linux-toradex.git/arch/Kconfig, branch v3.3.8

mm,x86,um: move CMPXCHG_DOUBLE config option

2012-01-13T04:13:03+00:00

Move CMPXCHG_DOUBLE and rename it to HAVE_CMPXCHG_DOUBLE so architectures
can simply select the option if it is supported.

Signed-off-by: Heiko Carstens 
Acked-by: Christoph Lameter 
Cc: Pekka Enberg 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: "H. Peter Anvin" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm,x86,um: move CMPXCHG_LOCAL config option

2012-01-13T04:13:03+00:00

Move CMPXCHG_LOCAL and rename it to HAVE_CMPXCHG_LOCAL so architectures
can simply select the option if it is supported.

Signed-off-by: Heiko Carstens 
Acked-by: Christoph Lameter 
Cc: Pekka Enberg 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: "H. Peter Anvin" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm,slub,x86: decouple size of struct page from CONFIG_CMPXCHG_LOCAL

2012-01-13T04:13:03+00:00

While implementing cmpxchg_double() on s390 I realized that we don't set
CONFIG_CMPXCHG_LOCAL despite the fact that we have support for it.

However setting that option will increase the size of struct page by
eight bytes on 64 bit, which we certainly do not want.  Also, it doesn't
make sense that a present cpu feature should increase the size of struct
page.

Besides that it looks like the dependency to CMPXCHG_LOCAL is wrong and
that it should depend on CMPXCHG_DOUBLE instead.

This patch:

If an architecture supports CMPXCHG_LOCAL this shouldn't result
automatically in larger struct pages if the SLUB allocator is used.
Instead introduce a new config option "HAVE_ALIGNED_STRUCT_PAGE" which
can be selected if a double word aligned struct page is required.  Also
update x86 Kconfig so that it should work as before.

Signed-off-by: Heiko Carstens 
Acked-by: Christoph Lameter 
Cc: Pekka Enberg 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: "H. Peter Anvin" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

oprofile, x86: Reimplement nmi timer mode using perf event

2011-11-04T15:27:18+00:00

The legacy x86 nmi watchdog code was removed with the implementation
of the perf based nmi watchdog. This broke Oprofile's nmi timer
mode. To run nmi timer mode we relied on a continuous ticking nmi
source which the nmi watchdog provided. The nmi tick was no longer
available and current watchdog can not be used anymore since it runs
with very long periods in the range of seconds. This patch
reimplements the nmi timer mode using a perf counter nmi source.

V2:
* removing pr_info()
* fix undefined reference to `__udivdi3' for 32 bit build
* fix section mismatch of .cpuinit.data:nmi_timer_cpu_nb
* removed nmi timer setup in arch/x86
* implemented function stubs for op_nmi_init/exit()
* made code more readable in oprofile_init()

V3:
* fix architectural initialization in oprofile_init()
* fix CONFIG_OPROFILE_NMI_TIMER dependencies

Acked-by: Peter Zijlstra 
Signed-off-by: Robert Richter

Add Kconfig option ARCH_HAVE_NMI_SAFE_CMPXCHG

2011-08-03T15:12:37+00:00

cmpxchg() is widely used by lockless code, including NMI-safe lockless
code.  But on some architectures, the cmpxchg() implementation is not
NMI-safe, on these architectures the lockless code may need a
spin_trylock_irqsave() based implementation.

This patch adds a Kconfig option: ARCH_HAVE_NMI_SAFE_CMPXCHG, so that
NMI-safe lockless code can depend on it or provide different
implementation according to it.

On many architectures, cmpxchg is only NMI-safe for several specific
operand sizes. So, ARCH_HAVE_NMI_SAFE_CMPXCHG define in this patch
only guarantees cmpxchg is NMI-safe for sizeof(unsigned long).

Signed-off-by: Huang Ying 
Acked-by: Mike Frysinger 
Acked-by: Paul Mundt 
Acked-by: Hans-Christian Egtvedt 
Acked-by: Benjamin Herrenschmidt 
Acked-by: Chris Metcalf 
Acked-by: Richard Henderson 
CC: Mikael Starvik 
Acked-by: David Howells 
CC: Yoshinori Sato 
CC: Tony Luck 
CC: Hirokazu Takata 
CC: Geert Uytterhoeven 
CC: Michal Simek 
Acked-by: Ralf Baechle 
CC: Kyle McMartin 
CC: Martin Schwidefsky 
CC: Chen Liqin 
CC: "David S. Miller" 
CC: Ingo Molnar 
CC: Chris Zankel 
Signed-off-by: Len Brown

mm, powerpc: move the RCU page-table freeing into generic code

2011-05-25T15:39:16+00:00

In case other architectures require RCU freed page-tables to implement
gup_fast() and software filled hashes and similar things, provide the
means to do so by moving the logic into generic code.

Signed-off-by: Peter Zijlstra 
Requested-by: David Miller 
Cc: Benjamin Herrenschmidt 
Cc: Martin Schwidefsky 
Cc: Russell King 
Cc: Paul Mundt 
Cc: Jeff Dike 
Cc: Richard Weinberger 
Cc: Tony Luck 
Cc: KAMEZAWA Hiroyuki 
Cc: Hugh Dickins 
Cc: Mel Gorman 
Cc: KOSAKI Motohiro 
Cc: Nick Piggin 
Cc: Namhyung Kim 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

arch:Kconfig.locks Remove unused config option.

2011-04-10T15:01:05+00:00

Signed-off-by: Justin P. Mattock 
Acked-by: Steven Rostedt 
Acked-by: Heiko Carstens 
Signed-off-by: Jiri Kosina

mutexes, sched: Introduce arch_mutex_cpu_relax()

2010-11-26T14:05:34+00:00

The spinning mutex implementation uses cpu_relax() in busy loops as a
compiler barrier. Depending on the architecture, cpu_relax() may do more
than needed in this specific mutex spin loops. On System z we also give
up the time slice of the virtual cpu in cpu_relax(), which prevents
effective spinning on the mutex.

This patch replaces cpu_relax() in the spinning mutex code with
arch_mutex_cpu_relax(), which can be defined by each architecture that
selects HAVE_ARCH_MUTEX_CPU_RELAX. The default is still cpu_relax(), so
this patch should not affect other architectures than System z for now.

Signed-off-by: Gerald Schaefer 
Signed-off-by: Peter Zijlstra 
LKML-Reference: <1290437256.7455.4.camel@thinkpad>
Signed-off-by: Ingo Molnar

jump label: Add work around to i386 gcc asm goto bug

2010-10-29T18:45:29+00:00

On i386 (not x86_64) early implementations of gcc would have a bug
with asm goto causing it to produce code like the following:

(This was noticed by Peter Zijlstra)

   56 pushl 0
   67 nopl         jmp 0x6f
      popl
      jmp 0x8c

   6f              mov
                   test
                   je 0x8c

   8c mov
      call *(%esp)

The jump added in the asm goto skipped over the popl that matched
the pushl 0, which lead up to a quick crash of the system when
the jump was enabled. The nopl is defined in the asm goto () statement
and when tracepoints are enabled, the nop changes to a jump to the label
that was specified by the asm goto. asm goto is suppose to tell gcc that
the code in the asm might jump to an external label. Here gcc obviously
fails to make that work.

The bug report for gcc is here:

  http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46226

The bug only appears on x86 when not compiled with
-maccumulate-outgoing-args. This option is always set on x86_64 and it
is also the work around for a function graph tracer i386 bug.
(See commit: 746357d6a526d6da9d89a2ec645b28406e959c2e)
This explains why the bug only showed up on i386 when function graph
tracer was not enabled.

This patch now adds a CONFIG_JUMP_LABEL option that is default
off instead of using jump labels by default. When jump labels are
enabled, the -maccumulate-outgoing-args will be used (causing a
slightly larger kernel image on i386). This option will exist
until we have a way to detect if the gcc compiler in use is safe
to use on all configurations without the work around.

Note, there exists such a test, but for now we will keep the enabling
of jump label as a manual option.

Archs that know the compiler is safe with asm goto, may choose to
select JUMP_LABEL and enable it by default.

Reported-by: Ingo Molnar 
Cause-discovered-by: Peter Zijlstra 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Jason Baron 
Cc: H. Peter Anvin 
Cc: David Daney 
Cc: Mathieu Desnoyers 
Cc: Masami Hiramatsu 
Cc: David Miller 
Cc: Richard Henderson 
LKML-Reference: <1288028746.3673.11.camel@laptop>
Signed-off-by: Steven Rostedt

Merge branch 'tip/perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core

2010-09-24T07:12:05+00:00