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From: Christoph Lameter <clameter@sgi.com>
From: Christoph Lameter <clameter@sgi.com>
To: linux-kernel@vger.kernel.org
Cc: akpm@osdl.org, Hugh Dickins <hugh@veritas.com>,
	Con Kolivas <kernel@kolivas.org>,
	Marcelo Tosatti <marcelo@kvack.org>,
	Nick Piggin <nickpiggin@yahoo.com.au>,
	linux-mm@kvack.org, Andi Kleen <ak@suse.de>,
	Dave Chinner <dgc@sgi.com>, Christoph Lameter <clameter@sgi.com>
Subject: [PATCH 19/21] swap_prefetch: Conversion of nr_unstable to ZVC
Subject: swap_prefetch: conversion of nr_unstable to per zone counter
Date: Mon, 12 Jun 2006 14:14:23 -0700 (PDT)	[thread overview]
Message-ID: <20060612211423.20862.41488.sendpatchset@schroedinger.engr.sgi.com> (raw)
In-Reply-To: <20060612211244.20862.41106.sendpatchset@schroedinger.engr.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 12:55:39.368358636 -0700
+++ linux-2.6.17-rc6-cl/mm/swap_prefetch.c	2006-06-12 12:55:41.321362692 -0700
@@ -298,7 +298,7 @@ static int prefetch_suitable(void)
 {
 	unsigned long limit;
 	struct zone *z;
-	int node, ret = 0, test_pagestate = 0;
+	int node, ret = 0;
 
 	/* Purposefully racy */
 	if (test_bit(0, &swapped.busy)) {
@@ -306,19 +306,6 @@ static int prefetch_suitable(void)
 		goto out;
 	}
 
-	/*
-	 * get_page_state and above_background_load are expensive so we only
-	 * perform them every SWAP_CLUSTER_MAX prefetched_pages.
-	 * We test to see if we're above_background_load as disk activity
-	 * even at low priority can cause interrupt induced scheduling
-	 * latencies.
-	 */
-	if (!(sp_stat.prefetched_pages % SWAP_CLUSTER_MAX)) {
-		if (above_background_load())
-			goto out;
-		test_pagestate = 1;
-	}
-
 	clear_current_prefetch_free();
 
 	/*
@@ -357,7 +344,6 @@ 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 +361,6 @@ 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 +375,8 @@ 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;

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  parent reply	other threads:[~2006-06-12 21:14 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-06-12 21:12 [PATCH 00/21] Zoned VM counters V3 Christoph Lameter
2006-06-12 21:12 ` [PATCH 01/21] Create vmstat.c/.h from page_alloc.c/.h Christoph Lameter
2006-06-12 21:12 ` [PATCH 02/21] Basic ZVC (zoned vm counter) implementation, zoned vm counters: per zone counter functionality Christoph Lameter, Christoph Lameter
2006-06-13  5:37   ` Nick Piggin
2006-06-13 15:55     ` Christoph Lameter
2006-06-14  1:21       ` Nick Piggin
2006-06-14  5:37         ` Hugh Dickins
2006-06-14  5:53           ` Andi Kleen
2006-06-14 16:14         ` Christoph Lameter
2006-06-12 21:13 ` [PATCH 03/21] Convert nr_mapped to per zone counter, zoned vm counters: conversion of nr_mapped to per zone counter Christoph Lameter, Christoph Lameter
2006-06-12 21:13 ` [PATCH 04/21] swap_prefetch: Convert nr_mapped to ZVC Christoph Lameter
2006-06-12 23:36   ` Con Kolivas
2006-06-12 21:13 ` [PATCH 05/21] Conversion of nr_pagecache to per zone counter, zoned vm counters: conversion of nr_pagecache to per zone counter Christoph Lameter, Christoph Lameter
2006-06-12 21:13 ` [PATCH 06/21] Remove nr_mapped from scan controls structure, zoned VM stats: Remove nr_mapped from scan control Christoph Lameter, Christoph Lameter
2006-06-12 21:13 ` [PATCH 07/21] Split NR_ANON off from NR_MAPPED, zoned VM stats: Add NR_ANON Christoph Lameter, Christoph Lameter
2006-06-12 21:13 ` [PATCH 08/21] swap_prefetch: Split NR_ANON off NR_MAPPED Christoph Lameter
2006-06-12 23:36   ` Con Kolivas
2006-06-12 21:13 ` [PATCH 09/21] zone_reclaim: remove /proc/sys/vm/zone_reclaim_interval, zoned vm counters: use per zone counters to remove zone_reclaim_interval Christoph Lameter, Christoph Lameter
2006-06-12 21:13 ` [PATCH 10/21] Conversion of nr_slab to per zone counter, zoned vm counters: conversion of nr_slab to per zone counter Christoph Lameter, Christoph Lameter
2006-06-12 21:13 ` [PATCH 11/21] swap_prefetch: Conversion of nr_slab to ZVC Christoph Lameter
2006-06-12 21:13 ` [PATCH 12/21] Conversion of nr_pagetables to per zone counter, zoned vm counters: conversion of nr_pagetable to per zone counter Christoph Lameter, Christoph Lameter
2006-06-12 21:13 ` [PATCH 13/21] Conversion of nr_dirty to per zone counter, zoned vm counters: conversion of nr_dirty " Christoph Lameter, Christoph Lameter
2006-06-12 21:13 ` [PATCH 14/21] swap_prefetch: Conversion of nr_dirty to ZVC Christoph Lameter
2006-06-12 23:38   ` Con Kolivas
2006-06-12 21:14 ` [PATCH 15/21] reiser4: Conversiion of nr_dirty to ZVC, reiser4: conversion of nr_dirty to per zone counter Christoph Lameter, Christoph Lameter
2006-06-12 21:14 ` [PATCH 16/21] Conversion of nr_writeback to per zone counter, zoned vm counters: conversion of nr_writeback " Christoph Lameter, Christoph Lameter
2006-06-12 21:14 ` [PATCH 17/21] swap_prefetch: Conversion of nr_writeback to ZVC, swap_prefetch: " Christoph Lameter, Christoph Lameter
2006-06-12 23:38   ` [PATCH 17/21] swap_prefetch: Conversion of nr_writeback to ZVC Con Kolivas
2006-06-12 21:14 ` [PATCH 18/21] Conversion of nr_unstable to per zone counter, zoned vm counters: conversion of nr_unstable to per zone counter Christoph Lameter, Christoph Lameter
2006-06-12 21:14 ` Christoph Lameter, Christoph Lameter [this message]
2006-06-12 23:40   ` [PATCH 19/21] swap_prefetch: Conversion of nr_unstable to ZVC Con Kolivas
2006-06-12 23:48     ` Christoph Lameter
2006-06-12 23:57       ` Con Kolivas
2006-06-12 23:59         ` Con Kolivas
2006-06-13  0:08           ` Christoph Lameter
2006-06-13  0:19             ` Con Kolivas
2006-06-12 21:14 ` [PATCH 20/21] Conversion of nr_bounce to per zone counter, zoned vm counters: conversion of nr_bounce to per zone counter Christoph Lameter, Christoph Lameter
2006-06-12 21:14 ` [PATCH 21/21] Remove useless struct wbs, zoned vm counters: remove useless writeback structure Christoph Lameter, Christoph Lameter

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