From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lee Schermerhorn Subject: [PATCH 10/12] mm: clear node in N_HIGH_MEMORY and stop kswapd when all memory is offlined Date: Thu, 08 Oct 2009 12:26:43 -0400 Message-ID: <20091008162643.23192.65918.sendpatchset@localhost.localdomain> References: <20091008162454.23192.91832.sendpatchset@localhost.localdomain> Return-path: In-Reply-To: <20091008162454.23192.91832.sendpatchset@localhost.localdomain> Sender: owner-linux-mm@kvack.org List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-mm@kvack.org, linux-numa@vger.kernel.org Cc: akpm@linux-foundation.org, Mel Gorman , Randy Dunlap , Nishanth Aravamudan , andi@firstfloor.org, David Rientjes , Adam Litke , Andy Whitcroft , eric.whitney@hp.com >From rientjes@google.com Wed Oct 7 02:25:10 2009 [PATCH 10/12] mm: clear node in N_HIGH_MEMORY and stop kswapd when all memory is offlined mm: clear node in N_HIGH_MEMORY and stop kswapd when all memory is offlined When memory is hot-removed, its node must be cleared in N_HIGH_MEMORY if there are no present pages left. In such a situation, kswapd must also be stopped since it has nothing left to do. Cc: Christoph Lameter Cc: Yasunori Goto Cc: Mel Gorman Cc: Rafael J. Wysocki Cc: Rik van Riel Signed-off-by: David Rientjes Signed-off-by: Lee Schermerhorn --- include/linux/swap.h | 1 + mm/memory_hotplug.c | 4 ++++ mm/vmscan.c | 28 ++++++++++++++++++++++------ 3 files changed, 27 insertions(+), 6 deletions(-) Index: linux-2.6.31-mmotm-090925-1435/include/linux/swap.h =================================================================== --- linux-2.6.31-mmotm-090925-1435.orig/include/linux/swap.h 2009-09-28 10:10:39.000000000 -0400 +++ linux-2.6.31-mmotm-090925-1435/include/linux/swap.h 2009-10-07 16:24:43.000000000 -0400 @@ -273,6 +273,7 @@ extern int scan_unevictable_register_nod extern void scan_unevictable_unregister_node(struct node *node); extern int kswapd_run(int nid); +extern void kswapd_stop(int nid); #ifdef CONFIG_MMU /* linux/mm/shmem.c */ Index: linux-2.6.31-mmotm-090925-1435/mm/memory_hotplug.c =================================================================== --- linux-2.6.31-mmotm-090925-1435.orig/mm/memory_hotplug.c 2009-09-28 10:10:39.000000000 -0400 +++ linux-2.6.31-mmotm-090925-1435/mm/memory_hotplug.c 2009-10-07 16:24:43.000000000 -0400 @@ -838,6 +838,10 @@ repeat: setup_per_zone_wmarks(); calculate_zone_inactive_ratio(zone); + if (!node_present_pages(node)) { + node_clear_state(node, N_HIGH_MEMORY); + kswapd_stop(node); + } vm_total_pages = nr_free_pagecache_pages(); writeback_set_ratelimit(); Index: linux-2.6.31-mmotm-090925-1435/mm/vmscan.c =================================================================== --- linux-2.6.31-mmotm-090925-1435.orig/mm/vmscan.c 2009-09-28 10:10:43.000000000 -0400 +++ linux-2.6.31-mmotm-090925-1435/mm/vmscan.c 2009-10-07 16:24:43.000000000 -0400 @@ -2167,6 +2167,7 @@ static int kswapd(void *p) order = 0; for ( ; ; ) { unsigned long new_order; + int ret; prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE); new_order = pgdat->kswapd_max_order; @@ -2178,19 +2179,23 @@ static int kswapd(void *p) */ order = new_order; } else { - if (!freezing(current)) + if (!freezing(current) && !kthread_should_stop()) schedule(); order = pgdat->kswapd_max_order; } finish_wait(&pgdat->kswapd_wait, &wait); - if (!try_to_freeze()) { - /* We can speed up thawing tasks if we don't call - * balance_pgdat after returning from the refrigerator - */ + ret = try_to_freeze(); + if (kthread_should_stop()) + break; + + /* + * We can speed up thawing tasks if we don't call balance_pgdat + * after returning from the refrigerator + */ + if (!ret) balance_pgdat(pgdat, order); - } } return 0; } @@ -2445,6 +2450,17 @@ int kswapd_run(int nid) return ret; } +/* + * Called by memory hotplug when all memory in a node is offlined. + */ +void kswapd_stop(int nid) +{ + struct task_struct *kswapd = NODE_DATA(nid)->kswapd; + + if (kswapd) + kthread_stop(kswapd); +} + static int __init kswapd_init(void) { int nid; -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org