Re: [PATCH 19/21] swap_prefetch: Conversion of nr_unstable to ZVC

Christoph Lameter
2006-06-12T23:49:23Z

On Tue, 13 Jun 2006, Con Kolivas wrote:

> Nack. You're changing some other code unintentionally.

Is this okay?

Subject: swap_prefetch: conversion of nr_unstable to per zone counter
From: Christoph Lameter <clameter@sgi.com>

The determination of the vm state is now not that expensive
anymore after we remove the use of the page state.
Remove the logic to avoid the expensive checks.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>

Index: linux-2.6.17-rc6-cl/mm/swap_prefetch.c
===================================================================
--- linux-2.6.17-rc6-cl.orig/mm/swap_prefetch.c 2006-06-12 13:37:47.283159568 -0700
+++ linux-2.6.17-rc6-cl/mm/swap_prefetch.c 2006-06-12 16:46:48.504626417 -0700
@@ -357,7 +357,6 @@ static int prefetch_suitable(void)
*/
for_each_node_mask(node, sp_stat.prefetch_nodes) {
struct node_stats *ns = &sp_stat.node[node];
- struct page_state ps;

/*
* We check to see that pages are not being allocated
@@ -375,11 +374,6 @@ static int prefetch_suitable(void)
} else
ns->last_free = ns->current_free;

- if (!test_pagestate)
- continue;
-
- get_page_state_node(&ps, node);
-
/* We shouldn't prefetch when we are doing writeback */
if (node_page_state(node, NR_WRITEBACK)) {
node_clear(node, sp_stat.prefetch_nodes);
@@ -394,7 +388,8 @@ static int prefetch_suitable(void)
node_page_state(node, NR_ANON) +
node_page_state(node, NR_SLAB) +
node_page_state(node, NR_DIRTY) +
- ps.nr_unstable + total_swapcache_pages;
+ node_page_state(node, NR_UNSTABLE) +
+ total_swapcache_pages;
if (limit > ns->prefetch_watermark) {
node_clear(node, sp_stat.prefetch_nodes);
continue;