> These Patches make page tables relocatable for numa, memory
> defragmentation, and memory hotblug. The potential need to rewalk the
> page tables before making any changes causes a 3% peformance
> degredation in the lmbench page miss micro benchmark.
>
> Signed-off-by:rossb@google.com
>
> ----
>
> These patches are against 2.6.23 kernel.org kernel.
>
> The lmbech results are available if any wants to see them. This
> version of the patch is x86_64 specific. The per archictecture part
> of the patch is limited to allocating new page tables and reloading
> the pgd. The main differences between this version and the previous
> one is that a flag in the MM is used to determine if the page tables
> need to be rewalked, a race when split page table locks were used was
> fixed, and per-arch page table allocation functions were used to
> allocate the new page tables.
>
> If there are no complaints, I intend to make a new version of these
> patches against the latest mm kernel, put some #ifdefs for supported vs
> unsuportted archs and request inclusion in the mm kernel.
>
> diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/arch/arm/kernel/smp.c 2.6.23a/arch/arm/kernel/smp.c
> --- 2.6.23/arch/arm/kernel/smp.c 2007-10-09 13:31:38.000000000 -0700
> +++ 2.6.23a/arch/arm/kernel/smp.c 2008-01-24 07:16:31.000000000 -0800
> @@ -713,6 +713,8 @@ void flush_tlb_mm(struct mm_struct *mm)
> {
> cpumask_t mask = mm->cpu_vm_mask;
>
> + clear_bit(MMF_NEED_FLUSH, mm->flags);
> +
> on_each_cpu_mask(ipi_flush_tlb_mm, mm, 1, 1, mask);
> }
>
> diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/arch/avr32/mm/tlb.c 2.6.23a/arch/avr32/mm/tlb.c
> --- 2.6.23/arch/avr32/mm/tlb.c 2007-10-09 13:31:38.000000000 -0700
> +++ 2.6.23a/arch/avr32/mm/tlb.c 2008-01-24 07:16:38.000000000 -0800
> @@ -249,6 +249,8 @@ void flush_tlb_kernel_range(unsigned lon
>
> void flush_tlb_mm(struct mm_struct *mm)
> {
> + clear_bit(MMF_NEED_FLUSH, mm->flags);
> +
> /* Invalidate all TLB entries of this process by getting a new ASID */
> if (mm->context != NO_CONTEXT) {
> unsigned long flags;
> diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/arch/cris/arch-v10/mm/tlb.c 2.6.23a/arch/cris/arch-v10/mm/tlb.c
> --- 2.6.23/arch/cris/arch-v10/mm/tlb.c 2007-10-09 13:31:38.000000000 -0700
> +++ 2.6.23a/arch/cris/arch-v10/mm/tlb.c 2008-01-24 07:16:44.000000000 -0800
> @@ -69,6 +69,8 @@ flush_tlb_mm(struct mm_struct *mm)
>
> D(printk("tlb: flush mm context %d (%p)\n", page_id, mm));
>
> + clear_bit(MMF_NEED_FLUSH, mm->flags);
> +
> if(page_id == NO_CONTEXT)
> return;
>
> diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/arch/cris/arch-v32/kernel/smp.c 2.6.23a/arch/cris/arch-v32/kernel/smp.c
> --- 2.6.23/arch/cris/arch-v32/kernel/smp.c 2007-10-09 13:31:38.000000000 -0700
> +++ 2.6.23a/arch/cris/arch-v32/kernel/smp.c 2008-01-24 07:16:50.000000000 -0800
> @@ -237,6 +237,7 @@ void flush_tlb_all(void)
>
> void flush_tlb_mm(struct mm_struct *mm)
> {
> + clear_bit(MMF_NEED_FLUSH, mm->flags);
> __flush_tlb_mm(mm);
> flush_tlb_common(mm, FLUSH_ALL, 0);
> /* No more mappings in other CPUs */
> diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/arch/i386/kernel/smp.c 2.6.23a/arch/i386/kernel/smp.c
> --- 2.6.23/arch/i386/kernel/smp.c 2007-10-09 13:31:38.000000000 -0700
> +++ 2.6.23a/arch/i386/kernel/smp.c 2008-01-24 07:16:55.000000000 -0800
> @@ -410,6 +410,8 @@ void flush_tlb_mm (struct mm_struct * mm
> {
> cpumask_t cpu_mask;
>
> + clear_bit(MMF_NEED_FLUSH, mm->flags);
> +
> preempt_disable();
> cpu_mask = mm->cpu_vm_mask;
> cpu_clear(smp_processor_id(), cpu_mask);
> diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/arch/i386/mach-voyager/voyager_smp.c 2.6.23a/arch/i386/mach-voyager/voyager_smp.c
> --- 2.6.23/arch/i386/mach-voyager/voyager_smp.c 2007-10-09 13:31:38.000000000 -0700
> +++ 2.6.23a/arch/i386/mach-voyager/voyager_smp.c 2008-01-24 07:17:01.000000000 -0800
> @@ -924,6 +924,8 @@ flush_tlb_mm (struct mm_struct * mm)
> {
> unsigned long cpu_mask;
>
> + clear_bit(MMF_NEED_FLUSH, mm->flags);
> +
> preempt_disable();
>
> cpu_mask = cpus_addr(mm->cpu_vm_mask)[0] & ~(1 << smp_processor_id());
> diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/arch/alpha/kernel/smp.c 2.6.23a/arch/alpha/kernel/smp.c
> --- 2.6.23/arch/alpha/kernel/smp.c 2007-10-09 13:31:38.000000000 -0700
> +++ 2.6.23a/arch/alpha/kernel/smp.c 2008-01-24 07:16:26.000000000 -0800
> @@ -850,6 +850,8 @@ flush_tlb_mm(struct mm_struct *mm)
> {
> preempt_disable();
>
> + clear_bit(MMF_NEED_FLUSH, mm->flags);
> +
> if (mm == current->active_mm) {
> flush_tlb_current(mm);
> if (atomic_read(&mm->mm_users) <= 1) {
> diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/arch/ia64/kernel/smp.c 2.6.23a/arch/ia64/kernel/smp.c
> --- 2.6.23/arch/ia64/kernel/smp.c 2007-10-09 13:31:38.000000000 -0700
> +++ 2.6.23a/arch/ia64/kernel/smp.c 2008-01-24 07:17:05.000000000 -0800
> @@ -325,6 +325,8 @@ smp_flush_tlb_all (void)
> void
> smp_flush_tlb_mm (struct mm_struct *mm)
> {
> + clear_bit(MMF_NEED_FLUSH, mm->flags);
> +
> preempt_disable();
> /* this happens for the common case of a single-threaded fork(): */
> if (likely(mm == current->active_mm && atomic_read(&mm->mm_users) == 1))
> diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/arch/m32r/kernel/smp.c 2.6.23a/arch/m32r/kernel/smp.c
> --- 2.6.23/arch/m32r/kernel/smp.c 2007-10-09 13:31:38.000000000 -0700
> +++ 2.6.23a/arch/m32r/kernel/smp.c 2008-01-24 07:17:10.000000000 -0800
> @@ -280,6 +280,8 @@ void smp_flush_tlb_mm(struct mm_struct *
> unsigned long *mmc;
> unsigned long flags;
>
> + clear_bit(MMF_NEED_FLUSH, mm->flags);
> +
> preempt_disable();
> cpu_id = smp_processor_id();
> mmc = &mm->context[cpu_id];
> diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/arch/mips/kernel/smp.c 2.6.23a/arch/mips/kernel/smp.c
> --- 2.6.23/arch/mips/kernel/smp.c 2007-10-09 13:31:38.000000000 -0700
> +++ 2.6.23a/arch/mips/kernel/smp.c 2008-01-24 07:17:15.000000000 -0800
> @@ -387,6 +387,8 @@ static inline void smp_on_each_tlb(void
>
> void flush_tlb_mm(struct mm_struct *mm)
> {
> + clear_bit(MMF_NEED_FLUSH, mm->flags);
> +
> preempt_disable();
>
> if ((atomic_read(&mm->mm_users) != 1) || (current->mm != mm)) {
> diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/arch/powerpc/mm/tlb_32.c 2.6.23a/arch/powerpc/mm/tlb_32.c
> --- 2.6.23/arch/powerpc/mm/tlb_32.c 2007-10-09 13:31:38.000000000 -0700
> +++ 2.6.23a/arch/powerpc/mm/tlb_32.c 2008-01-24 07:17:19.000000000 -0800
> @@ -144,6 +144,8 @@ void flush_tlb_mm(struct mm_struct *mm)
> {
> struct vm_area_struct *mp;
>
> + clear_bit(MMF_NEED_FLUSH, mm->flags);
> +
> if (Hash == 0) {
> _tlbia();
> return;
> diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/arch/ppc/mm/tlb.c 2.6.23a/arch/ppc/mm/tlb.c
> --- 2.6.23/arch/ppc/mm/tlb.c 2007-10-09 13:31:38.000000000 -0700
> +++ 2.6.23a/arch/ppc/mm/tlb.c 2008-01-24 07:17:23.000000000 -0800
> @@ -144,6 +144,8 @@ void flush_tlb_mm(struct mm_struct *mm)
> {
> struct vm_area_struct *mp;
>
> + clear_bit(MMF_NEED_FLUSH, mm->flags);
> +
> if (Hash == 0) {
> _tlbia();
> return;
> diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/arch/sh64/mm/fault.c 2.6.23a/arch/sh64/mm/fault.c
> --- 2.6.23/arch/sh64/mm/fault.c 2007-10-09 13:31:38.000000000 -0700
> +++ 2.6.23a/arch/sh64/mm/fault.c 2008-01-24 07:17:28.000000000 -0800
> @@ -517,6 +517,8 @@ void flush_tlb_mm(struct mm_struct *mm)
> ++calls_to_flush_tlb_mm;
> #endif
>
> + clear_bit(MMF_NEED_FLUSH, mm->flags);
> +
> if (mm->context == NO_CONTEXT)
> return;
>
> diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/arch/sparc/kernel/smp.c 2.6.23a/arch/sparc/kernel/smp.c
> --- 2.6.23/arch/sparc/kernel/smp.c 2007-10-09 13:31:38.000000000 -0700
> +++ 2.6.23a/arch/sparc/kernel/smp.c 2008-01-24 07:17:33.000000000 -0800
> @@ -163,6 +163,8 @@ void smp_flush_cache_mm(struct mm_struct
>
> void smp_flush_tlb_mm(struct mm_struct *mm)
> {
> + clear_bit(MMF_NEED_FLUSH, mm->flags);
> +
> if(mm->context != NO_CONTEXT) {
> cpumask_t cpu_mask = mm->cpu_vm_mask;
> cpu_clear(smp_processor_id(), cpu_mask);
> diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/arch/sparc64/kernel/smp.c 2.6.23a/arch/sparc64/kernel/smp.c
> --- 2.6.23/arch/sparc64/kernel/smp.c 2007-10-09 13:31:38.000000000 -0700
> +++ 2.6.23a/arch/sparc64/kernel/smp.c 2008-01-24 07:17:37.000000000 -0800
> @@ -1112,6 +1112,8 @@ void smp_flush_tlb_mm(struct mm_struct *
> u32 ctx = CTX_HWBITS(mm->context);
> int cpu = get_cpu();
>
> + clear_bit(MMF_NEED_FLUSH, mm->flags);
> +
> if (atomic_read(&mm->mm_users) == 1) {
> mm->cpu_vm_mask = cpumask_of_cpu(cpu);
> goto local_flush_and_out;
> diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/arch/um/kernel/tlb.c 2.6.23a/arch/um/kernel/tlb.c
> --- 2.6.23/arch/um/kernel/tlb.c 2007-10-09 13:31:38.000000000 -0700
> +++ 2.6.23a/arch/um/kernel/tlb.c 2008-01-24 07:17:41.000000000 -0800
> @@ -402,6 +402,7 @@ void flush_tlb_range(struct vm_area_stru
>
> void flush_tlb_mm(struct mm_struct *mm)
> {
> + clear_bit(MMF_NEED_FLUSH, mm->flags);
> CHOOSE_MODE_PROC(flush_tlb_mm_tt, flush_tlb_mm_skas, mm);
> }
>
> diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/arch/xtensa/mm/tlb.c 2.6.23a/arch/xtensa/mm/tlb.c
> --- 2.6.23/arch/xtensa/mm/tlb.c 2007-10-09 13:31:38.000000000 -0700
> +++ 2.6.23a/arch/xtensa/mm/tlb.c 2008-01-24 07:17:46.000000000 -0800
> @@ -63,6 +63,8 @@ void flush_tlb_all (void)
>
> void flush_tlb_mm(struct mm_struct *mm)
> {
> + clear_bit(MMF_NEED_FLUSH, mm->flags);
> +
> if (mm == current->active_mm) {
> int flags;
> local_save_flags(flags);
>
> --
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