[RFC:Patch: 004/008](memory hotplug) Use lock for for_each_online_node
From: Yasunori Goto
Date: Thu Jul 31 2008 - 08:02:20 EST
Add pgdat_remove_read_lock() and unlock() for parsing
for_each_online_node() (and for_each_node_state()).
(for_each_zone also needs same lock, but I don't implement
it yet.)
Signed-off-by: Yasunori Goto <y-goto@xxxxxxxxxxxxxx>
---
fs/buffer.c | 4 +++-
mm/mempolicy.c | 9 ++++++++-
mm/page-writeback.c | 2 ++
mm/page_alloc.c | 9 ++++++++-
mm/vmscan.c | 2 ++
mm/vmstat.c | 3 +++
6 files changed, 26 insertions(+), 3 deletions(-)
Index: current/mm/page_alloc.c
===================================================================
--- current.orig/mm/page_alloc.c 2008-07-29 21:21:33.000000000 +0900
+++ current/mm/page_alloc.c 2008-07-29 22:17:44.000000000 +0900
@@ -2345,6 +2345,7 @@ static int default_zonelist_order(void)
/* Is there ZONE_NORMAL ? (ex. ppc has only DMA zone..) */
low_kmem_size = 0;
total_size = 0;
+ pgdat_remove_read_lock();
for_each_online_node(nid) {
for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
z = &NODE_DATA(nid)->node_zones[zone_type];
@@ -2355,6 +2356,7 @@ static int default_zonelist_order(void)
}
}
}
+ pgdat_remove_read_unlock();
if (!low_kmem_size || /* there are no DMA area. */
low_kmem_size > total_size/2) /* DMA/DMA32 is big. */
return ZONELIST_ORDER_NODE;
@@ -2365,6 +2367,8 @@ static int default_zonelist_order(void)
*/
average_size = total_size /
(nodes_weight(node_states[N_HIGH_MEMORY]) + 1);
+
+ pgdat_remove_read_lock();
for_each_online_node(nid) {
low_kmem_size = 0;
total_size = 0;
@@ -2378,9 +2382,12 @@ static int default_zonelist_order(void)
}
if (low_kmem_size &&
total_size > average_size && /* ignore small node */
- low_kmem_size > total_size * 70/100)
+ low_kmem_size > total_size * 70/100){
+ pgdat_remove_read_unlock();
return ZONELIST_ORDER_NODE;
+ }
}
+ pgdat_remove_read_unlock();
return ZONELIST_ORDER_ZONE;
}
Index: current/mm/vmscan.c
===================================================================
--- current.orig/mm/vmscan.c 2008-07-29 21:20:42.000000000 +0900
+++ current/mm/vmscan.c 2008-07-29 22:17:44.000000000 +0900
@@ -2170,6 +2170,7 @@ static int __devinit cpu_callback(struct
int nid;
if (action == CPU_ONLINE || action == CPU_ONLINE_FROZEN) {
+ pgdat_remove_read_lock();
for_each_node_state(nid, N_HIGH_MEMORY) {
pg_data_t *pgdat = NODE_DATA(nid);
node_to_cpumask_ptr(mask, pgdat->node_id);
@@ -2178,6 +2179,7 @@ static int __devinit cpu_callback(struct
/* One of our CPUs online: restore mask */
set_cpus_allowed_ptr(pgdat->kswapd, mask);
}
+ pgdat_remove_read_unlock();
}
return NOTIFY_OK;
}
Index: current/mm/page-writeback.c
===================================================================
--- current.orig/mm/page-writeback.c 2008-07-29 21:20:42.000000000 +0900
+++ current/mm/page-writeback.c 2008-07-29 21:23:11.000000000 +0900
@@ -325,12 +325,14 @@ static unsigned long highmem_dirtyable_m
int node;
unsigned long x = 0;
+ pgdat_remove_read_lock();
for_each_node_state(node, N_HIGH_MEMORY) {
struct zone *z =
&NODE_DATA(node)->node_zones[ZONE_HIGHMEM];
x += zone_page_state(z, NR_FREE_PAGES) + zone_lru_pages(z);
}
+ pgdat_remove_read_unlock();
/*
* Make sure that the number of highmem pages is never larger
* than the number of the total dirtyable memory. This can only
Index: current/mm/mempolicy.c
===================================================================
--- current.orig/mm/mempolicy.c 2008-07-29 21:20:42.000000000 +0900
+++ current/mm/mempolicy.c 2008-07-29 22:17:44.000000000 +0900
@@ -129,15 +129,19 @@ static int is_valid_nodemask(const nodem
/* Check that there is something useful in this mask */
k = policy_zone;
+ pgdat_remove_read_lock();
for_each_node_mask(nd, *nodemask) {
struct zone *z;
for (k = 0; k <= policy_zone; k++) {
z = &NODE_DATA(nd)->node_zones[k];
- if (z->present_pages > 0)
+ if (z->present_pages > 0) {
+ pgdat_remove_read_unlock();
return 1;
+ }
}
}
+ pgdat_remove_read_unlock();
return 0;
}
@@ -1930,6 +1934,8 @@ void __init numa_policy_init(void)
* fall back to the largest node if they're all smaller.
*/
nodes_clear(interleave_nodes);
+
+ pgdat_remove_read_lock(); /* node_present_pages accesses pgdat */
for_each_node_state(nid, N_HIGH_MEMORY) {
unsigned long total_pages = node_present_pages(nid);
@@ -1943,6 +1949,7 @@ void __init numa_policy_init(void)
if ((total_pages << PAGE_SHIFT) >= (16 << 20))
node_set(nid, interleave_nodes);
}
+ pgdat_remove_read_unlock();
/* All too small, use the largest */
if (unlikely(nodes_empty(interleave_nodes)))
Index: current/fs/buffer.c
===================================================================
--- current.orig/fs/buffer.c 2008-07-29 21:20:42.000000000 +0900
+++ current/fs/buffer.c 2008-07-29 21:23:11.000000000 +0900
@@ -369,11 +369,12 @@ void invalidate_bdev(struct block_device
static void free_more_memory(void)
{
struct zone *zone;
- int nid;
+ int nid, idx;
wakeup_pdflush(1024);
yield();
+ idx = pgdat_remove_read_lock_sleepable();
for_each_online_node(nid) {
(void)first_zones_zonelist(node_zonelist(nid, GFP_NOFS),
gfp_zone(GFP_NOFS), NULL,
@@ -382,6 +383,7 @@ static void free_more_memory(void)
try_to_free_pages(node_zonelist(nid, GFP_NOFS), 0,
GFP_NOFS);
}
+ pgdat_remove_read_unlock_sleepable(idx);
}
/*
Index: current/mm/vmstat.c
===================================================================
--- current.orig/mm/vmstat.c 2008-07-29 22:06:46.000000000 +0900
+++ current/mm/vmstat.c 2008-07-29 22:07:13.000000000 +0900
@@ -400,6 +400,8 @@ static void *frag_start(struct seq_file
{
pg_data_t *pgdat;
loff_t node = *pos;
+
+ pgdat_remove_read_lock();
for (pgdat = first_online_pgdat();
pgdat && node;
pgdat = next_online_pgdat(pgdat))
@@ -418,6 +420,7 @@ static void *frag_next(struct seq_file *
static void frag_stop(struct seq_file *m, void *arg)
{
+ pgdat_remove_read_unlock();
}
/* Walk all the zones in a node and print using a callback */
--
Yasunori Goto
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