From 33c179b5020554722bcb4c5a3ff565192ac53f54 Mon Sep 17 00:00:00 2001 From: Chuyi Zhou Date: Thu, 9 Jul 2026 20:29:29 +0800 Subject: [PATCH] x86/mm: Factor out flush_tlb_info initialization get_flush_tlb_info() has two responsibilities: it reserves the per-CPU flush_tlb_info storage and it initializes the fields that describe the flush operation. The per-CPU storage also carries the DEBUG_VM reentrancy check and the matching put_flush_tlb_info() lifetime rules. Moving flush_tlb_info back to caller-provided storage requires the same field initialization without tying the caller to the per-CPU object. Leaving the field setup embedded in get_flush_tlb_info() would either keep those callers tied to the per-CPU object or duplicate the initialization logic. Split the field setup into init_flush_tlb_info(). Keep the per-CPU storage selection, DEBUG_VM reentrancy check and put_flush_tlb_info() lifetime rules in get_flush_tlb_info(). No functional change intended. Signed-off-by: Chuyi Zhou Signed-off-by: Thomas Gleixner Reviewed-by: Sebastian Andrzej Siewior Link: https://patch.msgid.link/20260709122933.4021501-11-zhouchuyi@bytedance.com --- arch/x86/mm/tlb.c | 50 ++++++++++++++++++++++++++--------------------- 1 file changed, 28 insertions(+), 22 deletions(-) diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index 1023acadd8f8..7f483424de1d 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -1379,10 +1379,33 @@ static DEFINE_PER_CPU_SHARED_ALIGNED(struct flush_tlb_info, flush_tlb_info); static DEFINE_PER_CPU(unsigned int, flush_tlb_info_idx); #endif -static struct flush_tlb_info *get_flush_tlb_info(struct mm_struct *mm, - unsigned long start, unsigned long end, - unsigned int stride_shift, bool freed_tables, - u64 new_tlb_gen) +static void init_flush_tlb_info(struct flush_tlb_info *info, struct mm_struct *mm, + unsigned long start, unsigned long end, + unsigned int stride_shift, bool freed_tables, + u64 new_tlb_gen) +{ + /* + * 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) { + start = 0; + end = TLB_FLUSH_ALL; + } + + info->start = start; + info->end = end; + info->mm = mm; + info->stride_shift = stride_shift; + info->freed_tables = freed_tables; + info->new_tlb_gen = new_tlb_gen; + info->initiating_cpu = smp_processor_id(); + info->trim_cpumask = 0; +} + +static struct flush_tlb_info *get_flush_tlb_info(struct mm_struct *mm, unsigned long start, + unsigned long end, unsigned int stride_shift, + bool freed_tables, u64 new_tlb_gen) { struct flush_tlb_info *info = this_cpu_ptr(&flush_tlb_info); @@ -1395,24 +1418,7 @@ static struct flush_tlb_info *get_flush_tlb_info(struct mm_struct *mm, BUG_ON(this_cpu_inc_return(flush_tlb_info_idx) != 1); #endif - /* - * 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) { - start = 0; - end = TLB_FLUSH_ALL; - } - - info->start = start; - info->end = end; - info->mm = mm; - info->stride_shift = stride_shift; - info->freed_tables = freed_tables; - info->new_tlb_gen = new_tlb_gen; - info->initiating_cpu = smp_processor_id(); - info->trim_cpumask = 0; - + init_flush_tlb_info(info, mm, start, end, stride_shift, freed_tables, new_tlb_gen); return info; }