I just created a third version of my swapin readahead patch.
It has all sorts of other kswapd fixes too, so you should
probably take a look even when you aren't interested in
swapin readahead at all. I'd really like your opinions on
this...
cheers,
Rik -- now completely used to dvorak kbd layout...
+-------------------------------------------------------------------+
| Linux memory management tour guide. H.H.vanRiel@phys.uu.nl |
| Scouting Vries cubscout leader. http://www.phys.uu.nl/~riel/ |
+-------------------------------------------------------------------+
--- ./mm/vmscan.c.orig Thu Nov 26 11:26:50 1998
+++ ./mm/vmscan.c Tue Dec 1 07:12:28 1998
@@ -431,6 +431,8 @@
kmem_cache_reap(gfp_mask);
if (buffer_over_borrow() || pgcache_over_borrow())
+ state = 0;
+ if (atomic_read(&nr_async_pages) > pager_daemon.swap_cluster / 2)
shrink_mmap(i, gfp_mask);
switch (state) {
--- ./mm/page_io.c.orig Thu Nov 26 11:26:49 1998
+++ ./mm/page_io.c Thu Nov 26 11:30:43 1998
@@ -60,7 +60,7 @@
}
/* Don't allow too many pending pages in flight.. */
- if (atomic_read(&nr_async_pages) > SWAP_CLUSTER_MAX)
+ if (atomic_read(&nr_async_pages) > pager_daemon.swap_cluster)
wait = 1;
p = &swap_info[type];
--- ./mm/page_alloc.c.orig Thu Nov 26 11:26:49 1998
+++ ./mm/page_alloc.c Tue Dec 1 07:25:51 1998
@@ -370,9 +370,30 @@
pte_t * page_table, unsigned long entry, int write_access)
{
unsigned long page;
- struct page *page_map;
-
- page_map = read_swap_cache(entry);
+ int i;
+ struct page *page_map = lookup_swap_cache(entry);
+ unsigned long offset = SWP_OFFSET(entry);
+ struct swap_info_struct *swapdev = SWP_TYPE(entry) + swap_info;
+
+ if (!page_map) {
+ page_map = read_swap_cache(entry);
+
+ /*
+ * Primitive swap readahead code. We simply read the
+ * next 16 entries in the swap area. The break below
+ * is needed or else the request queue will explode :)
+ */
+ for (i = 1; i++ < 16;) {
+ offset++;
+ if (!swapdev->swap_map[offset] || offset >= swapdev->max
+ || nr_free_pages - atomic_read(&nr_async_pages) <
+ (freepages.high + freepages.low)/2)
+ break;
+ read_swap_cache_async(SWP_ENTRY(SWP_TYPE(entry), offset),
+0);
+ break;
+ }
+ }
if (pte_val(*page_table) != entry) {
if (page_map)
--- ./mm/swap_state.c.orig Thu Nov 26 11:26:49 1998
+++ ./mm/swap_state.c Tue Dec 1 07:33:31 1998
@@ -258,7 +258,7 @@
* incremented.
*/
-static struct page * lookup_swap_cache(unsigned long entry)
+struct page * lookup_swap_cache(unsigned long entry)
{
struct page *found;
--- ./include/linux/swap.h.orig Tue Dec 1 07:29:56 1998
+++ ./include/linux/swap.h Tue Dec 1 07:31:03 1998
@@ -90,6 +90,7 @@
extern struct page * read_swap_cache_async(unsigned long, int);
#define read_swap_cache(entry) read_swap_cache_async(entry, 1);
extern int FASTCALL(swap_count(unsigned long));
+extern struct page * lookup_swap_cache(unsigned long);
/*
* Make these inline later once they are working properly.
*/
-
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