From 8b2bd3f69b50cfe59eee4506413715878bcbb901 Mon Sep 17 00:00:00 2001 From: Rik van Riel Date: Wed, 22 Jan 2025 23:23:22 -0500 Subject: x86/mm: consolidate full flush threshold decision Reduce code duplication by consolidating the decision point for whether to do individual invalidations or a full flush inside get_flush_tlb_info. Signed-off-by: Rik van Riel Suggested-by: Dave Hansen --- arch/x86/mm/tlb.c | 43 ++++++++++++++++++++----------------------- 1 file changed, 20 insertions(+), 23 deletions(-) --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -981,6 +981,15 @@ static struct flush_tlb_info *get_flush_ info->new_tlb_gen = new_tlb_gen; info->initiating_cpu = smp_processor_id(); + /* + * If the number of flushes is so large that a full flush + * would be faster, do a full flush. + */ + if ((end - start) >> stride_shift > tlb_single_page_flush_ceiling) { + info->start = 0; + info->end = TLB_FLUSH_ALL; + } + return info; } @@ -998,17 +1007,8 @@ void flush_tlb_mm_range(struct mm_struct bool freed_tables) { struct flush_tlb_info *info; + int cpu = get_cpu(); u64 new_tlb_gen; - int cpu; - - cpu = get_cpu(); - - /* Should we flush just the requested range? */ - if ((end == TLB_FLUSH_ALL) || - ((end - start) >> stride_shift) > tlb_single_page_flush_ceiling) { - start = 0; - end = TLB_FLUSH_ALL; - } /* This is also a barrier that synchronizes with switch_mm(). */ new_tlb_gen = inc_mm_tlb_gen(mm); @@ -1060,22 +1060,19 @@ static void do_kernel_range_flush(void * void flush_tlb_kernel_range(unsigned long start, unsigned long end) { - /* Balance as user space task's flush, a bit conservative */ - if (end == TLB_FLUSH_ALL || - (end - start) > tlb_single_page_flush_ceiling << PAGE_SHIFT) { - on_each_cpu(do_flush_tlb_all, NULL, 1); - } else { - struct flush_tlb_info *info; + struct flush_tlb_info *info; - preempt_disable(); - info = get_flush_tlb_info(NULL, start, end, 0, false, - TLB_GENERATION_INVALID); + guard(preempt)(); + + info = get_flush_tlb_info(NULL, start, end, PAGE_SHIFT, false, + TLB_GENERATION_INVALID); + if (info->end == TLB_FLUSH_ALL) + on_each_cpu(do_flush_tlb_all, NULL, 1); + else on_each_cpu(do_kernel_range_flush, info, 1); - put_flush_tlb_info(); - preempt_enable(); - } + put_flush_tlb_info(); } /* @@ -1247,7 +1244,7 @@ void arch_tlbbatch_flush(struct arch_tlb int cpu = get_cpu(); - info = get_flush_tlb_info(NULL, 0, TLB_FLUSH_ALL, 0, false, + info = get_flush_tlb_info(NULL, 0, TLB_FLUSH_ALL, PAGE_SHIFT, false, TLB_GENERATION_INVALID); /* * flush_tlb_multi() is not optimized for the common case in which only