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authorIngo Molnar <mingo@kernel.org>2014-01-12 14:12:44 +0100
committerIngo Molnar <mingo@kernel.org>2014-01-12 14:12:44 +0100
commitdba861461f88c12249ac78fb877866c04f99deb3 (patch)
tree5812b143581bcc66c7c542f01ba0cb22e489b8e5 /arch/x86/include/asm/preempt.h
parent0e6601eee039893a3f6420596ae4588d90d13cbe (diff)
parent228fdc083b017eaf90e578fa86fb1ecfd5ffae87 (diff)
downloadop-kernel-dev-dba861461f88c12249ac78fb877866c04f99deb3.zip
op-kernel-dev-dba861461f88c12249ac78fb877866c04f99deb3.tar.gz
Merge branch 'linus' into timers/core
Pick up the latest fixes and refresh the branch. 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.h11
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/x86/include/asm/preempt.h b/arch/x86/include/asm/preempt.h
index 8729723..c8b0519 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");
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