* git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched: (61 commits)
  sched: refine negative nice level granularity
  sched: fix update_stats_enqueue() reniced codepath
  sched: round a bit better
  sched: make the multiplication table more accurate
  sched: optimize update_rq_clock() calls in the load-balancer
  sched: optimize activate_task()
  sched: clean up set_curr_task_fair()
  sched: remove __update_rq_clock() call from entity_tick()
  sched: move the __update_rq_clock() call to scheduler_tick()
  sched debug: remove the 'u64 now' parameter from print_task()/_rq()
  sched: remove the 'u64 now' local variables
  sched: remove the 'u64 now' parameter from deactivate_task()
  sched: remove the 'u64 now' parameter from dequeue_task()
  sched: remove the 'u64 now' parameter from enqueue_task()
  sched: remove the 'u64 now' parameter from dec_nr_running()
  sched: remove the 'u64 now' parameter from inc_nr_running()
  sched: remove the 'u64 now' parameter from dec_load()
  sched: remove the 'u64 now' parameter from inc_load()
  sched: remove the 'u64 now' parameter from update_curr_load()
  sched: remove the 'u64 now' parameter from ->task_new()
  ...

Some versions of ld.so mmap the shared libraries right in over guest
memory, so compile lguest statically by default.

[ FC7 maps shared libraries very low, where the launcher maps guest's
  physical memory.  Quick fix is to link Launcher static, real fix is
  for 2.6.24. ]

-static is a simple fix. I expect this problem will be more common than we
like, as different distro's make different "improvements" to ld.so
Signed-off-by: Ronald G. Minnich <rminnich@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

If a Guest makes hypercall which sets a GDT entry to not present, we
currently set any segment registers using that GDT entry to 0.
Unfortunately, this is not sufficient: there are other ways of
altering GDT entries which will cause a fault.

The correct solution to do what Linux does: let them set any GDT value
they want and handle the #GP when popping causes a fault.  This has
the added benefit of making our Switcher slightly more robust in the
case of any other bugs which cause it to fault.

We kill the Guest if it causes a fault in the Switcher: it's the
Guest's responsibility to make sure it's not using segments when it
changes them.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lguest uses a host-supplied wallclock-based clocksource when the TSC
is not reliable.  As this is already in nanoseconds, I naively used a
multiplier of 1 and a shift of 0.

But update_wall_time() in its infinite wisdom decides to adjust the
clock a little (where does it think it's getting a more accurate time
from?)

It will happily tweak the multiplier... to 0, then -1.

So the "fix" is to use a shift of 22 like everyone else, and a
multiplier of 1 << 22.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This reverts commit 0fc4969b.  It was
always meant to be temporary, but it's generating more useless noise
than anything else, and we probably should never have done it in the
generic kernel (only had the people involved test it on their own).
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

refine the granularity of negative nice level tasks: let them
reschedule more often to offset the effect of them consuming
their wait_runtime proportionately slower. (This makes nice-0
task scheduling smoother in the presence of negatively
reniced tasks.)
Signed-off-by: Ingo Molnar <mingo@elte.hu>

the key has to be rescaled to /weight even if it has a positive value.

(this change only affects the scheduling of reniced tasks)
Signed-off-by: Ingo Molnar <mingo@elte.hu>

round a tiny bit better in high-frequency rescheduling scenarios,
by rounding around zero instead of rounding down.

(this is pretty theoretical though)
Signed-off-by: Ingo Molnar <mingo@elte.hu>

do small deltas in the weight and multiplication constant table so
that the worst-case numeric error is better than 1:100000000. (8 digits)

the current error table is:

     nice       mult *   inv_mult   error
     ------------------------------------------
     -20:      88761 *      48388  -0.0000000065
     -19:      71755 *      59856  -0.0000000037
     -18:      56483 *      76040   0.0000000056
     -17:      46273 *      92818   0.0000000042
     -16:      36291 *     118348  -0.0000000065
     -15:      29154 *     147320  -0.0000000037
     -14:      23254 *     184698  -0.0000000009
     -13:      18705 *     229616  -0.0000000037
     -12:      14949 *     287308  -0.0000000009
     -11:      11916 *     360437  -0.0000000009
     -10:       9548 *     449829  -0.0000000009
      -9:       7620 *     563644  -0.0000000037
      -8:       6100 *     704093   0.0000000009
      -7:       4904 *     875809   0.0000000093
      -6:       3906 *    1099582  -0.0000000009
      -5:       3121 *    1376151  -0.0000000058
      -4:       2501 *    1717300   0.0000000009
      -3:       1991 *    2157191  -0.0000000035
      -2:       1586 *    2708050   0.0000000009
      -1:       1277 *    3363326   0.0000000014
       0:       1024 *    4194304   0.0000000000
       1:        820 *    5237765   0.0000000009
       2:        655 *    6557202   0.0000000033
       3:        526 *    8165337  -0.0000000079
       4:        423 *   10153587   0.0000000012
       5:        335 *   12820798   0.0000000079
       6:        272 *   15790321   0.0000000037
       7:        215 *   19976592  -0.0000000037
       8:        172 *   24970740  -0.0000000037
       9:        137 *   31350126  -0.0000000079
      10:        110 *   39045157  -0.0000000061
      11:         87 *   49367440  -0.0000000037
      12:         70 *   61356676   0.0000000056
      13:         56 *   76695844  -0.0000000075
      14:         45 *   95443717  -0.0000000072
      15:         36 *  119304647  -0.0000000009
      16:         29 *  148102320  -0.0000000037
      17:         23 *  186737708  -0.0000000028
      18:         18 *  238609294  -0.0000000009
      19:         15 *  286331153  -0.0000000002
Signed-off-by: Ingo Molnar <mingo@elte.hu>

optimize update_rq_clock() calls in the load-balancer: update them
right after locking the runqueue(s) so that the pull functions do
not have to call it.
Signed-off-by: Ingo Molnar <mingo@elte.hu>

optimize activate_task() by removing update_rq_clock() from it.
(and add update_rq_clock() to all callsites of activate_task() that
did not have it before.)
Signed-off-by: Ingo Molnar <mingo@elte.hu>

clean up set_curr_task_fair().

( identity transformation that causes no change in functionality. )

   text    data     bss     dec     hex filename
  39170    3750      36   42956    a7cc sched.o.before
  39170    3750      36   42956    a7cc sched.o.after
Signed-off-by: Ingo Molnar <mingo@elte.hu>

remove __update_rq_clock() call from entity_tick().

no change in functionality because scheduler_tick() already calls
__update_rq_clock().
Signed-off-by: Ingo Molnar <mingo@elte.hu>

move the __update_rq_clock() call from update_cpu_load() to
scheduler_tick().

( identity transformation that causes no change in functionality. )

this allows the direct use of rq->clock in ->task_tick() functions.
Signed-off-by: Ingo Molnar <mingo@elte.hu>

remove the 'u64 now' parameter from sched_debug.c:print_task()/_rq().

( identity transformation that causes no change in functionality. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>

final step: remove all (now superfluous) 'u64 now' variables.

( identity transformation that causes no change in functionality. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>

remove the 'u64 now' parameter from deactivate_task().

( identity transformation that causes no change in functionality. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>

remove the 'u64 now' parameter from dequeue_task().

( identity transformation that causes no change in functionality. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>

remove the 'u64 now' parameter from enqueue_task().

( identity transformation that causes no change in functionality. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>

remove the 'u64 now' parameter from dec_nr_running().

( identity transformation that causes no change in functionality. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>

remove the 'u64 now' parameter from inc_nr_running().

( identity transformation that causes no change in functionality. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>

remove the 'u64 now' parameter from dec_load().

( identity transformation that causes no change in functionality. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>

remove the 'u64 now' parameter from inc_load().

( identity transformation that causes no change in functionality. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>

remove the 'u64 now' parameter from update_curr_load().

( identity transformation that causes no change in functionality. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>

remove the 'u64 now' parameter from ->task_new().

( identity transformation that causes no change in functionality. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>

remove the 'u64 now' parameter from ->put_prev_task().

( identity transformation that causes no change in functionality. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>

remove the 'u64 now' parameter from pick_next_task().

( identity transformation that causes no change in functionality. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>

remove the 'u64 now' parameter from ->pick_next_task().

( identity transformation that causes no change in functionality. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>

remove the 'u64 now' parameter from ->dequeue_task().

( identity transformation that causes no change in functionality. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>

remove the 'u64 now' parameter from ->enqueue_task().

( identity transformation that causes no change in functionality. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>

remove the 'u64 now' parameter from update_curr_rt().

( identity transformation that causes no change in functionality. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>

remove the 'u64 now' parameter from put_prev_entity().

( identity transformation that causes no change in functionality. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>

remove the 'u64 now' parameter from pick_next_entity().

( identity transformation that causes no change in functionality. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>

remove the 'u64 now' parameter from set_next_entity().

( identity transformation that causes no change in functionality. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>

remove the 'u64 now' parameter from dequeue_entity().

( identity transformation that causes no change in functionality. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>

remove the 'u64 now' parameter from enqueue_entity().

( identity transformation that causes no change in functionality. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>

remove the 'u64 now' parameter from enqueue_sleeper().

( identity transformation that causes no change in functionality. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>

remove the 'u64 now' parameter from __enqueue_sleeper().

( identity transformation that causes no change in functionality. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>

remove the 'u64 now' parameter from update_stats_curr_end().

( identity transformation that causes no change in functionality. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>

remove the 'u64 now' parameter from update_stats_dequeue().

( identity transformation that causes no change in functionality. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>