diff options
| author | Nicholas Piggin <npiggin@gmail.com> | 2020-12-17 16:47:30 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-02-08 17:09:45 +0300 |
| commit | 032b7f08932c9b212952d6d585e45b2941b3e8be (patch) | |
| tree | b177ec1a30b3623584c124d6957b580afe663ee6 /arch/powerpc/mm | |
| parent | 9393544842d6c85ebfc387c43a5059f8171d598f (diff) | |
| download | linux-032b7f08932c9b212952d6d585e45b2941b3e8be.tar.xz | |
powerpc/64s/radix: serialize_against_pte_lookup IPIs trim mm_cpumask
serialize_against_pte_lookup() performs IPIs to all CPUs in mm_cpumask.
Take this opportunity to try trim the CPU out of mm_cpumask. This can
reduce the cost of future serialize_against_pte_lookup() and/or the
cost of future TLB flushes.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201217134731.488135-7-npiggin@gmail.com
Diffstat (limited to 'arch/powerpc/mm')
| -rw-r--r-- | arch/powerpc/mm/book3s64/pgtable.c | 13 | ||||
| -rw-r--r-- | arch/powerpc/mm/book3s64/radix_tlb.c | 20 |
2 files changed, 23 insertions, 10 deletions
diff --git a/arch/powerpc/mm/book3s64/pgtable.c b/arch/powerpc/mm/book3s64/pgtable.c index 5b3a3bae21aa..78c492e86752 100644 --- a/arch/powerpc/mm/book3s64/pgtable.c +++ b/arch/powerpc/mm/book3s64/pgtable.c @@ -79,10 +79,17 @@ void set_pmd_at(struct mm_struct *mm, unsigned long addr, return set_pte_at(mm, addr, pmdp_ptep(pmdp), pmd_pte(pmd)); } -static void do_nothing(void *unused) -{ +void exit_lazy_flush_tlb(struct mm_struct *mm, bool always_flush); +static void do_serialize(void *arg) +{ + /* We've taken the IPI, so try to trim the mask while here */ + if (radix_enabled()) { + struct mm_struct *mm = arg; + exit_lazy_flush_tlb(mm, false); + } } + /* * Serialize against find_current_mm_pte which does lock-less * lookup in page tables with local interrupts disabled. For huge pages @@ -96,7 +103,7 @@ static void do_nothing(void *unused) void serialize_against_pte_lookup(struct mm_struct *mm) { smp_mb(); - smp_call_function_many(mm_cpumask(mm), do_nothing, NULL, 1); + smp_call_function_many(mm_cpumask(mm), do_serialize, mm, 1); } /* diff --git a/arch/powerpc/mm/book3s64/radix_tlb.c b/arch/powerpc/mm/book3s64/radix_tlb.c index 1ef5d4e1a50a..d7f1a6bd08ef 100644 --- a/arch/powerpc/mm/book3s64/radix_tlb.c +++ b/arch/powerpc/mm/book3s64/radix_tlb.c @@ -639,7 +639,11 @@ static bool mm_needs_flush_escalation(struct mm_struct *mm) return false; } -static void exit_lazy_flush_tlb(struct mm_struct *mm) +/* + * If always_flush is true, then flush even if this CPU can't be removed + * from mm_cpumask. + */ +void exit_lazy_flush_tlb(struct mm_struct *mm, bool always_flush) { unsigned long pid = mm->context.id; int cpu = smp_processor_id(); @@ -652,7 +656,7 @@ static void exit_lazy_flush_tlb(struct mm_struct *mm) * done with interrupts off. */ if (current->mm == mm) - goto out_flush; + goto out; if (current->active_mm == mm) { WARN_ON_ONCE(current->mm != NULL); @@ -674,17 +678,19 @@ static void exit_lazy_flush_tlb(struct mm_struct *mm) if (cpumask_test_cpu(cpu, mm_cpumask(mm))) { atomic_dec(&mm->context.active_cpus); cpumask_clear_cpu(cpu, mm_cpumask(mm)); + always_flush = true; } -out_flush: - _tlbiel_pid(pid, RIC_FLUSH_ALL); +out: + if (always_flush) + _tlbiel_pid(pid, RIC_FLUSH_ALL); } #ifdef CONFIG_SMP static void do_exit_flush_lazy_tlb(void *arg) { struct mm_struct *mm = arg; - exit_lazy_flush_tlb(mm); + exit_lazy_flush_tlb(mm, true); } static void exit_flush_lazy_tlbs(struct mm_struct *mm) @@ -746,7 +752,7 @@ static enum tlb_flush_type flush_type_needed(struct mm_struct *mm, bool fullmm) * to trim. */ if (tick_and_test_trim_clock()) { - exit_lazy_flush_tlb(mm); + exit_lazy_flush_tlb(mm, true); return FLUSH_TYPE_NONE; } } @@ -792,7 +798,7 @@ static enum tlb_flush_type flush_type_needed(struct mm_struct *mm, bool fullmm) if (current->mm == mm) return FLUSH_TYPE_LOCAL; if (cpumask_test_cpu(cpu, mm_cpumask(mm))) - exit_lazy_flush_tlb(mm); + exit_lazy_flush_tlb(mm, true); return FLUSH_TYPE_NONE; } |