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From: Rik van Riel <riel@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
	Lee Schermerhorn <Lee.Schermerhorn@hp.com>,
	linux-mm@kvack.org, Lee Schermerhorn <lee.schermerhorn@hp.com>
Subject: [patch 14/21] scan noreclaim list for reclaimable pages
Date: Thu, 28 Feb 2008 14:29:22 -0500	[thread overview]
Message-ID: <20080228192929.203173998@redhat.com> (raw)
In-Reply-To: <20080228192908.126720629@redhat.com>

[-- Attachment #1: noreclaim-01.3-scan-noreclaim-list-for-reclaimable-pages.patch --]
[-- Type: text/plain, Size: 8849 bytes --]

V2 -> V3:
+ rebase to 23-mm1 atop RvR's split LRU series

New in V2

This patch adds a function to scan individual or all zones' noreclaim
lists and move any pages that have become reclaimable onto the respective
zone's inactive list, where shrink_inactive_list() will deal with them.

This replaces the function to splice the entire noreclaim list onto the
active list for rescan by shrink_active_list().  That method had problems
with vmstat accounting and complicated '[__]isolate_lru_pages()'.  Now,
__isolate_lru_page() will never isolate a non-reclaimable page.  The
only time it should see one is when scanning nearby pages for lumpy
reclaim.

  TODO:  This approach may still need some refinement.
         E.g., put back to active list?

DEBUGGING ONLY: NOT FOR UPSTREAM MERGE

Signed-off-by:  Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by:  Rik van Riel <riel@redhat.com>


Index: linux-2.6.25-rc2-mm1/include/linux/swap.h
===================================================================
--- linux-2.6.25-rc2-mm1.orig/include/linux/swap.h	2008-02-28 12:05:42.000000000 -0500
+++ linux-2.6.25-rc2-mm1/include/linux/swap.h	2008-02-28 12:48:26.000000000 -0500
@@ -7,6 +7,7 @@
 #include <linux/list.h>
 #include <linux/memcontrol.h>
 #include <linux/sched.h>
+#include <linux/node.h>
 
 #include <asm/atomic.h>
 #include <asm/page.h>
@@ -244,12 +245,26 @@ static inline int zone_reclaim(struct zo
 
 #ifdef CONFIG_NORECLAIM
 extern int page_reclaimable(struct page *page, struct vm_area_struct *vma);
+extern void scan_zone_noreclaim_pages(struct zone *);
+extern void scan_all_zones_noreclaim_pages(void);
+extern unsigned long scan_noreclaim_pages;
+extern int scan_noreclaim_handler(struct ctl_table *, int, struct file *,
+					void __user *, size_t *, loff_t *);
+extern int scan_noreclaim_register_node(struct node *node);
+extern void scan_noreclaim_unregister_node(struct node *node);
 #else
 static inline int page_reclaimable(struct page *page,
 						struct vm_area_struct *vma)
 {
 	return 1;
 }
+static inline void scan_zone_noreclaim_pages(struct zone *z) { }
+static inline void scan_all_zones_noreclaim_pages(void) { }
+static inline int scan_noreclaim_register_node(struct node *node)
+{
+	return 0;
+}
+static inline void scan_noreclaim_unregister_node(struct node *node) { }
 #endif
 
 extern int kswapd_run(int nid);
Index: linux-2.6.25-rc2-mm1/mm/vmscan.c
===================================================================
--- linux-2.6.25-rc2-mm1.orig/mm/vmscan.c	2008-02-28 11:05:04.000000000 -0500
+++ linux-2.6.25-rc2-mm1/mm/vmscan.c	2008-02-28 12:48:01.000000000 -0500
@@ -39,6 +39,7 @@
 #include <linux/kthread.h>
 #include <linux/freezer.h>
 #include <linux/memcontrol.h>
+#include <linux/sysctl.h>
 
 #include <asm/tlbflush.h>
 #include <asm/div64.h>
@@ -2295,4 +2296,144 @@ int page_reclaimable(struct page *page, 
 
 	return 1;
 }
+
+/**
+ * scan_zone_noreclaim_pages(@zone)
+ * @zone - zone to scan
+ *
+ * Scan @zone's noreclaim LRU lists to check for pages that have become
+ * reclaimable.  Move those that have to @zone's inactive list where they
+ * become candidates for reclaim, unless shrink_inactive_zone() decides
+ * to reactivate them.  Pages that are still non-reclaimable are rotated
+ * back onto @zone's noreclaim list.
+ */
+#define SCAN_NORECLAIM_BATCH_SIZE 16UL	/* arbitrary lock hold batch size */
+void scan_zone_noreclaim_pages(struct zone *zone)
+{
+	struct list_head *l_noreclaim = &zone->list[LRU_NORECLAIM];
+	struct list_head *l_inactive_anon  = &zone->list[LRU_INACTIVE_ANON];
+	struct list_head *l_inactive_file  = &zone->list[LRU_INACTIVE_FILE];
+	unsigned long scan;
+	unsigned long nr_to_scan = zone_page_state(zone, NR_NORECLAIM);
+
+	while (nr_to_scan > 0) {
+		unsigned long batch_size = min(nr_to_scan,
+						SCAN_NORECLAIM_BATCH_SIZE);
+
+		spin_lock_irq(&zone->lru_lock);
+		for (scan = 0;  scan < batch_size; scan++) {
+			struct page* page = lru_to_page(l_noreclaim);
+
+			if (unlikely(!PageLRU(page) || !PageNoreclaim(page)))
+				continue;
+
+			prefetchw_prev_lru_page(page, l_noreclaim, flags);
+
+			ClearPageNoreclaim(page); /* for page_reclaimable() */
+			if(page_reclaimable(page, NULL)) {
+				__dec_zone_state(zone, NR_NORECLAIM);
+				if (page_file_cache(page)) {
+					list_move(&page->lru, l_inactive_file);
+					__inc_zone_state(zone, NR_INACTIVE_FILE);
+				} else {
+					list_move(&page->lru, l_inactive_anon);
+					__inc_zone_state(zone, NR_INACTIVE_ANON);
+				}
+			} else {
+				SetPageNoreclaim(page);
+				list_move(&page->lru, l_noreclaim);
+			}
+
+		}
+		spin_unlock_irq(&zone->lru_lock);
+
+		nr_to_scan -= batch_size;
+	}
+}
+
+
+/**
+ * scan_all_zones_noreclaim_pages()
+ *
+ * A really big hammer:  scan all zones' noreclaim LRU lists to check for
+ * pages that have become reclaimable.  Move those back to the zones'
+ * inactive list where they become candidates for reclaim.
+ * This occurs when, e.g., we have unswappable pages on the noreclaim lists,
+ * and we add swap to the system.  As such, it runs in the context of a task
+ * that has possibly/probably made some previously non-reclaimable pages
+ * reclaimable.
+//TODO:  or as a last resort under extreme memory pressure--before OOM?
+ */
+void scan_all_zones_noreclaim_pages(void)
+{
+	struct zone *zone;
+
+	for_each_zone(zone) {
+		scan_zone_noreclaim_pages(zone);
+	}
+}
+
+/*
+ * scan_noreclaim_pages [vm] sysctl handler.  On demand re-scan of
+ * all nodes' noreclaim lists for reclaimable pages
+ */
+unsigned long scan_noreclaim_pages;
+
+int scan_noreclaim_handler( struct ctl_table *table, int write,
+			   struct file *file, void __user *buffer,
+			   size_t *length, loff_t *ppos)
+{
+	proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
+
+	if (write && *(unsigned long *)table->data)
+		scan_all_zones_noreclaim_pages();
+
+	scan_noreclaim_pages = 0;
+	return 0;
+}
+
+/*
+ * per node 'scan_noreclaim_pages' attribute.  On demand re-scan of
+ * a specified node's per zone noreclaim lists for reclaimable pages.
+ */
+
+static ssize_t read_scan_noreclaim_node(struct sys_device *dev, char *buf)
+{
+	return sprintf(buf, "0\n");	/* always zero; should fit... */
+}
+
+static ssize_t write_scan_noreclaim_node(struct sys_device *dev,
+                                       const char *buf, size_t count)
+{
+	struct zone *node_zones = NODE_DATA(dev->id)->node_zones;
+	struct zone *zone;
+	unsigned long req = simple_strtoul(buf, NULL, 10);
+
+	if (!req)
+		return 1;	/* zero is no-op */
+
+	for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
+		if (!populated_zone(zone))
+			continue;
+		scan_zone_noreclaim_pages(zone);
+	}
+	return 1;
+}
+
+
+static SYSDEV_ATTR(scan_noreclaim_pages, S_IRUGO | S_IWUSR,
+			read_scan_noreclaim_node,
+			write_scan_noreclaim_node);
+
+int scan_noreclaim_register_node(struct node *node)
+{
+	return sysdev_create_file(&node->sysdev, &attr_scan_noreclaim_pages);
+}
+
+void scan_noreclaim_unregister_node(struct node *node)
+{
+	sysdev_remove_file(&node->sysdev, &attr_scan_noreclaim_pages);
+}
+
+
 #endif
Index: linux-2.6.25-rc2-mm1/kernel/sysctl.c
===================================================================
--- linux-2.6.25-rc2-mm1.orig/kernel/sysctl.c	2008-02-19 16:23:16.000000000 -0500
+++ linux-2.6.25-rc2-mm1/kernel/sysctl.c	2008-02-28 12:48:01.000000000 -0500
@@ -1165,6 +1165,16 @@ static struct ctl_table vm_table[] = {
 		.extra2		= &one,
 	},
 #endif
+#ifdef CONFIG_NORECLAIM
+	{
+		.ctl_name	= CTL_UNNUMBERED,
+		.procname	= "scan_noreclaim_pages",
+		.data		= &scan_noreclaim_pages,
+		.maxlen		= sizeof(scan_noreclaim_pages),
+		.mode		= 0644,
+		.proc_handler	= &scan_noreclaim_handler,
+	},
+#endif
 /*
  * NOTE: do not add new entries to this table unless you have read
  * Documentation/sysctl/ctl_unnumbered.txt
Index: linux-2.6.25-rc2-mm1/drivers/base/node.c
===================================================================
--- linux-2.6.25-rc2-mm1.orig/drivers/base/node.c	2008-02-28 12:47:36.000000000 -0500
+++ linux-2.6.25-rc2-mm1/drivers/base/node.c	2008-02-28 12:48:01.000000000 -0500
@@ -13,6 +13,7 @@
 #include <linux/nodemask.h>
 #include <linux/cpu.h>
 #include <linux/device.h>
+#include <linux/swap.h>
 
 static struct sysdev_class node_class = {
 	.name = "node",
@@ -162,6 +163,8 @@ int register_node(struct node *node, int
 		sysdev_create_file(&node->sysdev, &attr_meminfo);
 		sysdev_create_file(&node->sysdev, &attr_numastat);
 		sysdev_create_file(&node->sysdev, &attr_distance);
+
+		scan_noreclaim_register_node(node);
 	}
 	return error;
 }
@@ -180,6 +183,8 @@ void unregister_node(struct node *node)
 	sysdev_remove_file(&node->sysdev, &attr_numastat);
 	sysdev_remove_file(&node->sysdev, &attr_distance);
 
+	scan_noreclaim_unregister_node(node);
+
 	sysdev_unregister(&node->sysdev);
 }
 

-- 
All Rights Reversed


  parent reply	other threads:[~2008-02-28 19:48 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-28 19:29 [patch 00/21] VM pageout scalability improvements Rik van Riel
2008-02-28 19:29 ` [patch 01/21] move isolate_lru_page() to vmscan.c Rik van Riel
2008-02-29  2:29   ` KOSAKI Motohiro
2008-02-29  2:41     ` Rik van Riel
2008-02-29  2:47       ` KOSAKI Motohiro
2008-02-28 19:29 ` [patch 02/21] Use an indexed array for LRU variables Rik van Riel
2008-02-29 16:03   ` Andy Whitcroft
2008-03-03 18:57     ` Rik van Riel
2008-02-28 19:29 ` [patch 03/21] use an array for the LRU pagevecs Rik van Riel
2008-02-29 15:40   ` Andy Whitcroft
2008-03-01  7:02     ` KOSAKI Motohiro
2008-03-04 11:04       ` KOSAKI Motohiro
2008-03-04 20:38         ` Rik van Riel
2008-03-05  1:38           ` KOSAKI Motohiro
2008-02-28 19:29 ` [patch 04/21] free swap space on swap-in/activation Rik van Riel
2008-02-28 20:05   ` Lee Schermerhorn
2008-02-28 20:20     ` Rik van Riel
2008-02-28 19:29 ` [patch 05/21] define page_file_cache() function Rik van Riel
2008-02-29 11:53   ` KOSAKI Motohiro
2008-02-28 19:29 ` [patch 06/21] split LRU lists into anon & file sets Rik van Riel
2008-03-01 12:13   ` KOSAKI Motohiro
2008-03-01 12:46   ` KOSAKI Motohiro
2008-02-28 19:29 ` [patch 07/21] SEQ replacement for anonymous pages Rik van Riel
2008-03-03 10:50   ` barrioskmc@gmail
2008-02-28 19:29 ` [patch 08/21] (NEW) add some sanity checks to get_scan_ratio Rik van Riel
2008-03-04 10:40   ` minchan Kim
2008-02-28 19:29 ` [patch 09/21] (NEW) improve reclaim balancing Rik van Riel
2008-03-01 13:35   ` KOSAKI Motohiro
2008-03-03 19:26     ` Rik van Riel
2008-02-28 19:29 ` [patch 10/21] add newly swapped in pages to the inactive list Rik van Riel
2008-02-28 19:29 ` [patch 11/21] (NEW) more aggressively use lumpy reclaim Rik van Riel
2008-03-02 10:35   ` KOSAKI Motohiro
2008-03-02 14:23     ` Rik van Riel
2008-02-28 19:29 ` [patch 12/21] No Reclaim LRU Infrastructure Rik van Riel
     [not found]   ` <44c63dc40802282058h67f7597bvb614575f06c62e2c@mail.gmail.com>
2008-02-29 14:48     ` Lee Schermerhorn
     [not found]       ` <44c63dc40803021904n5de681datba400e08079c152d@mail.gmail.com>
2008-03-03  3:06         ` minchan Kim
2008-03-03 18:46         ` Rik van Riel
2008-03-03 23:38           ` barrioskmc@gmail
2008-03-04  1:55             ` Rik van Riel
2008-03-04 10:46   ` KOSAKI Motohiro
2008-03-04 15:05     ` Lee Schermerhorn
2008-03-04 21:21       ` Rik van Riel
2008-03-05  1:42       ` KOSAKI Motohiro
2008-02-28 19:29 ` [patch 13/21] Non-reclaimable page statistics Rik van Riel
2008-02-28 19:29 ` Rik van Riel [this message]
2008-02-28 23:41   ` [patch 14/21] scan noreclaim list for reclaimable pages Randy Dunlap
2008-02-29 14:38     ` Lee Schermerhorn
2008-02-28 19:29 ` [patch 15/21] ramfs pages are non-reclaimable Rik van Riel
2008-02-28 19:29 ` [patch 16/21] SHM_LOCKED pages are nonreclaimable Rik van Riel
2008-02-28 19:29 ` [patch 17/21] non-reclaimable mlocked pages Rik van Riel
     [not found]   ` <44c63dc40802282055q508af6ccsb0e8ac3fb5e67d24@mail.gmail.com>
2008-02-29 14:47     ` Lee Schermerhorn
2008-02-28 19:29 ` [patch 18/21] mlock vma pages under mmap_sem held for read Rik van Riel
2008-02-28 19:29 ` [patch 19/21] handle mlocked pages during map/unmap and truncate Rik van Riel
2008-02-28 19:29 ` [patch 20/21] account mlocked pages Rik van Riel
2008-02-28 19:29 ` [patch 21/21] cull non-reclaimable anon pages from the LRU at fault time Rik van Riel
2008-02-28 20:19   ` Lee Schermerhorn
2008-02-28 22:27     ` Rik van Riel
2008-02-28 19:49 ` [patch 00/21] VM pageout scalability improvements Rik van Riel
2008-02-28 20:14 ` John Stoffel
2008-02-28 20:23   ` Rik van Riel

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