kernel/linux.git/include/linux/memory_hotplug.h, branch v5.7.3

mm/memory_hotplug: add pgprot_t to mhp_params

2020-04-10T22:36:21+00:00

devm_memremap_pages() is currently used by the PCI P2PDMA code to create struct page mappings for IO memory. At present, these mappings are created with PAGE_KERNEL which implies setting the PAT bits to be WB. However, on x86, an mtrr register will typically override this and force the cache type to be UC-. In the case firmware doesn't set this register it is effectively WB and will typically result in a machine check exception when it's accessed. Other arches are not currently likely to function correctly seeing they don't have any MTRR registers to fall back on. To solve this, provide a way to specify the pgprot value explicitly to arch_add_memory(). Of the arches that support MEMORY_HOTPLUG: x86_64, and arm64 need a simple change to pass the pgprot_t down to their respective functions which set up the page tables. For x86_32, set the page tables explicitly using _set_memory_prot() (seeing they are already mapped). For ia64, s390 and sh, reject anything but PAGE_KERNEL settings -- this should be fine, for now, seeing these architectures don't support ZONE_DEVICE. A check in __add_pages() is also added to ensure the pgprot parameter was set for all arches. Signed-off-by: Logan Gunthorpe Signed-off-by: Andrew Morton Acked-by: David Hildenbrand Acked-by: Michal Hocko Acked-by: Dan Williams Cc: Andy Lutomirski Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Catalin Marinas Cc: Christoph Hellwig Cc: Dave Hansen Cc: Eric Badger Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jason Gunthorpe Cc: Michael Ellerman Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Will Deacon Link: http://lkml.kernel.org/r/20200306170846.9333-7-logang@deltatee.com Signed-off-by: Linus Torvalds

mm/memory_hotplug: rename mhp_restrictions to mhp_params

2020-04-10T22:36:21+00:00

The mhp_restrictions struct really doesn't specify anything resembling a restriction anymore so rename it to be mhp_params as it is a list of extended parameters. Signed-off-by: Logan Gunthorpe Signed-off-by: Andrew Morton Reviewed-by: David Hildenbrand Reviewed-by: Dan Williams Acked-by: Michal Hocko Cc: Andy Lutomirski Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Catalin Marinas Cc: Christoph Hellwig Cc: Dave Hansen Cc: Eric Badger Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jason Gunthorpe Cc: Michael Ellerman Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Will Deacon Link: http://lkml.kernel.org/r/20200306170846.9333-3-logang@deltatee.com Signed-off-by: Linus Torvalds

mm/memory_hotplug: drop the flags field from struct mhp_restrictions

2020-04-10T22:36:21+00:00

Patch series "Allow setting caching mode in arch_add_memory() for P2PDMA", v4. Currently, the page tables created using memremap_pages() are always created with the PAGE_KERNEL cacheing mode. However, the P2PDMA code is creating pages for PCI BAR memory which should never be accessed through the cache and instead use either WC or UC. This still works in most cases, on x86, because the MTRR registers typically override the caching settings in the page tables for all of the IO memory to be UC-. However, this tends not to work so well on other arches or some rare x86 machines that have firmware which does not setup the MTRR registers in this way. Instead of this, this series proposes a change to arch_add_memory() to take the pgprot required by the mapping which allows us to explicitly set pagetable entries for P2PDMA memory to UC. This changes is pretty routine for most of the arches: x86_64, arm64 and powerpc simply need to thread the pgprot through to where the page tables are setup. x86_32 unfortunately sets up the page tables at boot so must use _set_memory_prot() to change their caching mode. ia64, s390 and sh don't appear to have an easy way to change the page tables so, for now at least, we just return -EINVAL on such mappings and thus they will not support P2PDMA memory until the work for this is done. This should be fine as they don't yet support ZONE_DEVICE. This patch (of 7): This variable is not used anywhere and should therefore be removed from the structure. Signed-off-by: Logan Gunthorpe Signed-off-by: Andrew Morton Reviewed-by: David Hildenbrand Reviewed-by: Dan Williams Acked-by: Michal Hocko Cc: Christoph Hellwig Cc: Catalin Marinas Cc: Will Deacon Cc: Benjamin Herrenschmidt Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: Andy Lutomirski Cc: Peter Zijlstra Cc: Eric Badger Cc: "H. Peter Anvin" Cc: Jason Gunthorpe Cc: Michael Ellerman Cc: Paul Mackerras Link: http://lkml.kernel.org/r/20200306170846.9333-2-logang@deltatee.com Signed-off-by: Linus Torvalds

mm/memory_hotplug: allow to specify a default online_type

2020-04-07T17:43:41+00:00

For now, distributions implement advanced udev rules to essentially - Don't online any hotplugged memory (s390x) - Online all memory to ZONE_NORMAL (e.g., most virt environments like hyperv) - Online all memory to ZONE_MOVABLE in case the zone imbalance is taken care of (e.g., bare metal, special virt environments) In summary: All memory is usually onlined the same way, however, the kernel always has to ask user space to come up with the same answer. E.g., Hyper-V always waits for a memory block to get onlined before continuing, otherwise it might end up adding memory faster than onlining it, which can result in strange OOM situations. This waiting slows down adding of a bigger amount of memory. Let's allow to specify a default online_type, not just "online" and "offline". This allows distributions to configure the default online_type when booting up and be done with it. We can now specify "offline", "online", "online_movable" and "online_kernel" via - "memhp_default_state=" on the kernel cmdline - /sys/devices/system/memory/auto_online_blocks just like we are able to specify for a single memory block via /sys/devices/system/memory/memoryX/state Signed-off-by: David Hildenbrand Signed-off-by: Andrew Morton Reviewed-by: Wei Yang Reviewed-by: Baoquan He Acked-by: Michal Hocko Acked-by: Pankaj Gupta Cc: Greg Kroah-Hartman Cc: Oscar Salvador Cc: "Rafael J. Wysocki" Cc: Wei Yang Cc: Benjamin Herrenschmidt Cc: Eduardo Habkost Cc: Haiyang Zhang Cc: Igor Mammedov Cc: "K. Y. Srinivasan" Cc: Michael Ellerman Cc: Paul Mackerras Cc: Stephen Hemminger Cc: Vitaly Kuznetsov Cc: Wei Liu Cc: Yumei Huang Link: http://lkml.kernel.org/r/20200317104942.11178-9-david@redhat.com Signed-off-by: Linus Torvalds

mm/memory_hotplug: convert memhp_auto_online to store an online_type

2020-04-07T17:43:40+00:00

... and rename it to memhp_default_online_type. This is a preparation for more detailed default online behavior. Signed-off-by: David Hildenbrand Signed-off-by: Andrew Morton Reviewed-by: Wei Yang Reviewed-by: Baoquan He Acked-by: Michal Hocko Acked-by: Pankaj Gupta Cc: Greg Kroah-Hartman Cc: Oscar Salvador Cc: "Rafael J. Wysocki" Cc: Wei Yang Cc: Benjamin Herrenschmidt Cc: Eduardo Habkost Cc: Haiyang Zhang Cc: Igor Mammedov Cc: "K. Y. Srinivasan" Cc: Michael Ellerman Cc: Paul Mackerras Cc: Stephen Hemminger Cc: Vitaly Kuznetsov Cc: Wei Liu Cc: Yumei Huang Link: http://lkml.kernel.org/r/20200317104942.11178-8-david@redhat.com Signed-off-by: Linus Torvalds

drivers/base/memory: map MMOP_OFFLINE to 0

2020-04-07T17:43:40+00:00

Historically, we used the value -1. Just treat 0 as the special case now. Clarify a comment (which was wrong, when we come via device_online() the first time, the online_type would have been 0 / MEM_ONLINE). The default is now always MMOP_OFFLINE. This removes the last user of the manual "-1", which didn't use the enum value. This is a preparation to use the online_type as an array index. Signed-off-by: David Hildenbrand Signed-off-by: Andrew Morton Reviewed-by: Wei Yang Reviewed-by: Baoquan He Acked-by: Michal Hocko Acked-by: Pankaj Gupta Cc: Greg Kroah-Hartman Cc: Oscar Salvador Cc: "Rafael J. Wysocki" Cc: Wei Yang Cc: Benjamin Herrenschmidt Cc: Eduardo Habkost Cc: Haiyang Zhang Cc: Igor Mammedov Cc: "K. Y. Srinivasan" Cc: Michael Ellerman Cc: Paul Mackerras Cc: Stephen Hemminger Cc: Vitaly Kuznetsov Cc: Wei Liu Cc: Yumei Huang Link: http://lkml.kernel.org/r/20200317104942.11178-3-david@redhat.com Signed-off-by: Linus Torvalds

drivers/base/memory: rename MMOP_ONLINE_KEEP to MMOP_ONLINE

2020-04-07T17:43:40+00:00

Patch series "mm/memory_hotplug: allow to specify a default online_type", v3. Distributions nowadays use udev rules ([1] [2]) to specify if and how to online hotplugged memory. The rules seem to get more complex with many special cases. Due to the various special cases, CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE cannot be used. All memory hotplug is handled via udev rules. Every time we hotplug memory, the udev rule will come to the same conclusion. Especially Hyper-V (but also soon virtio-mem) add a lot of memory in separate memory blocks and wait for memory to get onlined by user space before continuing to add more memory blocks (to not add memory faster than it is getting onlined). This of course slows down the whole memory hotplug process. To make the job of distributions easier and to avoid udev rules that get more and more complicated, let's extend the mechanism provided by - /sys/devices/system/memory/auto_online_blocks - "memhp_default_state=" on the kernel cmdline to be able to specify also "online_movable" as well as "online_kernel" === Example /usr/libexec/config-memhotplug === #!/bin/bash VIRT=`systemd-detect-virt --vm` ARCH=`uname -p` sense_virtio_mem() { if [ -d "/sys/bus/virtio/drivers/virtio_mem/" ]; then DEVICES=`find /sys/bus/virtio/drivers/virtio_mem/ -maxdepth 1 -type l | wc -l` if [ $DEVICES != "0" ]; then return 0 fi fi return 1 } if [ ! -e "/sys/devices/system/memory/auto_online_blocks" ]; then echo "Memory hotplug configuration support missing in the kernel" exit 1 fi if grep "memhp_default_state=" /proc/cmdline > /dev/null; then echo "Memory hotplug configuration overridden in kernel cmdline (memhp_default_state=)" exit 1 fi if [ $VIRT == "microsoft" ]; then echo "Detected Hyper-V on $ARCH" # Hyper-V wants all memory in ZONE_NORMAL ONLINE_TYPE="online_kernel" elif sense_virtio_mem; then echo "Detected virtio-mem on $ARCH" # virtio-mem wants all memory in ZONE_NORMAL ONLINE_TYPE="online_kernel" elif [ $ARCH == "s390x" ] || [ $ARCH == "s390" ]; then echo "Detected $ARCH" # standby memory should not be onlined automatically ONLINE_TYPE="offline" elif [ $ARCH == "ppc64" ] || [ $ARCH == "ppc64le" ]; then echo "Detected" $ARCH # PPC64 onlines all hotplugged memory right from the kernel ONLINE_TYPE="offline" elif [ $VIRT == "none" ]; then echo "Detected bare-metal on $ARCH" # Bare metal users expect hotplugged memory to be unpluggable. We assume # that ZONE imbalances on such enterpise servers cannot happen and is # properly documented ONLINE_TYPE="online_movable" else # TODO: Hypervisors that want to unplug DIMMs and can guarantee that ZONE # imbalances won't happen echo "Detected $VIRT on $ARCH" # Usually, ballooning is used in virtual environments, so memory should go to # ZONE_NORMAL. However, sometimes "movable_node" is relevant. ONLINE_TYPE="online" fi echo "Selected online_type:" $ONLINE_TYPE # Configure what to do with memory that will be hotplugged in the future echo $ONLINE_TYPE 2>/dev/null > /sys/devices/system/memory/auto_online_blocks if [ $? != "0" ]; then echo "Memory hotplug cannot be configured (e.g., old kernel or missing permissions)" # A backup udev rule should handle old kernels if necessary exit 1 fi # Process all already pluggedd blocks (e.g., DIMMs, but also Hyper-V or virtio-mem) if [ $ONLINE_TYPE != "offline" ]; then for MEMORY in /sys/devices/system/memory/memory*; do STATE=`cat $MEMORY/state` if [ $STATE == "offline" ]; then echo $ONLINE_TYPE > $MEMORY/state fi done fi === Example /usr/lib/systemd/system/config-memhotplug.service === [Unit] Description=Configure memory hotplug behavior DefaultDependencies=no Conflicts=shutdown.target Before=sysinit.target shutdown.target After=systemd-modules-load.service ConditionPathExists=|/sys/devices/system/memory/auto_online_blocks [Service] ExecStart=/usr/libexec/config-memhotplug Type=oneshot TimeoutSec=0 RemainAfterExit=yes [Install] WantedBy=sysinit.target === Example modification to the 40-redhat.rules [2] === : diff --git a/40-redhat.rules b/40-redhat.rules-new : index 2c690e5..168fd03 100644 : --- a/40-redhat.rules : +++ b/40-redhat.rules-new : @@ -6,6 +6,9 @@ SUBSYSTEM=="cpu", ACTION=="add", TEST=="online", ATTR{online}=="0", ATTR{online} : # Memory hotadd request : SUBSYSTEM!="memory", GOTO="memory_hotplug_end" : ACTION!="add", GOTO="memory_hotplug_end" : +# memory hotplug behavior configured : +PROGRAM=="grep online /sys/devices/system/memory/auto_online_blocks", GOTO="memory_hotplug_end" : + : PROGRAM="/bin/uname -p", RESULT=="s390*", GOTO="memory_hotplug_end" : : ENV{.state}="online" === [1] https://github.com/lnykryn/systemd-rhel/pull/281 [2] https://github.com/lnykryn/systemd-rhel/blob/staging/rules/40-redhat.rules This patch (of 8): The name is misleading and it's not really clear what is "kept". Let's just name it like the online_type name we expose to user space ("online"). Add some documentation to the types. Signed-off-by: David Hildenbrand Signed-off-by: Andrew Morton Reviewed-by: Wei Yang Reviewed-by: Baoquan He Acked-by: Pankaj Gupta Cc: Greg Kroah-Hartman Cc: Michal Hocko Cc: Oscar Salvador Cc: "Rafael J. Wysocki" Cc: Wei Yang Cc: Vitaly Kuznetsov Cc: Yumei Huang Cc: Igor Mammedov Cc: Eduardo Habkost Cc: Benjamin Herrenschmidt Cc: Haiyang Zhang Cc: K. Y. Srinivasan Cc: Michael Ellerman (powerpc) Cc: Paul Mackerras Cc: Stephen Hemminger Cc: Wei Liu Link: http://lkml.kernel.org/r/20200319131221.14044-1-david@redhat.com Link: http://lkml.kernel.org/r/20200317104942.11178-2-david@redhat.com Signed-off-by: Linus Torvalds

mm/memory_hotplug: drop valid_start/valid_end from test_pages_in_a_zone()

2020-02-04T03:05:23+00:00

The callers are only interested in the actual zone, they don't care about boundaries. Return the zone instead to simplify. Link: http://lkml.kernel.org/r/20200110183308.11849-1-david@redhat.com Signed-off-by: David Hildenbrand Cc: Greg Kroah-Hartman Cc: "Rafael J. Wysocki" Cc: Michal Hocko Cc: Oscar Salvador Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/memory_hotplug: pass in nid to online_pages()

2020-01-31T18:30:39+00:00

Patch series "mm/memory_hotplug: pass in nid to online_pages()". Simplify onlining code and get rid of find_memory_block(). Pass in the nid from the memory block we are trying to online directly, instead of manually looking it up. This patch (of 2): No need to lookup the memory block, we can directly pass in the nid. Link: http://lkml.kernel.org/r/20200113113354.6341-2-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Andrew Morton Cc: Greg Kroah-Hartman Cc: "Rafael J. Wysocki" Cc: Michal Hocko Cc: Oscar Salvador Cc: Anshuman Khandual Cc: Dan Williams Cc: Pavel Tatashin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/memory_hotplug: shrink zones when offlining memory

2020-01-04T21:55:08+00:00

We currently try to shrink a single zone when removing memory. We use the zone of the first page of the memory we are removing. If that memmap was never initialized (e.g., memory was never onlined), we will read garbage and can trigger kernel BUGs (due to a stale pointer): BUG: unable to handle page fault for address: 000000000000353d #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP PTI CPU: 1 PID: 7 Comm: kworker/u8:0 Not tainted 5.3.0-rc5-next-20190820+ #317 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.4 Workqueue: kacpi_hotplug acpi_hotplug_work_fn RIP: 0010:clear_zone_contiguous+0x5/0x10 Code: 48 89 c6 48 89 c3 e8 2a fe ff ff 48 85 c0 75 cf 5b 5d c3 c6 85 fd 05 00 00 01 5b 5d c3 0f 1f 840 RSP: 0018:ffffad2400043c98 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000200000000 RCX: 0000000000000000 RDX: 0000000000200000 RSI: 0000000000140000 RDI: 0000000000002f40 RBP: 0000000140000000 R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000140000 R13: 0000000000140000 R14: 0000000000002f40 R15: ffff9e3e7aff3680 FS: 0000000000000000(0000) GS:ffff9e3e7bb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000000353d CR3: 0000000058610000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __remove_pages+0x4b/0x640 arch_remove_memory+0x63/0x8d try_remove_memory+0xdb/0x130 __remove_memory+0xa/0x11 acpi_memory_device_remove+0x70/0x100 acpi_bus_trim+0x55/0x90 acpi_device_hotplug+0x227/0x3a0 acpi_hotplug_work_fn+0x1a/0x30 process_one_work+0x221/0x550 worker_thread+0x50/0x3b0 kthread+0x105/0x140 ret_from_fork+0x3a/0x50 Modules linked in: CR2: 000000000000353d Instead, shrink the zones when offlining memory or when onlining failed. Introduce and use remove_pfn_range_from_zone(() for that. We now properly shrink the zones, even if we have DIMMs whereby - Some memory blocks fall into no zone (never onlined) - Some memory blocks fall into multiple zones (offlined+re-onlined) - Multiple memory blocks that fall into different zones Drop the zone parameter (with a potential dubious value) from __remove_pages() and __remove_section(). Link: http://lkml.kernel.org/r/20191006085646.5768-6-david@redhat.com Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online") [visible after d0dc12e86b319] Signed-off-by: David Hildenbrand Reviewed-by: Oscar Salvador Cc: Michal Hocko Cc: "Matthew Wilcox (Oracle)" Cc: "Aneesh Kumar K.V" Cc: Pavel Tatashin Cc: Greg Kroah-Hartman Cc: Dan Williams Cc: Logan Gunthorpe Cc: [5.0+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds