[patch 189/262] mm/memory_hotplug: remove HIGHMEM leftovers

Andrew Morton
2021-11-05T20:44:35Z

From: David Hildenbrand <david@redhat.com>
Subject: mm/memory_hotplug: remove HIGHMEM leftovers

We don't support CONFIG_MEMORY_HOTPLUG on 32 bit and consequently not
HIGHMEM. Let's remove any leftover code -- including the unused
"status_change_nid_high" field part of the memory notifier.

Link: https://lkml.kernel.org/r/20210929143600.49379-5-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Alex Shi <alexs@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

Documentation/core-api/memory-hotplug.rst | 3
Documentation/translations/zh_CN/core-api/memory-hotplug.rst | 4 -
include/linux/memory.h | 1
mm/memory_hotplug.c | 36 ----------
4 files changed, 2 insertions(+), 42 deletions(-)

--- a/Documentation/core-api/memory-hotplug.rst~mm-memory_hotplug-remove-highmem-leftovers
+++ a/Documentation/core-api/memory-hotplug.rst
@@ -57,7 +57,6 @@ The third argument (arg) passes a pointe
unsigned long start_pfn;
unsigned long nr_pages;
int status_change_nid_normal;
- int status_change_nid_high;
int status_change_nid;
}

@@ -65,8 +64,6 @@ The third argument (arg) passes a pointe
- nr_pages is # of pages of online/offline memory.
- status_change_nid_normal is set node id when N_NORMAL_MEMORY of nodemask
is (will be) set/clear, if this is -1, then nodemask status is not changed.
-- status_change_nid_high is set node id when N_HIGH_MEMORY of nodemask
- is (will be) set/clear, if this is -1, then nodemask status is not changed.
- status_change_nid is set node id when N_MEMORY of nodemask is (will be)
set/clear. It means a new(memoryless) node gets new memory by online and a
node loses all memory. If this is -1, then nodemask status is not changed.
--- a/Documentation/translations/zh_CN/core-api/memory-hotplug.rst~mm-memory_hotplug-remove-highmem-leftovers
+++ a/Documentation/translations/zh_CN/core-api/memory-hotplug.rst
@@ -63,7 +63,6 @@ memory_notify结构体的指针::
unsigned long start_pfn;
unsigned long nr_pages;
int status_change_nid_normal;
- int status_change_nid_high;
int status_change_nid;
}

@@ -74,9 +73,6 @@ memory_notify结构体的指针::
- status_change_nid_normal是当nodemask的N_NORMAL_MEMORY被设置/清除时设置节
点id，如果是-1，则nodemask状态不改变。

-- status_change_nid_high是当nodemask的N_HIGH_MEMORY被设置/清除时设置的节点
- id，如果这个值为-1，那么nodemask状态不会改变。
-
- status_change_nid是当nodemask的N_MEMORY被（将）设置/清除时设置的节点id。这
意味着一个新的（没上线的）节点通过联机获得新的内存，而一个节点失去了所有的内
存。如果这个值为-1，那么nodemask的状态就不会改变。
--- a/include/linux/memory.h~mm-memory_hotplug-remove-highmem-leftovers
+++ a/include/linux/memory.h
@@ -96,7 +96,6 @@ struct memory_notify {
unsigned long start_pfn;
unsigned long nr_pages;
int status_change_nid_normal;
- int status_change_nid_high;
int status_change_nid;
};

--- a/mm/memory_hotplug.c~mm-memory_hotplug-remove-highmem-leftovers
+++ a/mm/memory_hotplug.c
@@ -21,7 +21,6 @@
#include <linux/memory.h>
#include <linux/memremap.h>
#include <linux/memory_hotplug.h>
-#include <linux/highmem.h>
#include <linux/vmalloc.h>
#include <linux/ioport.h>
#include <linux/delay.h>
@@ -585,10 +584,6 @@ void generic_online_page(struct page *pa
debug_pagealloc_map_pages(page, 1 << order);
__free_pages_core(page, order);
totalram_pages_add(1UL << order);
-#ifdef CONFIG_HIGHMEM
- if (PageHighMem(page))
- totalhigh_pages_add(1UL << order);
-#endif
}
EXPORT_SYMBOL_GPL(generic_online_page);

@@ -625,16 +620,11 @@ static void node_states_check_changes_on

arg->status_change_nid = NUMA_NO_NODE;
arg->status_change_nid_normal = NUMA_NO_NODE;
- arg->status_change_nid_high = NUMA_NO_NODE;

if (!node_state(nid, N_MEMORY))
arg->status_change_nid = nid;
if (zone_idx(zone) <= ZONE_NORMAL && !node_state(nid, N_NORMAL_MEMORY))
arg->status_change_nid_normal = nid;
-#ifdef CONFIG_HIGHMEM
- if (zone_idx(zone) <= ZONE_HIGHMEM && !node_state(nid, N_HIGH_MEMORY))
- arg->status_change_nid_high = nid;
-#endif
}

static void node_states_set_node(int node, struct memory_notify *arg)
@@ -642,9 +632,6 @@ static void node_states_set_node(int nod
if (arg->status_change_nid_normal >= 0)
node_set_state(node, N_NORMAL_MEMORY);

- if (arg->status_change_nid_high >= 0)
- node_set_state(node, N_HIGH_MEMORY);
-
if (arg->status_change_nid >= 0)
node_set_state(node, N_MEMORY);
}
@@ -1801,7 +1788,6 @@ static void node_states_check_changes_of

arg->status_change_nid = NUMA_NO_NODE;
arg->status_change_nid_normal = NUMA_NO_NODE;
- arg->status_change_nid_high = NUMA_NO_NODE;

/*
* Check whether node_states[N_NORMAL_MEMORY] will be changed.
@@ -1816,24 +1802,9 @@ static void node_states_check_changes_of
if (zone_idx(zone) <= ZONE_NORMAL && nr_pages >= present_pages)
arg->status_change_nid_normal = zone_to_nid(zone);

-#ifdef CONFIG_HIGHMEM
/*
- * node_states[N_HIGH_MEMORY] contains nodes which
- * have normal memory or high memory.
- * Here we add the present_pages belonging to ZONE_HIGHMEM.
- * If the zone is within the range of [0..ZONE_HIGHMEM), and
- * we determine that the zones in that range become empty,
- * we need to clear the node for N_HIGH_MEMORY.
- */
- present_pages += pgdat->node_zones[ZONE_HIGHMEM].present_pages;
- if (zone_idx(zone) <= ZONE_HIGHMEM && nr_pages >= present_pages)
- arg->status_change_nid_high = zone_to_nid(zone);
-#endif
-
- /*
- * We have accounted the pages from [0..ZONE_NORMAL), and
- * in case of CONFIG_HIGHMEM the pages from ZONE_HIGHMEM
- * as well.
+ * We have accounted the pages from [0..ZONE_NORMAL); ZONE_HIGHMEM
+ * does not apply as we don't support 32bit.
* Here we count the possible pages from ZONE_MOVABLE.
* If after having accounted all the pages, we see that the nr_pages
* to be offlined is over or equal to the accounted pages,
@@ -1851,9 +1822,6 @@ static void node_states_clear_node(int n
if (arg->status_change_nid_normal >= 0)
node_clear_state(node, N_NORMAL_MEMORY);

- if (arg->status_change_nid_high >= 0)
- node_clear_state(node, N_HIGH_MEMORY);
-
if (arg->status_change_nid >= 0)
node_clear_state(node, N_MEMORY);
}
_