linux-stable/drivers/base/memory.c
Sumanth Korikkar c5f1e2d189 mm/memory_hotplug: introduce MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE notifiers
Patch series "implement "memmap on memory" feature on s390".

This series provides "memmap on memory" support on s390 platform.  "memmap
on memory" allows struct pages array to be allocated from the hotplugged
memory range instead of allocating it from main system memory.

s390 currently preallocates struct pages array for all potentially
possible memory, which ensures memory onlining always succeeds, but with
the cost of significant memory consumption from the available system
memory during boottime.  In certain extreme configuration, this could lead
to ipl failure.

"memmap on memory" ensures struct pages array are populated from self
contained hotplugged memory range instead of depleting the available
system memory and this could eliminate ipl failure on s390 platform.

On other platforms, system might go OOM when the physically hotplugged
memory depletes the available memory before it is onlined.  Hence, "memmap
on memory" feature was introduced as described in commit a08a2ae346
("mm,memory_hotplug: allocate memmap from the added memory range").

Unlike other architectures, s390 memory blocks are not physically
accessible until it is online.  To make it physically accessible two new
memory notifiers MEM_PREPARE_ONLINE / MEM_FINISH_OFFLINE are added and
this notifier lets the hypervisor inform that the memory should be made
physically accessible.  This allows for "memmap on memory" initialization
during memory hotplug onlining phase, which is performed before calling
MEM_GOING_ONLINE notifier.

Patch 1 introduces MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE memory notifiers
to prepare the transition of memory to and from a physically accessible
state.  New mhp_flag MHP_OFFLINE_INACCESSIBLE is introduced to ensure
altmap cannot be written when adding memory - before it is set online. 
This enhancement is crucial for implementing the "memmap on memory"
feature for s390 in a subsequent patch.

Patches 2 allocates vmemmap pages from self-contained memory range for
s390.  It allocates memory map (struct pages array) from the hotplugged
memory range, rather than using system memory by passing altmap to vmemmap
functions.

Patch 3 removes unhandled memory notifier types on s390.

Patch 4 implements MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE memory notifiers
on s390.  MEM_PREPARE_ONLINE memory notifier makes memory block physical
accessible via sclp assign command.  The notifier ensures self-contained
memory maps are accessible and hence enabling the "memmap on memory" on
s390.  MEM_FINISH_OFFLINE memory notifier shifts the memory block to an
inaccessible state via sclp unassign command.

Patch 5 finally enables MHP_MEMMAP_ON_MEMORY on s390.


This patch (of 5):

Introduce MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE memory notifiers to
prepare the transition of memory to and from a physically accessible
state.  This enhancement is crucial for implementing the "memmap on
memory" feature for s390 in a subsequent patch.

Platforms such as x86 can support physical memory hotplug via ACPI.  When
there is physical memory hotplug, ACPI event leads to the memory addition
with the following callchain:

acpi_memory_device_add()
  -> acpi_memory_enable_device()
     -> __add_memory()

After this, the hotplugged memory is physically accessible, and altmap
support prepared, before the "memmap on memory" initialization in
memory_block_online() is called.

On s390, memory hotplug works in a different way.  The available hotplug
memory has to be defined upfront in the hypervisor, but it is made
physically accessible only when the user sets it online via sysfs,
currently in the MEM_GOING_ONLINE notifier.  This is too late and "memmap
on memory" initialization is performed before calling MEM_GOING_ONLINE
notifier.

During the memory hotplug addition phase, altmap support is prepared and
during the memory onlining phase s390 requires memory to be physically
accessible and then subsequently initiate the "memmap on memory"
initialization process.

The memory provider will handle new MEM_PREPARE_ONLINE /
MEM_FINISH_OFFLINE notifications and make the memory accessible.

The mhp_flag MHP_OFFLINE_INACCESSIBLE is introduced and is relevant when
used along with MHP_MEMMAP_ON_MEMORY, because the altmap cannot be written
(e.g., poisoned) when adding memory -- before it is set online.  This
allows for adding memory with an altmap that is not currently made
available by a hypervisor.  When onlining that memory, the hypervisor can
be instructed to make that memory accessible via the new notifiers and the
onlining phase will not require any memory allocations, which is helpful
in low-memory situations.

All architectures ignore unknown memory notifiers.  Therefore, the
introduction of these new notifiers does not result in any functional
modifications across architectures.

Link: https://lkml.kernel.org/r/20240108132747.3238763-1-sumanthk@linux.ibm.com
Link: https://lkml.kernel.org/r/20240108132747.3238763-2-sumanthk@linux.ibm.com
Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Suggested-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-02-21 16:00:01 -08:00

1252 lines
32 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Memory subsystem support
*
* Written by Matt Tolentino <matthew.e.tolentino@intel.com>
* Dave Hansen <haveblue@us.ibm.com>
*
* This file provides the necessary infrastructure to represent
* a SPARSEMEM-memory-model system's physical memory in /sysfs.
* All arch-independent code that assumes MEMORY_HOTPLUG requires
* SPARSEMEM should be contained here, or in mm/memory_hotplug.c.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/topology.h>
#include <linux/capability.h>
#include <linux/device.h>
#include <linux/memory.h>
#include <linux/memory_hotplug.h>
#include <linux/mm.h>
#include <linux/stat.h>
#include <linux/slab.h>
#include <linux/xarray.h>
#include <linux/atomic.h>
#include <linux/uaccess.h>
#define MEMORY_CLASS_NAME "memory"
static const char *const online_type_to_str[] = {
[MMOP_OFFLINE] = "offline",
[MMOP_ONLINE] = "online",
[MMOP_ONLINE_KERNEL] = "online_kernel",
[MMOP_ONLINE_MOVABLE] = "online_movable",
};
int mhp_online_type_from_str(const char *str)
{
int i;
for (i = 0; i < ARRAY_SIZE(online_type_to_str); i++) {
if (sysfs_streq(str, online_type_to_str[i]))
return i;
}
return -EINVAL;
}
#define to_memory_block(dev) container_of(dev, struct memory_block, dev)
static int sections_per_block;
static inline unsigned long memory_block_id(unsigned long section_nr)
{
return section_nr / sections_per_block;
}
static inline unsigned long pfn_to_block_id(unsigned long pfn)
{
return memory_block_id(pfn_to_section_nr(pfn));
}
static inline unsigned long phys_to_block_id(unsigned long phys)
{
return pfn_to_block_id(PFN_DOWN(phys));
}
static int memory_subsys_online(struct device *dev);
static int memory_subsys_offline(struct device *dev);
static const struct bus_type memory_subsys = {
.name = MEMORY_CLASS_NAME,
.dev_name = MEMORY_CLASS_NAME,
.online = memory_subsys_online,
.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);
/*
* Memory groups, indexed by memory group id (mgid).
*/
static DEFINE_XARRAY_FLAGS(memory_groups, XA_FLAGS_ALLOC);
#define MEMORY_GROUP_MARK_DYNAMIC XA_MARK_1
static BLOCKING_NOTIFIER_HEAD(memory_chain);
int register_memory_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_register(&memory_chain, nb);
}
EXPORT_SYMBOL(register_memory_notifier);
void unregister_memory_notifier(struct notifier_block *nb)
{
blocking_notifier_chain_unregister(&memory_chain, nb);
}
EXPORT_SYMBOL(unregister_memory_notifier);
static void memory_block_release(struct device *dev)
{
struct memory_block *mem = to_memory_block(dev);
/* Verify that the altmap is freed */
WARN_ON(mem->altmap);
kfree(mem);
}
unsigned long __weak memory_block_size_bytes(void)
{
return MIN_MEMORY_BLOCK_SIZE;
}
EXPORT_SYMBOL_GPL(memory_block_size_bytes);
/* Show the memory block ID, relative to the memory block size */
static ssize_t phys_index_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct memory_block *mem = to_memory_block(dev);
return sysfs_emit(buf, "%08lx\n", memory_block_id(mem->start_section_nr));
}
/*
* Legacy interface that we cannot remove. Always indicate "removable"
* with CONFIG_MEMORY_HOTREMOVE - bad heuristic.
*/
static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
return sysfs_emit(buf, "%d\n", (int)IS_ENABLED(CONFIG_MEMORY_HOTREMOVE));
}
/*
* online, offline, going offline, etc.
*/
static ssize_t state_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct memory_block *mem = to_memory_block(dev);
const char *output;
/*
* We can probably put these states in a nice little array
* so that they're not open-coded
*/
switch (mem->state) {
case MEM_ONLINE:
output = "online";
break;
case MEM_OFFLINE:
output = "offline";
break;
case MEM_GOING_OFFLINE:
output = "going-offline";
break;
default:
WARN_ON(1);
return sysfs_emit(buf, "ERROR-UNKNOWN-%ld\n", mem->state);
}
return sysfs_emit(buf, "%s\n", output);
}
int memory_notify(unsigned long val, void *v)
{
return blocking_notifier_call_chain(&memory_chain, val, v);
}
#if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_MEMORY_HOTPLUG)
static unsigned long memblk_nr_poison(struct memory_block *mem);
#else
static inline unsigned long memblk_nr_poison(struct memory_block *mem)
{
return 0;
}
#endif
/*
* Must acquire mem_hotplug_lock in write mode.
*/
static int memory_block_online(struct memory_block *mem)
{
unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr);
unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
unsigned long nr_vmemmap_pages = 0;
struct memory_notify arg;
struct zone *zone;
int ret;
if (memblk_nr_poison(mem))
return -EHWPOISON;
zone = zone_for_pfn_range(mem->online_type, mem->nid, mem->group,
start_pfn, nr_pages);
/*
* Although vmemmap pages have a different lifecycle than the pages
* they describe (they remain until the memory is unplugged), doing
* their initialization and accounting at memory onlining/offlining
* stage helps to keep accounting easier to follow - e.g vmemmaps
* belong to the same zone as the memory they backed.
*/
if (mem->altmap)
nr_vmemmap_pages = mem->altmap->free;
arg.altmap_start_pfn = start_pfn;
arg.altmap_nr_pages = nr_vmemmap_pages;
arg.start_pfn = start_pfn + nr_vmemmap_pages;
arg.nr_pages = nr_pages - nr_vmemmap_pages;
mem_hotplug_begin();
ret = memory_notify(MEM_PREPARE_ONLINE, &arg);
ret = notifier_to_errno(ret);
if (ret)
goto out_notifier;
if (nr_vmemmap_pages) {
ret = mhp_init_memmap_on_memory(start_pfn, nr_vmemmap_pages,
zone, mem->altmap->inaccessible);
if (ret)
goto out;
}
ret = online_pages(start_pfn + nr_vmemmap_pages,
nr_pages - nr_vmemmap_pages, zone, mem->group);
if (ret) {
if (nr_vmemmap_pages)
mhp_deinit_memmap_on_memory(start_pfn, nr_vmemmap_pages);
goto out;
}
/*
* Account once onlining succeeded. If the zone was unpopulated, it is
* now already properly populated.
*/
if (nr_vmemmap_pages)
adjust_present_page_count(pfn_to_page(start_pfn), mem->group,
nr_vmemmap_pages);
mem->zone = zone;
mem_hotplug_done();
return ret;
out:
memory_notify(MEM_FINISH_OFFLINE, &arg);
out_notifier:
mem_hotplug_done();
return ret;
}
/*
* Must acquire mem_hotplug_lock in write mode.
*/
static int memory_block_offline(struct memory_block *mem)
{
unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr);
unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
unsigned long nr_vmemmap_pages = 0;
struct memory_notify arg;
int ret;
if (!mem->zone)
return -EINVAL;
/*
* Unaccount before offlining, such that unpopulated zone and kthreads
* can properly be torn down in offline_pages().
*/
if (mem->altmap)
nr_vmemmap_pages = mem->altmap->free;
mem_hotplug_begin();
if (nr_vmemmap_pages)
adjust_present_page_count(pfn_to_page(start_pfn), mem->group,
-nr_vmemmap_pages);
ret = offline_pages(start_pfn + nr_vmemmap_pages,
nr_pages - nr_vmemmap_pages, mem->zone, mem->group);
if (ret) {
/* offline_pages() failed. Account back. */
if (nr_vmemmap_pages)
adjust_present_page_count(pfn_to_page(start_pfn),
mem->group, nr_vmemmap_pages);
goto out;
}
if (nr_vmemmap_pages)
mhp_deinit_memmap_on_memory(start_pfn, nr_vmemmap_pages);
mem->zone = NULL;
arg.altmap_start_pfn = start_pfn;
arg.altmap_nr_pages = nr_vmemmap_pages;
arg.start_pfn = start_pfn + nr_vmemmap_pages;
arg.nr_pages = nr_pages - nr_vmemmap_pages;
memory_notify(MEM_FINISH_OFFLINE, &arg);
out:
mem_hotplug_done();
return ret;
}
/*
* MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is
* OK to have direct references to sparsemem variables in here.
*/
static int
memory_block_action(struct memory_block *mem, unsigned long action)
{
int ret;
switch (action) {
case MEM_ONLINE:
ret = memory_block_online(mem);
break;
case MEM_OFFLINE:
ret = memory_block_offline(mem);
break;
default:
WARN(1, KERN_WARNING "%s(%ld, %ld) unknown action: "
"%ld\n", __func__, mem->start_section_nr, action, action);
ret = -EINVAL;
}
return ret;
}
static int memory_block_change_state(struct memory_block *mem,
unsigned long to_state, unsigned long from_state_req)
{
int ret = 0;
if (mem->state != from_state_req)
return -EINVAL;
if (to_state == MEM_OFFLINE)
mem->state = MEM_GOING_OFFLINE;
ret = memory_block_action(mem, to_state);
mem->state = ret ? from_state_req : to_state;
return ret;
}
/* The device lock serializes operations on memory_subsys_[online|offline] */
static int memory_subsys_online(struct device *dev)
{
struct memory_block *mem = to_memory_block(dev);
int ret;
if (mem->state == MEM_ONLINE)
return 0;
/*
* When called via device_online() without configuring the online_type,
* we want to default to MMOP_ONLINE.
*/
if (mem->online_type == MMOP_OFFLINE)
mem->online_type = MMOP_ONLINE;
ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
mem->online_type = MMOP_OFFLINE;
return ret;
}
static int memory_subsys_offline(struct device *dev)
{
struct memory_block *mem = to_memory_block(dev);
if (mem->state == MEM_OFFLINE)
return 0;
return memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);
}
static ssize_t state_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
const int online_type = mhp_online_type_from_str(buf);
struct memory_block *mem = to_memory_block(dev);
int ret;
if (online_type < 0)
return -EINVAL;
ret = lock_device_hotplug_sysfs();
if (ret)
return ret;
switch (online_type) {
case MMOP_ONLINE_KERNEL:
case MMOP_ONLINE_MOVABLE:
case MMOP_ONLINE:
/* mem->online_type is protected by device_hotplug_lock */
mem->online_type = online_type;
ret = device_online(&mem->dev);
break;
case MMOP_OFFLINE:
ret = device_offline(&mem->dev);
break;
default:
ret = -EINVAL; /* should never happen */
}
unlock_device_hotplug();
if (ret < 0)
return ret;
if (ret)
return -EINVAL;
return count;
}
/*
* Legacy interface that we cannot remove: s390x exposes the storage increment
* covered by a memory block, allowing for identifying which memory blocks
* comprise a storage increment. Since a memory block spans complete
* storage increments nowadays, this interface is basically unused. Other
* archs never exposed != 0.
*/
static ssize_t phys_device_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct memory_block *mem = to_memory_block(dev);
unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr);
return sysfs_emit(buf, "%d\n",
arch_get_memory_phys_device(start_pfn));
}
#ifdef CONFIG_MEMORY_HOTREMOVE
static int print_allowed_zone(char *buf, int len, int nid,
struct memory_group *group,
unsigned long start_pfn, unsigned long nr_pages,
int online_type, struct zone *default_zone)
{
struct zone *zone;
zone = zone_for_pfn_range(online_type, nid, group, start_pfn, nr_pages);
if (zone == default_zone)
return 0;
return sysfs_emit_at(buf, len, " %s", zone->name);
}
static ssize_t valid_zones_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct memory_block *mem = to_memory_block(dev);
unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr);
unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
struct memory_group *group = mem->group;
struct zone *default_zone;
int nid = mem->nid;
int len = 0;
/*
* Check the existing zone. Make sure that we do that only on the
* online nodes otherwise the page_zone is not reliable
*/
if (mem->state == MEM_ONLINE) {
/*
* If !mem->zone, the memory block spans multiple zones and
* cannot get offlined.
*/
default_zone = mem->zone;
if (!default_zone)
return sysfs_emit(buf, "%s\n", "none");
len += sysfs_emit_at(buf, len, "%s", default_zone->name);
goto out;
}
default_zone = zone_for_pfn_range(MMOP_ONLINE, nid, group,
start_pfn, nr_pages);
len += sysfs_emit_at(buf, len, "%s", default_zone->name);
len += print_allowed_zone(buf, len, nid, group, start_pfn, nr_pages,
MMOP_ONLINE_KERNEL, default_zone);
len += print_allowed_zone(buf, len, nid, group, start_pfn, nr_pages,
MMOP_ONLINE_MOVABLE, default_zone);
out:
len += sysfs_emit_at(buf, len, "\n");
return len;
}
static DEVICE_ATTR_RO(valid_zones);
#endif
static DEVICE_ATTR_RO(phys_index);
static DEVICE_ATTR_RW(state);
static DEVICE_ATTR_RO(phys_device);
static DEVICE_ATTR_RO(removable);
/*
* Show the memory block size (shared by all memory blocks).
*/
static ssize_t block_size_bytes_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sysfs_emit(buf, "%lx\n", memory_block_size_bytes());
}
static DEVICE_ATTR_RO(block_size_bytes);
/*
* Memory auto online policy.
*/
static ssize_t auto_online_blocks_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sysfs_emit(buf, "%s\n",
online_type_to_str[mhp_default_online_type]);
}
static ssize_t auto_online_blocks_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
const int online_type = mhp_online_type_from_str(buf);
if (online_type < 0)
return -EINVAL;
mhp_default_online_type = online_type;
return count;
}
static DEVICE_ATTR_RW(auto_online_blocks);
#ifdef CONFIG_CRASH_HOTPLUG
#include <linux/kexec.h>
static ssize_t crash_hotplug_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sysfs_emit(buf, "%d\n", crash_hotplug_memory_support());
}
static DEVICE_ATTR_RO(crash_hotplug);
#endif
/*
* Some architectures will have custom drivers to do this, and
* will not need to do it from userspace. The fake hot-add code
* as well as ppc64 will do all of their discovery in userspace
* and will require this interface.
*/
#ifdef CONFIG_ARCH_MEMORY_PROBE
static ssize_t probe_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
u64 phys_addr;
int nid, ret;
unsigned long pages_per_block = PAGES_PER_SECTION * sections_per_block;
ret = kstrtoull(buf, 0, &phys_addr);
if (ret)
return ret;
if (phys_addr & ((pages_per_block << PAGE_SHIFT) - 1))
return -EINVAL;
ret = lock_device_hotplug_sysfs();
if (ret)
return ret;
nid = memory_add_physaddr_to_nid(phys_addr);
ret = __add_memory(nid, phys_addr,
MIN_MEMORY_BLOCK_SIZE * sections_per_block,
MHP_NONE);
if (ret)
goto out;
ret = count;
out:
unlock_device_hotplug();
return ret;
}
static DEVICE_ATTR_WO(probe);
#endif
#ifdef CONFIG_MEMORY_FAILURE
/*
* Support for offlining pages of memory
*/
/* Soft offline a page */
static ssize_t soft_offline_page_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
int ret;
u64 pfn;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (kstrtoull(buf, 0, &pfn) < 0)
return -EINVAL;
pfn >>= PAGE_SHIFT;
ret = soft_offline_page(pfn, 0);
return ret == 0 ? count : ret;
}
/* Forcibly offline a page, including killing processes. */
static ssize_t hard_offline_page_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
int ret;
u64 pfn;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (kstrtoull(buf, 0, &pfn) < 0)
return -EINVAL;
pfn >>= PAGE_SHIFT;
ret = memory_failure(pfn, MF_SW_SIMULATED);
if (ret == -EOPNOTSUPP)
ret = 0;
return ret ? ret : count;
}
static DEVICE_ATTR_WO(soft_offline_page);
static DEVICE_ATTR_WO(hard_offline_page);
#endif
/* See phys_device_show(). */
int __weak arch_get_memory_phys_device(unsigned long start_pfn)
{
return 0;
}
/*
* 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 memory_block *mem;
mem = xa_load(&memory_blocks, block_id);
if (mem)
get_device(&mem->dev);
return mem;
}
/*
* Called under device_hotplug_lock.
*/
struct memory_block *find_memory_block(unsigned long section_nr)
{
unsigned long block_id = memory_block_id(section_nr);
return find_memory_block_by_id(block_id);
}
static struct attribute *memory_memblk_attrs[] = {
&dev_attr_phys_index.attr,
&dev_attr_state.attr,
&dev_attr_phys_device.attr,
&dev_attr_removable.attr,
#ifdef CONFIG_MEMORY_HOTREMOVE
&dev_attr_valid_zones.attr,
#endif
NULL
};
static const struct attribute_group memory_memblk_attr_group = {
.attrs = memory_memblk_attrs,
};
static const struct attribute_group *memory_memblk_attr_groups[] = {
&memory_memblk_attr_group,
NULL,
};
static int __add_memory_block(struct memory_block *memory)
{
int ret;
memory->dev.bus = &memory_subsys;
memory->dev.id = memory->start_section_nr / sections_per_block;
memory->dev.release = memory_block_release;
memory->dev.groups = memory_memblk_attr_groups;
memory->dev.offline = memory->state == MEM_OFFLINE;
ret = device_register(&memory->dev);
if (ret) {
put_device(&memory->dev);
return ret;
}
ret = xa_err(xa_store(&memory_blocks, memory->dev.id, memory,
GFP_KERNEL));
if (ret)
device_unregister(&memory->dev);
return ret;
}
static struct zone *early_node_zone_for_memory_block(struct memory_block *mem,
int nid)
{
const unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr);
const unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
struct zone *zone, *matching_zone = NULL;
pg_data_t *pgdat = NODE_DATA(nid);
int i;
/*
* This logic only works for early memory, when the applicable zones
* already span the memory block. We don't expect overlapping zones on
* a single node for early memory. So if we're told that some PFNs
* of a node fall into this memory block, we can assume that all node
* zones that intersect with the memory block are actually applicable.
* No need to look at the memmap.
*/
for (i = 0; i < MAX_NR_ZONES; i++) {
zone = pgdat->node_zones + i;
if (!populated_zone(zone))
continue;
if (!zone_intersects(zone, start_pfn, nr_pages))
continue;
if (!matching_zone) {
matching_zone = zone;
continue;
}
/* Spans multiple zones ... */
matching_zone = NULL;
break;
}
return matching_zone;
}
#ifdef CONFIG_NUMA
/**
* memory_block_add_nid() - Indicate that system RAM falling into this memory
* block device (partially) belongs to the given node.
* @mem: The memory block device.
* @nid: The node id.
* @context: The memory initialization context.
*
* Indicate that system RAM falling into this memory block (partially) belongs
* to the given node. If the context indicates ("early") that we are adding the
* node during node device subsystem initialization, this will also properly
* set/adjust mem->zone based on the zone ranges of the given node.
*/
void memory_block_add_nid(struct memory_block *mem, int nid,
enum meminit_context context)
{
if (context == MEMINIT_EARLY && mem->nid != nid) {
/*
* For early memory we have to determine the zone when setting
* the node id and handle multiple nodes spanning a single
* memory block by indicate via zone == NULL that we're not
* dealing with a single zone. So if we're setting the node id
* the first time, determine if there is a single zone. If we're
* setting the node id a second time to a different node,
* invalidate the single detected zone.
*/
if (mem->nid == NUMA_NO_NODE)
mem->zone = early_node_zone_for_memory_block(mem, nid);
else
mem->zone = NULL;
}
/*
* If this memory block spans multiple nodes, we only indicate
* the last processed node. If we span multiple nodes (not applicable
* to hotplugged memory), zone == NULL will prohibit memory offlining
* and consequently unplug.
*/
mem->nid = nid;
}
#endif
static int add_memory_block(unsigned long block_id, unsigned long state,
struct vmem_altmap *altmap,
struct memory_group *group)
{
struct memory_block *mem;
int ret = 0;
mem = find_memory_block_by_id(block_id);
if (mem) {
put_device(&mem->dev);
return -EEXIST;
}
mem = kzalloc(sizeof(*mem), GFP_KERNEL);
if (!mem)
return -ENOMEM;
mem->start_section_nr = block_id * sections_per_block;
mem->state = state;
mem->nid = NUMA_NO_NODE;
mem->altmap = altmap;
INIT_LIST_HEAD(&mem->group_next);
#ifndef CONFIG_NUMA
if (state == MEM_ONLINE)
/*
* MEM_ONLINE at this point implies early memory. With NUMA,
* we'll determine the zone when setting the node id via
* memory_block_add_nid(). Memory hotplug updated the zone
* manually when memory onlining/offlining succeeds.
*/
mem->zone = early_node_zone_for_memory_block(mem, NUMA_NO_NODE);
#endif /* CONFIG_NUMA */
ret = __add_memory_block(mem);
if (ret)
return ret;
if (group) {
mem->group = group;
list_add(&mem->group_next, &group->memory_blocks);
}
return 0;
}
static int __init add_boot_memory_block(unsigned long base_section_nr)
{
int section_count = 0;
unsigned long nr;
for (nr = base_section_nr; nr < base_section_nr + sections_per_block;
nr++)
if (present_section_nr(nr))
section_count++;
if (section_count == 0)
return 0;
return add_memory_block(memory_block_id(base_section_nr),
MEM_ONLINE, NULL, NULL);
}
static int add_hotplug_memory_block(unsigned long block_id,
struct vmem_altmap *altmap,
struct memory_group *group)
{
return add_memory_block(block_id, MEM_OFFLINE, altmap, group);
}
static void remove_memory_block(struct memory_block *memory)
{
if (WARN_ON_ONCE(memory->dev.bus != &memory_subsys))
return;
WARN_ON(xa_erase(&memory_blocks, memory->dev.id) == NULL);
if (memory->group) {
list_del(&memory->group_next);
memory->group = NULL;
}
/* drop the ref. we got via find_memory_block() */
put_device(&memory->dev);
device_unregister(&memory->dev);
}
/*
* Create memory block devices for the given memory area. Start and size
* have to be aligned to memory block granularity. Memory block devices
* will be initialized as offline.
*
* Called under device_hotplug_lock.
*/
int create_memory_block_devices(unsigned long start, unsigned long size,
struct vmem_altmap *altmap,
struct memory_group *group)
{
const unsigned long start_block_id = pfn_to_block_id(PFN_DOWN(start));
unsigned long end_block_id = pfn_to_block_id(PFN_DOWN(start + size));
struct memory_block *mem;
unsigned long block_id;
int ret = 0;
if (WARN_ON_ONCE(!IS_ALIGNED(start, memory_block_size_bytes()) ||
!IS_ALIGNED(size, memory_block_size_bytes())))
return -EINVAL;
for (block_id = start_block_id; block_id != end_block_id; block_id++) {
ret = add_hotplug_memory_block(block_id, altmap, group);
if (ret)
break;
}
if (ret) {
end_block_id = block_id;
for (block_id = start_block_id; block_id != end_block_id;
block_id++) {
mem = find_memory_block_by_id(block_id);
if (WARN_ON_ONCE(!mem))
continue;
remove_memory_block(mem);
}
}
return ret;
}
/*
* Remove memory block devices for the given memory area. Start and size
* have to be aligned to memory block granularity. Memory block devices
* have to be offline.
*
* Called under device_hotplug_lock.
*/
void remove_memory_block_devices(unsigned long start, unsigned long size)
{
const unsigned long start_block_id = pfn_to_block_id(PFN_DOWN(start));
const unsigned long end_block_id = pfn_to_block_id(PFN_DOWN(start + size));
struct memory_block *mem;
unsigned long block_id;
if (WARN_ON_ONCE(!IS_ALIGNED(start, memory_block_size_bytes()) ||
!IS_ALIGNED(size, memory_block_size_bytes())))
return;
for (block_id = start_block_id; block_id != end_block_id; block_id++) {
mem = find_memory_block_by_id(block_id);
if (WARN_ON_ONCE(!mem))
continue;
num_poisoned_pages_sub(-1UL, memblk_nr_poison(mem));
unregister_memory_block_under_nodes(mem);
remove_memory_block(mem);
}
}
static struct attribute *memory_root_attrs[] = {
#ifdef CONFIG_ARCH_MEMORY_PROBE
&dev_attr_probe.attr,
#endif
#ifdef CONFIG_MEMORY_FAILURE
&dev_attr_soft_offline_page.attr,
&dev_attr_hard_offline_page.attr,
#endif
&dev_attr_block_size_bytes.attr,
&dev_attr_auto_online_blocks.attr,
#ifdef CONFIG_CRASH_HOTPLUG
&dev_attr_crash_hotplug.attr,
#endif
NULL
};
static const struct attribute_group memory_root_attr_group = {
.attrs = memory_root_attrs,
};
static const struct attribute_group *memory_root_attr_groups[] = {
&memory_root_attr_group,
NULL,
};
/*
* Initialize the sysfs support for memory devices. At the time this function
* is called, we cannot have concurrent creation/deletion of memory block
* devices, the device_hotplug_lock is not needed.
*/
void __init memory_dev_init(void)
{
int ret;
unsigned long block_sz, nr;
/* Validate the configured memory block size */
block_sz = memory_block_size_bytes();
if (!is_power_of_2(block_sz) || block_sz < MIN_MEMORY_BLOCK_SIZE)
panic("Memory block size not suitable: 0x%lx\n", block_sz);
sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
ret = subsys_system_register(&memory_subsys, memory_root_attr_groups);
if (ret)
panic("%s() failed to register subsystem: %d\n", __func__, ret);
/*
* Create entries for memory sections that were found
* during boot and have been initialized
*/
for (nr = 0; nr <= __highest_present_section_nr;
nr += sections_per_block) {
ret = add_boot_memory_block(nr);
if (ret)
panic("%s() failed to add memory block: %d\n", __func__,
ret);
}
}
/**
* walk_memory_blocks - walk through all present memory blocks overlapped
* by the range [start, start + size)
*
* @start: start address of the memory range
* @size: size of the memory range
* @arg: argument passed to func
* @func: callback for each memory section walked
*
* This function walks through all present memory blocks overlapped by the
* range [start, start + size), calling func on each memory block.
*
* 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)
{
const unsigned long start_block_id = phys_to_block_id(start);
const unsigned long end_block_id = phys_to_block_id(start + size - 1);
struct memory_block *mem;
unsigned long block_id;
int ret = 0;
if (!size)
return 0;
for (block_id = start_block_id; block_id <= end_block_id; block_id++) {
mem = find_memory_block_by_id(block_id);
if (!mem)
continue;
ret = func(mem, arg);
put_device(&mem->dev);
if (ret)
break;
}
return ret;
}
struct for_each_memory_block_cb_data {
walk_memory_blocks_func_t func;
void *arg;
};
static int for_each_memory_block_cb(struct device *dev, void *data)
{
struct memory_block *mem = to_memory_block(dev);
struct for_each_memory_block_cb_data *cb_data = data;
return cb_data->func(mem, cb_data->arg);
}
/**
* for_each_memory_block - walk through all present memory blocks
*
* @arg: argument passed to func
* @func: callback for each memory block walked
*
* This function walks through all present memory blocks, calling func on
* each memory block.
*
* In case func() returns an error, walking is aborted and the error is
* returned.
*/
int for_each_memory_block(void *arg, walk_memory_blocks_func_t func)
{
struct for_each_memory_block_cb_data cb_data = {
.func = func,
.arg = arg,
};
return bus_for_each_dev(&memory_subsys, NULL, &cb_data,
for_each_memory_block_cb);
}
/*
* This is an internal helper to unify allocation and initialization of
* memory groups. Note that the passed memory group will be copied to a
* dynamically allocated memory group. After this call, the passed
* memory group should no longer be used.
*/
static int memory_group_register(struct memory_group group)
{
struct memory_group *new_group;
uint32_t mgid;
int ret;
if (!node_possible(group.nid))
return -EINVAL;
new_group = kzalloc(sizeof(group), GFP_KERNEL);
if (!new_group)
return -ENOMEM;
*new_group = group;
INIT_LIST_HEAD(&new_group->memory_blocks);
ret = xa_alloc(&memory_groups, &mgid, new_group, xa_limit_31b,
GFP_KERNEL);
if (ret) {
kfree(new_group);
return ret;
} else if (group.is_dynamic) {
xa_set_mark(&memory_groups, mgid, MEMORY_GROUP_MARK_DYNAMIC);
}
return mgid;
}
/**
* memory_group_register_static() - Register a static memory group.
* @nid: The node id.
* @max_pages: The maximum number of pages we'll have in this static memory
* group.
*
* Register a new static memory group and return the memory group id.
* All memory in the group belongs to a single unit, such as a DIMM. All
* memory belonging to a static memory group is added in one go to be removed
* in one go -- it's static.
*
* Returns an error if out of memory, if the node id is invalid, if no new
* memory groups can be registered, or if max_pages is invalid (0). Otherwise,
* returns the new memory group id.
*/
int memory_group_register_static(int nid, unsigned long max_pages)
{
struct memory_group group = {
.nid = nid,
.s = {
.max_pages = max_pages,
},
};
if (!max_pages)
return -EINVAL;
return memory_group_register(group);
}
EXPORT_SYMBOL_GPL(memory_group_register_static);
/**
* memory_group_register_dynamic() - Register a dynamic memory group.
* @nid: The node id.
* @unit_pages: Unit in pages in which is memory added/removed in this dynamic
* memory group.
*
* Register a new dynamic memory group and return the memory group id.
* Memory within a dynamic memory group is added/removed dynamically
* in unit_pages.
*
* Returns an error if out of memory, if the node id is invalid, if no new
* memory groups can be registered, or if unit_pages is invalid (0, not a
* power of two, smaller than a single memory block). Otherwise, returns the
* new memory group id.
*/
int memory_group_register_dynamic(int nid, unsigned long unit_pages)
{
struct memory_group group = {
.nid = nid,
.is_dynamic = true,
.d = {
.unit_pages = unit_pages,
},
};
if (!unit_pages || !is_power_of_2(unit_pages) ||
unit_pages < PHYS_PFN(memory_block_size_bytes()))
return -EINVAL;
return memory_group_register(group);
}
EXPORT_SYMBOL_GPL(memory_group_register_dynamic);
/**
* memory_group_unregister() - Unregister a memory group.
* @mgid: the memory group id
*
* Unregister a memory group. If any memory block still belongs to this
* memory group, unregistering will fail.
*
* Returns -EINVAL if the memory group id is invalid, returns -EBUSY if some
* memory blocks still belong to this memory group and returns 0 if
* unregistering succeeded.
*/
int memory_group_unregister(int mgid)
{
struct memory_group *group;
if (mgid < 0)
return -EINVAL;
group = xa_load(&memory_groups, mgid);
if (!group)
return -EINVAL;
if (!list_empty(&group->memory_blocks))
return -EBUSY;
xa_erase(&memory_groups, mgid);
kfree(group);
return 0;
}
EXPORT_SYMBOL_GPL(memory_group_unregister);
/*
* This is an internal helper only to be used in core memory hotplug code to
* lookup a memory group. We don't care about locking, as we don't expect a
* memory group to get unregistered while adding memory to it -- because
* the group and the memory is managed by the same driver.
*/
struct memory_group *memory_group_find_by_id(int mgid)
{
return xa_load(&memory_groups, mgid);
}
/*
* This is an internal helper only to be used in core memory hotplug code to
* walk all dynamic memory groups excluding a given memory group, either
* belonging to a specific node, or belonging to any node.
*/
int walk_dynamic_memory_groups(int nid, walk_memory_groups_func_t func,
struct memory_group *excluded, void *arg)
{
struct memory_group *group;
unsigned long index;
int ret = 0;
xa_for_each_marked(&memory_groups, index, group,
MEMORY_GROUP_MARK_DYNAMIC) {
if (group == excluded)
continue;
#ifdef CONFIG_NUMA
if (nid != NUMA_NO_NODE && group->nid != nid)
continue;
#endif /* CONFIG_NUMA */
ret = func(group, arg);
if (ret)
break;
}
return ret;
}
#if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_MEMORY_HOTPLUG)
void memblk_nr_poison_inc(unsigned long pfn)
{
const unsigned long block_id = pfn_to_block_id(pfn);
struct memory_block *mem = find_memory_block_by_id(block_id);
if (mem)
atomic_long_inc(&mem->nr_hwpoison);
}
void memblk_nr_poison_sub(unsigned long pfn, long i)
{
const unsigned long block_id = pfn_to_block_id(pfn);
struct memory_block *mem = find_memory_block_by_id(block_id);
if (mem)
atomic_long_sub(i, &mem->nr_hwpoison);
}
static unsigned long memblk_nr_poison(struct memory_block *mem)
{
return atomic_long_read(&mem->nr_hwpoison);
}
#endif