releases/4.19.27/irq-matrix-split-out-the-cpu-selection-code-into-a-h.patch

   1 From 504302562cb34ba1a9b73753f9735da29d8f5ef2 Mon Sep 17 00:00:00 2001
   2 From: Dou Liyang <douly.fnst@cn.fujitsu.com>
   3 Date: Sun, 9 Sep 2018 01:58:37 +0800
   4 Subject: irq/matrix: Split out the CPU selection code into a helper
   5
   6 [ Upstream commit 8ffe4e61c06a48324cfd97f1199bb9838acce2f2 ]
   7
   8 Linux finds the CPU which has the lowest vector allocation count to spread
   9 out the non managed interrupts across the possible target CPUs, but does
  10 not do so for managed interrupts.
  11
  12 Split out the CPU selection code into a helper function for reuse. No
  13 functional change.
  14
  15 Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
  16 Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
  17 Cc: hpa@zytor.com
  18 Link: https://lkml.kernel.org/r/20180908175838.14450-1-dou_liyang@163.com
  19 Signed-off-by: Sasha Levin <sashal@kernel.org>
  20 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  21 ---
  22  kernel/irq/matrix.c |   65 ++++++++++++++++++++++++++++++----------------------
  23  1 file changed, 38 insertions(+), 27 deletions(-)
  24
  25 --- a/kernel/irq/matrix.c
  26 +++ b/kernel/irq/matrix.c
  27 @@ -124,6 +124,27 @@ static unsigned int matrix_alloc_area(st
  28         return area;
  29  }
  30
  31 +/* Find the best CPU which has the lowest vector allocation count */
  32 +static unsigned int matrix_find_best_cpu(struct irq_matrix *m,
  33 +                                       const struct cpumask *msk)
  34 +{
  35 +       unsigned int cpu, best_cpu, maxavl = 0;
  36 +       struct cpumap *cm;
  37 +
  38 +       best_cpu = UINT_MAX;
  39 +
  40 +       for_each_cpu(cpu, msk) {
  41 +               cm = per_cpu_ptr(m->maps, cpu);
  42 +
  43 +               if (!cm->online || cm->available <= maxavl)
  44 +                       continue;
  45 +
  46 +               best_cpu = cpu;
  47 +               maxavl = cm->available;
  48 +       }
  49 +       return best_cpu;
  50 +}
  51 +
  52  /**
  53   * irq_matrix_assign_system - Assign system wide entry in the matrix
  54   * @m:         Matrix pointer
  55 @@ -322,37 +343,27 @@ void irq_matrix_remove_reserved(struct i
  56  int irq_matrix_alloc(struct irq_matrix *m, const struct cpumask *msk,
  57                      bool reserved, unsigned int *mapped_cpu)
  58  {
  59 -       unsigned int cpu, best_cpu, maxavl = 0;
  60 +       unsigned int cpu, bit;
  61         struct cpumap *cm;
  62 -       unsigned int bit;
  63
  64 -       best_cpu = UINT_MAX;
  65 -       for_each_cpu(cpu, msk) {
  66 -               cm = per_cpu_ptr(m->maps, cpu);
  67 -
  68 -               if (!cm->online || cm->available <= maxavl)
  69 -                       continue;
  70 +       cpu = matrix_find_best_cpu(m, msk);
  71 +       if (cpu == UINT_MAX)
  72 +               return -ENOSPC;
  73
  74 -               best_cpu = cpu;
  75 -               maxavl = cm->available;
  76 -       }
  77 +       cm = per_cpu_ptr(m->maps, cpu);
  78 +       bit = matrix_alloc_area(m, cm, 1, false);
  79 +       if (bit >= m->alloc_end)
  80 +               return -ENOSPC;
  81 +       cm->allocated++;
  82 +       cm->available--;
  83 +       m->total_allocated++;
  84 +       m->global_available--;
  85 +       if (reserved)
  86 +               m->global_reserved--;
  87 +       *mapped_cpu = cpu;
  88 +       trace_irq_matrix_alloc(bit, cpu, m, cm);
  89 +       return bit;
  90
  91 -       if (maxavl) {
  92 -               cm = per_cpu_ptr(m->maps, best_cpu);
  93 -               bit = matrix_alloc_area(m, cm, 1, false);
  94 -               if (bit < m->alloc_end) {
  95 -                       cm->allocated++;
  96 -                       cm->available--;
  97 -                       m->total_allocated++;
  98 -                       m->global_available--;
  99 -                       if (reserved)
 100 -                               m->global_reserved--;
 101 -                       *mapped_cpu = best_cpu;
 102 -                       trace_irq_matrix_alloc(bit, best_cpu, m, cm);
 103 -                       return bit;
 104 -               }
 105 -       }
 106 -       return -ENOSPC;
 107  }
 108
 109  /**