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authorJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>2009-02-17 23:53:19 -0800
committerJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>2009-03-29 23:36:02 -0700
commit2829b449276aed45f3d649efb21e3418e39dd5d1 (patch)
treeeb16821bc9ad330f8c2f289510603ca528feaeae /arch/x86/kernel/paravirt.c
parent224101ed69d3fbb486868e0f6e0f9fa37302efb4 (diff)
x86/paravirt: allow preemption with lazy mmu mode
Impact: remove obsolete checks, simplification Lift restrictions on preemption with lazy mmu mode, as it is now allowed. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Diffstat (limited to 'arch/x86/kernel/paravirt.c')
-rw-r--r--arch/x86/kernel/paravirt.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index cf1437503ba..bf2e86eee80 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -247,7 +247,6 @@ static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LA
static inline void enter_lazy(enum paravirt_lazy_mode mode)
{
BUG_ON(__get_cpu_var(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE);
- BUG_ON(preemptible());
__get_cpu_var(paravirt_lazy_mode) = mode;
}
@@ -255,7 +254,6 @@ static inline void enter_lazy(enum paravirt_lazy_mode mode)
static void leave_lazy(enum paravirt_lazy_mode mode)
{
BUG_ON(__get_cpu_var(paravirt_lazy_mode) != mode);
- BUG_ON(preemptible());
__get_cpu_var(paravirt_lazy_mode) = PARAVIRT_LAZY_NONE;
}
@@ -272,6 +270,8 @@ void paravirt_leave_lazy_mmu(void)
void paravirt_start_context_switch(struct task_struct *prev)
{
+ BUG_ON(preemptible());
+
if (percpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) {
arch_leave_lazy_mmu_mode();
set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES);
@@ -281,6 +281,8 @@ void paravirt_start_context_switch(struct task_struct *prev)
void paravirt_end_context_switch(struct task_struct *next)
{
+ BUG_ON(preemptible());
+
leave_lazy(PARAVIRT_LAZY_CPU);
if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES))
@@ -300,7 +302,6 @@ void arch_flush_lazy_mmu_mode(void)
preempt_disable();
if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) {
- WARN_ON(preempt_count() == 1);
arch_leave_lazy_mmu_mode();
arch_enter_lazy_mmu_mode();
}