Hi Wen, 2012/07/13 12:35, Wen Congyang wrote: > At 07/09/2012 06:24 PM, Yasuaki Ishimatsu Wrote: >> acpi_memory_device_remove() has been prepared to remove physical memory. >> But, the function only frees acpi_memory_device currentlry. >> >> The patch adds following functions into acpi_memory_device_remove(): >> - offline memory >> - remove physical memory (only return -EBUSY) >> - free acpi_memory_device >> >> CC: David Rientjes <rient...@google.com> >> CC: Jiang Liu <liu...@gmail.com> >> CC: Len Brown <len.br...@intel.com> >> CC: Benjamin Herrenschmidt <b...@kernel.crashing.org> >> CC: Paul Mackerras <pau...@samba.org> >> CC: Christoph Lameter <c...@linux.com> >> Cc: Minchan Kim <minchan....@gmail.com> >> CC: Andrew Morton <a...@linux-foundation.org> >> CC: KOSAKI Motohiro <kosaki.motoh...@jp.fujitsu.com> >> CC: Wen Congyang <we...@cn.fujitsu.com> >> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasu...@jp.fujitsu.com> >> >> --- >> drivers/acpi/acpi_memhotplug.c | 26 +++++++++++++++++++++++++- >> drivers/base/memory.c | 39 >> +++++++++++++++++++++++++++++++++++++++ >> include/linux/memory.h | 5 +++++ >> include/linux/memory_hotplug.h | 1 + >> mm/memory_hotplug.c | 8 ++++++++ >> 5 files changed, 78 insertions(+), 1 deletion(-) >> >> Index: linux-3.5-rc6/drivers/acpi/acpi_memhotplug.c >> =================================================================== >> --- linux-3.5-rc6.orig/drivers/acpi/acpi_memhotplug.c 2012-07-09 >> 18:08:29.946888653 +0900 >> +++ linux-3.5-rc6/drivers/acpi/acpi_memhotplug.c 2012-07-09 >> 18:08:43.470719531 +0900 >> @@ -29,6 +29,7 @@ >> #include <linux/module.h> >> #include <linux/init.h> >> #include <linux/types.h> >> +#include <linux/memory.h> >> #include <linux/memory_hotplug.h> >> #include <linux/slab.h> >> #include <acpi/acpi_drivers.h> >> @@ -452,12 +453,35 @@ static int acpi_memory_device_add(struct >> static int acpi_memory_device_remove(struct acpi_device *device, int type) >> { >> struct acpi_memory_device *mem_device = NULL; >> - >> + struct acpi_memory_info *info, *tmp; >> + int result; >> + int node; >> >> if (!device || !acpi_driver_data(device)) >> return -EINVAL; >> >> mem_device = acpi_driver_data(device); >> + >> + node = acpi_get_node(mem_device->device->handle); >> + >> + list_for_each_entry_safe(info, tmp, &mem_device->res_list, list) { >> + if (!info->enabled) >> + continue; >> + >> + if (!is_memblk_offline(info->start_addr, info->length)) { >> + result = offline_memory(info->start_addr, info->length); >> + if (result) >> + return result; >> + } >> + >> + result = remove_memory(node, info->start_addr, info->length); > > The user may online the memory between offline_memory() and remove_memory(). > So I think we should lock memory hotplug before check the memory's status > and release it after remove_memory().
How about get "mem_block->state_mutex" of removed memory? When offlining memory, we need to change "memory_block->state" into "MEM_OFFLINE". In this case, we get mem_block->state_mutex. So I think the mutex lock is beneficial. Thanks, Yasuaki Ishimatsu > > Thanks > Wen Congyang > >> + if (result) >> + return result; >> + >> + list_del(&info->list); >> + kfree(info); >> + } >> + >> kfree(mem_device); >> >> return 0; >> Index: linux-3.5-rc6/include/linux/memory_hotplug.h >> =================================================================== >> --- linux-3.5-rc6.orig/include/linux/memory_hotplug.h 2012-07-09 >> 18:08:29.955888542 +0900 >> +++ linux-3.5-rc6/include/linux/memory_hotplug.h 2012-07-09 >> 18:08:43.471719518 +0900 >> @@ -233,6 +233,7 @@ static inline int is_mem_section_removab >> extern int mem_online_node(int nid); >> extern int add_memory(int nid, u64 start, u64 size); >> extern int arch_add_memory(int nid, u64 start, u64 size); >> +extern int remove_memory(int nid, u64 start, u64 size); >> extern int offline_memory(u64 start, u64 size); >> extern int sparse_add_one_section(struct zone *zone, unsigned long >> start_pfn, >> int nr_pages); >> Index: linux-3.5-rc6/mm/memory_hotplug.c >> =================================================================== >> --- linux-3.5-rc6.orig/mm/memory_hotplug.c 2012-07-09 18:08:29.953888567 >> +0900 >> +++ linux-3.5-rc6/mm/memory_hotplug.c 2012-07-09 18:08:43.476719455 >> +0900 >> @@ -659,6 +659,14 @@ out: >> } >> EXPORT_SYMBOL_GPL(add_memory); >> >> +int remove_memory(int nid, u64 start, u64 size) >> +{ >> + return -EBUSY; >> + >> +} >> +EXPORT_SYMBOL_GPL(remove_memory); >> + >> + >> #ifdef CONFIG_MEMORY_HOTREMOVE >> /* >> * A free page on the buddy free lists (not the per-cpu lists) has >> PageBuddy >> Index: linux-3.5-rc6/drivers/base/memory.c >> =================================================================== >> --- linux-3.5-rc6.orig/drivers/base/memory.c 2012-07-09 18:08:29.947888640 >> +0900 >> +++ linux-3.5-rc6/drivers/base/memory.c 2012-07-09 18:10:54.880076739 >> +0900 >> @@ -70,6 +70,45 @@ void unregister_memory_isolate_notifier( >> } >> EXPORT_SYMBOL(unregister_memory_isolate_notifier); >> >> +bool is_memblk_offline(unsigned long start, unsigned long size) >> +{ >> + struct memory_block *mem = NULL; >> + struct mem_section *section; >> + unsigned long start_pfn, end_pfn; >> + unsigned long pfn, section_nr; >> + >> + start_pfn = PFN_DOWN(start); >> + end_pfn = start_pfn + PFN_DOWN(start); >> + >> + for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { >> + section_nr = pfn_to_section_nr(pfn); >> + if (!present_section_nr(section_nr)); >> + continue; >> + >> + section = __nr_to_section(section_nr); >> + /* same memblock? */ >> + if (mem) >> + if((section_nr >= mem->start_section_nr) && >> + (section_nr <= mem->end_section_nr)) >> + continue; >> + >> + mem = find_memory_block_hinted(section, mem); >> + if (!mem) >> + continue; >> + if (mem->state == MEM_OFFLINE) >> + continue; >> + >> + kobject_put(&mem->dev.kobj); >> + return false; >> + } >> + >> + if (mem) >> + kobject_put(&mem->dev.kobj); >> + >> + return true; >> +} >> +EXPORT_SYMBOL(is_memblk_offline); >> + >> /* >> * register_memory - Setup a sysfs device for a memory block >> */ >> Index: linux-3.5-rc6/include/linux/memory.h >> =================================================================== >> --- linux-3.5-rc6.orig/include/linux/memory.h 2012-07-08 >> 09:23:56.000000000 +0900 >> +++ linux-3.5-rc6/include/linux/memory.h 2012-07-09 18:08:43.484719355 >> +0900 >> @@ -106,6 +106,10 @@ static inline int memory_isolate_notify( >> { >> return 0; >> } >> +static inline bool is_memblk_offline(unsigned long start, unsigned long >> size) >> +{ >> + return false; >> +} >> #else >> extern int register_memory_notifier(struct notifier_block *nb); >> extern void unregister_memory_notifier(struct notifier_block *nb); >> @@ -120,6 +124,7 @@ extern int memory_isolate_notify(unsigne >> extern struct memory_block *find_memory_block_hinted(struct mem_section *, >> struct memory_block *); >> extern struct memory_block *find_memory_block(struct mem_section *); >> +extern bool is_memblk_offline(unsigned long start, unsigned long size); >> #define CONFIG_MEM_BLOCK_SIZE (PAGES_PER_SECTION<<PAGE_SHIFT) >> enum mem_add_context { BOOT, HOTPLUG }; >> #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */ >> >> > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majord...@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"d...@kvack.org"> em...@kvack.org </a> > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/