On 2014/8/18 14:11, Yasuaki Ishimatsu wrote: > (2014/08/13 13:10), Zhang Zhen wrote: >> Currently memory-hotplug has two limits: >> 1. If the memory block is in ZONE_NORMAL, you can change it to >> ZONE_MOVABLE, but this memory block must be adjacent to ZONE_MOVABLE. >> 2. If the memory block is in ZONE_MOVABLE, you can change it to >> ZONE_NORMAL, but this memory block must be adjacent to ZONE_NORMAL. >> >> With this patch, we can easy to know a memory block can be onlined to >> which zone, and don't need to know the above two limits. >> >> Updated the related Documentation. >> >> Change v1 -> v2: >> - optimize the implementation following Dave Hansen's suggestion >> >> Signed-off-by: Zhang Zhen <zhenzhang.zhang@xxxxxxxxxx> >> --- >> Documentation/ABI/testing/sysfs-devices-memory | 8 ++++ >> Documentation/memory-hotplug.txt | 4 +- >> drivers/base/memory.c | 62 ++++++++++++++++++++++++++ >> include/linux/memory_hotplug.h | 1 + >> mm/memory_hotplug.c | 2 +- >> 5 files changed, 75 insertions(+), 2 deletions(-) >> >> diff --git a/Documentation/ABI/testing/sysfs-devices-memory b/Documentation/ABI/testing/sysfs-devices-memory >> index 7405de2..2b2a1d7 100644 >> --- a/Documentation/ABI/testing/sysfs-devices-memory >> +++ b/Documentation/ABI/testing/sysfs-devices-memory >> @@ -61,6 +61,14 @@ Users: hotplug memory remove tools >> http://www.ibm.com/developerworks/wikis/display/LinuxP/powerpc-utils >> >> >> +What: /sys/devices/system/memory/memoryX/zones_online_to >> +Date: July 2014 >> +Contact: Zhang Zhen <zhenzhang.zhang@xxxxxxxxxx> >> +Description: >> + The file /sys/devices/system/memory/memoryX/zones_online_to >> + is read-only and is designed to show which zone this memory block can >> + be onlined to. >> + >> What: /sys/devices/system/memoryX/nodeY >> Date: October 2009 >> Contact: Linux Memory Management list <linux-mm@xxxxxxxxx> >> diff --git a/Documentation/memory-hotplug.txt b/Documentation/memory-hotplug.txt >> index 45134dc..5b34e33 100644 >> --- a/Documentation/memory-hotplug.txt >> +++ b/Documentation/memory-hotplug.txt >> @@ -155,6 +155,7 @@ Under each memory block, you can see 4 files: >> /sys/devices/system/memory/memoryXXX/phys_device >> /sys/devices/system/memory/memoryXXX/state >> /sys/devices/system/memory/memoryXXX/removable >> +/sys/devices/system/memory/memoryXXX/zones_online_to >> >> 'phys_index' : read-only and contains memory block id, same as XXX. >> 'state' : read-write >> @@ -170,6 +171,8 @@ Under each memory block, you can see 4 files: >> block is removable and a value of 0 indicates that >> it is not removable. A memory block is removable only if >> every section in the block is removable. >> +'zones_online_to' : read-only: designed to show which zone this memory block >> + can be onlined to. >> >> NOTE: >> These directories/files appear after physical memory hotplug phase. >> @@ -408,7 +411,6 @@ node if necessary. >> - allowing memory hot-add to ZONE_MOVABLE. maybe we need some switch like >> sysctl or new control file. >> - showing memory block and physical device relationship. >> - - showing memory block is under ZONE_MOVABLE or not >> - test and make it better memory offlining. >> - support HugeTLB page migration and offlining. >> - memmap removing at memory offline. >> diff --git a/drivers/base/memory.c b/drivers/base/memory.c >> index a2e13e2..b5d693f 100644 >> --- a/drivers/base/memory.c >> +++ b/drivers/base/memory.c >> @@ -373,10 +373,71 @@ static ssize_t show_phys_device(struct device *dev, >> return sprintf(buf, "%d\n", mem->phys_device); >> } >> >> +static int __zones_online_to(unsigned long end_pfn, >> + struct page *first_page, unsigned long nr_pages) >> +{ >> + struct zone *zone_next; >> + > >> + /*The mem block is the last block of memory.*/ >> + if (!pfn_valid(end_pfn + 1)) >> + return 1; > > The check is not enough if memory has hole as follows: > > PFN 0x00 0xd0 0xe0 0xf0 > +-------------+-------------+-------------+ > zone type | Normal | hole | Normal | > +-------------+-------------+-------------+ > > In this case, 0xd1 is invalid pfn. But __zones_online_to should return 0 > since 0xe0-0xf0 is Normal zone. > > Thanks, > Yasuaki Ishimatsu > You are right, it is not enough. Here we should make a check as follows. if ((end_pfn + 1) > zone_end_pfn(page_zone(first_page))) return 1; I will send a patch to fix it. Thanks ! > >> + zone_next = page_zone(first_page + nr_pages); >> + if (zone_idx(zone_next) == ZONE_MOVABLE) >> + return 1; >> + return 0; >> +} >> + >> +static ssize_t show_zones_online_to(struct device *dev, >> + struct device_attribute *attr, char *buf) >> +{ >> + struct memory_block *mem = to_memory_block(dev); >> + unsigned long start_pfn, end_pfn; >> + unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block; >> + struct page *first_page; >> + struct zone *zone, *zone_prev; >> + >> + start_pfn = section_nr_to_pfn(mem->start_section_nr); >> + end_pfn = start_pfn + nr_pages; >> + first_page = pfn_to_page(start_pfn); >> + >> + /*The block contains more than one zone can not be offlined.*/ >> + if (!test_pages_in_a_zone(start_pfn, end_pfn)) >> + return sprintf(buf, "none\n"); >> + >> + zone = page_zone(first_page); >> + >> +#ifdef CONFIG_HIGHMEM >> + if (zone_idx(zone) == ZONE_HIGHMEM) { >> + if (__zones_online_to(end_pfn, first_page, nr_pages)) >> + return sprintf(buf, "%s %s\n", >> + zone->name, (zone + 1)->name); >> + } >> +#else >> + if (zone_idx(zone) == ZONE_NORMAL) { >> + if (__zones_online_to(end_pfn, first_page, nr_pages)) >> + return sprintf(buf, "%s %s\n", >> + zone->name, (zone + 1)->name); >> + } >> +#endif >> + >> + if (zone_idx(zone) == ZONE_MOVABLE) { >> + if (!pfn_valid(start_pfn - nr_pages)) >> + return sprintf(buf, "%s %s\n", >> + zone->name, (zone - 1)->name); >> + zone_prev = page_zone(first_page - nr_pages); >> + if (zone_idx(zone_prev) != ZONE_MOVABLE) >> + return sprintf(buf, "%s %s\n", >> + zone->name, (zone - 1)->name); >> + } >> + >> + return sprintf(buf, "%s\n", zone->name); >> +} >> + >> static DEVICE_ATTR(phys_index, 0444, show_mem_start_phys_index, NULL); >> static DEVICE_ATTR(state, 0644, show_mem_state, store_mem_state); >> static DEVICE_ATTR(phys_device, 0444, show_phys_device, NULL); >> static DEVICE_ATTR(removable, 0444, show_mem_removable, NULL); >> +static DEVICE_ATTR(zones_online_to, 0444, show_zones_online_to, NULL); >> >> /* >> * Block size attribute stuff >> @@ -523,6 +584,7 @@ static struct attribute *memory_memblk_attrs[] = { >> &dev_attr_state.attr, >> &dev_attr_phys_device.attr, >> &dev_attr_removable.attr, >> + &dev_attr_zones_online_to.attr, >> NULL >> }; >> >> diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h >> index d9524c4..8f1a419 100644 >> --- a/include/linux/memory_hotplug.h >> +++ b/include/linux/memory_hotplug.h >> @@ -84,6 +84,7 @@ extern int zone_grow_waitqueues(struct zone *zone, unsigned long nr_pages); >> extern int add_one_highpage(struct page *page, int pfn, int bad_ppro); >> /* VM interface that may be used by firmware interface */ >> extern int online_pages(unsigned long, unsigned long, int); >> +extern int test_pages_in_a_zone(unsigned long, unsigned long); >> extern void __offline_isolated_pages(unsigned long, unsigned long); >> >> typedef void (*online_page_callback_t)(struct page *page); >> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c >> index 2ff8c23..29d8693 100644 >> --- a/mm/memory_hotplug.c >> +++ b/mm/memory_hotplug.c >> @@ -1307,7 +1307,7 @@ int is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages) >> /* >> * Confirm all pages in a range [start, end) is belongs to the same zone. >> */ >> -static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn) >> +int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn) >> { >> unsigned long pfn; >> struct zone *zone = NULL; >> > > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@xxxxxxxxx. 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