88 lines
2.6 KiB
Diff
88 lines
2.6 KiB
Diff
From 170f37d1499a28f7a1902e007111867c7cf0147f Mon Sep 17 00:00:00 2001
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From: Rik van Riel <riel@surriel.com>
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Date: Tue, 25 Feb 2025 22:00:36 -0500
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Subject: x86/mm: Consolidate full flush threshold decision
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Reduce code duplication by consolidating the decision point for whether to do
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individual invalidations or a full flush inside get_flush_tlb_info().
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Suggested-by: Dave Hansen <dave.hansen@intel.com>
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Signed-off-by: Rik van Riel <riel@surriel.com>
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Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
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Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
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Acked-by: Dave Hansen <dave.hansen@intel.com>
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Link: https://lore.kernel.org/r/20250226030129.530345-2-riel@surriel.com
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---
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arch/x86/mm/tlb.c | 41 +++++++++++++++++++----------------------
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1 file changed, 19 insertions(+), 22 deletions(-)
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--- a/arch/x86/mm/tlb.c
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+++ b/arch/x86/mm/tlb.c
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@@ -1019,6 +1019,15 @@ static struct flush_tlb_info *get_flush_
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BUG_ON(this_cpu_inc_return(flush_tlb_info_idx) != 1);
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#endif
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+ /*
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+ * If the number of flushes is so large that a full flush
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+ * would be faster, do a full flush.
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+ */
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+ if ((end - start) >> stride_shift > tlb_single_page_flush_ceiling) {
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+ start = 0;
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+ end = TLB_FLUSH_ALL;
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+ }
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+
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info->start = start;
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info->end = end;
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info->mm = mm;
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@@ -1045,17 +1054,8 @@ void flush_tlb_mm_range(struct mm_struct
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bool freed_tables)
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{
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struct flush_tlb_info *info;
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+ int cpu = get_cpu();
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u64 new_tlb_gen;
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- int cpu;
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-
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- cpu = get_cpu();
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-
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- /* Should we flush just the requested range? */
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- if ((end == TLB_FLUSH_ALL) ||
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- ((end - start) >> stride_shift) > tlb_single_page_flush_ceiling) {
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- start = 0;
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- end = TLB_FLUSH_ALL;
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- }
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/* This is also a barrier that synchronizes with switch_mm(). */
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new_tlb_gen = inc_mm_tlb_gen(mm);
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@@ -1108,22 +1108,19 @@ static void do_kernel_range_flush(void *
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void flush_tlb_kernel_range(unsigned long start, unsigned long end)
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{
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- /* Balance as user space task's flush, a bit conservative */
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- if (end == TLB_FLUSH_ALL ||
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- (end - start) > tlb_single_page_flush_ceiling << PAGE_SHIFT) {
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- on_each_cpu(do_flush_tlb_all, NULL, 1);
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- } else {
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- struct flush_tlb_info *info;
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+ struct flush_tlb_info *info;
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- preempt_disable();
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- info = get_flush_tlb_info(NULL, start, end, 0, false,
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- TLB_GENERATION_INVALID);
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+ guard(preempt)();
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+ info = get_flush_tlb_info(NULL, start, end, PAGE_SHIFT, false,
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+ TLB_GENERATION_INVALID);
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+
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+ if (info->end == TLB_FLUSH_ALL)
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+ on_each_cpu(do_flush_tlb_all, NULL, 1);
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+ else
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on_each_cpu(do_kernel_range_flush, info, 1);
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- put_flush_tlb_info();
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- preempt_enable();
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- }
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+ put_flush_tlb_info();
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}
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/*
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