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  1. 17 Aug, 2007 1 commit
    • David S. Miller's avatar
      [MATH-EMU]: Fix underflow exception reporting. · 40584961
      David S. Miller authored 
      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: default avatarDavid S. Miller <davem@davemloft.net>
      40584961
  3. 16 Aug, 2007 5 commits
  5. 15 Aug, 2007 2 commits
  7. 10 Aug, 2007 4 commits
    • Robert Reif's avatar
      [SPARC32]: Remove iommu from struct sbus_bus and use archdata like sparc64. · 3ac4c949
      Robert Reif authored 
      Signed-off-by: default avatarRobert Reif <reif@earthlink.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      3ac4c949
    • Jesper Juhl's avatar
      SLUB: Fix format specifier in Documentation/vm/slabinfo.c · ac078602
      Jesper Juhl authored 
      There's a little problem in Documentation/vm/slabinfo.c
The code is using "%d" in a printf() call to print an 'unsigned long'.
This patch corrects it to use "%lu" instead.
Signed-off-by: default avatarJesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      ac078602
    • Christoph Lameter's avatar
      SLUB: Fix dynamic dma kmalloc cache creation · 1ceef402
      Christoph Lameter authored 
      The dynamic dma kmalloc creation can run into trouble if a
GFP_ATOMIC allocation is the first one performed for a certain size
of dma kmalloc slab.

- Move the adding of the slab to sysfs into a workqueue
  (sysfs does GFP_KERNEL allocations)
- Do not call kmem_cache_destroy() (uses slub_lock)
- Only acquire the slub_lock once and--if we cannot wait--do a trylock.

  This introduces a slight risk of the first kmalloc(x, GFP_DMA|GFP_ATOMIC)
  for a range of sizes failing due to another process holding the slub_lock.
  However, we only need to acquire the spinlock once in order to establish
  each power of two DMA kmalloc cache. The possible conflict is with the
  slub_lock taken during slab management actions (create / remove slab cache).

  It is rather typical that a driver will first fill its buffers using
  GFP_KERNEL allocations which will wait until the slub_lock can be acquired.
  Drivers will also create its slab caches first outside of an atomic
  context before starting to use atomic kmalloc from an interrupt context.

  If there are any failures then they will occur early after boot or when
  loading of multiple drivers concurrently. Drivers can already accomodate
  failures of GFP_ATOMIC for other reasons. Retries will then create the slab.
Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      1ceef402
    • Christoph Lameter's avatar
      SLUB: Remove checks for MAX_PARTIAL from kmem_cache_shrink · fcda3d89
      Christoph Lameter authored 
      The MAX_PARTIAL checks were supposed to be an optimization. However, slab
shrinking is a manually triggered process either through running slabinfo
or by the kernel calling kmem_cache_shrink.

If one really wants to shrink a slab then all operations should be done
regardless of the size of the partial list. This also fixes an issue that
could surface if the number of partial slabs was initially above MAX_PARTIAL
in kmem_cache_shrink and later drops below MAX_PARTIAL through the
elimination of empty slabs on the partial list (rare). In that case a few
slabs may be left off the partial list (and only be put back when they
are empty).
Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      fcda3d89
  9. 09 Aug, 2007 28 commits
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