user/sven/linux.git/include/linux/memory_hotplug.h, branch v4.13.10

mm, memory_hotplug: move movable_node to the hotplug proper

2017-07-06T23:24:35Z

movable_node_is_enabled is defined in memblock proper while it is initialized from the memory hotplug proper. This is quite messy and it makes a dependency between the two so move movable_node along with the helper functions to memory_hotplug. To make it more entertaining the kernel parameter is ignored unless CONFIG_HAVE_MEMBLOCK_NODE_MAP=y because we do not have the node information for each memblock otherwise. So let's warn when the option is disabled. Link: http://lkml.kernel.org/r/20170529114141.536-4-mhocko@kernel.org Signed-off-by: Michal Hocko Acked-by: Reza Arbab Acked-by: Vlastimil Babka Cc: Mel Gorman Cc: Andrea Arcangeli Cc: Jerome Glisse Cc: Yasuaki Ishimatsu Cc: Xishi Qiu Cc: Kani Toshimitsu Cc: Chen Yucong Cc: Joonsoo Kim Cc: Andi Kleen Cc: David Rientjes Cc: Daniel Kiper Cc: Igor Mammedov Cc: Vitaly Kuznetsov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm, memory_hotplug: remove unused cruft after memory hotplug rework

2017-07-06T23:24:32Z

zone_for_memory doesn't have any user anymore as well as the whole zone shifting infrastructure so drop them all. This shouldn't introduce any functional changes. Link: http://lkml.kernel.org/r/20170515085827.16474-15-mhocko@kernel.org Signed-off-by: Michal Hocko Acked-by: Vlastimil Babka Cc: Andi Kleen Cc: Andrea Arcangeli Cc: Balbir Singh Cc: Dan Williams Cc: Daniel Kiper Cc: David Rientjes Cc: Heiko Carstens Cc: Igor Mammedov Cc: Jerome Glisse Cc: Joonsoo Kim Cc: Martin Schwidefsky Cc: Mel Gorman Cc: Reza Arbab Cc: Tobias Regnery Cc: Toshi Kani Cc: Vitaly Kuznetsov Cc: Xishi Qiu Cc: Yasuaki Ishimatsu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm, memory_hotplug: replace for_device by want_memblock in arch_add_memory

2017-07-06T23:24:32Z

arch_add_memory gets for_device argument which then controls whether we want to create memblocks for created memory sections. Simplify the logic by telling whether we want memblocks directly rather than going through pointless negation. This also makes the api easier to understand because it is clear what we want rather than nothing telling for_device which can mean anything. This shouldn't introduce any functional change. Link: http://lkml.kernel.org/r/20170515085827.16474-13-mhocko@kernel.org Signed-off-by: Michal Hocko Tested-by: Dan Williams Acked-by: Vlastimil Babka Cc: Andi Kleen Cc: Andrea Arcangeli Cc: Balbir Singh Cc: Daniel Kiper Cc: David Rientjes Cc: Heiko Carstens Cc: Igor Mammedov Cc: Jerome Glisse Cc: Joonsoo Kim Cc: Martin Schwidefsky Cc: Mel Gorman Cc: Reza Arbab Cc: Tobias Regnery Cc: Toshi Kani Cc: Vitaly Kuznetsov Cc: Xishi Qiu Cc: Yasuaki Ishimatsu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm, memory_hotplug: do not assume ZONE_NORMAL is default kernel zone

2017-07-06T23:24:32Z

Heiko Carstens has noticed that he can generate overlapping zones for ZONE_DMA and ZONE_NORMAL: DMA [mem 0x0000000000000000-0x000000007fffffff] Normal [mem 0x0000000080000000-0x000000017fffffff] $ cat /sys/devices/system/memory/block_size_bytes 10000000 $ cat /sys/devices/system/memory/memory5/valid_zones DMA $ echo 0 > /sys/devices/system/memory/memory5/online $ cat /sys/devices/system/memory/memory5/valid_zones Normal $ echo 1 > /sys/devices/system/memory/memory5/online Normal $ cat /proc/zoneinfo Node 0, zone DMA spanned 524288 <----- present 458752 managed 455078 start_pfn: 0 <----- Node 0, zone Normal spanned 720896 present 589824 managed 571648 start_pfn: 327680 <----- The reason is that we assume that the default zone for kernel onlining is ZONE_NORMAL. This was a simplification introduced by the memory hotplug rework and it is easily fixable by checking the range overlap in the zone order and considering the first matching zone as the default one. If there is no such zone then assume ZONE_NORMAL as we have been doing so far. Fixes: "mm, memory_hotplug: do not associate hotadded memory to zones until online" Link: http://lkml.kernel.org/r/20170601083746.4924-3-mhocko@kernel.org Signed-off-by: Michal Hocko Reported-by: Heiko Carstens Tested-by: Heiko Carstens Acked-by: Vlastimil Babka Cc: Dan Williams Cc: Reza Arbab Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm, memory_hotplug: do not associate hotadded memory to zones until online

2017-07-06T23:24:32Z

The current memory hotplug implementation relies on having all the struct pages associate with a zone/node during the physical hotplug phase (arch_add_memory->__add_pages->__add_section->__add_zone). In the vast majority of cases this means that they are added to ZONE_NORMAL. This has been so since 9d99aaa31f59 ("[PATCH] x86_64: Support memory hotadd without sparsemem") and it wasn't a big deal back then because movable onlining didn't exist yet. Much later memory hotplug wanted to (ab)use ZONE_MOVABLE for movable onlining 511c2aba8f07 ("mm, memory-hotplug: dynamic configure movable memory and portion memory") and then things got more complicated. Rather than reconsidering the zone association which was no longer needed (because the memory hotplug already depended on SPARSEMEM) a convoluted semantic of zone shifting has been developed. Only the currently last memblock or the one adjacent to the zone_movable can be onlined movable. This essentially means that the online type changes as the new memblocks are added. Let's simulate memory hot online manually $ echo 0x100000000 > /sys/devices/system/memory/probe $ grep . /sys/devices/system/memory/memory32/valid_zones Normal Movable $ echo $((0x100000000+(128<<20))) > /sys/devices/system/memory/probe $ grep . /sys/devices/system/memory/memory3?/valid_zones /sys/devices/system/memory/memory32/valid_zones:Normal /sys/devices/system/memory/memory33/valid_zones:Normal Movable $ echo $((0x100000000+2*(128<<20))) > /sys/devices/system/memory/probe $ grep . /sys/devices/system/memory/memory3?/valid_zones /sys/devices/system/memory/memory32/valid_zones:Normal /sys/devices/system/memory/memory33/valid_zones:Normal /sys/devices/system/memory/memory34/valid_zones:Normal Movable $ echo online_movable > /sys/devices/system/memory/memory34/state $ grep . /sys/devices/system/memory/memory3?/valid_zones /sys/devices/system/memory/memory32/valid_zones:Normal /sys/devices/system/memory/memory33/valid_zones:Normal Movable /sys/devices/system/memory/memory34/valid_zones:Movable Normal This is an awkward semantic because an udev event is sent as soon as the block is onlined and an udev handler might want to online it based on some policy (e.g. association with a node) but it will inherently race with new blocks showing up. This patch changes the physical online phase to not associate pages with any zone at all. All the pages are just marked reserved and wait for the onlining phase to be associated with the zone as per the online request. There are only two requirements - existing ZONE_NORMAL and ZONE_MOVABLE cannot overlap - ZONE_NORMAL precedes ZONE_MOVABLE in physical addresses the latter one is not an inherent requirement and can be changed in the future. It preserves the current behavior and made the code slightly simpler. This is subject to change in future. This means that the same physical online steps as above will lead to the following state: Normal Movable /sys/devices/system/memory/memory32/valid_zones:Normal Movable /sys/devices/system/memory/memory33/valid_zones:Normal Movable /sys/devices/system/memory/memory32/valid_zones:Normal Movable /sys/devices/system/memory/memory33/valid_zones:Normal Movable /sys/devices/system/memory/memory34/valid_zones:Normal Movable /sys/devices/system/memory/memory32/valid_zones:Normal Movable /sys/devices/system/memory/memory33/valid_zones:Normal Movable /sys/devices/system/memory/memory34/valid_zones:Movable Implementation: The current move_pfn_range is reimplemented to check the above requirements (allow_online_pfn_range) and then updates the respective zone (move_pfn_range_to_zone), the pgdat and links all the pages in the pfn range with the zone/node. __add_pages is updated to not require the zone and only initializes sections in the range. This allowed to simplify the arch_add_memory code (s390 could get rid of quite some of code). devm_memremap_pages is the only user of arch_add_memory which relies on the zone association because it only hooks into the memory hotplug only half way. It uses it to associate the new memory with ZONE_DEVICE but doesn't allow it to be {on,off}lined via sysfs. This means that this particular code path has to call move_pfn_range_to_zone explicitly. The original zone shifting code is kept in place and will be removed in the follow up patch for an easier review. Please note that this patch also changes the original behavior when offlining a memory block adjacent to another zone (Normal vs. Movable) used to allow to change its movable type. This will be handled later. [richard.weiyang@gmail.com: simplify zone_intersects()] Link: http://lkml.kernel.org/r/20170616092335.5177-1-richard.weiyang@gmail.com [richard.weiyang@gmail.com: remove duplicate call for set_page_links] Link: http://lkml.kernel.org/r/20170616092335.5177-2-richard.weiyang@gmail.com [akpm@linux-foundation.org: remove unused local `i'] Link: http://lkml.kernel.org/r/20170515085827.16474-12-mhocko@kernel.org Signed-off-by: Michal Hocko Signed-off-by: Wei Yang Tested-by: Dan Williams Tested-by: Reza Arbab Acked-by: Heiko Carstens # For s390 bits Acked-by: Vlastimil Babka Cc: Martin Schwidefsky Cc: Andi Kleen Cc: Andrea Arcangeli Cc: Balbir Singh Cc: Daniel Kiper Cc: David Rientjes Cc: Igor Mammedov Cc: Jerome Glisse Cc: Joonsoo Kim Cc: Mel Gorman Cc: Tobias Regnery Cc: Toshi Kani Cc: Vitaly Kuznetsov Cc: Xishi Qiu Cc: Yasuaki Ishimatsu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: consider zone which is not fully populated to have holes

2017-07-06T23:24:32Z

__pageblock_pfn_to_page has two users currently, set_zone_contiguous which checks whether the given zone contains holes and pageblock_pfn_to_page which then carefully returns a first valid page from the given pfn range for the given zone. This doesn't handle zones which are not fully populated though. Memory pageblocks can be offlined or might not have been onlined yet. In such a case the zone should be considered to have holes otherwise pfn walkers can touch and play with offline pages. Current callers of pageblock_pfn_to_page in compaction seem to work properly right now because they only isolate PageBuddy (isolate_freepages_block) or PageLRU resp. __PageMovable (isolate_migratepages_block) which will be always false for these pages. It would be safer to skip these pages altogether, though. In order to do this patch adds a new memory section state (SECTION_IS_ONLINE) which is set in memory_present (during boot time) or in online_pages_range during the memory hotplug. Similarly offline_mem_sections clears the bit and it is called when the memory range is offlined. pfn_to_online_page helper is then added which check the mem section and only returns a page if it is onlined already. Use the new helper in __pageblock_pfn_to_page and skip the whole page block in such a case. [mhocko@suse.com: check valid section number in pfn_to_online_page (Vlastimil), mark sections online after all struct pages are initialized in online_pages_range (Vlastimil)] Link: http://lkml.kernel.org/r/20170518164210.GD18333@dhcp22.suse.cz Link: http://lkml.kernel.org/r/20170515085827.16474-8-mhocko@kernel.org Signed-off-by: Michal Hocko Acked-by: Vlastimil Babka Cc: Andi Kleen Cc: Andrea Arcangeli Cc: Balbir Singh Cc: Dan Williams Cc: Daniel Kiper Cc: David Rientjes Cc: Heiko Carstens Cc: Igor Mammedov Cc: Jerome Glisse Cc: Joonsoo Kim Cc: Martin Schwidefsky Cc: Mel Gorman Cc: Reza Arbab Cc: Tobias Regnery Cc: Toshi Kani Cc: Vitaly Kuznetsov Cc: Xishi Qiu Cc: Yasuaki Ishimatsu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm, memory_hotplug: get rid of is_zone_device_section

2017-07-06T23:24:32Z

Device memory hotplug hooks into regular memory hotplug only half way. It needs memory sections to track struct pages but there is no need/desire to associate those sections with memory blocks and export them to the userspace via sysfs because they cannot be onlined anyway. This is currently expressed by for_device argument to arch_add_memory which then makes sure to associate the given memory range with ZONE_DEVICE. register_new_memory then relies on is_zone_device_section to distinguish special memory hotplug from the regular one. While this works now, later patches in this series want to move __add_zone outside of arch_add_memory path so we have to come up with something else. Add want_memblock down the __add_pages path and use it to control whether the section->memblock association should be done. arch_add_memory then just trivially want memblock for everything but for_device hotplug. remove_memory_section doesn't need is_zone_device_section either. We can simply skip all the memblock specific cleanup if there is no memblock for the given section. This shouldn't introduce any functional change. Link: http://lkml.kernel.org/r/20170515085827.16474-5-mhocko@kernel.org Signed-off-by: Michal Hocko Tested-by: Dan Williams Acked-by: Vlastimil Babka Cc: Andi Kleen Cc: Andrea Arcangeli Cc: Balbir Singh Cc: Daniel Kiper Cc: David Rientjes Cc: Heiko Carstens Cc: Igor Mammedov Cc: Jerome Glisse Cc: Joonsoo Kim Cc: Martin Schwidefsky Cc: Mel Gorman Cc: Reza Arbab Cc: Tobias Regnery Cc: Toshi Kani Cc: Vitaly Kuznetsov Cc: Xishi Qiu Cc: Yasuaki Ishimatsu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

base/memory, hotplug: fix a kernel oops in show_valid_zones()

2017-02-03T22:13:19Z

Reading a sysfs "memoryN/valid_zones" file leads to the following oops when the first page of a range is not backed by struct page. show_valid_zones() assumes that 'start_pfn' is always valid for page_zone(). BUG: unable to handle kernel paging request at ffffea017a000000 IP: show_valid_zones+0x6f/0x160 This issue may happen on x86-64 systems with 64GiB or more memory since their memory block size is bumped up to 2GiB. [1] An example of such systems is desribed below. 0x3240000000 is only aligned by 1GiB and this memory block starts from 0x3200000000, which is not backed by struct page. BIOS-e820: [mem 0x0000003240000000-0x000000603fffffff] usable Since test_pages_in_a_zone() already checks holes, fix this issue by extending this function to return 'valid_start' and 'valid_end' for a given range. show_valid_zones() then proceeds with the valid range. [1] 'Commit bdee237c0343 ("x86: mm: Use 2GB memory block size on large-memory x86-64 systems")' Link: http://lkml.kernel.org/r/20170127222149.30893-3-toshi.kani@hpe.com Signed-off-by: Toshi Kani Cc: Greg Kroah-Hartman Cc: Zhang Zhen Cc: Reza Arbab Cc: David Rientjes Cc: Dan Williams Cc: [4.4+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

memory_hotplug: make zone_can_shift() return a boolean value

2017-01-25T00:26:14Z

online_{kernel|movable} is used to change the memory zone to ZONE_{NORMAL|MOVABLE} and online the memory. To check that memory zone can be changed, zone_can_shift() is used. Currently the function returns minus integer value, plus integer value and 0. When the function returns minus or plus integer value, it means that the memory zone can be changed to ZONE_{NORNAL|MOVABLE}. But when the function returns 0, there are two meanings. One of the meanings is that the memory zone does not need to be changed. For example, when memory is in ZONE_NORMAL and onlined by online_kernel the memory zone does not need to be changed. Another meaning is that the memory zone cannot be changed. When memory is in ZONE_NORMAL and onlined by online_movable, the memory zone may not be changed to ZONE_MOVALBE due to memory online limitation(see Documentation/memory-hotplug.txt). In this case, memory must not be onlined. The patch changes the return type of zone_can_shift() so that memory online operation fails when memory zone cannot be changed as follows: Before applying patch: # grep -A 35 "Node 2" /proc/zoneinfo Node 2, zone Normal node_scanned 0 spanned 8388608 present 7864320 managed 7864320 # echo online_movable > memory4097/state # grep -A 35 "Node 2" /proc/zoneinfo Node 2, zone Normal node_scanned 0 spanned 8388608 present 8388608 managed 8388608 online_movable operation succeeded. But memory is onlined as ZONE_NORMAL, not ZONE_MOVABLE. After applying patch: # grep -A 35 "Node 2" /proc/zoneinfo Node 2, zone Normal node_scanned 0 spanned 8388608 present 7864320 managed 7864320 # echo online_movable > memory4097/state bash: echo: write error: Invalid argument # grep -A 35 "Node 2" /proc/zoneinfo Node 2, zone Normal node_scanned 0 spanned 8388608 present 7864320 managed 7864320 online_movable operation failed because of failure of changing the memory zone from ZONE_NORMAL to ZONE_MOVABLE Fixes: df429ac03936 ("memory-hotplug: more general validation of zone during online") Link: http://lkml.kernel.org/r/2f9c3837-33d7-b6e5-59c0-6ca4372b2d84@gmail.com Signed-off-by: Yasuaki Ishimatsu Reviewed-by: Reza Arbab Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

memory-hotplug: more general validation of zone during online

2016-07-26T23:19:19Z

When memory is onlined, we are only able to rezone from ZONE_MOVABLE to ZONE_KERNEL, or from (ZONE_MOVABLE - 1) to ZONE_MOVABLE. To be more flexible, use the following criteria instead; to online memory from zone X into zone Y, * Any zones between X and Y must be unused. * If X is lower than Y, the onlined memory must lie at the end of X. * If X is higher than Y, the onlined memory must lie at the start of X. Add zone_can_shift() to make this determination. Link: http://lkml.kernel.org/r/1462816419-4479-3-git-send-email-arbab@linux.vnet.ibm.com Signed-off-by: Reza Arbab Reviewd-by: Yasuaki Ishimatsu Cc: Greg Kroah-Hartman Cc: Daniel Kiper Cc: Dan Williams Cc: Vlastimil Babka Cc: Tang Chen Cc: Joonsoo Kim Cc: David Vrabel Cc: Vitaly Kuznetsov Cc: David Rientjes Cc: Andrew Banman Cc: Chen Yucong Cc: Yasunori Goto Cc: Zhang Zhen Cc: Shaohua Li Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds