linux/mm/memory_hotplug.c, branch v3.13

mem-hotplug: introduce movable_node boot option

2013-11-13T03:09:09Z

The hot-Pluggable field in SRAT specifies which memory is hotpluggable. As we mentioned before, if hotpluggable memory is used by the kernel, it cannot be hot-removed. So memory hotplug users may want to set all hotpluggable memory in ZONE_MOVABLE so that the kernel won't use it. Memory hotplug users may also set a node as movable node, which has ZONE_MOVABLE only, so that the whole node can be hot-removed. But the kernel cannot use memory in ZONE_MOVABLE. By doing this, the kernel cannot use memory in movable nodes. This will cause NUMA performance down. And other users may be unhappy. So we need a way to allow users to enable and disable this functionality. In this patch, we introduce movable_node boot option to allow users to choose to not to consume hotpluggable memory at early boot time and later we can set it as ZONE_MOVABLE. To achieve this, the movable_node boot option will control the memblock allocation direction. That said, after memblock is ready, before SRAT is parsed, we should allocate memory near the kernel image as we explained in the previous patches. So if movable_node boot option is set, the kernel does the following: 1. After memblock is ready, make memblock allocate memory bottom up. 2. After SRAT is parsed, make memblock behave as default, allocate memory top down. Users can specify "movable_node" in kernel commandline to enable this functionality. For those who don't use memory hotplug or who don't want to lose their NUMA performance, just don't specify anything. The kernel will work as before. Signed-off-by: Tang Chen Signed-off-by: Zhang Yanfei Suggested-by: Kamezawa Hiroyuki Suggested-by: Ingo Molnar Acked-by: Tejun Heo Acked-by: Toshi Kani Cc: Thomas Gleixner Cc: "H. Peter Anvin" Cc: Wanpeng Li Cc: Thomas Renninger Cc: Yinghai Lu Cc: Jiang Liu Cc: Wen Congyang Cc: Lai Jiangshan Cc: Yasuaki Ishimatsu Cc: Taku Izumi Cc: Mel Gorman Cc: Michal Nazarewicz Cc: Minchan Kim Cc: Rik van Riel Cc: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/sparsemem: use PAGES_PER_SECTION to remove redundant nr_pages parameter

2013-11-13T03:09:06Z

For below functions, - sparse_add_one_section() - kmalloc_section_memmap() - __kmalloc_section_memmap() - __kfree_section_memmap() they are always invoked to operate on one memory section, so it is redundant to always pass a nr_pages parameter, which is the page numbers in one section. So we can directly use predefined macro PAGES_PER_SECTION instead of passing the parameter. Signed-off-by: Zhang Yanfei Cc: Wen Congyang Cc: Tang Chen Cc: Toshi Kani Cc: Yasuaki Ishimatsu Cc: Yinghai Lu Cc: Yasunori Goto Cc: Andy Whitcroft Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

cpu/mem hotplug: add try_online_node() for cpu_up()

2013-11-13T03:09:04Z

cpu_up() has #ifdef CONFIG_MEMORY_HOTPLUG code blocks, which call mem_online_node() to put its node online if offlined and then call build_all_zonelists() to initialize the zone list. These steps are specific to memory hotplug, and should be managed in mm/memory_hotplug.c. lock_memory_hotplug() should also be held for the whole steps. For this reason, this patch replaces mem_online_node() with try_online_node(), which performs the whole steps with lock_memory_hotplug() held. try_online_node() is named after try_offline_node() as they have similar purpose. There is no functional change in this patch. Signed-off-by: Toshi Kani Reviewed-by: Yasuaki Ishimatsu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/memory_hotplug.c: use pfn_to_nid() instead of page_to_nid(pfn_to_page())

2013-11-13T03:09:04Z

Use "pfn_to_nid(pfn)" instead of "page_to_nid(pfn_to_page(pfn))". Signed-off-by: Xishi Qiu Acked-by: Yasuaki Ishimatsu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/memory_hotplug.c: rename the function is_memblock_offlined_cb()

2013-11-13T03:09:04Z

A is_memblock_offlined() return or 1 means memory block is offlined, but is_memblock_offlined_cb() returning 1 means memory block is not offlined, this will confuse somebody, so rename the function. Signed-off-by: Xishi Qiu Acked-by: Yasuaki Ishimatsu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: use pgdat_end_pfn() to simplify the code in others

2013-11-13T03:09:03Z

Use "pgdat_end_pfn()" instead of "pgdat->node_start_pfn + pgdat->node_spanned_pages". Simplify the code, no functional change. Signed-off-by: Xishi Qiu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge tag 'pm+acpi-fixes-3.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

2013-09-12T18:22:45Z

Pull ACPI and power management fixes from Rafael Wysocki: "All of these commits are fixes that have emerged recently and some of them fix bugs introduced during this merge window. Specifics: 1) ACPI-based PCI hotplug (ACPIPHP) fixes related to spurious events After the recent ACPIPHP changes we've seen some interesting breakage on a system that triggers device check notifications during boot for non-existing devices. Although those notifications are really spurious, we should be able to deal with them nevertheless and that shouldn't introduce too much overhead. Four commits to make that work properly. 2) Memory hotplug and hibernation mutual exclusion rework This was maent to be a cleanup, but it happens to fix a classical ABBA deadlock between system suspend/hibernation and ACPI memory hotplug which is possible if they are started roughly at the same time. Three commits rework memory hotplug so that it doesn't acquire pm_mutex and make hibernation use device_hotplug_lock which prevents it from racing with memory hotplug. 3) ACPI Intel LPSS (Low-Power Subsystem) driver crash fix The ACPI LPSS driver crashes during boot on Apple Macbook Air with Haswell that has slightly unusual BIOS configuration in which one of the LPSS device's _CRS method doesn't return all of the information expected by the driver. Fix from Mika Westerberg, for stable. 4) ACPICA fix related to Store->ArgX operation AML interpreter fix for obscure breakage that causes AML to be executed incorrectly on some machines (observed in practice). From Bob Moore. 5) ACPI core fix for PCI ACPI device objects lookup There still are cases in which there is more than one ACPI device object matching a given PCI device and we don't choose the one that the BIOS expects us to choose, so this makes the lookup take more criteria into account in those cases. 6) Fix to prevent cpuidle from crashing in some rare cases If the result of cpuidle_get_driver() is NULL, which can happen on some systems, cpuidle_driver_ref() will crash trying to use that pointer and the Daniel Fu's fix prevents that from happening. 7) cpufreq fixes related to CPU hotplug Stephen Boyd reported a number of concurrency problems with cpufreq related to CPU hotplug which are addressed by a series of fixes from Srivatsa S Bhat and Viresh Kumar. 8) cpufreq fix for time conversion in time_in_state attribute Time conversion carried out by cpufreq when user space attempts to read /sys/devices/system/cpu/cpu*/cpufreq/stats/time_in_state won't work correcty if cputime_t doesn't map directly to jiffies. Fix from Andreas Schwab. 9) Revert of a troublesome cpufreq commit Commit 7c30ed5 (cpufreq: make sure frequency transitions are serialized) was intended to address some known concurrency problems in cpufreq related to the ordering of transitions, but unfortunately it introduced several problems of its own, so I decided to revert it now and address the original problems later in a more robust way. 10) Intel Haswell CPU models for intel_pstate from Nell Hardcastle. 11) cpufreq fixes related to system suspend/resume The recent cpufreq changes that made it preserve CPU sysfs attributes over suspend/resume cycles introduced a possible NULL pointer dereference that caused it to crash during the second attempt to suspend. Three commits from Srivatsa S Bhat fix that problem and a couple of related issues. 12) cpufreq locking fix cpufreq_policy_restore() should acquire the lock for reading, but it acquires it for writing. Fix from Lan Tianyu" * tag 'pm+acpi-fixes-3.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (25 commits) cpufreq: Acquire the lock in cpufreq_policy_restore() for reading cpufreq: Prevent problems in update_policy_cpu() if last_cpu == new_cpu cpufreq: Restructure if/else block to avoid unintended behavior cpufreq: Fix crash in cpufreq-stats during suspend/resume intel_pstate: Add Haswell CPU models Revert "cpufreq: make sure frequency transitions are serialized" cpufreq: Use signed type for 'ret' variable, to store negative error values cpufreq: Remove temporary fix for race between CPU hotplug and sysfs-writes cpufreq: Synchronize the cpufreq store_*() routines with CPU hotplug cpufreq: Invoke __cpufreq_remove_dev_finish() after releasing cpu_hotplug.lock cpufreq: Split __cpufreq_remove_dev() into two parts cpufreq: Fix wrong time unit conversion cpufreq: serialize calls to __cpufreq_governor() cpufreq: don't allow governor limits to be changed when it is disabled ACPI / bind: Prefer device objects with _STA to those without it ACPI / hotplug / PCI: Avoid parent bus rescans on spurious device checks ACPI / hotplug / PCI: Use _OST to notify firmware about notify status ACPI / hotplug / PCI: Avoid doing too much for spurious notifies ACPICA: Fix for a Store->ArgX when ArgX contains a reference to a field. ACPI / hotplug / PCI: Don't trim devices before scanning the namespace ...

mm: memory-hotplug: enable memory hotplug to handle hugepage

2013-09-11T22:57:48Z

Until now we can't offline memory blocks which contain hugepages because a hugepage is considered as an unmovable page. But now with this patch series, a hugepage has become movable, so by using hugepage migration we can offline such memory blocks. What's different from other users of hugepage migration is that we need to decompose all the hugepages inside the target memory block into free buddy pages after hugepage migration, because otherwise free hugepages remaining in the memory block intervene the memory offlining. For this reason we introduce new functions dissolve_free_huge_page() and dissolve_free_huge_pages(). Other than that, what this patch does is straightforwardly to add hugepage migration code, that is, adding hugepage code to the functions which scan over pfn and collect hugepages to be migrated, and adding a hugepage allocation function to alloc_migrate_target(). As for larger hugepages (1GB for x86_64), it's not easy to do hotremove over them because it's larger than memory block. So we now simply leave it to fail as it is. [yongjun_wei@trendmicro.com.cn: remove duplicated include] Signed-off-by: Naoya Horiguchi Acked-by: Andi Kleen Cc: Hillf Danton Cc: Wanpeng Li Cc: Mel Gorman Cc: Hugh Dickins Cc: KOSAKI Motohiro Cc: Michal Hocko Cc: Rik van Riel Cc: "Aneesh Kumar K.V" Signed-off-by: Wei Yongjun Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/hotplug: remove stop_machine() from try_offline_node()

2013-09-11T22:57:41Z

lock_device_hotplug() serializes hotplug & online/offline operations. The lock is held in common sysfs online/offline interfaces and ACPI hotplug code paths. And here are the code paths: - CPU & Mem online/offline via sysfs online store_online()->lock_device_hotplug() - Mem online via sysfs state: store_mem_state()->lock_device_hotplug() - ACPI CPU & Mem hot-add: acpi_scan_bus_device_check()->lock_device_hotplug() - ACPI CPU & Mem hot-delete: acpi_scan_hot_remove()->lock_device_hotplug() try_offline_node() off-lines a node if all memory sections and cpus are removed on the node. It is called from acpi_processor_remove() and acpi_memory_remove_memory()->remove_memory() paths, both of which are in the ACPI hotplug code. try_offline_node() calls stop_machine() to stop all cpus while checking all cpu status with the assumption that the caller is not protected from CPU hotplug or CPU online/offline operations. However, the caller is always serialized with lock_device_hotplug(). Also, the code needs to be properly serialized with a lock, not by stopping all cpus at a random place with stop_machine(). This patch removes the use of stop_machine() in try_offline_node() and adds comments to try_offline_node() and remove_memory() that lock_device_hotplug() is required. Signed-off-by: Toshi Kani Acked-by: Rafael J. Wysocki Cc: KOSAKI Motohiro Cc: KAMEZAWA Hiroyuki Cc: Tang Chen Cc: Yasuaki Ishimatsu Cc: Wanpeng Li Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/hotplug: verify hotplug memory range

2013-09-11T22:57:39Z

add_memory() and remove_memory() can only handle a memory range aligned with section. There are problems when an unaligned range is added and then deleted as follows: - add_memory() with an unaligned range succeeds, but __add_pages() called from add_memory() adds a whole section of pages even though a given memory range is less than the section size. - remove_memory() to the added unaligned range hits BUG_ON() in __remove_pages(). This patch changes add_memory() and remove_memory() to check if a given memory range is aligned with section at the beginning. As the result, add_memory() fails with -EINVAL when a given range is unaligned, and does not add such memory range. This prevents remove_memory() to be called with an unaligned range as well. Note that remove_memory() has to use BUG_ON() since this function cannot fail. [akpm@linux-foundation.org: avoid printk warnings] Signed-off-by: Toshi Kani Acked-by: KOSAKI Motohiro Reviewed-by: Tang Chen Reviewed-by: Wanpeng Li Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds