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author | Badari Pulavarty <pbadari@us.ibm.com> | 2008-07-24 04:28:19 (GMT) |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-07-24 17:47:21 (GMT) |
commit | 5c755e9fd813810680abd56ec09a5f90143e815b (patch) | |
tree | 1686c0666f6bd630441957a53c546d90b0f61723 /drivers/base/memory.c | |
parent | 2f7f24eca31c4fc2fdb134b2ef743ccd67cfb9a9 (diff) | |
download | linux-fsl-qoriq-5c755e9fd813810680abd56ec09a5f90143e815b.tar.xz |
memory-hotplug: add sysfs removable attribute for hotplug memory remove
Memory may be hot-removed on a per-memory-block basis, particularly on
POWER where the SPARSEMEM section size often matches the memory-block
size. A user-level agent must be able to identify which sections of
memory are likely to be removable before attempting the potentially
expensive operation. This patch adds a file called "removable" to the
memory directory in sysfs to help such an agent. In this patch, a memory
block is considered removable if;
o It contains only MOVABLE pageblocks
o It contains only pageblocks with free pages regardless of pageblock type
On the other hand, a memory block starting with a PageReserved() page will
never be considered removable. Without this patch, the user-agent is
forced to choose a memory block to remove randomly.
Sample output of the sysfs files:
./memory/memory0/removable: 0
./memory/memory1/removable: 0
./memory/memory2/removable: 0
./memory/memory3/removable: 0
./memory/memory4/removable: 0
./memory/memory5/removable: 0
./memory/memory6/removable: 0
./memory/memory7/removable: 1
./memory/memory8/removable: 0
./memory/memory9/removable: 0
./memory/memory10/removable: 0
./memory/memory11/removable: 0
./memory/memory12/removable: 0
./memory/memory13/removable: 0
./memory/memory14/removable: 0
./memory/memory15/removable: 0
./memory/memory16/removable: 0
./memory/memory17/removable: 1
./memory/memory18/removable: 1
./memory/memory19/removable: 1
./memory/memory20/removable: 1
./memory/memory21/removable: 1
./memory/memory22/removable: 1
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/base/memory.c')
-rw-r--r-- | drivers/base/memory.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/drivers/base/memory.c b/drivers/base/memory.c index 4d4e0e7..855ed1a 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -101,6 +101,21 @@ static ssize_t show_mem_phys_index(struct sys_device *dev, } /* + * Show whether the section of memory is likely to be hot-removable + */ +static ssize_t show_mem_removable(struct sys_device *dev, char *buf) +{ + unsigned long start_pfn; + int ret; + struct memory_block *mem = + container_of(dev, struct memory_block, sysdev); + + start_pfn = section_nr_to_pfn(mem->phys_index); + ret = is_mem_section_removable(start_pfn, PAGES_PER_SECTION); + return sprintf(buf, "%d\n", ret); +} + +/* * online, offline, going offline, etc. */ static ssize_t show_mem_state(struct sys_device *dev, @@ -262,6 +277,7 @@ static ssize_t show_phys_device(struct sys_device *dev, static SYSDEV_ATTR(phys_index, 0444, show_mem_phys_index, NULL); static SYSDEV_ATTR(state, 0644, show_mem_state, store_mem_state); static SYSDEV_ATTR(phys_device, 0444, show_phys_device, NULL); +static SYSDEV_ATTR(removable, 0444, show_mem_removable, NULL); #define mem_create_simple_file(mem, attr_name) \ sysdev_create_file(&mem->sysdev, &attr_##attr_name) @@ -350,6 +366,8 @@ static int add_memory_block(unsigned long node_id, struct mem_section *section, ret = mem_create_simple_file(mem, state); if (!ret) ret = mem_create_simple_file(mem, phys_device); + if (!ret) + ret = mem_create_simple_file(mem, removable); return ret; } @@ -394,6 +412,7 @@ int remove_memory_block(unsigned long node_id, struct mem_section *section, mem_remove_simple_file(mem, phys_index); mem_remove_simple_file(mem, state); mem_remove_simple_file(mem, phys_device); + mem_remove_simple_file(mem, removable); unregister_memory(mem, section); return 0; |