linux-toradex.git/lib, branch v2.6.26-rc2

BKL: revert back to the old spinlock implementation

2008-05-11T03:58:02+00:00

The generic semaphore rewrite had a huge performance regression on AIM7
(and potentially other BKL-heavy benchmarks) because the generic
semaphores had been rewritten to be simple to understand and fair.  The
latter, in particular, turns a semaphore-based BKL implementation into a
mess of scheduling.

The attempt to fix the performance regression failed miserably (see the
previous commit 00b41ec2611dc98f87f30753ee00a53db648d662 'Revert
"semaphore: fix"'), and so for now the simple and sane approach is to
instead just go back to the old spinlock-based BKL implementation that
never had any issues like this.

This patch also has the advantage of being reported to fix the
regression completely according to Yanmin Zhang, unlike the semaphore
hack which still left a couple percentage point regression.

As a spinlock, the BKL obviously has the potential to be a latency
issue, but it's not really any different from any other spinlock in that
respect.  We do want to get rid of the BKL asap, but that has been the
plan for several years.

These days, the biggest users are in the tty layer (open/release in
particular) and Alan holds out some hope:

  "tty release is probably a few months away from getting cured - I'm
   afraid it will almost certainly be the very last user of the BKL in
   tty to get fixed as it depends on everything else being sanely locked."

so while we're not there yet, we do have a plan of action.

Tested-by: Yanmin Zhang 
Cc: Ingo Molnar 
Cc: Andi Kleen 
Cc: Matthew Wilcox 
Cc: Alexander Viro 
Cc: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'powerpc-next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc

2008-05-05T22:48:53+00:00

* 'powerpc-next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc:
  [POWERPC] Assign PDE->data before gluing PDE into /proc tree
  [POWERPC] devres: Add devm_ioremap_prot()
  [POWERPC] macintosh: ADB driver: adb_handler_sem semaphore to mutex
  [POWERPC] macintosh: windfarm_smu_sat: semaphore to mutex
  [POWERPC] macintosh: therm_pm72: driver_lock semaphore to mutex

kgdb: kconfig fix xconfig/menuconfig element

2008-05-05T12:13:21+00:00

Kconfig.kgdb: fix menuconfig element

Signed-off-by: Jan Engelhardt 
Signed-off-by: Jason Wessel

[POWERPC] devres: Add devm_ioremap_prot()

2008-05-05T06:47:14+00:00

We provide an ioremap_flags, so this provides a corresponding
devm_ioremap_prot.  The slight name difference is at Ben
Herrenschmidt's request as he plans on changing ioremap_flags to
ioremap_prot in the future.

Signed-off-by: Emil Medve 
Signed-off-by: Kumar Gala 
Acked-by: Tejun Heo 
Cc: Benjamin Herrenschmidt 
Signed-off-by: Andrew Morton 
Signed-off-by: Paul Mackerras

idr: fix idr_remove()

2008-05-01T15:04:00+00:00

The return inside the loop makes us free only a single layer.

Signed-off-by: Nadia Derbey 
Cc: "Paul E. McKenney" 
Cc: Manfred Spraul 
Cc: Jim Houston 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Add a new sysfs_streq() string comparison function

2008-05-01T15:03:59+00:00

Add a new sysfs_streq() string comparison function, which ignores
the trailing newlines found in sysfs inputs.  By example:

	sysfs_streq("a", "b")	==> false
	sysfs_streq("a", "a")	==> true
	sysfs_streq("a", "a\n")	==> true
	sysfs_streq("a\n", "a")	==> true

This is intended to simplify parsing of sysfs inputs, letting them
avoid the need to manually strip off newlines from inputs.

Signed-off-by: David Brownell 
Acked-by: Greg KH 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

rename div64_64 to div64_u64

2008-05-01T15:03:58+00:00

Rename div64_64 to div64_u64 to make it consistent with the other divide
functions, so it clearly includes the type of the divide.  Move its definition
to math64.h as currently no architecture overrides the generic implementation.
 They can still override it of course, but the duplicated declarations are
avoided.

Signed-off-by: Roman Zippel 
Cc: Avi Kivity 
Cc: Russell King 
Cc: Geert Uytterhoeven 
Cc: Ralf Baechle 
Cc: David Howells 
Cc: Jeff Dike 
Cc: Ingo Molnar 
Cc: "David S. Miller" 
Cc: Patrick McHardy 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

introduce explicit signed/unsigned 64bit divide

2008-05-01T15:03:58+00:00

The current do_div doesn't explicitly say that it's unsigned and the signed
counterpart is missing, which is e.g.  needed when dealing with time values.

This introduces 64bit signed/unsigned divide functions which also attempts to
cleanup the somewhat awkward calling API, which often requires the use of
temporary variables for the dividend.  To avoid the need for temporary
variables everywhere for the remainder, each divide variant also provides a
version which doesn't return the remainder.

Each architecture can now provide optimized versions of these function,
otherwise generic fallback implementations will be used.

As an example I provided an alternative for the current x86 divide, which
avoids the asm casts and using an union allows gcc to generate better code.
It also avoids the upper divde in a few more cases, where the result is known
(i.e.  upper quotient is zero).

Signed-off-by: Roman Zippel 
Cc: john stultz 
Cc: Thomas Gleixner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

klist: fix coding style errors in klist.h and klist.c

2008-04-30T23:52:58+00:00

Finally clean up the odd spacing in these files.

Signed-off-by: Greg Kroah-Hartman

devres: support addresses greater than an unsigned long via dev_ioremap

2008-04-30T23:52:48+00:00

Use a resource_size_t instead of unsigned long since some arch's are
capable of having ioremap deal with addresses greater than the size of a
unsigned long.

Signed-off-by: Kumar Gala 
Cc: Tejun Heo 
Cc: Jeff Garzik 
Signed-off-by: Greg Kroah-Hartman