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authorJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>2009-02-17 23:46:21 -0800
committerJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>2009-03-29 23:36:00 -0700
commitb407fc57b815b2016186220baabc76cc8264206e (patch)
tree29949f727af8b6c19fd689fa10f123ea84c03cb0 /arch/x86/kernel/paravirt.c
parent7fd7d83d49914f03aefffba6aee09032fcd54cce (diff)
x86/paravirt: flush pending mmu updates on context switch
Impact: allow preemption during lazy mmu updates If we're in lazy mmu mode when context switching, leave lazy mmu mode, but remember the task's state in TIF_LAZY_MMU_UPDATES. When we resume the task, check this flag and re-enter lazy mmu mode if its set. This sets things up for allowing lazy mmu mode while preemptible, though that won't actually be active until the next change. 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.c13
1 files changed, 10 insertions, 3 deletions
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 5eea9548216b..430a0e30577b 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -252,7 +252,7 @@ static inline void enter_lazy(enum paravirt_lazy_mode mode)
__get_cpu_var(paravirt_lazy_mode) = mode;
}
-void paravirt_leave_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());
@@ -267,17 +267,24 @@ void paravirt_enter_lazy_mmu(void)
void paravirt_leave_lazy_mmu(void)
{
- paravirt_leave_lazy(PARAVIRT_LAZY_MMU);
+ leave_lazy(PARAVIRT_LAZY_MMU);
}
void paravirt_enter_lazy_cpu(void)
{
+ if (percpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) {
+ arch_leave_lazy_mmu_mode();
+ set_thread_flag(TIF_LAZY_MMU_UPDATES);
+ }
enter_lazy(PARAVIRT_LAZY_CPU);
}
void paravirt_leave_lazy_cpu(void)
{
- paravirt_leave_lazy(PARAVIRT_LAZY_CPU);
+ leave_lazy(PARAVIRT_LAZY_CPU);
+
+ if (test_and_clear_thread_flag(TIF_LAZY_MMU_UPDATES))
+ arch_enter_lazy_mmu_mode();
}
enum paravirt_lazy_mode paravirt_get_lazy_mode(void)