linux.git/include/asm-arm/thread_info.h, branch v2.6.20

[PATCH] PM: Fix SMP races in the freezer

2006-12-13T17:05:49+00:00

Currently, to tell a task that it should go to the refrigerator, we set the
PF_FREEZE flag for it and send a fake signal to it.  Unfortunately there
are two SMP-related problems with this approach.  First, a task running on
another CPU may be updating its flags while the freezer attempts to set
PF_FREEZE for it and this may leave the task's flags in an inconsistent
state.  Second, there is a potential race between freeze_process() and
refrigerator() in which freeze_process() running on one CPU is reading a
task's PF_FREEZE flag while refrigerator() running on another CPU has just
set PF_FROZEN for the same task and attempts to reset PF_FREEZE for it.  If
the refrigerator wins the race, freeze_process() will state that PF_FREEZE
hasn't been set for the task and will set it unnecessarily, so the task
will go to the refrigerator once again after it's been thawed.

To solve first of these problems we need to stop using PF_FREEZE to tell
tasks that they should go to the refrigerator.  Instead, we can introduce a
special TIF_*** flag and use it for this purpose, since it is allowed to
change the other tasks' TIF_*** flags and there are special calls for it.

To avoid the freeze_process()-refrigerator() race we can make
freeze_process() to always check the task's PF_FROZEN flag after it's read
its "freeze" flag.  We should also make sure that refrigerator() will
always reset the task's "freeze" flag after it's set PF_FROZEN for it.

Signed-off-by: Rafael J. Wysocki 
Acked-by: Pavel Machek 
Cc: Russell King 
Cc: David Howells 
Cc: Andi Kleen 
Cc: "Luck, Tony" 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Paul Mundt 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[ARM] 3911/2: Simplify alloc_thread_info on ARM

2006-11-30T15:27:03+00:00

Remove ARM local cache of 4 struct thread_info.
Can cause oops under certain circumstances.

Russell indicated the original optimization was
required on older kernels to avoid thread starvation
on memory fragmentation, but may no longer be
required.  I've updated the patch to 19rc4 and
ensured no  dain-bramage slipped in this
time (sorry about that).

Original description follows:

I was given some test results which pointed to an
Oops in alloc_thread_info (happened 2x), and after
looking at the code, I see that ARM has its own
local cache of 4 struct thread_info. There wasn't
any clear (to me) synchronization between the
alloc_thread_info and the free_thread_info.

I looked over the other arch, and they all simply
allocate them on an as needed basis, so I simplified
the ARM to do the same, based on the other arch
(e.g. PPC) and the folks doing the testing have
indicated that this fixed the oops.

Signed-off-by: Paul Gortmaker 
Signed-off-by: Russell King

Merge branch 'devel' of master.kernel.org:/home/rmk/linux-2.6-arm

2006-07-02T22:04:12+00:00

* 'devel' of master.kernel.org:/home/rmk/linux-2.6-arm: (44 commits)
  [ARM] 3541/2: workaround for PXA27x erratum E7
  [ARM] nommu: provide a way for correct control register value selection
  [ARM] 3705/1: add supersection support to ioremap()
  [ARM] 3707/1: iwmmxt: use the generic thread notifier infrastructure
  [ARM] 3706/2: ep93xx: add cirrus logic edb9315a support
  [ARM] 3704/1: format IOP Kconfig with tabs, create more consistency
  [ARM] 3703/1: Add help description for ARCH_EP80219
  [ARM] 3678/1: MMC: Make OMAP MMC work
  [ARM] 3677/1: OMAP: Update H2 defconfig
  [ARM] 3676/1: ARM: OMAP: Fix dmtimers and timer32k to compile on OMAP1
  [ARM] Add section support to ioremap
  [ARM] Fix sa11x0 SDRAM selection
  [ARM] Set bit 4 on section mappings correctly depending on CPU
  [ARM] 3666/1: TRIZEPS4 [1/5] core
  ARM: OMAP: Multiplexing for 24xx GPMC wait pin monitoring
  ARM: OMAP: Fix SRAM to use MT_MEMORY instead of MT_DEVICE
  ARM: OMAP: Update dmtimers
  ARM: OMAP: Make clock variables static
  ARM: OMAP: Fix GPMC compilation when DEBUG is defined
  ARM: OMAP: Mux updates for external DMA and GPIO
  ...

[ARM] 3707/1: iwmmxt: use the generic thread notifier infrastructure

2006-07-01T18:56:48+00:00

Patch from Lennert Buytenhek

This patch makes the iWMMXt context switch hook use the generic
thread notifier infrastructure that was recently merged in commit
d6551e884cf66de072b81f8b6d23259462c40baf.

Signed-off-by: Lennert Buytenhek 
Signed-off-by: Russell King

typo fixes: occuring -> occurring

2006-06-30T16:27:16+00:00

Signed-off-by: Adrian Bunk

[ARM] 3370/2: ep93xx: add crunch support

2006-06-28T16:55:01+00:00

Patch from Lennert Buytenhek

Add the necessary kernel bits for crunch task switching.

Signed-off-by: Lennert Buytenhek 
Signed-off-by: Russell King

[ARM] iwmmxt thread state alignment

2006-03-12T22:36:06+00:00

This patch removes the reliance of iwmmxt on hand coded alignments.
Since thread_info is always 8K aligned, specifying that fpstate is
8-byte aligned achieves the same effect without needing to resort
to hand coded alignments.

Signed-off-by: Russell King

[PATCH] death of get_thread_info/put_thread_info

2006-01-12T17:08:59+00:00

{get,put}_thread_info() were introduced in 2.5.4 and never
had been called by anything in the tree.

Signed-off-by: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] arm: task_thread_info()

2006-01-12T17:08:55+00:00

Signed-off-by: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[ARM] Add linux/compiler.h includes where required

2005-11-16T17:23:57+00:00

atomic.h, bitops.h and mmu_context.h are using likely/unlikely.
thread_info.h uses __attribute_const__.  Hence these files require
linux/compiler.h to be included.

Signed-off-by: Russell King