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-rw-r--r--mm/memory_hotplug.c142
1 files changed, 101 insertions, 41 deletions
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index a650db29606f..2906873a1502 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -46,19 +46,84 @@
static void generic_online_page(struct page *page);
static online_page_callback_t online_page_callback = generic_online_page;
+static DEFINE_MUTEX(online_page_callback_lock);
-DEFINE_MUTEX(mem_hotplug_mutex);
+/* The same as the cpu_hotplug lock, but for memory hotplug. */
+static struct {
+ struct task_struct *active_writer;
+ struct mutex lock; /* Synchronizes accesses to refcount, */
+ /*
+ * Also blocks the new readers during
+ * an ongoing mem hotplug operation.
+ */
+ int refcount;
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ struct lockdep_map dep_map;
+#endif
+} mem_hotplug = {
+ .active_writer = NULL,
+ .lock = __MUTEX_INITIALIZER(mem_hotplug.lock),
+ .refcount = 0,
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ .dep_map = {.name = "mem_hotplug.lock" },
+#endif
+};
+
+/* Lockdep annotations for get/put_online_mems() and mem_hotplug_begin/end() */
+#define memhp_lock_acquire_read() lock_map_acquire_read(&mem_hotplug.dep_map)
+#define memhp_lock_acquire() lock_map_acquire(&mem_hotplug.dep_map)
+#define memhp_lock_release() lock_map_release(&mem_hotplug.dep_map)
+
+void get_online_mems(void)
+{
+ might_sleep();
+ if (mem_hotplug.active_writer == current)
+ return;
+ memhp_lock_acquire_read();
+ mutex_lock(&mem_hotplug.lock);
+ mem_hotplug.refcount++;
+ mutex_unlock(&mem_hotplug.lock);
+
+}
-void lock_memory_hotplug(void)
+void put_online_mems(void)
{
- mutex_lock(&mem_hotplug_mutex);
+ if (mem_hotplug.active_writer == current)
+ return;
+ mutex_lock(&mem_hotplug.lock);
+
+ if (WARN_ON(!mem_hotplug.refcount))
+ mem_hotplug.refcount++; /* try to fix things up */
+
+ if (!--mem_hotplug.refcount && unlikely(mem_hotplug.active_writer))
+ wake_up_process(mem_hotplug.active_writer);
+ mutex_unlock(&mem_hotplug.lock);
+ memhp_lock_release();
+
}
-void unlock_memory_hotplug(void)
+static void mem_hotplug_begin(void)
{
- mutex_unlock(&mem_hotplug_mutex);
+ mem_hotplug.active_writer = current;
+
+ memhp_lock_acquire();
+ for (;;) {
+ mutex_lock(&mem_hotplug.lock);
+ if (likely(!mem_hotplug.refcount))
+ break;
+ __set_current_state(TASK_UNINTERRUPTIBLE);
+ mutex_unlock(&mem_hotplug.lock);
+ schedule();
+ }
}
+static void mem_hotplug_done(void)
+{
+ mem_hotplug.active_writer = NULL;
+ mutex_unlock(&mem_hotplug.lock);
+ memhp_lock_release();
+}
/* add this memory to iomem resource */
static struct resource *register_memory_resource(u64 start, u64 size)
@@ -727,14 +792,16 @@ int set_online_page_callback(online_page_callback_t callback)
{
int rc = -EINVAL;
- lock_memory_hotplug();
+ get_online_mems();
+ mutex_lock(&online_page_callback_lock);
if (online_page_callback == generic_online_page) {
online_page_callback = callback;
rc = 0;
}
- unlock_memory_hotplug();
+ mutex_unlock(&online_page_callback_lock);
+ put_online_mems();
return rc;
}
@@ -744,14 +811,16 @@ int restore_online_page_callback(online_page_callback_t callback)
{
int rc = -EINVAL;
- lock_memory_hotplug();
+ get_online_mems();
+ mutex_lock(&online_page_callback_lock);
if (online_page_callback == callback) {
online_page_callback = generic_online_page;
rc = 0;
}
- unlock_memory_hotplug();
+ mutex_unlock(&online_page_callback_lock);
+ put_online_mems();
return rc;
}
@@ -899,7 +968,7 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
int ret;
struct memory_notify arg;
- lock_memory_hotplug();
+ mem_hotplug_begin();
/*
* This doesn't need a lock to do pfn_to_page().
* The section can't be removed here because of the
@@ -907,23 +976,18 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
*/
zone = page_zone(pfn_to_page(pfn));
+ ret = -EINVAL;
if ((zone_idx(zone) > ZONE_NORMAL || online_type == ONLINE_MOVABLE) &&
- !can_online_high_movable(zone)) {
- unlock_memory_hotplug();
- return -EINVAL;
- }
+ !can_online_high_movable(zone))
+ goto out;
if (online_type == ONLINE_KERNEL && zone_idx(zone) == ZONE_MOVABLE) {
- if (move_pfn_range_left(zone - 1, zone, pfn, pfn + nr_pages)) {
- unlock_memory_hotplug();
- return -EINVAL;
- }
+ if (move_pfn_range_left(zone - 1, zone, pfn, pfn + nr_pages))
+ goto out;
}
if (online_type == ONLINE_MOVABLE && zone_idx(zone) == ZONE_MOVABLE - 1) {
- if (move_pfn_range_right(zone, zone + 1, pfn, pfn + nr_pages)) {
- unlock_memory_hotplug();
- return -EINVAL;
- }
+ if (move_pfn_range_right(zone, zone + 1, pfn, pfn + nr_pages))
+ goto out;
}
/* Previous code may changed the zone of the pfn range */
@@ -939,8 +1003,7 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
ret = notifier_to_errno(ret);
if (ret) {
memory_notify(MEM_CANCEL_ONLINE, &arg);
- unlock_memory_hotplug();
- return ret;
+ goto out;
}
/*
* If this zone is not populated, then it is not in zonelist.
@@ -964,8 +1027,7 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
(((unsigned long long) pfn + nr_pages)
<< PAGE_SHIFT) - 1);
memory_notify(MEM_CANCEL_ONLINE, &arg);
- unlock_memory_hotplug();
- return ret;
+ goto out;
}
zone->present_pages += onlined_pages;
@@ -995,9 +1057,9 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
if (onlined_pages)
memory_notify(MEM_ONLINE, &arg);
- unlock_memory_hotplug();
-
- return 0;
+out:
+ mem_hotplug_done();
+ return ret;
}
#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
@@ -1055,7 +1117,7 @@ int try_online_node(int nid)
if (node_online(nid))
return 0;
- lock_memory_hotplug();
+ mem_hotplug_begin();
pgdat = hotadd_new_pgdat(nid, 0);
if (!pgdat) {
pr_err("Cannot online node %d due to NULL pgdat\n", nid);
@@ -1073,7 +1135,7 @@ int try_online_node(int nid)
}
out:
- unlock_memory_hotplug();
+ mem_hotplug_done();
return ret;
}
@@ -1117,7 +1179,7 @@ int __ref add_memory(int nid, u64 start, u64 size)
new_pgdat = !p;
}
- lock_memory_hotplug();
+ mem_hotplug_begin();
new_node = !node_online(nid);
if (new_node) {
@@ -1158,7 +1220,7 @@ error:
release_memory_resource(res);
out:
- unlock_memory_hotplug();
+ mem_hotplug_done();
return ret;
}
EXPORT_SYMBOL_GPL(add_memory);
@@ -1565,7 +1627,7 @@ static int __ref __offline_pages(unsigned long start_pfn,
if (!test_pages_in_a_zone(start_pfn, end_pfn))
return -EINVAL;
- lock_memory_hotplug();
+ mem_hotplug_begin();
zone = page_zone(pfn_to_page(start_pfn));
node = zone_to_nid(zone);
@@ -1672,7 +1734,7 @@ repeat:
writeback_set_ratelimit();
memory_notify(MEM_OFFLINE, &arg);
- unlock_memory_hotplug();
+ mem_hotplug_done();
return 0;
failed_removal:
@@ -1684,7 +1746,7 @@ failed_removal:
undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
out:
- unlock_memory_hotplug();
+ mem_hotplug_done();
return ret;
}
@@ -1888,7 +1950,7 @@ void __ref remove_memory(int nid, u64 start, u64 size)
BUG_ON(check_hotplug_memory_range(start, size));
- lock_memory_hotplug();
+ mem_hotplug_begin();
/*
* All memory blocks must be offlined before removing memory. Check
@@ -1897,10 +1959,8 @@ void __ref remove_memory(int nid, u64 start, u64 size)
*/
ret = walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1), NULL,
check_memblock_offlined_cb);
- if (ret) {
- unlock_memory_hotplug();
+ if (ret)
BUG();
- }
/* remove memmap entry */
firmware_map_remove(start, start + size, "System RAM");
@@ -1909,7 +1969,7 @@ void __ref remove_memory(int nid, u64 start, u64 size)
try_offline_node(nid);
- unlock_memory_hotplug();
+ mem_hotplug_done();
}
EXPORT_SYMBOL_GPL(remove_memory);
#endif /* CONFIG_MEMORY_HOTREMOVE */
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 13:58:53 +0000