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| author | Ingo Molnar <mingo@kernel.org> | 2014-01-13 11:44:41 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-01-13 11:44:41 +0100 |
| commit | 1c62448e39285b23b4770aaf46d32368fff990df (patch) | |
| tree | c6c6cf1a80a762a5859bfdaf3941294a47ea8eee /arch/x86/include/asm/preempt.h | |
| parent | arch: Introduce smp_load_acquire(), smp_store_release() (diff) | |
| parent | Linux 3.13-rc8 (diff) | |
| download | linux-1c62448e39285b23b4770aaf46d32368fff990df.tar.xz linux-1c62448e39285b23b4770aaf46d32368fff990df.zip | |
Merge tag 'v3.13-rc8' into core/locking
Refresh the tree with the latest fixes, before applying new changes.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/include/asm/preempt.h')
| -rw-r--r-- | arch/x86/include/asm/preempt.h | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/x86/include/asm/preempt.h b/arch/x86/include/asm/preempt.h index 8729723636fd..c8b051933b1b 100644 --- a/arch/x86/include/asm/preempt.h +++ b/arch/x86/include/asm/preempt.h @@ -8,6 +8,12 @@ DECLARE_PER_CPU(int, __preempt_count); /* + * We use the PREEMPT_NEED_RESCHED bit as an inverted NEED_RESCHED such + * that a decrement hitting 0 means we can and should reschedule. + */ +#define PREEMPT_ENABLED (0 + PREEMPT_NEED_RESCHED) + +/* * We mask the PREEMPT_NEED_RESCHED bit so as not to confuse all current users * that think a non-zero value indicates we cannot preempt. */ @@ -74,6 +80,11 @@ static __always_inline void __preempt_count_sub(int val) __this_cpu_add_4(__preempt_count, -val); } +/* + * Because we keep PREEMPT_NEED_RESCHED set when we do _not_ need to reschedule + * a decrement which hits zero means we have no preempt_count and should + * reschedule. + */ static __always_inline bool __preempt_count_dec_and_test(void) { GEN_UNARY_RMWcc("decl", __preempt_count, __percpu_arg(0), "e"); |