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authorLinus Torvalds <torvalds@linux-foundation.org>2020-06-03 20:24:15 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-03 20:24:15 -0700
commitee01c4d72adffb7d424535adf630f2955748fa8b (patch)
tree9ea9f40473e105e936e7477ab7dc7248d899af21 /drivers/base
parentc444eb564fb16645c172d550359cb3d75fe8a040 (diff)
parent09587a09ada2ed7c39aedfa2681152b5ac5641ee (diff)
downloadlinux-ee01c4d72adffb7d424535adf630f2955748fa8b.tar.bz2
Merge branch 'akpm' (patches from Andrew)
Merge more updates from Andrew Morton: "More mm/ work, plenty more to come Subsystems affected by this patch series: slub, memcg, gup, kasan, pagealloc, hugetlb, vmscan, tools, mempolicy, memblock, hugetlbfs, thp, mmap, kconfig" * akpm: (131 commits) arm64: mm: use ARCH_HAS_DEBUG_WX instead of arch defined x86: mm: use ARCH_HAS_DEBUG_WX instead of arch defined riscv: support DEBUG_WX mm: add DEBUG_WX support drivers/base/memory.c: cache memory blocks in xarray to accelerate lookup mm/thp: rename pmd_mknotpresent() as pmd_mkinvalid() powerpc/mm: drop platform defined pmd_mknotpresent() mm: thp: don't need to drain lru cache when splitting and mlocking THP hugetlbfs: get unmapped area below TASK_UNMAPPED_BASE for hugetlbfs sparc32: register memory occupied by kernel as memblock.memory include/linux/memblock.h: fix minor typo and unclear comment mm, mempolicy: fix up gup usage in lookup_node tools/vm/page_owner_sort.c: filter out unneeded line mm: swap: memcg: fix memcg stats for huge pages mm: swap: fix vmstats for huge pages mm: vmscan: limit the range of LRU type balancing mm: vmscan: reclaim writepage is IO cost mm: vmscan: determine anon/file pressure balance at the reclaim root mm: balance LRU lists based on relative thrashing mm: only count actual rotations as LRU reclaim cost ...
Diffstat (limited to 'drivers/base')
-rw-r--r--drivers/base/memory.c44
1 files changed, 32 insertions, 12 deletions
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index dbec3a05590a..2b09b68b9f78 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -21,6 +21,7 @@
#include <linux/mm.h>
#include <linux/stat.h>
#include <linux/slab.h>
+#include <linux/xarray.h>
#include <linux/atomic.h>
#include <linux/uaccess.h>
@@ -74,6 +75,13 @@ static struct bus_type memory_subsys = {
.offline = memory_subsys_offline,
};
+/*
+ * Memory blocks are cached in a local radix tree to avoid
+ * a costly linear search for the corresponding device on
+ * the subsystem bus.
+ */
+static DEFINE_XARRAY(memory_blocks);
+
static BLOCKING_NOTIFIER_HEAD(memory_chain);
int register_memory_notifier(struct notifier_block *nb)
@@ -489,22 +497,23 @@ int __weak arch_get_memory_phys_device(unsigned long start_pfn)
return 0;
}
-/* A reference for the returned memory block device is acquired. */
+/*
+ * A reference for the returned memory block device is acquired.
+ *
+ * Called under device_hotplug_lock.
+ */
static struct memory_block *find_memory_block_by_id(unsigned long block_id)
{
- struct device *dev;
+ struct memory_block *mem;
- dev = subsys_find_device_by_id(&memory_subsys, block_id, NULL);
- return dev ? to_memory_block(dev) : NULL;
+ mem = xa_load(&memory_blocks, block_id);
+ if (mem)
+ get_device(&mem->dev);
+ return mem;
}
/*
- * For now, we have a linear search to go find the appropriate
- * memory_block corresponding to a particular phys_index. If
- * this gets to be a real problem, we can always use a radix
- * tree or something here.
- *
- * This could be made generic for all device subsystems.
+ * Called under device_hotplug_lock.
*/
struct memory_block *find_memory_block(struct mem_section *section)
{
@@ -548,9 +557,16 @@ int register_memory(struct memory_block *memory)
memory->dev.offline = memory->state == MEM_OFFLINE;
ret = device_register(&memory->dev);
- if (ret)
+ if (ret) {
put_device(&memory->dev);
-
+ return ret;
+ }
+ ret = xa_err(xa_store(&memory_blocks, memory->dev.id, memory,
+ GFP_KERNEL));
+ if (ret) {
+ put_device(&memory->dev);
+ device_unregister(&memory->dev);
+ }
return ret;
}
@@ -604,6 +620,8 @@ static void unregister_memory(struct memory_block *memory)
if (WARN_ON_ONCE(memory->dev.bus != &memory_subsys))
return;
+ WARN_ON(xa_erase(&memory_blocks, memory->dev.id) == NULL);
+
/* drop the ref. we got via find_memory_block() */
put_device(&memory->dev);
device_unregister(&memory->dev);
@@ -750,6 +768,8 @@ void __init memory_dev_init(void)
*
* In case func() returns an error, walking is aborted and the error is
* returned.
+ *
+ * Called under device_hotplug_lock.
*/
int walk_memory_blocks(unsigned long start, unsigned long size,
void *arg, walk_memory_blocks_func_t func)