hot-remove initiated by acpi_memhotplug driver tries to offline pages and then remove section/sysfs files in remove_memory(). remove_memory() will only proceed if is_memblk_offline() returns true, i.e. only if the corresponding memblock is in MEM_OFFLINE state. However, the memblock state is currently only updated if the offlining has been initiated from the sysfs interface (echo offline > /sys/devices/system/memory/memoryXX/state). The acpi hot-remove codepath does not use the sysfs interface but directly calls offline_pages. So remove_memory() will always fail, even if offline_pages has succeeded.
This patch solves this by registering a memblock_state notifier function in the memory_notify chain. This will change state of memblocks independently of sysfs usage. The patch is based on work-in-progress patches for memory hot-remove, see: http://lwn.net/Articles/507244/ Signed-off-by: Vasilis Liaskovitis <[email protected]> --- drivers/base/memory.c | 37 +++++++++++++++++++++++++++++++++++++ 1 files changed, 37 insertions(+), 0 deletions(-) diff --git a/drivers/base/memory.c b/drivers/base/memory.c index 8981568..4095f3f 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -706,6 +706,42 @@ int unregister_memory_section(struct mem_section *section) return remove_memory_block(0, section, 0); } +static int memblock_state_notifier_nb(struct notifier_block *nb, unsigned long + val, void *v) +{ + struct memory_notify *arg = (struct memory_notify *)v; + struct memory_block *mem = NULL; + struct mem_section *ms; + unsigned long section_nr; + + section_nr = pfn_to_section_nr(arg->start_pfn); + ms = __nr_to_section(section_nr); + mem = find_memory_block(ms); + if (!mem) + goto out; + + switch (val) { + case MEM_GOING_OFFLINE: + case MEM_OFFLINE: + case MEM_GOING_ONLINE: + case MEM_ONLINE: + case MEM_CANCEL_ONLINE: + case MEM_CANCEL_OFFLINE: + mem->state = val; + break; + default: + printk(KERN_WARNING "invalid memblock state\n"); + break; + } +out: + return NOTIFY_OK; +} + +static struct notifier_block memblock_state_nb = { + .notifier_call = memblock_state_notifier_nb, + .priority = 0 +}; + /* * Initialize the sysfs support for memory devices... */ @@ -724,6 +760,7 @@ int __init memory_dev_init(void) block_sz = get_memory_block_size(); sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE; + register_memory_notifier(&memblock_state_nb); /* * Create entries for memory sections that were found * during boot and have been initialized -- 1.7.9 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
