linux/arch/x86
Peter Zijlstra 609ca06638 sched/core: Create preempt_count invariant
Assuming units of PREEMPT_DISABLE_OFFSET for preempt_count() numbers.

Now that TASK_DEAD no longer results in preempt_count() == 3 during
scheduling, we will always call context_switch() with preempt_count()
== 2.

However, we don't always end up with preempt_count() == 2 in
finish_task_switch() because new tasks get created with
preempt_count() == 1.

Create FORK_PREEMPT_COUNT and set it to 2 and use that in the right
places. Note that we cannot use INIT_PREEMPT_COUNT as that serves
another purpose (boot).

After this, preempt_count() is invariant across the context switch,
with exception of PREEMPT_ACTIVE.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-10-06 17:08:14 +02:00
..
boot lib/decompressors: use real out buf size for gunzip with kernel 2015-09-10 13:29:01 -07:00
configs Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux 2015-09-04 15:49:32 -07:00
crypto crypto: ghash-clmulni: specify context size for ghash async algorithm 2015-09-04 23:21:07 +08:00
entry x86/nmi/64: Fix a paravirt stack-clobbering bug in the NMI code 2015-09-22 22:40:36 +02:00
ia32
include sched/core: Create preempt_count invariant 2015-10-06 17:08:14 +02:00
kernel Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-10-03 10:53:05 -04:00
kvm Use WARN_ON_ONCE for missing X86_FEATURE_NRIPS 2015-10-01 14:59:37 +02:00
lguest genirq: Remove irq argument from irq flow handlers 2015-09-16 15:47:51 +02:00
lib x86/asm/delay: Introduce an MWAITX-based delay with a configurable timer 2015-08-22 14:52:16 +02:00
math-emu
mm x86/mm: Set NX on gap between __ex_table and rodata 2015-10-02 09:21:06 +02:00
net
oprofile
pci PCI: Revert "PCI: Call pci_read_bridge_bases() from core instead of arch code" 2015-09-15 13:18:04 -05:00
platform x86/efi: Fix boot crash by mapping EFI memmap entries bottom-up at runtime, instead of top-down 2015-10-01 12:51:28 +02:00
power
purgatory
ras
realmode
tools
um
video
xen xen: MFN/GFN/BFN terminology changes for 4.3-rc0 2015-09-10 16:21:11 -07:00
.gitignore
Kbuild
Kconfig Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-09-17 11:01:34 -07:00
Kconfig.cpu
Kconfig.debug
Makefile Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-09-01 08:40:25 -07:00
Makefile.um
Makefile_32.cpu