lkml.org 
[lkml]   [2007]   [May]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] mm: swap prefetch more improvements
Date
akpm, please queue on top of "mm: swap prefetch improvements"

---
Failed radix_tree_insert wasn't being handled leaving stale kmem.
The list should be iterated over in the reverse order when prefetching.

Make the yield within kprefetchd stronger through the use of cond_resched.

Check that the pos entry hasn't been removed while unlocked.

Signed-off-by: Con Kolivas <kernel@kolivas.org>

---
mm/swap_prefetch.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)
Index: linux-2.6.21-ck1/mm/swap_prefetch.c
===================================================================
--- linux-2.6.21-ck1.orig/mm/swap_prefetch.c 2007-05-14 09:39:37.000000000 +1000
+++ linux-2.6.21-ck1/mm/swap_prefetch.c 2007-05-14 10:21:47.000000000 +1000
@@ -117,7 +117,8 @@ void add_to_swapped_list(struct page *pa
if (likely(!radix_tree_insert(&swapped.swap_tree, index, entry))) {
list_add(&entry->swapped_list, &swapped.list);
swapped.count++;
- }
+ } else
+ kmem_cache_free(swapped.cache, entry);

out_locked:
spin_unlock_irqrestore(&swapped.lock, flags);
@@ -427,7 +428,7 @@ out:
static enum trickle_return trickle_swap(void)
{
enum trickle_return ret = TRICKLE_DELAY;
- struct list_head *p, *next;
+ struct swapped_entry *pos, *n;
unsigned long flags;

if (!prefetch_enabled())
@@ -440,19 +441,19 @@ static enum trickle_return trickle_swap(
return TRICKLE_FAILED;

spin_lock_irqsave(&swapped.lock, flags);
- list_for_each_safe(p, next, &swapped.list) {
- struct swapped_entry *entry;
+ list_for_each_entry_safe_reverse(pos, n, &swapped.list, swapped_list) {
swp_entry_t swp_entry;
int node;

spin_unlock_irqrestore(&swapped.lock, flags);
- might_sleep();
- if (!prefetch_suitable())
+ /* Yield to anything else running */
+ if (cond_resched() || !prefetch_suitable())
goto out_unlocked;

spin_lock_irqsave(&swapped.lock, flags);
- entry = list_entry(p, struct swapped_entry, swapped_list);
- node = get_swap_entry_node(entry);
+ if (unlikely(!pos))
+ continue;
+ node = get_swap_entry_node(pos);
if (!node_isset(node, sp_stat.prefetch_nodes)) {
/*
* We found an entry that belongs to a node that is
@@ -460,7 +461,7 @@ static enum trickle_return trickle_swap(
*/
continue;
}
- swp_entry = entry->swp_entry;
+ swp_entry = pos->swp_entry;
spin_unlock_irqrestore(&swapped.lock, flags);

if (trickle_swap_cache_async(swp_entry, node) == TRICKLE_DELAY)
--
-ck
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-05-14 02:57    [from the cache]
©2003-2011 Jasper Spaans