From: Oscar Salvador <osalvador@xxxxxxx>
This patch tries to simplify node_states_check_changes_offline
and make the code more understandable by:
- Removing the if (N_MEMORY == N_NORMAL_MEMORY) wrong statement
- Removing the if (N_MEMORY == N_HIGH_MEMORY) wrong statement
- Re-structure the code a bit
- Removing confusing comments
Signed-off-by: Oscar Salvador <osalvador@xxxxxxx>
---
mm/memory_hotplug.c | 81 ++++++++++++++++++++++-------------------------------
1 file changed, 33 insertions(+), 48 deletions(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 006a7b817724..b45bc681e6db 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1487,51 +1487,40 @@ static void node_states_check_changes_offline(unsigned long nr_pages,
enum zone_type zt, zone_last = ZONE_NORMAL;
/*
- * If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY]
- * contains nodes which have zones of 0...ZONE_NORMAL,
- * set zone_last to ZONE_NORMAL.
- *
- * If we don't have HIGHMEM nor movable node,
- * node_states[N_NORMAL_MEMORY] contains nodes which have zones of
- * 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE.
+ * If the current zone is whithin (0..ZONE_NORMAL],
+ * check if the amount of pages that are going to be
+ * offlined is above or equal to the sum of the present
+ * pages of these zones.
+ * If that happens, we need to take this node out of
+ * node_state[N_NORMAL_MEMORY]
*/
- if (N_MEMORY == N_NORMAL_MEMORY)
- zone_last = ZONE_MOVABLE;
+ if (zone_idx(zone) <= zone_last) {
+ for (zt = 0; zt <= zone_last; zt++)
+ present_pages += pgdat->node_zones[zt].present_pages;
- /*
- * check whether node_states[N_NORMAL_MEMORY] will be changed.
- * If the memory to be offline is in a zone of 0...zone_last,
- * and it is the last present memory, 0...zone_last will
- * become empty after offline , thus we can determind we will
- * need to clear the node from node_states[N_NORMAL_MEMORY].
- */
- for (zt = 0; zt <= zone_last; zt++)
- present_pages += pgdat->node_zones[zt].present_pages;
- if (zone_idx(zone) <= zone_last && nr_pages >= present_pages)
- arg->status_change_nid_normal = zone_to_nid(zone);
- else
- arg->status_change_nid_normal = -1;
+ if (nr_pages >= present_pages)
+ arg->status_change_nid_normal = zone_to_nid(zone);
+ else
+ arg->status_change_nid_normal = -1;
+ }
#ifdef CONFIG_HIGHMEM
/*
- * If we have movable node, node_states[N_HIGH_MEMORY]
- * contains nodes which have zones of 0...ZONE_HIGHMEM,
- * set zone_last to ZONE_HIGHMEM.
- *
- * If we don't have movable node, node_states[N_NORMAL_MEMORY]
- * contains nodes which have zones of 0...ZONE_MOVABLE,
- * set zone_last to ZONE_MOVABLE.
+ * If the current zone is whithin (0..ZONE_HIGHMEM], check if
+ * the amount of pages that are going to be offlined is above
+ * or equal to the sum of the present pages of these zones.
+ * If that happens, we need to take this node out of
+ * node_state[N_HIGH_MEMORY]
*/
- zone_last = ZONE_HIGHMEM;
- if (N_MEMORY == N_HIGH_MEMORY)
- zone_last = ZONE_MOVABLE;
-
- for (; zt <= zone_last; zt++)
+ if (zone_idx(zone) <= ZONE_HIGHMEM) {
+ zt = ZONE_HIGHMEM;
present_pages += pgdat->node_zones[zt].present_pages;
- if (zone_idx(zone) <= zone_last && nr_pages >= present_pages)
- arg->status_change_nid_high = zone_to_nid(zone);
- else
- arg->status_change_nid_high = -1;
+
+ if (nr_pages >= present_pages)
+ arg->status_change_nid_high = zone_to_nid(zone);
+ else
+ arg->status_change_nid_high = -1;
+ }
#else
/*
* When !CONFIG_HIGHMEM, N_HIGH_MEMORY equals N_NORMAL_MEMORY
@@ -1541,18 +1530,14 @@ static void node_states_check_changes_offline(unsigned long nr_pages,
#endif
/*
- * node_states[N_HIGH_MEMORY] contains nodes which have 0...ZONE_MOVABLE
+ * Count pages from ZONE_MOVABLE as well.
+ * If the amount of pages that are going to be offlined is above
+ * or equal the sum of the present pages of all zones, we need
+ * to remove this node from node_state[N_MEMORY]
*/
- zone_last = ZONE_MOVABLE;
+ zt = ZONE_MOVABLE;
+ present_pages += pgdat->node_zones[zt].present_pages;
- /*
- * check whether node_states[N_HIGH_MEMORY] will be changed
- * If we try to offline the last present @nr_pages from the node,
- * we can determind we will need to clear the node from
- * node_states[N_HIGH_MEMORY].
- */
- for (; zt <= zone_last; zt++)
- present_pages += pgdat->node_zones[zt].present_pages;
if (nr_pages >= present_pages)
arg->status_change_nid = zone_to_nid(zone);
else
--
2.13.6
