kernel/drivers/base/node.c, branch linux-6.5.y

Merge tag 'driver-core-6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2023-07-03T19:56:23Z

Pull driver core updates from Greg KH: "Here are a small set of changes for 6.5-rc1 for some driver core changes. Included in here are: - device property cleanups to make it easier to write "agnostic" drivers when regards to the firmware layer underneath them (DT vs. ACPI) - debugfs documentation updates - devres additions - sysfs documentation and changes to handle empty directory creation logic better - tiny kernfs optimizations - other tiny changes All of these have been in linux-next for a while with no reported problems" * tag 'driver-core-6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: sysfs: Skip empty folders creation sysfs: Improve readability by following the kernel coding style drivers: fwnode: fix fwnode_irq_get[_byname]() ata: ahci_platform: Make code agnostic to OF/ACPI device property: Implement device_is_compatible() ACPI: Move ACPI_DEVICE_CLASS() to mod_devicetable.h base/node: Use 'property' to identify an access parameter driver core: device.h: add some missing kerneldocs kernfs: fix missing kernfs_idr_lock to remove an ID from the IDR isa: Remove unnecessary checks MAINTAINERS: add entry for auxiliary bus debugfs: Correct the 'debugfs_create_str' docs serial: qcom_geni: Comment use of devm_krealloc rather than devm_krealloc_array iio: adc: Use devm_krealloc_array hwmon: pmbus: Use devm_krealloc_array

mm: Add support for unaccepted memory

2023-06-06T14:38:22Z

UEFI Specification version 2.9 introduces the concept of memory acceptance. Some Virtual Machine platforms, such as Intel TDX or AMD SEV-SNP, require memory to be accepted before it can be used by the guest. Accepting happens via a protocol specific to the Virtual Machine platform. There are several ways the kernel can deal with unaccepted memory: 1. Accept all the memory during boot. It is easy to implement and it doesn't have runtime cost once the system is booted. The downside is very long boot time. Accept can be parallelized to multiple CPUs to keep it manageable (i.e. via DEFERRED_STRUCT_PAGE_INIT), but it tends to saturate memory bandwidth and does not scale beyond the point. 2. Accept a block of memory on the first use. It requires more infrastructure and changes in page allocator to make it work, but it provides good boot time. On-demand memory accept means latency spikes every time kernel steps onto a new memory block. The spikes will go away once workload data set size gets stabilized or all memory gets accepted. 3. Accept all memory in background. Introduce a thread (or multiple) that gets memory accepted proactively. It will minimize time the system experience latency spikes on memory allocation while keeping low boot time. This approach cannot function on its own. It is an extension of #2: background memory acceptance requires functional scheduler, but the page allocator may need to tap into unaccepted memory before that. The downside of the approach is that these threads also steal CPU cycles and memory bandwidth from the user's workload and may hurt user experience. Implement #1 and #2 for now. #2 is the default. Some workloads may want to use #1 with accept_memory=eager in kernel command line. #3 can be implemented later based on user's demands. Support of unaccepted memory requires a few changes in core-mm code: - memblock accepts memory on allocation. It serves early boot memory allocations and doesn't limit them to pre-accepted pool of memory. - page allocator accepts memory on the first allocation of the page. When kernel runs out of accepted memory, it accepts memory until the high watermark is reached. It helps to minimize fragmentation. EFI code will provide two helpers if the platform supports unaccepted memory: - accept_memory() makes a range of physical addresses accepted. - range_contains_unaccepted_memory() checks anything within the range of physical addresses requires acceptance. Signed-off-by: Kirill A. Shutemov Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Vlastimil Babka Acked-by: Mike Rapoport # memblock Link: https://lore.kernel.org/r/20230606142637.5171-2-kirill.shutemov@linux.intel.com

base/node: Use 'property' to identify an access parameter

2023-05-31T19:26:00Z

Usage of 'attr' and 'name' in the context of a sysfs attribute definition are confusing because those read as being related to: struct attribute .name Rename 'name' to 'property' in preparation for renaming 'struct node_hmem_attr' to a more generic name that can be used in more contexts ('struct access_coordinate'), and not be confused with 'struct attribute'. Suggested-by: Dan Williams Reviewed-by: Dan Williams Signed-off-by: Dave Jiang Link: https://lore.kernel.org/r/168332213518.2189163.18377767521423011290.stgit@djiang5-mobl3 Signed-off-by: Greg Kroah-Hartman

mm: memory-failure: add memory failure stats to sysfs

2023-02-03T06:33:28Z

Patch series "Introduce per NUMA node memory error statistics", v2. Background ========== In the RFC for Kernel Support of Memory Error Detection [1], one advantage of software-based scanning over hardware patrol scrubber is the ability to make statistics visible to system administrators. The statistics include 2 categories: * Memory error statistics, for example, how many memory error are encountered, how many of them are recovered by the kernel. Note these memory errors are non-fatal to kernel: during the machine check exception (MCE) handling kernel already classified MCE's severity to be unnecessary to panic (but either action required or optional). * Scanner statistics, for example how many times the scanner have fully scanned a NUMA node, how many errors are first detected by the scanner. The memory error statistics are useful to userspace and actually not specific to scanner detected memory errors, and are the focus of this patchset. Motivation ========== Memory error stats are important to userspace but insufficient in kernel today. Datacenter administrators can better monitor a machine's memory health with the visible stats. For example, while memory errors are inevitable on servers with 10+ TB memory, starting server maintenance when there are only 1~2 recovered memory errors could be overreacting; in cloud production environment maintenance usually means live migrate all the workload running on the server and this usually causes nontrivial disruption to the customer. Providing insight into the scope of memory errors on a system helps to determine the appropriate follow-up action. In addition, the kernel's existing memory error stats need to be standardized so that userspace can reliably count on their usefulness. Today kernel provides following memory error info to userspace, but they are not sufficient or have disadvantages: * HardwareCorrupted in /proc/meminfo: number of bytes poisoned in total, not per NUMA node stats though * ras:memory_failure_event: only available after explicitly enabled * /dev/mcelog provides many useful info about the MCEs, but doesn't capture how memory_failure recovered memory MCEs * kernel logs: userspace needs to process log text Exposing memory error stats is also a good start for the in-kernel memory error detector. Today the data source of memory error stats are either direct memory error consumption, or hardware patrol scrubber detection (either signaled as UCNA or SRAO). Once in-kernel memory scanner is implemented, it will be the main source as it is usually configured to scan memory DIMMs constantly and faster than hardware patrol scrubber. How Implemented =============== As Naoya pointed out [2], exposing memory error statistics to userspace is useful independent of software or hardware scanner. Therefore we implement the memory error statistics independent of the in-kernel memory error detector. It exposes the following per NUMA node memory error counters: /sys/devices/system/node/node${X}/memory_failure/total /sys/devices/system/node/node${X}/memory_failure/recovered /sys/devices/system/node/node${X}/memory_failure/ignored /sys/devices/system/node/node${X}/memory_failure/failed /sys/devices/system/node/node${X}/memory_failure/delayed These counters describe how many raw pages are poisoned and after the attempted recoveries by the kernel, their resolutions: how many are recovered, ignored, failed, or delayed respectively. This approach can be easier to extend for future use cases than /proc/meminfo, trace event, and log. The following math holds for the statistics: * total = recovered + ignored + failed + delayed These memory error stats are reset during machine boot. The 1st commit introduces these sysfs entries. The 2nd commit populates memory error stats every time memory_failure attempts memory error recovery. The 3rd commit adds documentations for introduced stats. [1] https://lore.kernel.org/linux-mm/7E670362-C29E-4626-B546-26530D54F937@gmail.com/T/#mc22959244f5388891c523882e61163c6e4d703af [2] https://lore.kernel.org/linux-mm/7E670362-C29E-4626-B546-26530D54F937@gmail.com/T/#m52d8d7a333d8536bd7ce74253298858b1c0c0ac6 This patch (of 3): Today kernel provides following memory error info to userspace, but each has its own disadvantage * HardwareCorrupted in /proc/meminfo: number of bytes poisoned in total, not per NUMA node stats though * ras:memory_failure_event: only available after explicitly enabled * /dev/mcelog provides many useful info about the MCEs, but doesn't capture how memory_failure recovered memory MCEs * kernel logs: userspace needs to process log text Exposes per NUMA node memory error stats as sysfs entries: /sys/devices/system/node/node${X}/memory_failure/total /sys/devices/system/node/node${X}/memory_failure/recovered /sys/devices/system/node/node${X}/memory_failure/ignored /sys/devices/system/node/node${X}/memory_failure/failed /sys/devices/system/node/node${X}/memory_failure/delayed These counters describe how many raw pages are poisoned and after the attempted recoveries by the kernel, their resolutions: how many are recovered, ignored, failed, or delayed respectively. The following math holds for the statistics: * total = recovered + ignored + failed + delayed Link: https://lkml.kernel.org/r/20230120034622.2698268-1-jiaqiyan@google.com Link: https://lkml.kernel.org/r/20230120034622.2698268-2-jiaqiyan@google.com Signed-off-by: Jiaqi Yan Acked-by: David Rientjes Acked-by: Naoya Horiguchi Cc: Kefeng Wang Cc: Tony Luck Cc: Yang Shi Signed-off-by: Andrew Morton

Merge tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2022-10-11T00:53:04Z

Pull MM updates from Andrew Morton: - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in linux-next for a couple of months without, to my knowledge, any negative reports (or any positive ones, come to that). - Also the Maple Tree from Liam Howlett. An overlapping range-based tree for vmas. It it apparently slightly more efficient in its own right, but is mainly targeted at enabling work to reduce mmap_lock contention. Liam has identified a number of other tree users in the kernel which could be beneficially onverted to mapletrees. Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat at [1]. This has yet to be addressed due to Liam's unfortunately timed vacation. He is now back and we'll get this fixed up. - Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses clang-generated instrumentation to detect used-unintialized bugs down to the single bit level. KMSAN keeps finding bugs. New ones, as well as the legacy ones. - Yang Shi adds a userspace mechanism (madvise) to induce a collapse of memory into THPs. - Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to support file/shmem-backed pages. - userfaultfd updates from Axel Rasmussen - zsmalloc cleanups from Alexey Romanov - cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and memory-failure - Huang Ying adds enhancements to NUMA balancing memory tiering mode's page promotion, with a new way of detecting hot pages. - memcg updates from Shakeel Butt: charging optimizations and reduced memory consumption. - memcg cleanups from Kairui Song. - memcg fixes and cleanups from Johannes Weiner. - Vishal Moola provides more folio conversions - Zhang Yi removed ll_rw_block() :( - migration enhancements from Peter Xu - migration error-path bugfixes from Huang Ying - Aneesh Kumar added ability for a device driver to alter the memory tiering promotion paths. For optimizations by PMEM drivers, DRM drivers, etc. - vma merging improvements from Jakub Matěn. - NUMA hinting cleanups from David Hildenbrand. - xu xin added aditional userspace visibility into KSM merging activity. - THP & KSM code consolidation from Qi Zheng. - more folio work from Matthew Wilcox. - KASAN updates from Andrey Konovalov. - DAMON cleanups from Kaixu Xia. - DAMON work from SeongJae Park: fixes, cleanups. - hugetlb sysfs cleanups from Muchun Song. - Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core. Link: https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com [1] * tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (555 commits) hugetlb: allocate vma lock for all sharable vmas hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer hugetlb: fix vma lock handling during split vma and range unmapping mglru: mm/vmscan.c: fix imprecise comments mm/mglru: don't sync disk for each aging cycle mm: memcontrol: drop dead CONFIG_MEMCG_SWAP config symbol mm: memcontrol: use do_memsw_account() in a few more places mm: memcontrol: deprecate swapaccounting=0 mode mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled mm/secretmem: remove reduntant return value mm/hugetlb: add available_huge_pages() func mm: remove unused inline functions from include/linux/mm_inline.h selftests/vm: add selftest for MADV_COLLAPSE of uffd-minor memory selftests/vm: add file/shmem MADV_COLLAPSE selftest for cleared pmd selftests/vm: add thp collapse shmem testing selftests/vm: add thp collapse file and tmpfs testing selftests/vm: modularize thp collapse memory operations selftests/vm: dedup THP helpers mm/khugepaged: add tracepoint to hpage_collapse_scan_file() mm/madvise: add file and shmem support to MADV_COLLAPSE ...

mm: hugetlb: eliminate memory-less nodes handling

2022-10-03T21:03:15Z

The memory-notify-based approach aims to handle meory-less nodes, however, it just adds the complexity of code as pointed by David in thread [1]. The handling of memory-less nodes is introduced by commit 4faf8d950ec4 ("hugetlb: handle memory hot-plug events"). >From its commit message, we cannot find any necessity of handling this case. So, we can simply register/unregister sysfs entries in register_node/unregister_node to simlify the code. BTW, hotplug callback added because in hugetlb_register_all_nodes() we register sysfs nodes only for N_MEMORY nodes, seeing commit 9b5e5d0fdc91, which said it was a preparation for handling memory-less nodes via memory hotplug. Since we want to remove memory hotplug, so make sure we only register per-node sysfs for online (N_ONLINE) nodes in hugetlb_register_all_nodes(). https://lore.kernel.org/linux-mm/60933ffc-b850-976c-78a0-0ee6e0ea9ef0@redhat.com/ [1] Link: https://lkml.kernel.org/r/20220914072603.60293-3-songmuchun@bytedance.com Suggested-by: David Hildenbrand Signed-off-by: Muchun Song Acked-by: David Hildenbrand Cc: Andi Kleen Cc: Greg Kroah-Hartman Cc: Mike Kravetz Cc: Oscar Salvador Cc: Rafael J. Wysocki Signed-off-by: Andrew Morton

mm: hugetlb: simplify per-node sysfs creation and removal

2022-10-03T21:03:15Z

Patch series "simplify handling of per-node sysfs creation and removal", v4. This patch (of 2): The following commit offload per-node sysfs creation and removal to a kworker and did not say why it is needed. And it also said "I don't know that this is absolutely required". It seems like the author was not sure as well. Since it only complicates the code, this patch will revert the changes to simplify the code. 39da08cb074c ("hugetlb: offload per node attribute registrations") We could use memory hotplug notifier to do per-node sysfs creation and removal instead of inserting those operations to node registration and unregistration. Then, it can reduce the code coupling between node.c and hugetlb.c. Also, it can simplify the code. Link: https://lkml.kernel.org/r/20220914072603.60293-1-songmuchun@bytedance.com Link: https://lkml.kernel.org/r/20220914072603.60293-2-songmuchun@bytedance.com Signed-off-by: Muchun Song Acked-by: Mike Kravetz Acked-by: David Hildenbrand Cc: Andi Kleen Cc: Greg Kroah-Hartman Cc: Muchun Song Cc: Oscar Salvador Cc: Rafael J. Wysocki Signed-off-by: Andrew Morton

mm: add NR_SECONDARY_PAGETABLE to count secondary page table uses.

2022-08-24T20:51:42Z

We keep track of several kernel memory stats (total kernel memory, page tables, stack, vmalloc, etc) on multiple levels (global, per-node, per-memcg, etc). These stats give insights to users to how much memory is used by the kernel and for what purposes. Currently, memory used by KVM mmu is not accounted in any of those kernel memory stats. This patch series accounts the memory pages used by KVM for page tables in those stats in a new NR_SECONDARY_PAGETABLE stat. This stat can be later extended to account for other types of secondary pages tables (e.g. iommu page tables). KVM has a decent number of large allocations that aren't for page tables, but for most of them, the number/size of those allocations scales linearly with either the number of vCPUs or the amount of memory assigned to the VM. KVM's secondary page table allocations do not scale linearly, especially when nested virtualization is in use. From a KVM perspective, NR_SECONDARY_PAGETABLE will scale with KVM's per-VM pages_{4k,2m,1g} stats unless the guest is doing something bizarre (e.g. accessing only 4kb chunks of 2mb pages so that KVM is forced to allocate a large number of page tables even though the guest isn't accessing that much memory). However, someone would need to either understand how KVM works to make that connection, or know (or be told) to go look at KVM's stats if they're running VMs to better decipher the stats. Furthermore, having NR_PAGETABLE side-by-side with NR_SECONDARY_PAGETABLE is informative. For example, when backing a VM with THP vs. HugeTLB, NR_SECONDARY_PAGETABLE is roughly the same, but NR_PAGETABLE is an order of magnitude higher with THP. So having this stat will at the very least prove to be useful for understanding tradeoffs between VM backing types, and likely even steer folks towards potential optimizations. The original discussion with more details about the rationale: https://lore.kernel.org/all/87ilqoi77b.wl-maz@kernel.org This stat will be used by subsequent patches to count KVM mmu memory usage. Signed-off-by: Yosry Ahmed Acked-by: Shakeel Butt Acked-by: Marc Zyngier Link: https://lore.kernel.org/r/20220823004639.2387269-2-yosryahmed@google.com Signed-off-by: Sean Christopherson

drivers/base: fix userspace break from using bin_attributes for cpumap and cpulist

2022-07-15T15:36:33Z

Using bin_attributes with a 0 size causes fstat and friends to return that 0 size. This breaks userspace code that retrieves the size before reading the file. Rather than reverting 75bd50fa841 ("drivers/base/node.c: use bin_attribute to break the size limitation of cpumap ABI") let's put in a size value at compile time. For cpulist the maximum size is on the order of NR_CPUS * (ceil(log10(NR_CPUS)) + 1)/2 which for 8192 is 20480 (8192 * 5)/2. In order to get near that you'd need a system with every other CPU on one node. For example: (0,2,4,8, ... ). To simplify the math and support larger NR_CPUS in the future we are using (NR_CPUS * 7)/2. We also set it to a min of PAGE_SIZE to retain the older behavior for smaller NR_CPUS. The cpumap file the size works out to be NR_CPUS/4 + NR_CPUS/32 - 1 (or NR_CPUS * 9/32 - 1) including the ","s. Add a set of macros for these values to cpumask.h so they can be used in multiple places. Apply these to the handful of such files in drivers/base/topology.c as well as node.c. As an example, on an 80 cpu 4-node system (NR_CPUS == 8192): before: -r--r--r--. 1 root root 0 Jul 12 14:08 system/node/node0/cpulist -r--r--r--. 1 root root 0 Jul 11 17:25 system/node/node0/cpumap after: -r--r--r--. 1 root root 28672 Jul 13 11:32 system/node/node0/cpulist -r--r--r--. 1 root root 4096 Jul 13 11:31 system/node/node0/cpumap CONFIG_NR_CPUS = 16384 -r--r--r--. 1 root root 57344 Jul 13 14:03 system/node/node0/cpulist -r--r--r--. 1 root root 4607 Jul 13 14:02 system/node/node0/cpumap The actual number of cpus doesn't matter for the reported size since they are based on NR_CPUS. Fixes: 75bd50fa841d ("drivers/base/node.c: use bin_attribute to break the size limitation of cpumap ABI") Fixes: bb9ec13d156e ("topology: use bin_attribute to break the size limitation of cpumap ABI") Cc: Greg Kroah-Hartman Cc: "Rafael J. Wysocki" Cc: Yury Norov Cc: stable@vger.kernel.org Acked-by: Yury Norov (for include/linux/cpumask.h) Signed-off-by: Phil Auld Link: https://lore.kernel.org/r/20220715134924.3466194-1-pauld@redhat.com Signed-off-by: Greg Kroah-Hartman

drivers/base/node.c: fix compaction sysfs file leak

2022-04-29T06:16:06Z

Compaction sysfs file is created via compaction_register_node in register_node. But we forgot to remove it in unregister_node. Thus compaction sysfs file is leaked. Using compaction_unregister_node to fix this issue. Link: https://lkml.kernel.org/r/20220401070905.43679-1-linmiaohe@huawei.com Fixes: ed4a6d7f0676 ("mm: compaction: add /sys trigger for per-node memory compaction") Signed-off-by: Miaohe Lin Cc: Greg Kroah-Hartman Cc: Rafael J. Wysocki Cc: Mel Gorman Cc: Minchan Kim Cc: KAMEZAWA Hiroyuki Cc: KOSAKI Motohiro Signed-off-by: Andrew Morton