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| author |   Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> | 2009-02-17 23:53:19 -0800 |
|---|---|---|
| committer | Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> | 2009-03-29 23:36:02 -0700 |
| commit | 2829b449276aed45f3d649efb21e3418e39dd5d1 (patch) | |
| tree | eb16821bc9ad330f8c2f289510603ca528feaeae /arch | |
| parent | x86/paravirt: finish change from lazy cpu to context switch start/end (diff) | |
| download | linux-dev-2829b449276aed45f3d649efb21e3418e39dd5d1.tar.xz linux-dev-2829b449276aed45f3d649efb21e3418e39dd5d1.zip | |
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')
| -rw-r--r-- | arch/x86/kernel/paravirt.c | 7 | ||||
| -rw-r--r-- | arch/x86/xen/mmu.c | 8 |
2 files changed, 5 insertions, 10 deletions
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c index cf1437503bab..bf2e86eee80c 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(); } diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index f5f8faa4f76c..3f2d0fe5e6a8 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -419,10 +419,6 @@ void set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags) void xen_set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pteval) { - /* updates to init_mm may be done without lock */ - if (mm == &init_mm) - preempt_disable(); - ADD_STATS(set_pte_at, 1); // ADD_STATS(set_pte_at_pinned, xen_page_pinned(ptep)); ADD_STATS(set_pte_at_current, mm == current->mm); @@ -443,9 +439,7 @@ void xen_set_pte_at(struct mm_struct *mm, unsigned long addr, } xen_set_pte(ptep, pteval); -out: - if (mm == &init_mm) - preempt_enable(); +out: return; } pte_t xen_ptep_modify_prot_start(struct mm_struct *mm, |