src/patches/suse-2.6.27.25/patches.arch/x86_sgi_cpus4096-01-fix-smp_call_function.patch

   1 From: Mike Travis <travis@sgi.com>
   2 Date: Fri, 5 Sep 2008 14:40:20 -0700
   3 Subject: [PATCH] smp: reduce stack requirements for smp_call_function_mask
   4 References: bnc#425240 FATE304266
   5 Patch-mainline: 2.6.28
   6
   7 * Cleanup cpumask_t usages in smp_call_function_mask to remove stack
   8     overflow problem when NR_CPUS=4096.  This removes over 1000 bytes
   9     from the stack with NR_CPUS=4096.
  10
  11 Signed-off-by: Mike Travis <travis@sgi.com>
  12 Signed-off-by: Ingo Molnar <mingo@elte.hu>
  13 Signed-off-by: Jiri Slaby <jslaby@suse.cz>
  14 Signed-off-by: Thomas Renninger <trenn@suse.de>
  15 ---
  16  kernel/smp.c |   12 +++++-------
  17  1 files changed, 5 insertions(+), 7 deletions(-)
  18
  19 diff --git a/kernel/smp.c b/kernel/smp.c
  20 index f362a85..069d066 100644
  21 --- a/kernel/smp.c
  22 +++ b/kernel/smp.c
  23 @@ -287,7 +287,7 @@ static void quiesce_dummy(void *unused)
  24   * If a faster scheme can be made, we could go back to preferring stack based
  25   * data -- the data allocation/free is non-zero cost.
  26   */
  27 -static void smp_call_function_mask_quiesce_stack(cpumask_t mask)
  28 +static void smp_call_function_mask_quiesce_stack(const cpumask_t *mask)
  29  {
  30         struct call_single_data data;
  31         int cpu;
  32 @@ -295,7 +295,7 @@ static void smp_call_function_mask_quiesce_stack(cpumask_t mask)
  33         data.func = quiesce_dummy;
  34         data.info = NULL;
  35
  36 -       for_each_cpu_mask(cpu, mask) {
  37 +       for_each_cpu_mask_nr(cpu, *mask) {
  38                 data.flags = CSD_FLAG_WAIT;
  39                 generic_exec_single(cpu, &data);
  40         }
  41 @@ -323,7 +323,6 @@ int smp_call_function_mask(cpumask_t mask, void (*func)(void *), void *info,
  42  {
  43         struct call_function_data d;
  44         struct call_function_data *data = NULL;
  45 -       cpumask_t allbutself;
  46         unsigned long flags;
  47         int cpu, num_cpus;
  48         int slowpath = 0;
  49 @@ -332,9 +331,8 @@ int smp_call_function_mask(cpumask_t mask, void (*func)(void *), void *info,
  50         WARN_ON(irqs_disabled());
  51
  52         cpu = smp_processor_id();
  53 -       allbutself = cpu_online_map;
  54 -       cpu_clear(cpu, allbutself);
  55 -       cpus_and(mask, mask, allbutself);
  56 +       cpus_and(mask, mask, cpu_online_map);
  57 +       cpu_clear(cpu, mask);
  58         num_cpus = cpus_weight(mask);
  59
  60         /*
  61 @@ -377,7 +375,7 @@ int smp_call_function_mask(cpumask_t mask, void (*func)(void *), void *info,
  62         if (wait) {
  63                 csd_flag_wait(&data->csd);
  64                 if (unlikely(slowpath))
  65 -                       smp_call_function_mask_quiesce_stack(mask);
  66 +                       smp_call_function_mask_quiesce_stack(&mask);
  67         }
  68
  69         return 0;
  70 --
  71 1.6.0.2
  72