The patch titled
Subject: mm/memory_hotplug.c: make add_memory_resource use __try_online_node
has been added to the -mm tree. Its filename is
mm-memory_hotplug-make-add_memory_resource-use-__try_online_node.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-memory_hotplug-make-add_memory_resource-use-__try_online_node.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-memory_hotplug-make-add_memory_resource-use-__try_online_node.patch
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------------------------------------------------------
From: Oscar Salvador <osalvador@xxxxxxx>
Subject: mm/memory_hotplug.c: make add_memory_resource use __try_online_node
this is a small cleanup for the memhotplug's code. A lot more could be
done, but it is better to start somewhere. I tried to unify/remove
duplicated code.
The following is what this patchset does:
1) add_memory_resource() has code to allocate a node in case it was
offline. Since try_online_node has some code for that as well, I just
made add_memory_resource() to use that so we can remove duplicated
code.. This is better explained in patch 1/4.
2) register_mem_sect_under_node() will be called only from
link_mem_sections()
3) Make register_mem_sect_under_node() a callback of
walk_memory_range()
4) Drop unnecessary checks from register_mem_sect_under_node()
I have done some tests and I could not see anything broken because of this
patchset.
add_memory_resource() contains code to allocate a new node in case it is
necessary. Since try_online_node() also has some code for this purpose,
let us make use of that and remove duplicate code.
This introduces __try_online_node(), which is called by
add_memory_resource() and try_online_node(). __try_online_node() has two
new parameters, start_addr of the node, and if the node should be onlined
and registered right away. This is always wanted if we are calling from
do_cpu_up(), but not when we are calling from memhotplug code. Nothing
changes from the point of view of the users of try_online_node(), since
try_online_node passes start_addr=0 and online_node=true to
__try_online_node().
Link: http://lkml.kernel.org/r/20180622111839.10071-2-osalvador@xxxxxxxxxxxxxxxxxx
Signed-off-by: Oscar Salvador <osalvador@xxxxxxx>
Reviewed-by: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Tested-by: Reza Arbab <arbab@xxxxxxxxxxxxxxxxxx>
Tested-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory_hotplug.c | 67 ++++++++++++++++++++++++------------------
1 file changed, 39 insertions(+), 28 deletions(-)
diff -puN mm/memory_hotplug.c~mm-memory_hotplug-make-add_memory_resource-use-__try_online_node mm/memory_hotplug.c
--- a/mm/memory_hotplug.c~mm-memory_hotplug-make-add_memory_resource-use-__try_online_node
+++ a/mm/memory_hotplug.c
@@ -1034,8 +1034,10 @@ static pg_data_t __ref *hotadd_new_pgdat
return pgdat;
}
-static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
+static void rollback_node_hotadd(int nid)
{
+ pg_data_t *pgdat = NODE_DATA(nid);
+
arch_refresh_nodedata(nid, NULL);
free_percpu(pgdat->per_cpu_nodestats);
arch_free_nodedata(pgdat);
@@ -1046,28 +1048,48 @@ static void rollback_node_hotadd(int nid
/**
* try_online_node - online a node if offlined
* @nid: the node ID
- *
+ * @start: start addr of the node
+ * @set_node_online: Whether we want to online the node
* called by cpu_up() to online a node without onlined memory.
+ *
+ * Returns:
+ * 1 -> a new node has been allocated
+ * 0 -> the node is already online
+ * -ENOMEM -> the node could not be allocated
*/
-int try_online_node(int nid)
+static int __try_online_node(int nid, u64 start, bool set_node_online)
{
- pg_data_t *pgdat;
- int ret;
+ pg_data_t *pgdat;
+ int ret = 1;
if (node_online(nid))
return 0;
- mem_hotplug_begin();
- pgdat = hotadd_new_pgdat(nid, 0);
+ pgdat = hotadd_new_pgdat(nid, start);
if (!pgdat) {
pr_err("Cannot online node %d due to NULL pgdat\n", nid);
ret = -ENOMEM;
goto out;
}
- node_set_online(nid);
- ret = register_one_node(nid);
- BUG_ON(ret);
+
+ if (set_node_online) {
+ node_set_online(nid);
+ ret = register_one_node(nid);
+ BUG_ON(ret);
+ }
out:
+ return ret;
+}
+
+/*
+ * Users of this function always want to online/register the node
+ */
+int try_online_node(int nid)
+{
+ int ret;
+
+ mem_hotplug_begin();
+ ret = __try_online_node(nid, 0, true);
mem_hotplug_done();
return ret;
}
@@ -1099,9 +1121,7 @@ static int online_memory_block(struct me
int __ref add_memory_resource(int nid, struct resource *res, bool online)
{
u64 start, size;
- pg_data_t *pgdat = NULL;
- bool new_pgdat;
- bool new_node;
+ bool new_node = false;
int ret;
start = res->start;
@@ -1111,11 +1131,6 @@ int __ref add_memory_resource(int nid, s
if (ret)
return ret;
- { /* Stupid hack to suppress address-never-null warning */
- void *p = NODE_DATA(nid);
- new_pgdat = !p;
- }
-
mem_hotplug_begin();
/*
@@ -1126,17 +1141,13 @@ int __ref add_memory_resource(int nid, s
*/
memblock_add_node(start, size, nid);
- new_node = !node_online(nid);
- if (new_node) {
- pgdat = hotadd_new_pgdat(nid, start);
- ret = -ENOMEM;
- if (!pgdat)
- goto error;
- }
+ ret = __try_online_node(nid, start, false);
+ if (ret < 0)
+ goto error;
+ new_node = ret;
/* call arch's memory hotadd */
ret = arch_add_memory(nid, start, size, NULL, true);
-
if (ret < 0)
goto error;
@@ -1180,8 +1191,8 @@ register_fail:
error:
/* rollback pgdat allocation and others */
- if (new_pgdat && pgdat)
- rollback_node_hotadd(nid, pgdat);
+ if (new_node)
+ rollback_node_hotadd(nid);
memblock_remove(start, size);
out:
_
Patches currently in -mm which might be from osalvador@xxxxxxx are
mm-memory_hotplug-make-add_memory_resource-use-__try_online_node.patch
mm-memory_hotplug-call-register_mem_sect_under_node.patch
mm-memory_hotplug-make-register_mem_sect_under_node-a-cb-of-walk_memory_range.patch
mm-memory_hotplug-drop-unnecessary-checks-from-register_mem_sect_under_node.patch
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