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Memory hotplug / ACPI: Simplify memory removal

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Now that the memory offlining should be taken care of by the
companion device offlining code in acpi_scan_hot_remove(), the
ACPI memory hotplug driver doesn't need to offline it in
remove_memory() any more.  Moreover, since the return value of
remove_memory() is not used, it's better to make it be a void
function and trigger a BUG() if the memory scheduled for removal is
not offline.

Change the code in accordance with the above observations.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Toshi Kani <toshi.kani@hp.com>
This commit is contained in:
Rafael J. Wysocki 2013-05-27 12:58:46 +02:00
parent 303bfdb1a1
commit 242831eb15
3 changed files with 12 additions and 74 deletions
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13
drivers/acpi/acpi_memhotplug.c
View file

@ -271,13 +271,11 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
return 0;
}
static int acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
static void acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
{
acpi_handle handle = mem_device->device->handle;
int result = 0, nid;
struct acpi_memory_info *info, *n;
nid = acpi_get_node(handle);
int nid = acpi_get_node(handle);
list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
if (!info->enabled)
@ -287,15 +285,10 @@ static int acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
nid = memory_add_physaddr_to_nid(info->start_addr);
acpi_unbind_memory_blocks(info, handle);
result = remove_memory(nid, info->start_addr, info->length);
if (result)
return result;
remove_memory(nid, info->start_addr, info->length);
list_del(&info->list);
kfree(info);
}
return result;
}
static void acpi_memory_device_free(struct acpi_memory_device *mem_device)

2
include/linux/memory_hotplug.h
View file

@ -252,7 +252,7 @@ extern int add_memory(int nid, u64 start, u64 size);
extern int arch_add_memory(int nid, u64 start, u64 size);
extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
extern bool is_memblock_offlined(struct memory_block *mem);
extern int remove_memory(int nid, u64 start, u64 size);
extern void remove_memory(int nid, u64 start, u64 size);
extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn,
int nr_pages);
extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms);

71
mm/memory_hotplug.c
View file

@ -1670,24 +1670,6 @@ int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
}
#ifdef CONFIG_MEMORY_HOTREMOVE
/**
* offline_memory_block_cb - callback function for offlining memory block
* @mem: the memory block to be offlined
* @arg: buffer to hold error msg
*
* Always return 0, and put the error msg in arg if any.
*/
static int offline_memory_block_cb(struct memory_block *mem, void *arg)
{
int *ret = arg;
int error = device_offline(&mem->dev);
if (error != 0 && *ret == 0)
*ret = error;
return 0;
}
static int is_memblock_offlined_cb(struct memory_block *mem, void *arg)
{
int ret = !is_memblock_offlined(mem);
@ -1813,54 +1795,22 @@ void try_offline_node(int nid)
}
EXPORT_SYMBOL(try_offline_node);
int __ref remove_memory(int nid, u64 start, u64 size)
void __ref remove_memory(int nid, u64 start, u64 size)
{
unsigned long start_pfn, end_pfn;
int ret = 0;
int retry = 1;
start_pfn = PFN_DOWN(start);
end_pfn = PFN_UP(start + size - 1);
/*
* When CONFIG_MEMCG is on, one memory block may be used by other
* blocks to store page cgroup when onlining pages. But we don't know
* in what order pages are onlined. So we iterate twice to offline
* memory:
* 1st iterate: offline every non primary memory block.
* 2nd iterate: offline primary (i.e. first added) memory block.
*/
repeat:
walk_memory_range(start_pfn, end_pfn, &ret,
offline_memory_block_cb);
if (ret) {
if (!retry)
return ret;
retry = 0;
ret = 0;
goto repeat;
}
int ret;
lock_memory_hotplug();
/*
* we have offlined all memory blocks like this:
* 1. lock memory hotplug
* 2. offline a memory block
* 3. unlock memory hotplug
*
* repeat step1-3 to offline the memory block. All memory blocks
* must be offlined before removing memory. But we don't hold the
* lock in the whole operation. So we should check whether all
* memory blocks are offlined.
* All memory blocks must be offlined before removing memory. Check
* whether all memory blocks in question are offline and trigger a BUG()
* if this is not the case.
*/
ret = walk_memory_range(start_pfn, end_pfn, NULL,
ret = walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1), NULL,
is_memblock_offlined_cb);
if (ret) {
unlock_memory_hotplug();
return ret;
BUG();
}
/* remove memmap entry */
@ -1871,17 +1821,12 @@ int __ref remove_memory(int nid, u64 start, u64 size)
try_offline_node(nid);
unlock_memory_hotplug();
return 0;
}
#else
int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
{
return -EINVAL;
}
int remove_memory(int nid, u64 start, u64 size)
{
return -EINVAL;
}
void remove_memory(int nid, u64 start, u64 size) {}
#endif /* CONFIG_MEMORY_HOTREMOVE */
EXPORT_SYMBOL_GPL(remove_memory);