diff options
author | Tejun Heo <tj@kernel.org> | 2009-01-21 08:26:06 (GMT) |
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committer | Tejun Heo <tj@kernel.org> | 2009-01-21 08:26:06 (GMT) |
commit | 02cf94c370e0dc9bf408fe45eb86fe9ad58eaf7f (patch) | |
tree | e12620b5fead5ec6d90b54046a5025c2b28234a0 /arch/x86/kernel/tlb_32.c | |
parent | 6dd01bedee6c3191643db303a1dc530bad56ec55 (diff) | |
download | linux-fsl-qoriq-02cf94c370e0dc9bf408fe45eb86fe9ad58eaf7f.tar.xz |
x86: make x86_32 use tlb_64.c
Impact: less contention when issuing invalidate IPI, cleanup
Make x86_32 use the same tlb code as 64bit. The 64bit code uses
multiple IPI vectors for tlb shootdown to reduce contention. This
patch makes x86_32 allocate the same 8 IPIs as x86_64 and share the
code paths.
Note that the usage of asmlinkage is inconsistent for x86_32 and 64
and calls for further cleanup. This has been noted with a FIXME
comment in tlb_64.c.
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'arch/x86/kernel/tlb_32.c')
-rw-r--r-- | arch/x86/kernel/tlb_32.c | 239 |
1 files changed, 0 insertions, 239 deletions
diff --git a/arch/x86/kernel/tlb_32.c b/arch/x86/kernel/tlb_32.c deleted file mode 100644 index 93fcb05..0000000 --- a/arch/x86/kernel/tlb_32.c +++ /dev/null @@ -1,239 +0,0 @@ -#include <linux/spinlock.h> -#include <linux/cpu.h> -#include <linux/interrupt.h> - -#include <asm/tlbflush.h> - -DEFINE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate) - = { &init_mm, 0, }; - -/* must come after the send_IPI functions above for inlining */ -#include <mach_ipi.h> - -/* - * Smarter SMP flushing macros. - * c/o Linus Torvalds. - * - * These mean you can really definitely utterly forget about - * writing to user space from interrupts. (Its not allowed anyway). - * - * Optimizations Manfred Spraul <manfred@colorfullife.com> - */ - -static cpumask_var_t flush_cpumask; -static struct mm_struct *flush_mm; -static unsigned long flush_va; -static DEFINE_SPINLOCK(tlbstate_lock); - -/* - * We cannot call mmdrop() because we are in interrupt context, - * instead update mm->cpu_vm_mask. - * - * We need to reload %cr3 since the page tables may be going - * away from under us.. - */ -void leave_mm(int cpu) -{ - BUG_ON(percpu_read(cpu_tlbstate.state) == TLBSTATE_OK); - cpu_clear(cpu, percpu_read(cpu_tlbstate.active_mm)->cpu_vm_mask); - load_cr3(swapper_pg_dir); -} -EXPORT_SYMBOL_GPL(leave_mm); - -/* - * - * The flush IPI assumes that a thread switch happens in this order: - * [cpu0: the cpu that switches] - * 1) switch_mm() either 1a) or 1b) - * 1a) thread switch to a different mm - * 1a1) cpu_clear(cpu, old_mm->cpu_vm_mask); - * Stop ipi delivery for the old mm. This is not synchronized with - * the other cpus, but smp_invalidate_interrupt ignore flush ipis - * for the wrong mm, and in the worst case we perform a superfluous - * tlb flush. - * 1a2) set cpu_tlbstate to TLBSTATE_OK - * Now the smp_invalidate_interrupt won't call leave_mm if cpu0 - * was in lazy tlb mode. - * 1a3) update cpu_tlbstate[].active_mm - * Now cpu0 accepts tlb flushes for the new mm. - * 1a4) cpu_set(cpu, new_mm->cpu_vm_mask); - * Now the other cpus will send tlb flush ipis. - * 1a4) change cr3. - * 1b) thread switch without mm change - * cpu_tlbstate[].active_mm is correct, cpu0 already handles - * flush ipis. - * 1b1) set cpu_tlbstate to TLBSTATE_OK - * 1b2) test_and_set the cpu bit in cpu_vm_mask. - * Atomically set the bit [other cpus will start sending flush ipis], - * and test the bit. - * 1b3) if the bit was 0: leave_mm was called, flush the tlb. - * 2) switch %%esp, ie current - * - * The interrupt must handle 2 special cases: - * - cr3 is changed before %%esp, ie. it cannot use current->{active_,}mm. - * - the cpu performs speculative tlb reads, i.e. even if the cpu only - * runs in kernel space, the cpu could load tlb entries for user space - * pages. - * - * The good news is that cpu_tlbstate is local to each cpu, no - * write/read ordering problems. - */ - -/* - * TLB flush IPI: - * - * 1) Flush the tlb entries if the cpu uses the mm that's being flushed. - * 2) Leave the mm if we are in the lazy tlb mode. - * - * Interrupts are disabled. - */ - -void smp_invalidate_interrupt(struct pt_regs *regs) -{ - unsigned int cpu; - - cpu = smp_processor_id(); - - if (!cpumask_test_cpu(cpu, flush_cpumask)) - goto out; - /* - * This was a BUG() but until someone can quote me the - * line from the intel manual that guarantees an IPI to - * multiple CPUs is retried _only_ on the erroring CPUs - * its staying as a return - * - * BUG(); - */ - - if (flush_mm == percpu_read(cpu_tlbstate.active_mm)) { - if (percpu_read(cpu_tlbstate.state) == TLBSTATE_OK) { - if (flush_va == TLB_FLUSH_ALL) - local_flush_tlb(); - else - __flush_tlb_one(flush_va); - } else - leave_mm(cpu); - } -out: - ack_APIC_irq(); - smp_mb__before_clear_bit(); - cpumask_clear_cpu(cpu, flush_cpumask); - smp_mb__after_clear_bit(); - inc_irq_stat(irq_tlb_count); -} - -void native_flush_tlb_others(const struct cpumask *cpumask, - struct mm_struct *mm, unsigned long va) -{ - /* - * - mask must exist :) - */ - BUG_ON(cpumask_empty(cpumask)); - BUG_ON(!mm); - - /* - * i'm not happy about this global shared spinlock in the - * MM hot path, but we'll see how contended it is. - * AK: x86-64 has a faster method that could be ported. - */ - spin_lock(&tlbstate_lock); - - cpumask_andnot(flush_cpumask, cpumask, cpumask_of(smp_processor_id())); -#ifdef CONFIG_HOTPLUG_CPU - /* If a CPU which we ran on has gone down, OK. */ - cpumask_and(flush_cpumask, flush_cpumask, cpu_online_mask); - if (unlikely(cpumask_empty(flush_cpumask))) { - spin_unlock(&tlbstate_lock); - return; - } -#endif - flush_mm = mm; - flush_va = va; - - /* - * Make the above memory operations globally visible before - * sending the IPI. - */ - smp_mb(); - /* - * We have to send the IPI only to - * CPUs affected. - */ - send_IPI_mask(flush_cpumask, INVALIDATE_TLB_VECTOR); - - while (!cpumask_empty(flush_cpumask)) - /* nothing. lockup detection does not belong here */ - cpu_relax(); - - flush_mm = NULL; - flush_va = 0; - spin_unlock(&tlbstate_lock); -} - -void flush_tlb_current_task(void) -{ - struct mm_struct *mm = current->mm; - - preempt_disable(); - - local_flush_tlb(); - if (cpumask_any_but(&mm->cpu_vm_mask, smp_processor_id()) < nr_cpu_ids) - flush_tlb_others(&mm->cpu_vm_mask, mm, TLB_FLUSH_ALL); - preempt_enable(); -} - -void flush_tlb_mm(struct mm_struct *mm) -{ - - preempt_disable(); - - if (current->active_mm == mm) { - if (current->mm) - local_flush_tlb(); - else - leave_mm(smp_processor_id()); - } - if (cpumask_any_but(&mm->cpu_vm_mask, smp_processor_id()) < nr_cpu_ids) - flush_tlb_others(&mm->cpu_vm_mask, mm, TLB_FLUSH_ALL); - - preempt_enable(); -} - -void flush_tlb_page(struct vm_area_struct *vma, unsigned long va) -{ - struct mm_struct *mm = vma->vm_mm; - - preempt_disable(); - - if (current->active_mm == mm) { - if (current->mm) - __flush_tlb_one(va); - else - leave_mm(smp_processor_id()); - } - - if (cpumask_any_but(&mm->cpu_vm_mask, smp_processor_id()) < nr_cpu_ids) - flush_tlb_others(&mm->cpu_vm_mask, mm, va); - preempt_enable(); -} - -static void do_flush_tlb_all(void *info) -{ - unsigned long cpu = smp_processor_id(); - - __flush_tlb_all(); - if (percpu_read(cpu_tlbstate.state) == TLBSTATE_LAZY) - leave_mm(cpu); -} - -void flush_tlb_all(void) -{ - on_each_cpu(do_flush_tlb_all, NULL, 1); -} - -static int init_flush_cpumask(void) -{ - alloc_cpumask_var(&flush_cpumask, GFP_KERNEL); - return 0; -} -early_initcall(init_flush_cpumask); |