stacktrace.c:97: warning: data definition has no type or storage class
arch/s390/kernel/stacktrace.c:97: warning: type defaults to 'int' in declaration of 'EXPORT_SYMBOL_GPL'
arch/s390/kernel/stacktrace.c:97: warning: parameter names (without types) in function declaration
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>

Compiling a kernel with allmodconfig or allyesconfig results in tons
of gcc warnings, because the default maximum stacksize from which on
gcc will emit a warning is just 256 bytes.
Increase this to 2048, so these warnings don't distract from the real
warnings that we need to watch at.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>

Kernel headers shouldn't expose functions to userspace.

Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>

Add missing schedule_bh and check that there is 32 bit sense data.
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>

The kernel part of zfcpdump establishes a new debugfs file zcore/memmap
which exports information on memory layout (start address and length of each
memory chunk) to its userspace counterpart.
Signed-off-by: Frank Munzert <munzert@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>

-tip testing found a bootup hang here:

  initcall anon_inode_init+0x0/0x130 returned 0 after 0 msecs
  calling  acpi_event_init+0x0/0x57

the bootup should have continued with:

  initcall acpi_event_init+0x0/0x57 returned 0 after 45 msecs

but it hung hard there instead.

bisection led to this commit:

| commit 5806b81a
| Merge: d14c8a68... 6712e299...
| Author: Ingo Molnar <mingo@elte.hu>
| Date:   Mon Jul 14 16:11:52 2008 +0200
|     Merge branch 'auto-ftrace-next' into tracing/for-linus

turns out that i made this mistake in the merge:

  ifdef CONFIG_FTRACE
  # Do not profile debug utilities
  CFLAGS_REMOVE_tsc_64.o = -pg
  CFLAGS_REMOVE_tsc_32.o = -pg

those two files got unified meanwhile - so the dont-profile annotation
got lost. The proper rule is:

  CFLAGS_REMOVE_tsc.o = -pg

i guess this could have been caught sooner if the CFLAGS_REMOVE* kbuild
rule aborted the build if it met a target that does not exist anymore?
Signed-off-by: Ingo Molnar <mingo@elte.hu>

This fixes an arcane bug that we think was a regression introduced
by commit b2b2cbc4.  When a parent
ignores SIGCHLD (or uses SA_NOCLDWAIT), its children would self-reap
but they don't if it's using ptrace on them.  When the parent thread
later exits and ceases to ptrace a child but leaves other live
threads in the parent's thread group, any zombie children are left
dangling.  The fix makes them self-reap then, as they would have
done earlier if ptrace had not been in use.
Signed-off-by: Roland McGrath <roland@redhat.com>

This reverts the effect of commit f2cc3eb1
"do_wait: fix security checks".  That change reverted the effect of commit
73243284.  The rationale for the original
commit still stands.  The inconsistent treatment of children hidden by
ptrace was an unintended omission in the original change and in no way
invalidates its purpose.

This makes do_wait return the error returned by security_task_wait()
(usually -EACCES) in place of -ECHILD when there are some children the
caller would be able to wait for if not for the permission failure.  A
permission error will give the user a clue to look for security policy
problems, rather than for mysterious wait bugs.
Signed-off-by: Roland McGrath <roland@redhat.com>

ptrace no longer fiddles with the children/sibling links, and the
old ptrace_children list is gone.  Now ptrace, whether of one's own
children or another's via PTRACE_ATTACH, just uses the new ptraced
list instead.

There should be no user-visible difference that matters.  The only
change is the order in which do_wait() sees multiple stopped
children and stopped ptrace attachees.  Since wait_task_stopped()
was changed earlier so it no longer reorders the children list, we
already know this won't cause any new problems.
Signed-off-by: Roland McGrath <roland@redhat.com>

This breaks out the guts of do_wait into three subfunctions.
The control flow is less nonobvious without so much goto.
do_wait_thread and ptrace_do_wait contain the main work of the outer loop.
wait_consider_task contains the main work of the inner loop.
Signed-off-by: Roland McGrath <roland@redhat.com>