diff options
Diffstat (limited to 'arch/x86/mm/tlb.c')
| -rw-r--r-- | arch/x86/mm/tlb.c | 31 |
1 files changed, 28 insertions, 3 deletions
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index d400b6d9d246..c1e31e9a85d7 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -734,10 +734,10 @@ static void flush_tlb_func(void *info) const struct flush_tlb_info *f = info; struct mm_struct *loaded_mm = this_cpu_read(cpu_tlbstate.loaded_mm); u32 loaded_mm_asid = this_cpu_read(cpu_tlbstate.loaded_mm_asid); - u64 mm_tlb_gen = atomic64_read(&loaded_mm->context.tlb_gen); u64 local_tlb_gen = this_cpu_read(cpu_tlbstate.ctxs[loaded_mm_asid].tlb_gen); bool local = smp_processor_id() == f->initiating_cpu; unsigned long nr_invalidate = 0; + u64 mm_tlb_gen; /* This code cannot presently handle being reentered. */ VM_WARN_ON(!irqs_disabled()); @@ -771,6 +771,23 @@ static void flush_tlb_func(void *info) return; } + if (unlikely(f->new_tlb_gen != TLB_GENERATION_INVALID && + f->new_tlb_gen <= local_tlb_gen)) { + /* + * The TLB is already up to date in respect to f->new_tlb_gen. + * While the core might be still behind mm_tlb_gen, checking + * mm_tlb_gen unnecessarily would have negative caching effects + * so avoid it. + */ + return; + } + + /* + * Defer mm_tlb_gen reading as long as possible to avoid cache + * contention. + */ + mm_tlb_gen = atomic64_read(&loaded_mm->context.tlb_gen); + if (unlikely(local_tlb_gen == mm_tlb_gen)) { /* * There's nothing to do: we're already up to date. This can @@ -827,6 +844,12 @@ static void flush_tlb_func(void *info) /* Partial flush */ unsigned long addr = f->start; + /* Partial flush cannot have invalid generations */ + VM_WARN_ON(f->new_tlb_gen == TLB_GENERATION_INVALID); + + /* Partial flush must have valid mm */ + VM_WARN_ON(f->mm == NULL); + nr_invalidate = (f->end - f->start) >> f->stride_shift; while (addr < f->end) { @@ -1029,7 +1052,8 @@ void flush_tlb_kernel_range(unsigned long start, unsigned long end) struct flush_tlb_info *info; preempt_disable(); - info = get_flush_tlb_info(NULL, start, end, 0, false, 0); + info = get_flush_tlb_info(NULL, start, end, 0, false, + TLB_GENERATION_INVALID); on_each_cpu(do_kernel_range_flush, info, 1); @@ -1198,7 +1222,8 @@ void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch) int cpu = get_cpu(); - info = get_flush_tlb_info(NULL, 0, TLB_FLUSH_ALL, 0, false, 0); + info = get_flush_tlb_info(NULL, 0, TLB_FLUSH_ALL, 0, false, + TLB_GENERATION_INVALID); /* * flush_tlb_multi() is not optimized for the common case in which only * a local TLB flush is needed. Optimize this use-case by calling |