Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756812Ab0BLMD0 (ORCPT ); Fri, 12 Feb 2010 07:03:26 -0500 Received: from gir.skynet.ie ([193.1.99.77]:55589 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756192Ab0BLMBF (ORCPT ); Fri, 12 Feb 2010 07:01:05 -0500 From: Mel Gorman To: Andrea Arcangeli Cc: Christoph Lameter , Adam Litke , Avi Kivity , David Rientjes , KOSAKI Motohiro , Mel Gorman , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 06/12] Add /proc trigger for memory compaction Date: Fri, 12 Feb 2010 12:00:53 +0000 Message-Id: <1265976059-7459-7-git-send-email-mel@csn.ul.ie> X-Mailer: git-send-email 1.6.5 In-Reply-To: <1265976059-7459-1-git-send-email-mel@csn.ul.ie> References: <1265976059-7459-1-git-send-email-mel@csn.ul.ie> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5016 Lines: 175 This patch adds a proc file /proc/sys/vm/compact_memory. When an arbitrary value is written to the file, all zones are compacted. The expected user of such a trigger is a job scheduler that prepares the system before the target application runs. Signed-off-by: Mel Gorman --- Documentation/sysctl/vm.txt | 11 ++++++++ include/linux/compaction.h | 5 +++ kernel/sysctl.c | 11 ++++++++ mm/compaction.c | 60 +++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 87 insertions(+), 0 deletions(-) diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt index fc5790d..92b5b00 100644 --- a/Documentation/sysctl/vm.txt +++ b/Documentation/sysctl/vm.txt @@ -19,6 +19,7 @@ files can be found in mm/swap.c. Currently, these files are in /proc/sys/vm: - block_dump +- compact_memory - dirty_background_bytes - dirty_background_ratio - dirty_bytes @@ -64,6 +65,16 @@ information on block I/O debugging is in Documentation/laptops/laptop-mode.txt. ============================================================== +compact_memory + +Available only when CONFIG_COMPACTION is set. When an arbitrary value +is written to the file, all zones are compacted such that free memory +is available in contiguous blocks where possible. This can be important +for example in the allocation of huge pages although processes will also +directly compact memory as required. + +============================================================== + dirty_background_bytes Contains the amount of dirty memory at which the pdflush background writeback diff --git a/include/linux/compaction.h b/include/linux/compaction.h index 6201371..facaa3d 100644 --- a/include/linux/compaction.h +++ b/include/linux/compaction.h @@ -5,4 +5,9 @@ #define COMPACT_INCOMPLETE 0 #define COMPACT_COMPLETE 1 +#ifdef CONFIG_COMPACTION +extern int sysctl_compaction_handler(struct ctl_table *table, int write, + void __user *buffer, size_t *length, loff_t *ppos); +#endif /* CONFIG_COMPACTION */ + #endif /* _LINUX_COMPACTION_H */ diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 8a68b24..a02c816 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -50,6 +50,7 @@ #include #include #include +#include #include #include @@ -80,6 +81,7 @@ extern int pid_max; extern int min_free_kbytes; extern int pid_max_min, pid_max_max; extern int sysctl_drop_caches; +extern int sysctl_compact_memory; extern int percpu_pagelist_fraction; extern int compat_log; extern int latencytop_enabled; @@ -1109,6 +1111,15 @@ static struct ctl_table vm_table[] = { .mode = 0644, .proc_handler = drop_caches_sysctl_handler, }, +#ifdef CONFIG_COMPACTION + { + .procname = "compact_memory", + .data = &sysctl_compact_memory, + .maxlen = sizeof(int), + .mode = 0200, + .proc_handler = sysctl_compaction_handler, + }, +#endif /* CONFIG_COMPACTION */ { .procname = "min_free_kbytes", .data = &min_free_kbytes, diff --git a/mm/compaction.c b/mm/compaction.c index 51ec864..c0b9dc9 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -11,6 +11,7 @@ #include #include #include +#include #include "internal.h" /* @@ -339,3 +340,62 @@ static int compact_zone(struct zone *zone, struct compact_control *cc) return ret; } +/* Compact all zones within a node */ +static int compact_node(int nid) +{ + int zoneid; + pg_data_t *pgdat; + struct zone *zone; + + if (nid < 0 || nid > nr_node_ids || !node_online(nid)) + return -EINVAL; + pgdat = NODE_DATA(nid); + + /* Flush pending updates to the LRU lists */ + lru_add_drain_all(); + + for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) { + struct compact_control cc; + + zone = &pgdat->node_zones[zoneid]; + if (!populated_zone(zone)) + continue; + + cc.nr_freepages = 0; + cc.nr_migratepages = 0; + cc.zone = zone; + INIT_LIST_HEAD(&cc.freepages); + INIT_LIST_HEAD(&cc.migratepages); + + compact_zone(zone, &cc); + + VM_BUG_ON(!list_empty(&cc.freepages)); + VM_BUG_ON(!list_empty(&cc.migratepages)); + } + + return 0; +} + +/* Compact all nodes in the system */ +static int compact_nodes(void) +{ + int nid; + + for_each_online_node(nid) + compact_node(nid); + + return COMPACT_COMPLETE; +} + +/* The written value is actually unused, all memory is compacted */ +int sysctl_compact_memory; + +/* This is the entry point for compacting all nodes via /proc/sys/vm */ +int sysctl_compaction_handler(struct ctl_table *table, int write, + void __user *buffer, size_t *length, loff_t *ppos) +{ + if (write) + return compact_nodes(); + + return 0; +} -- 1.6.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/