rt-patches/0046-mm-workingset-Do-not-protect-workingset_shadow_nodes.patch

   1 From 8bd00bc3ee3c0d2703954a1f09c1d96031d5a1a8 Mon Sep 17 00:00:00 2001
   2 From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
   3 Date: Thu, 29 Jan 2015 17:19:44 +0100
   4 Subject: [PATCH 046/366] mm/workingset: Do not protect workingset_shadow_nodes
   5  with irq off
   6
   7 workingset_shadow_nodes is protected by local_irq_disable(). Some users
   8 use spin_lock_irq().
   9 Replace the irq/on with a local_lock(). Rename workingset_shadow_nodes
  10 so I catch users of it which will be introduced later.
  11
  12 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
  13 ---
  14  include/linux/swap.h |  4 +++-
  15  mm/filemap.c         | 11 ++++++++---
  16  mm/truncate.c        |  7 +++++--
  17  mm/workingset.c      | 23 ++++++++++++-----------
  18  4 files changed, 28 insertions(+), 17 deletions(-)
  19
  20 diff --git a/include/linux/swap.h b/include/linux/swap.h
  21 index d8ca2ea..973b384 100644
  22 --- a/include/linux/swap.h
  23 +++ b/include/linux/swap.h
  24 @@ -11,6 +11,7 @@
  25  #include <linux/fs.h>
  26  #include <linux/atomic.h>
  27  #include <linux/page-flags.h>
  28 +#include <linux/locallock.h>
  29  #include <asm/page.h>
  30
  31  struct notifier_block;
  32 @@ -252,7 +253,8 @@ struct swap_info_struct {
  33  void *workingset_eviction(struct address_space *mapping, struct page *page);
  34  bool workingset_refault(void *shadow);
  35  void workingset_activation(struct page *page);
  36 -extern struct list_lru workingset_shadow_nodes;
  37 +extern struct list_lru __workingset_shadow_nodes;
  38 +DECLARE_LOCAL_IRQ_LOCK(workingset_shadow_lock);
  39
  40  static inline unsigned int workingset_node_pages(struct radix_tree_node *node)
  41  {
  42 diff --git a/mm/filemap.c b/mm/filemap.c
  43 index fad46b1..7fb06d4 100644
  44 --- a/mm/filemap.c
  45 +++ b/mm/filemap.c
  46 @@ -144,9 +144,12 @@ static int page_cache_tree_insert(struct address_space *mapping,
  47                  * node->private_list is protected by
  48                  * mapping->tree_lock.
  49                  */
  50 -               if (!list_empty(&node->private_list))
  51 -                       list_lru_del(&workingset_shadow_nodes,
  52 +               if (!list_empty(&node->private_list)) {
  53 +                       local_lock(workingset_shadow_lock);
  54 +                       list_lru_del(&__workingset_shadow_nodes,
  55                                      &node->private_list);
  56 +                       local_unlock(workingset_shadow_lock);
  57 +               }
  58         }
  59         return 0;
  60  }
  61 @@ -218,7 +221,9 @@ static void page_cache_tree_delete(struct address_space *mapping,
  62         if (!workingset_node_pages(node) &&
  63             list_empty(&node->private_list)) {
  64                 node->private_data = mapping;
  65 -               list_lru_add(&workingset_shadow_nodes, &node->private_list);
  66 +               local_lock(workingset_shadow_lock);
  67 +               list_lru_add(&__workingset_shadow_nodes, &node->private_list);
  68 +               local_unlock(workingset_shadow_lock);
  69         }
  70  }
  71
  72 diff --git a/mm/truncate.c b/mm/truncate.c
  73 index 76e35ad..5f19642 100644
  74 --- a/mm/truncate.c
  75 +++ b/mm/truncate.c
  76 @@ -56,8 +56,11 @@ static void clear_exceptional_entry(struct address_space *mapping,
  77          * protected by mapping->tree_lock.
  78          */
  79         if (!workingset_node_shadows(node) &&
  80 -           !list_empty(&node->private_list))
  81 -               list_lru_del(&workingset_shadow_nodes, &node->private_list);
  82 +           !list_empty(&node->private_list)) {
  83 +               local_lock(workingset_shadow_lock);
  84 +               list_lru_del(&__workingset_shadow_nodes, &node->private_list);
  85 +               local_unlock(workingset_shadow_lock);
  86 +       }
  87         __radix_tree_delete_node(&mapping->page_tree, node);
  88  unlock:
  89         spin_unlock_irq(&mapping->tree_lock);
  90 diff --git a/mm/workingset.c b/mm/workingset.c
  91 index df66f42..6db7b24 100644
  92 --- a/mm/workingset.c
  93 +++ b/mm/workingset.c
  94 @@ -264,7 +264,8 @@ void workingset_activation(struct page *page)
  95   * point where they would still be useful.
  96   */
  97
  98 -struct list_lru workingset_shadow_nodes;
  99 +struct list_lru __workingset_shadow_nodes;
 100 +DEFINE_LOCAL_IRQ_LOCK(workingset_shadow_lock);
 101
 102  static unsigned long count_shadow_nodes(struct shrinker *shrinker,
 103                                         struct shrink_control *sc)
 104 @@ -274,9 +275,9 @@ static unsigned long count_shadow_nodes(struct shrinker *shrinker,
 105         unsigned long pages;
 106
 107         /* list_lru lock nests inside IRQ-safe mapping->tree_lock */
 108 -       local_irq_disable();
 109 -       shadow_nodes = list_lru_shrink_count(&workingset_shadow_nodes, sc);
 110 -       local_irq_enable();
 111 +       local_lock_irq(workingset_shadow_lock);
 112 +       shadow_nodes = list_lru_shrink_count(&__workingset_shadow_nodes, sc);
 113 +       local_unlock_irq(workingset_shadow_lock);
 114
 115         pages = node_present_pages(sc->nid);
 116         /*
 117 @@ -361,9 +362,9 @@ static enum lru_status shadow_lru_isolate(struct list_head *item,
 118         spin_unlock(&mapping->tree_lock);
 119         ret = LRU_REMOVED_RETRY;
 120  out:
 121 -       local_irq_enable();
 122 +       local_unlock_irq(workingset_shadow_lock);
 123         cond_resched();
 124 -       local_irq_disable();
 125 +       local_lock_irq(workingset_shadow_lock);
 126         spin_lock(lru_lock);
 127         return ret;
 128  }
 129 @@ -374,10 +375,10 @@ static unsigned long scan_shadow_nodes(struct shrinker *shrinker,
 130         unsigned long ret;
 131
 132         /* list_lru lock nests inside IRQ-safe mapping->tree_lock */
 133 -       local_irq_disable();
 134 -       ret =  list_lru_shrink_walk(&workingset_shadow_nodes, sc,
 135 +       local_lock_irq(workingset_shadow_lock);
 136 +       ret =  list_lru_shrink_walk(&__workingset_shadow_nodes, sc,
 137                                     shadow_lru_isolate, NULL);
 138 -       local_irq_enable();
 139 +       local_unlock_irq(workingset_shadow_lock);
 140         return ret;
 141  }
 142
 143 @@ -398,7 +399,7 @@ static int __init workingset_init(void)
 144  {
 145         int ret;
 146
 147 -       ret = list_lru_init_key(&workingset_shadow_nodes, &shadow_nodes_key);
 148 +       ret = list_lru_init_key(&__workingset_shadow_nodes, &shadow_nodes_key);
 149         if (ret)
 150                 goto err;
 151         ret = register_shrinker(&workingset_shadow_shrinker);
 152 @@ -406,7 +407,7 @@ static int __init workingset_init(void)
 153                 goto err_list_lru;
 154         return 0;
 155  err_list_lru:
 156 -       list_lru_destroy(&workingset_shadow_nodes);
 157 +       list_lru_destroy(&__workingset_shadow_nodes);
 158  err:
 159         return ret;
 160  }
 161 --
 162 1.9.1
 163