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  1. 18 8月, 2007 1 次提交
  3. 17 8月, 2007 2 次提交
    • D
      [MATH-EMU]: Fix underflow exception reporting. · 40584961
      由 David S. Miller 提交于 
      The underflow exception cases were wrong.

This is one weird area of ieee1754 handling in that the underflow
behavior changes based upon whether underflow is enabled in the trap
enable mask of the FPU control register.  As a specific case the Sparc
V9 manual gives us the following description:

--------------------
If UFM = 0:     Underflow occurs if a nonzero result is tiny and a
                loss of accuracy occurs.  Tininess may be detected
                before or after rounding.  Loss of accuracy may be
                either a denormalization loss or an inexact result.

If UFM = 1:     Underflow occurs if a nonzero result is tiny.
                Tininess may be detected before or after rounding.
--------------------

What this amounts to in the packing case is if we go subnormal,
we set underflow if any of the following are true:

1) rounding sets inexact
2) we ended up rounding back up to normal (this is the case where
   we set the exponent to 1 and set the fraction to zero), this
   should set inexact too
3) underflow is set in FPU control register trap-enable mask

The initially discovered example was "DBL_MIN / 16.0" which
incorrectly generated an underflow.  It should not, unless underflow
is set in the trap-enable mask of the FPU csr.

Another example, "0x0.0000000000001p-1022 / 16.0", should signal both
inexact and underflow.  The cpu implementations and ieee1754
literature is very clear about this.  This is case #2 above.

However, if underflow is set in the trap enable mask, only underflow
should be set and reported as a trap.  That is handled properly by the
prioritization logic in

arch/sparc{,64}/math-emu/math.c:record_exception().

Based upon a report and test case from Jakub Jelinek.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      40584961
    • D
      [SPARC64]: Create a HWCAP_SPARC_N2 and report it to userspace on Niagara-2. · 8b224b81
      由 David S. Miller 提交于 
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      8b224b81
  5. 15 8月, 2007 4 次提交
  7. 14 8月, 2007 3 次提交
  9. 13 8月, 2007 1 次提交
  11. 12 8月, 2007 14 次提交
  13. 11 8月, 2007 1 次提交
  15. 10 8月, 2007 4 次提交
  17. 09 8月, 2007 10 次提交
    • R
      Fix Alpha O_CLOEXEC definition · 620b5e68
      由 Richard Henderson 提交于 
      The default definition in asm-generic conflicts with Alpha's O_DIRECT,
so, like several other arches, it needs to be redefined.
Signed-off-by: NRichard Hendersion  <rth@twiddle.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      620b5e68
    • A
      hexdump: use const notation · 6a0ed91e
      由 Artem Bityutskiy 提交于 
      Trivial fix: mark the buffer to hexdump as const so callers could avoid
casting their const buffers when calling print_hex_dump().

The patch is really trivial and I suggest to consider it as a fix
(it fixes GCC warnings) and push it to current tree.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      6a0ed91e
    • I
      sched: remove the 'u64 now' parameter from ->task_new() · ee0827d8
      由 Ingo Molnar 提交于 
      remove the 'u64 now' parameter from ->task_new().

( identity transformation that causes no change in functionality. )
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      ee0827d8
    • I
      sched: remove the 'u64 now' parameter from ->put_prev_task() · 31ee529c
      由 Ingo Molnar 提交于 
      remove the 'u64 now' parameter from ->put_prev_task().

( identity transformation that causes no change in functionality. )
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      31ee529c
    • I
      sched: remove the 'u64 now' parameter from ->pick_next_task() · fb8d4724
      由 Ingo Molnar 提交于 
      remove the 'u64 now' parameter from ->pick_next_task().

( identity transformation that causes no change in functionality. )
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      fb8d4724
    • I
      sched: remove the 'u64 now' parameter from ->dequeue_task() · f02231e5
      由 Ingo Molnar 提交于 
      remove the 'u64 now' parameter from ->dequeue_task().

( identity transformation that causes no change in functionality. )
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      f02231e5
    • I
      sched: remove the 'u64 now' parameter from ->enqueue_task() · fd390f6a
      由 Ingo Molnar 提交于 
      remove the 'u64 now' parameter from ->enqueue_task().

( identity transformation that causes no change in functionality. )
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      fd390f6a
    • I
      sched: remove the 'u64 now' parameter from print_cfs_rq() · 5cef9eca
      由 Ingo Molnar 提交于 
      remove the 'u64 now' parameter from print_cfs_rq().

( identity transformation that causes no change in functionality. )
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      5cef9eca
    • P
      sched: fix bug in balance_tasks() · a4ac01c3
      由 Peter Williams 提交于 
      There are two problems with balance_tasks() and how it used:

1. The variables best_prio and best_prio_seen (inherited from the old
move_tasks()) were only required to handle problems caused by the
active/expired arrays, the order in which they were processed and the
possibility that the task with the highest priority could be on either.
  These issues are no longer present and the extra overhead associated
with their use is unnecessary (and possibly wrong).

2. In the absence of CONFIG_FAIR_GROUP_SCHED being set, the same
this_best_prio variable needs to be used by all scheduling classes or
there is a risk of moving too much load.  E.g. if the highest priority
task on this at the beginning is a fairly low priority task and the rt
class migrates a task (during its turn) then that moved task becomes the
new highest priority task on this_rq but when the sched_fair class
initializes its copy of this_best_prio it will get the priority of the
original highest priority task as, due to the run queue locks being
held, the reschedule triggered by pull_task() will not have taken place.
  This could result in inappropriate overriding of skip_for_load and
excessive load being moved.

The attached patch addresses these problems by deleting all reference to
best_prio and best_prio_seen and making this_best_prio a reference
parameter to the various functions involved.

load_balance_fair() has also been modified so that this_best_prio is
only reset (in the loop) if CONFIG_FAIR_GROUP_SCHED is set.  This should
preserve the effect of helping spread groups' higher priority tasks
around the available CPUs while improving system performance when
CONFIG_FAIR_GROUP_SCHED isn't set.
Signed-off-by: NPeter Williams <pwil3058@bigpond.net.au>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      a4ac01c3
    • P
      sched: simplify move_tasks() · 43010659
      由 Peter Williams 提交于 
      The move_tasks() function is currently multiplexed with two distinct
capabilities:

1. attempt to move a specified amount of weighted load from one run
queue to another; and
2. attempt to move a specified number of tasks from one run queue to
another.

The first of these capabilities is used in two places, load_balance()
and load_balance_idle(), and in both of these cases the return value of
move_tasks() is used purely to decide if tasks/load were moved and no
notice of the actual number of tasks moved is taken.

The second capability is used in exactly one place,
active_load_balance(), to attempt to move exactly one task and, as
before, the return value is only used as an indicator of success or failure.

This multiplexing of sched_task() was introduced, by me, as part of the
smpnice patches and was motivated by the fact that the alternative, one
function to move specified load and one to move a single task, would
have led to two functions of roughly the same complexity as the old
move_tasks() (or the new balance_tasks()).  However, the new modular
design of the new CFS scheduler allows a simpler solution to be adopted
and this patch addresses that solution by:

1. adding a new function, move_one_task(), to be used by
active_load_balance(); and
2. making move_tasks() a single purpose function that tries to move a
specified weighted load and returns 1 for success and 0 for failure.

One of the consequences of these changes is that neither move_one_task()
or the new move_tasks() care how many tasks sched_class.load_balance()
moves and this enables its interface to be simplified by returning the
amount of load moved as its result and removing the load_moved pointer
from the argument list.  This helps simplify the new move_tasks() and
slightly reduces the amount of work done in each of
sched_class.load_balance()'s implementations.

Further simplification, e.g. changes to balance_tasks(), are possible
but (slightly) complicated by the special needs of load_balance_fair()
so I've left them to a later patch (if this one gets accepted).

NB Since move_tasks() gets called with two run queue locks held even
small reductions in overhead are worthwhile.

[ mingo@elte.hu ]

this change also reduces code size nicely:

   text    data     bss     dec     hex filename
   39216    3618      24   42858    a76a sched.o.before
   39173    3618      24   42815    a73f sched.o.after
Signed-off-by: NPeter Williams <pwil3058@bigpond.net.au>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      43010659