Re: [PATCH] VM improvements for 2.1.131

[Andrea Arcangeli <andrea@e-mind.com>]

On Mon, 7 Dec 1998, Stephen C. Tweedie wrote:

>Right: 2.1.131 + Rik's fixes + my fix to Rik's fixes (see below) has set
>a new record for my 8MB benchmarks.  In 64MB, it is behaving much more

I think that my state = 0 in do_try_to_free_page() helped a lot to handle
the better kernel performance.

>--- mm/vmscan.c.~1~	Mon Dec  7 12:05:54 1998
>+++ mm/vmscan.c	Mon Dec  7 18:55:55 1998
>@@ -432,6 +432,8 @@
> 
> 	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);
> 

Doing that we risk to shrink too much cache even if not necessary but this
part of the patch improve a _lot_ swapping performance even if I don' t know
why ;)

And why not to use GFP_USER in the userspace swaping code?

Index: linux/mm/swap_state.c
diff -u linux/mm/swap_state.c:1.1.3.2 linux/mm/swap_state.c:1.1.1.1.2.4
--- linux/mm/swap_state.c:1.1.3.2	Wed Dec  9 16:11:46 1998
+++ linux/mm/swap_state.c	Wed Dec  9 18:39:03 1998
@@ -261,7 +261,9 @@
 struct page * lookup_swap_cache(unsigned long entry)
 {
 	struct page *found;
+#ifdef	SWAP_CACHE_INFO
 	swap_cache_find_total++;
+#endif
 	
 	while (1) {
 		found = find_page(&swapper_inode, entry);
@@ -270,7 +272,9 @@
 		if (found->inode != &swapper_inode || !PageSwapCache(found))
 			goto out_bad;
 		if (!PageLocked(found)) {
+#ifdef	SWAP_CACHE_INFO
 			swap_cache_find_success++;
+#endif
 			return found;
 		}
 		__free_page(found);
@@ -308,7 +336,7 @@
 	if (found_page)
 		goto out;
 
-	new_page_addr = __get_free_page(GFP_KERNEL);
+	new_page_addr = __get_free_page(GFP_USER);
 	if (!new_page_addr)
 		goto out;	/* Out of memory */
 	new_page = mem_map + MAP_NR(new_page_addr);


Andrea Arcangeli

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