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2024-09-01mm: create promo_wmark_pages and clean up open-coded sitesKaiyang Zhao
Patch series "mm: print the promo watermark in zoneinfo", v2. This patch (of 2): Define promo_wmark_pages and convert current call sites of wmark_pages with fixed WMARK_PROMO to using it instead. Link: https://lkml.kernel.org/r/20240801232548.36604-1-kaiyang2@cs.cmu.edu Link: https://lkml.kernel.org/r/20240801232548.36604-2-kaiyang2@cs.cmu.edu Signed-off-by: Kaiyang Zhao <kaiyang2@cs.cmu.edu> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01mm, memcg: cg2 memory{.swap,}.peak write handlersDavid Finkel
Patch series "mm, memcg: cg2 memory{.swap,}.peak write handlers", v7. This patch (of 2): Other mechanisms for querying the peak memory usage of either a process or v1 memory cgroup allow for resetting the high watermark. Restore parity with those mechanisms, but with a less racy API. For example: - Any write to memory.max_usage_in_bytes in a cgroup v1 mount resets the high watermark. - writing "5" to the clear_refs pseudo-file in a processes's proc directory resets the peak RSS. This change is an evolution of a previous patch, which mostly copied the cgroup v1 behavior, however, there were concerns about races/ownership issues with a global reset, so instead this change makes the reset filedescriptor-local. Writing any non-empty string to the memory.peak and memory.swap.peak pseudo-files reset the high watermark to the current usage for subsequent reads through that same FD. Notably, following Johannes's suggestion, this implementation moves the O(FDs that have written) behavior onto the FD write(2) path. Instead, on the page-allocation path, we simply add one additional watermark to conditionally bump per-hierarchy level in the page-counter. Additionally, this takes Longman's suggestion of nesting the page-charging-path checks for the two watermarks to reduce the number of common-case comparisons. This behavior is particularly useful for work scheduling systems that need to track memory usage of worker processes/cgroups per-work-item. Since memory can't be squeezed like CPU can (the OOM-killer has opinions), these systems need to track the peak memory usage to compute system/container fullness when binpacking workitems. Most notably, Vimeo's use-case involves a system that's doing global binpacking across many Kubernetes pods/containers, and while we can use PSI for some local decisions about overload, we strive to avoid packing workloads too tightly in the first place. To facilitate this, we track the peak memory usage. However, since we run with long-lived workers (to amortize startup costs) we need a way to track the high watermark while a work-item is executing. Polling runs the risk of missing short spikes that last for timescales below the polling interval, and peak memory tracking at the cgroup level is otherwise perfect for this use-case. As this data is used to ensure that binpacked work ends up with sufficient headroom, this use-case mostly avoids the inaccuracies surrounding reclaimable memory. Link: https://lkml.kernel.org/r/20240730231304.761942-1-davidf@vimeo.com Link: https://lkml.kernel.org/r/20240729143743.34236-1-davidf@vimeo.com Link: https://lkml.kernel.org/r/20240729143743.34236-2-davidf@vimeo.com Signed-off-by: David Finkel <davidf@vimeo.com> Suggested-by: Johannes Weiner <hannes@cmpxchg.org> Suggested-by: Waiman Long <longman@redhat.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Michal Koutný <mkoutny@suse.com> Acked-by: Tejun Heo <tj@kernel.org> Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Shuah Khan <shuah@kernel.org> Cc: Zefan Li <lizefan.x@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01mm: turn USE_SPLIT_PTE_PTLOCKS / USE_SPLIT_PTE_PTLOCKS into Kconfig optionsDavid Hildenbrand
Patch series "mm: split PTE/PMD PT table Kconfig cleanups+clarifications". This series is a follow up to the fixes: "[PATCH v1 0/2] mm/hugetlb: fix hugetlb vs. core-mm PT locking" When working on the fixes, I wondered why 8xx is fine (-> never uses split PT locks) and how PT locking even works properly with PMD page table sharing (-> always requires split PMD PT locks). Let's improve the split PT lock detection, make hugetlb properly depend on it and make 8xx bail out if it would ever get enabled by accident. As an alternative to patch #3 we could extend the Kconfig SPLIT_PTE_PTLOCKS option from patch #2 -- but enforcing it closer to the code that actually implements it feels a bit nicer for documentation purposes, and there is no need to actually disable it because it should always be disabled (!SMP). Did a bunch of cross-compilations to make sure that split PTE/PMD PT locks are still getting used where we would expect them. [1] https://lkml.kernel.org/r/20240725183955.2268884-1-david@redhat.com This patch (of 3): Let's clean that up a bit and prepare for depending on CONFIG_SPLIT_PMD_PTLOCKS in other Kconfig options. More cleanups would be reasonable (like the arch-specific "depends on" for CONFIG_SPLIT_PTE_PTLOCKS), but we'll leave that for another day. Link: https://lkml.kernel.org/r/20240726150728.3159964-1-david@redhat.com Link: https://lkml.kernel.org/r/20240726150728.3159964-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Reviewed-by: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Borislav Petkov <bp@alien8.de> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Muchun Song <muchun.song@linux.dev> Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Peter Xu <peterx@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01task_stack: uninline stack_not_usedPasha Tatashin
Given that stack_not_used() is not performance critical function uninline it. Link: https://lkml.kernel.org/r/20240730150158.832783-4-pasha.tatashin@soleen.com Link: https://lkml.kernel.org/r/20240724203322.2765486-4-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Acked-by: Shakeel Butt <shakeel.butt@linux.dev> Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Li Zhijian <lizhijian@fujitsu.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01vmstat: kernel stack usage histogramPasha Tatashin
As part of the dynamic kernel stack project, we need to know the amount of data that can be saved by reducing the default kernel stack size [1]. Provide a kernel stack usage histogram to aid in optimizing kernel stack sizes and minimizing memory waste in large-scale environments. The histogram divides stack usage into power-of-two buckets and reports the results in /proc/vmstat. This information is especially valuable in environments with millions of machines, where even small optimizations can have a significant impact. The histogram data is presented in /proc/vmstat with entries like "kstack_1k", "kstack_2k", and so on, indicating the number of threads that exited with stack usage falling within each respective bucket. Example outputs: Intel: $ grep kstack /proc/vmstat kstack_1k 3 kstack_2k 188 kstack_4k 11391 kstack_8k 243 kstack_16k 0 ARM with 64K page_size: $ grep kstack /proc/vmstat kstack_1k 1 kstack_2k 340 kstack_4k 25212 kstack_8k 1659 kstack_16k 0 kstack_32k 0 kstack_64k 0 Note: once the dynamic kernel stack is implemented it will depend on the implementation the usability of this feature: On hardware that supports faults on kernel stacks, we will have other metrics that show the total number of pages allocated for stacks. On hardware where faults are not supported, we will most likely have some optimization where only some threads are extended, and for those, these metrics will still be very useful. [1] https://lwn.net/Articles/974367 Link: https://lkml.kernel.org/r/20240730150158.832783-3-pasha.tatashin@soleen.com Link: https://lkml.kernel.org/r/20240724203322.2765486-3-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Kent Overstreet <kent.overstreet@linux.dev> Acked-by: Shakeel Butt <shakeel.butt@linux.dev> Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com> Cc: Li Zhijian <lizhijian@fujitsu.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01memory tiering: introduce folio_use_access_time() checkZi Yan
If memory tiering mode is on and a folio is not in the top tier memory, folio's cpupid field is repurposed to store page access time. Instead of an open coded check, use a function to encapsulate the check. Link: https://lkml.kernel.org/r/20240724130115.793641-3-ziy@nvidia.com Signed-off-by: Zi Yan <ziy@nvidia.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01mm: kvmalloc: align kvrealloc() with krealloc()Danilo Krummrich
Besides the obvious (and desired) difference between krealloc() and kvrealloc(), there is some inconsistency in their function signatures and behavior: - krealloc() frees the memory when the requested size is zero, whereas kvrealloc() simply returns a pointer to the existing allocation. - krealloc() behaves like kmalloc() if a NULL pointer is passed, whereas kvrealloc() does not accept a NULL pointer at all and, if passed, would fault instead. - krealloc() is self-contained, whereas kvrealloc() relies on the caller to provide the size of the previous allocation. Inconsistent behavior throughout allocation APIs is error prone, hence make kvrealloc() behave like krealloc(), which seems superior in all mentioned aspects. Besides that, implementing kvrealloc() by making use of krealloc() and vrealloc() provides oppertunities to grow (and shrink) allocations more efficiently. For instance, vrealloc() can be optimized to allocate and map additional pages to grow the allocation or unmap and free unused pages to shrink the allocation. [dakr@kernel.org: document concurrency restrictions] Link: https://lkml.kernel.org/r/20240725125442.4957-1-dakr@kernel.org [dakr@kernel.org: disable KASAN when switching to vmalloc] Link: https://lkml.kernel.org/r/20240730185049.6244-2-dakr@kernel.org [dakr@kernel.org: properly document __GFP_ZERO behavior] Link: https://lkml.kernel.org/r/20240730185049.6244-5-dakr@kernel.org Link: https://lkml.kernel.org/r/20240722163111.4766-3-dakr@kernel.org Signed-off-by: Danilo Krummrich <dakr@kernel.org> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Chandan Babu R <chandan.babu@oracle.com> Cc: Christian König <christian.koenig@amd.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kees Cook <kees@kernel.org> Cc: Marc Zyngier <maz@kernel.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Oliver Upton <oliver.upton@linux.dev> Cc: Pekka Enberg <penberg@kernel.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Uladzislau Rezki <urezki@gmail.com> Cc: Wedson Almeida Filho <wedsonaf@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01kexec_file: fix elfcorehdr digest exclusion when CONFIG_CRASH_HOTPLUG=yPetr Tesarik
Fix the condition to exclude the elfcorehdr segment from the SHA digest calculation. The j iterator is an index into the output sha_regions[] array, not into the input image->segment[] array. Once it reaches image->elfcorehdr_index, all subsequent segments are excluded. Besides, if the purgatory segment precedes the elfcorehdr segment, the elfcorehdr may be wrongly included in the calculation. Link: https://lkml.kernel.org/r/20240805150750.170739-1-petr.tesarik@suse.com Fixes: f7cc804a9fd4 ("kexec: exclude elfcorehdr from the segment digest") Signed-off-by: Petr Tesarik <ptesarik@suse.com> Acked-by: Baoquan He <bhe@redhat.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Hari Bathini <hbathini@linux.ibm.com> Cc: Sourabh Jain <sourabhjain@linux.ibm.com> Cc: Eric DeVolder <eric_devolder@yahoo.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01Merge tag 'x86-urgent-2024-09-01' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fixes from Thomas Gleixner: - x2apic_disable() clears x2apic_state and x2apic_mode unconditionally, even when the state is X2APIC_ON_LOCKED, which prevents the kernel to disable it thereby creating inconsistent state. Reorder the logic so it actually works correctly - The XSTATE logic for handling LBR is incorrect as it assumes that XSAVES supports LBR when the CPU supports LBR. In fact both conditions need to be true. Otherwise the enablement of LBR in the IA32_XSS MSR fails and subsequently the machine crashes on the next XRSTORS operation because IA32_XSS is not initialized. Cache the XSTATE support bit during init and make the related functions use this cached information and the LBR CPU feature bit to cure this. - Cure a long standing bug in KASLR KASLR uses the full address space between PAGE_OFFSET and vaddr_end to randomize the starting points of the direct map, vmalloc and vmemmap regions. It thereby limits the size of the direct map by using the installed memory size plus an extra configurable margin for hot-plug memory. This limitation is done to gain more randomization space because otherwise only the holes between the direct map, vmalloc, vmemmap and vaddr_end would be usable for randomizing. The limited direct map size is not exposed to the rest of the kernel, so the memory hot-plug and resource management related code paths still operate under the assumption that the available address space can be determined with MAX_PHYSMEM_BITS. request_free_mem_region() allocates from (1 << MAX_PHYSMEM_BITS) - 1 downwards. That means the first allocation happens past the end of the direct map and if unlucky this address is in the vmalloc space, which causes high_memory to become greater than VMALLOC_START and consequently causes iounmap() to fail for valid ioremap addresses. Cure this by exposing the end of the direct map via PHYSMEM_END and use that for the memory hot-plug and resource management related places instead of relying on MAX_PHYSMEM_BITS. In the KASLR case PHYSMEM_END maps to a variable which is initialized by the KASLR initialization and otherwise it is based on MAX_PHYSMEM_BITS as before. - Prevent a data leak in mmio_read(). The TDVMCALL exposes the value of an initialized variabled on the stack to the VMM. The variable is only required as output value, so it does not have to exposed to the VMM in the first place. - Prevent an array overrun in the resource control code on systems with Sub-NUMA Clustering enabled because the code failed to adjust the index by the number of SNC nodes per L3 cache. * tag 'x86-urgent-2024-09-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/resctrl: Fix arch_mbm_* array overrun on SNC x86/tdx: Fix data leak in mmio_read() x86/kaslr: Expose and use the end of the physical memory address space x86/fpu: Avoid writing LBR bit to IA32_XSS unless supported x86/apic: Make x2apic_disable() work correctly
2024-09-01Merge tag 'locking-urgent-2024-08-25' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking fix from Thomas Gleixner: "A single fix for rt_mutex. The deadlock detection code drops into an infinite scheduling loop while still holding rt_mutex::wait_lock, which rightfully triggers a 'scheduling in atomic' warning. Unlock it before that" * tag 'locking-urgent-2024-08-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: rtmutex: Drop rt_mutex::wait_lock before scheduling
2024-09-01tinyconfig: remove unnecessary 'is not set' for choice blocksMasahiro Yamada
This reverts the following commits: - 236dec051078 ("kconfig: tinyconfig: provide whole choice blocks to avoid warnings") - b0f269728ccd ("x86/config: Fix warning for 'make ARCH=x86_64 tinyconfig'") Since commit f79dc03fe68c ("kconfig: refactor choice value calculation"), it is no longer necessary to disable the remaining options in choice blocks. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Thomas Gleixner <tglx@linutronix.de>
2024-08-30sched_ext: Use sched_clock_cpu() instead of rq_clock_task() in ↵Tejun Heo
touch_core_sched() Since 3cf78c5d01d6 ("sched_ext: Unpin and repin rq lock from balance_scx()"), sched_ext's balance path terminates rq_pin in the outermost function. This is simpler and in line with what other balance functions are doing but it loses control over rq->clock_update_flags which makes assert_clock_udpated() trigger if other CPUs pins the rq lock. The only place this matters is touch_core_sched() which uses the timestamp to order tasks from sibling rq's. Switch to sched_clock_cpu(). Later, it may be better to use per-core dispatch sequence number. v2: Use sched_clock_cpu() instead of ktime_get_ns() per David. Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: 3cf78c5d01d6 ("sched_ext: Unpin and repin rq lock from balance_scx()") Acked-by: David Vernet <void@manifault.com> Cc: Peter Zijlstra <peterz@infradead.org>
2024-08-30sched_ext: Use task_can_run_on_remote_rq() test in dispatch_to_local_dsq()Tejun Heo
When deciding whether a task can be migrated to a CPU, dispatch_to_local_dsq() was open-coding p->cpus_allowed and scx_rq_online() tests instead of using task_can_run_on_remote_rq(). This had two problems. - It was missing is_migration_disabled() check and thus could try to migrate a task which shouldn't leading to assertion and scheduling failures. - It was testing p->cpus_ptr directly instead of using task_allowed_on_cpu() and thus failed to consider ISA compatibility. Update dispatch_to_local_dsq() to use task_can_run_on_remote_rq(): - Move scx_ops_error() triggering into task_can_run_on_remote_rq(). - When migration isn't allowed, fall back to the global DSQ instead of the source DSQ by returning DTL_INVALID. This is both simpler and an overall better behavior. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Acked-by: David Vernet <void@manifault.com>
2024-08-30cgroup/cpuset: guard cpuset-v1 code under CONFIG_CPUSETS_V1Chen Ridong
This patch introduces CONFIG_CPUSETS_V1 and guard cpuset-v1 code under CONFIG_CPUSETS_V1. The default value of CONFIG_CPUSETS_V1 is N, so that user who adopted v2 don't have 'pay' for cpuset v1. Signed-off-by: Chen Ridong <chenridong@huawei.com> Acked-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-08-30cgroup/cpuset: rename functions shared between v1 and v2Chen Ridong
Some functions name declared in cpuset-internel.h are generic. To avoid confilicting with other variables for the same name, rename these functions with cpuset_/cpuset1_ prefix to make them unique to cpuset. Signed-off-by: Chen Ridong <chenridong@huawei.com> Acked-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-08-30cgroup/cpuset: move v1 interfaces to cpuset-v1.cChen Ridong
Move legacy cpuset controller interfaces files and corresponding code into cpuset-v1.c. 'update_flag', 'cpuset_write_resmask' and 'cpuset_common_seq_show' are also used for v1, so declare them in cpuset-internal.h. 'cpuset_write_s64', 'cpuset_read_s64' and 'fmeter_getrate' are only used cpuset-v1.c now, make it static. Signed-off-by: Chen Ridong <chenridong@huawei.com> Acked-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-08-30cgroup/cpuset: move validate_change_legacy to cpuset-v1.cChen Ridong
The validate_change_legacy functions is used for v1, move it to cpuset-v1.c. And two micro 'cpuset_for_each_child' and 'cpuset_for_each_descendant_pre' are common for v1 and v2, move them to cpuset-internal.h. Signed-off-by: Chen Ridong <chenridong@huawei.com> Acked-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-08-30cgroup/cpuset: move legacy hotplug update to cpuset-v1.cChen Ridong
There are some differents about hotplug update between cpuset v1 and cpuset v2. Move the legacy code to cpuset-v1.c. 'update_tasks_cpumask' and 'update_tasks_nodemask' are both used in cpuset v1 and cpuset v2, declare them in cpuset-internal.h. The change from original code is that use callback_lock helpers to get callback_lock lock/unlock. Signed-off-by: Chen Ridong <chenridong@huawei.com> Acked-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-08-30cgroup/cpuset: add callback_lock helperChen Ridong
To modify cpuset, both cpuset_mutex and callback_lock are needed. Add helpers for cpuset-v1 to get callback_lock. Signed-off-by: Chen Ridong <chenridong@huawei.com> Acked-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-08-30cgroup/cpuset: move memory_spread to cpuset-v1.cChen Ridong
'memory_spread' is only set in cpuset v1. move corresponding code into cpuset-v1.c. Currently, 'cpuset_update_task_spread_flags' and 'update_tasks_flags' are exposed to cpuset.c. Signed-off-by: Chen Ridong <chenridong@huawei.com> Acked-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-08-30cgroup/cpuset: move relax_domain_level to cpuset-v1.cChen Ridong
Setting domain level is not supported at cpuset v2, so move corresponding code into cpuset-v1.c. The 'cpuset_write_s64' and 'cpuset_read_s64' are only used for setting domain level, move them to cpuset-v1.c. Currently, expose to cpuset.c. After cpuset legacy interface files are move to cpuset-v1.c, they can be static. The 'rebuild_sched_domains_locked' is exposed to cpuset-v1.c. The change from original code is that using 'cpuset_lock' and 'cpuset_unlock' functions to lock or unlock cpuset_mutex. Signed-off-by: Chen Ridong <chenridong@huawei.com> Acked-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-08-30cgroup/cpuset: move memory_pressure to cpuset-v1.cChen Ridong
Collection of memory_pressure can be enabled by writing 1 to the cpuset file 'memory_pressure_enabled', which is only for cpuset-v1. Therefore, move the corresponding code to cpuset-v1.c. Currently, the 'fmeter_init' and 'fmeter_getrate' functions are called at cpuset.c, so expose them to cpuset.c. Signed-off-by: Chen Ridong <chenridong@huawei.com> Acked-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-08-30cgroup/cpuset: move common code to cpuset-internal.hChen Ridong
Move some declarations that will be used for cpuset v1 and v2, including 'cpuset struct', 'cpuset_flagbits_t', cpuset_filetype_t,etc. No logical change. Signed-off-by: Chen Ridong <chenridong@huawei.com> Acked-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-08-30cgroup/cpuset: introduce cpuset-v1.cChen Ridong
This patch introduces the cgroup/cpuset-v1.c source file which will be used for all legacy (cgroup v1) cpuset cgroup code. It also introduces cgroup/cpuset-internal.h to keep declarations shared between cgroup/cpuset.c and cpuset/cpuset-v1.c. As of now, let's compile it if CONFIG_CPUSET is set. Later on it can be switched to use a separate config option, so that the legacy code won't be compiled if not required. Signed-off-by: Chen Ridong <chenridong@huawei.com> Acked-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-08-30cgroup/cpuset: Account for boot time isolated CPUsWaiman Long
With the "isolcpus" boot command line parameter, we are able to create isolated CPUs at boot time. These isolated CPUs aren't fully accounted for in the cpuset code. For instance, the root cgroup's "cpuset.cpus.isolated" control file does not include the boot time isolated CPUs. Fix that by looking for pre-isolated CPUs at init time. The prstate_housekeeping_conflict() function does check the HK_TYPE_DOMAIN housekeeping cpumask to make sure that CPUs outside of it can only be used in isolated partition. Given the fact that we are going to make housekeeping cpumasks dynamic, the current check may not be right anymore. Save the boot time HK_TYPE_DOMAIN cpumask and check against it instead of the upcoming dynamic HK_TYPE_DOMAIN housekeeping cpumask. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-08-30bpf: Fix a crash when btf_parse_base() returns an error pointerMartin KaFai Lau
The pointer returned by btf_parse_base could be an error pointer. IS_ERR() check is needed before calling btf_free(base_btf). Fixes: 8646db238997 ("libbpf,bpf: Share BTF relocate-related code with kernel") Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: Alan Maguire <alan.maguire@oracle.com> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20240830012214.1646005-1-martin.lau@linux.dev
2024-08-30bpf: Use sockfd_put() helperJinjie Ruan
Replace fput() with sockfd_put() in bpf_fd_reuseport_array_update_elem(). Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://lore.kernel.org/r/20240830020756.607877-1-ruanjinjie@huawei.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-30bpf: Remove custom build ruleAlexey Gladkov
According to the documentation, when building a kernel with the C=2 parameter, all source files should be checked. But this does not happen for the kernel/bpf/ directory. $ touch kernel/bpf/core.o $ make C=2 CHECK=true kernel/bpf/core.o Outputs: CHECK scripts/mod/empty.c CALL scripts/checksyscalls.sh DESCEND objtool INSTALL libsubcmd_headers CC kernel/bpf/core.o As can be seen the compilation is done, but CHECK is not executed. This happens because kernel/bpf/Makefile has defined its own rule for compilation and forgotten the macro that does the check. There is no need to duplicate the build code, and this rule can be removed to use generic rules. Acked-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Oleg Nesterov <oleg@redhat.com> Tested-by: Alan Maguire <alan.maguire@oracle.com> Signed-off-by: Alexey Gladkov <legion@kernel.org> Link: https://lore.kernel.org/r/20240830074350.211308-1-legion@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-30drivers/perf: arm_spe: Use perf_allow_kernel() for permissionsJames Clark
Use perf_allow_kernel() for 'pa_enable' (physical addresses), 'pct_enable' (physical timestamps) and context IDs. This means that perf_event_paranoid is now taken into account and LSM hooks can be used, which is more consistent with other perf_event_open calls. For example PERF_SAMPLE_PHYS_ADDR uses perf_allow_kernel() rather than just perfmon_capable(). This also indirectly fixes the following error message which is misleading because perf_event_paranoid is not taken into account by perfmon_capable(): $ perf record -e arm_spe/pa_enable/ Error: Access to performance monitoring and observability operations is limited. Consider adjusting /proc/sys/kernel/perf_event_paranoid setting ... Suggested-by: Al Grant <al.grant@arm.com> Signed-off-by: James Clark <james.clark@linaro.org> Link: https://lore.kernel.org/r/20240827145113.1224604-1-james.clark@linaro.org Link: https://lore.kernel.org/all/20240807120039.GD37996@noisy.programming.kicks-ass.net/ Signed-off-by: Will Deacon <will@kernel.org>
2024-08-30padata: Honor the caller's alignment in case of chunk_size 0Kamlesh Gurudasani
In the case where we are forcing the ps.chunk_size to be at least 1, we are ignoring the caller's alignment. Move the forcing of ps.chunk_size to be at least 1 before rounding it up to caller's alignment, so that caller's alignment is honored. While at it, use max() to force the ps.chunk_size to be at least 1 to improve readability. Fixes: 6d45e1c948a8 ("padata: Fix possible divide-by-0 panic in padata_mt_helper()") Signed-off-by: Kamlesh Gurudasani <kamlesh@ti.com> Acked-by:  Waiman Long <longman@redhat.com> Acked-by: Daniel Jordan <daniel.m.jordan@oracle.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2024-08-29bpf: Make the pointer returned by iter next method validJuntong Deng
Currently we cannot pass the pointer returned by iter next method as argument to KF_TRUSTED_ARGS or KF_RCU kfuncs, because the pointer returned by iter next method is not "valid". This patch sets the pointer returned by iter next method to be valid. This is based on the fact that if the iterator is implemented correctly, then the pointer returned from the iter next method should be valid. This does not make NULL pointer valid. If the iter next method has KF_RET_NULL flag, then the verifier will ask the ebpf program to check NULL pointer. KF_RCU_PROTECTED iterator is a special case, the pointer returned by iter next method should only be valid within RCU critical section, so it should be with MEM_RCU, not PTR_TRUSTED. Another special case is bpf_iter_num_next, which returns a pointer with base type PTR_TO_MEM. PTR_TO_MEM should not be combined with type flag PTR_TRUSTED (PTR_TO_MEM already means the pointer is valid). The pointer returned by iter next method of other types of iterators is with PTR_TRUSTED. In addition, this patch adds get_iter_from_state to help us get the current iterator from the current state. Signed-off-by: Juntong Deng <juntong.deng@outlook.com> Link: https://lore.kernel.org/r/AM6PR03MB584869F8B448EA1C87B7CDA399962@AM6PR03MB5848.eurprd03.prod.outlook.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29bpf: Export bpf_base_func_protoMartin KaFai Lau
The bpf_testmod needs to use the bpf_tail_call helper in a later selftest patch. This patch is to EXPORT_GPL_SYMBOL the bpf_base_func_proto. Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Link: https://lore.kernel.org/r/20240829210833.388152-5-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29bpf: Add gen_epilogue to bpf_verifier_opsMartin KaFai Lau
This patch adds a .gen_epilogue to the bpf_verifier_ops. It is similar to the existing .gen_prologue. Instead of allowing a subsystem to run code at the beginning of a bpf prog, it allows the subsystem to run code just before the bpf prog exit. One of the use case is to allow the upcoming bpf qdisc to ensure that the skb->dev is the same as the qdisc->dev_queue->dev. The bpf qdisc struct_ops implementation could either fix it up or drop the skb. Another use case could be in bpf_tcp_ca.c to enforce snd_cwnd has sane value (e.g. non zero). The epilogue can do the useful thing (like checking skb->dev) if it can access the bpf prog's ctx. Unlike prologue, r1 may not hold the ctx pointer. This patch saves the r1 in the stack if the .gen_epilogue has returned some instructions in the "epilogue_buf". The existing .gen_prologue is done in convert_ctx_accesses(). The new .gen_epilogue is done in the convert_ctx_accesses() also. When it sees the (BPF_JMP | BPF_EXIT) instruction, it will be patched with the earlier generated "epilogue_buf". The epilogue patching is only done for the main prog. Only one epilogue will be patched to the main program. When the bpf prog has multiple BPF_EXIT instructions, a BPF_JA is used to goto the earlier patched epilogue. Majority of the archs support (BPF_JMP32 | BPF_JA): x86, arm, s390, risv64, loongarch, powerpc and arc. This patch keeps it simple and always use (BPF_JMP32 | BPF_JA). A new macro BPF_JMP32_A is added to generate the (BPF_JMP32 | BPF_JA) insn. Acked-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Link: https://lore.kernel.org/r/20240829210833.388152-4-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29bpf: Adjust BPF_JMP that jumps to the 1st insn of the prologueMartin KaFai Lau
The next patch will add a ctx ptr saving instruction "(r1 = *(u64 *)(r10 -8)" at the beginning for the main prog when there is an epilogue patch (by the .gen_epilogue() verifier ops added in the next patch). There is one corner case if the bpf prog has a BPF_JMP that jumps to the 1st instruction. It needs an adjustment such that those BPF_JMP instructions won't jump to the newly added ctx saving instruction. The commit 5337ac4c9b80 ("bpf: Fix the corner case with may_goto and jump to the 1st insn.") has the details on this case. Note that the jump back to 1st instruction is not limited to the ctx ptr saving instruction. The same also applies to the prologue. A later test, pro_epilogue_goto_start.c, has a test for the prologue only case. Thus, this patch does one adjustment after gen_prologue and the future ctx ptr saving. It is done by adjust_jmp_off(env->prog, 0, delta) where delta has the total number of instructions in the prologue and the future ctx ptr saving instruction. The adjust_jmp_off(env->prog, 0, delta) assumes that the prologue does not have a goto 1st instruction itself. To accommodate the prologue might have a goto 1st insn itself, this patch changes the adjust_jmp_off() to skip considering the instructions between [tgt_idx, tgt_idx + delta). Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Link: https://lore.kernel.org/r/20240829210833.388152-3-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29bpf: Move insn_buf[16] to bpf_verifier_envMartin KaFai Lau
This patch moves the 'struct bpf_insn insn_buf[16]' stack usage to the bpf_verifier_env. A '#define INSN_BUF_SIZE 16' is also added to replace the ARRAY_SIZE(insn_buf) usages. Both convert_ctx_accesses() and do_misc_fixup() are changed to use the env->insn_buf. It is a refactoring work for adding the epilogue_buf[16] in a later patch. With this patch, the stack size usage decreased. Before: ./kernel/bpf/verifier.c:22133:5: warning: stack frame size (2584) After: ./kernel/bpf/verifier.c:22184:5: warning: stack frame size (2264) Reviewed-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Link: https://lore.kernel.org/r/20240829210833.388152-2-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29bpf: Use kvmemdup to simplify the codeHongbo Li
Use kvmemdup instead of kvmalloc() + memcpy() to simplify the code. No functional change intended. Acked-by: Yonghong Song <yonghong.song@linux.dev> Signed-off-by: Hongbo Li <lihongbo22@huawei.com> Link: https://lore.kernel.org/r/20240828062128.1223417-1-lihongbo22@huawei.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29irqdomain: Use IS_ERR_OR_NULL() in irq_domain_trim_hierarchy()Hongbo Li
Use IS_ERR_OR_NULL() instead of open-coding a NULL and a error pointer check. Signed-off-by: Hongbo Li <lihongbo22@huawei.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20240828122724.3697447-1-lihongbo22@huawei.com
2024-08-29genirq/msi: Use kmemdup_array() instead of kmemdup()Jinjie Ruan
Let kmemdup_array() take care about sizing instead of doing it open coded. Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20240828072219.1249250-1-ruanjinjie@huawei.com
2024-08-29genirq/proc: Change the return value for set affinity permission errorJeff Xie
Currently, when the affinity of an irq cannot be set due to lack of permission, the write_irq_affinity() returns the error code -EIO. Change the return value to -EPERM as that reflects the cause of error correctly. Signed-off-by: Jeff Xie <jeff.xie@linux.dev> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20240826145805.5938-1-jeff.xie@linux.dev
2024-08-29genirq/proc: Use irq_move_pending() in show_irq_affinity()Jinjie Ruan
irq_move_pending() encapsulates irqd_is_setaffinity_pending() depending on CONFIG_GENERIC_PENDING_IRQ. Replace the open coded #ifdeffery with it. Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20240829111522.230595-1-ruanjinjie@huawei.com
2024-08-29genirq/proc: Correctly set file permissions for affinity control filesJeff Xie
The kernel already knows at the time of interrupt allocation whether affinity of an interrupt can be controlled by userspace or not. It still creates all related procfs control files with read/write permissions. That's inconsistent and non-intuitive for system administrators and tools. Therefore set the file permissions to read-only for such interrupts. [ tglx: Massage change log, fixed UP build ] Signed-off-by: Jeff Xie <jeff.xie@linux.dev> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20240825131911.107119-1-jeff.xie@linux.dev
2024-08-29timers: Remove historical extra jiffie for timeout in msleep()Anna-Maria Behnsen
msleep() and msleep_interruptible() add a jiffie to the requested timeout. This extra jiffie was introduced to ensure that the timeout will not happen earlier than specified. Since the rework of the timer wheel, the enqueue path already takes care of this. So the extra jiffie added by msleep*() is pointless now. Remove this extra jiffie in msleep() and msleep_interruptible(). Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://lore.kernel.org/all/20240829074133.4547-1-anna-maria@linutronix.de
2024-08-28bpf: Relax KF_ACQUIRE kfuncs strict type matching constraintJuntong Deng
Currently we cannot pass zero offset (implicit cast) or non-zero offset pointers to KF_ACQUIRE kfuncs. This is because KF_ACQUIRE kfuncs requires strict type matching, but zero offset or non-zero offset does not change the type of pointer, which causes the ebpf program to be rejected by the verifier. This can cause some problems, one example is that bpf_skb_peek_tail kfunc [0] cannot be implemented by just passing in non-zero offset pointers. We cannot pass pointers like &sk->sk_write_queue (non-zero offset) or &sk->__sk_common (zero offset) to KF_ACQUIRE kfuncs. This patch makes KF_ACQUIRE kfuncs not require strict type matching. [0]: https://lore.kernel.org/bpf/AM6PR03MB5848CA39CB4B7A4397D380B099B12@AM6PR03MB5848.eurprd03.prod.outlook.com/ Signed-off-by: Juntong Deng <juntong.deng@outlook.com> Link: https://lore.kernel.org/r/AM6PR03MB5848FD2BD89BF0B6B5AA3B4C99952@AM6PR03MB5848.eurprd03.prod.outlook.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-28audit: use task_tgid_nr() instead of task_pid_nr()Ricardo Robaina
In a few audit records, PIDs were being recorded with task_pid_nr() instead of task_tgid_nr(). $ grep "task_pid_nr" kernel/audit*.c audit.c: task_pid_nr(current), auditfilter.c: pid = task_pid_nr(current); auditsc.c: audit_log_format(ab, " pid=%u", task_pid_nr(current)); For single-thread applications, the process id (pid) and the thread group id (tgid) are the same. However, on multi-thread applications, task_pid_nr() returns the current thread id (user-space's TID), while task_tgid_nr() returns the main thread id (user-space's PID). Since the users are more interested in the process id (pid), rather than the thread id (tid), this patch converts these callers to the correct method. Link: https://github.com/linux-audit/audit-kernel/issues/126 Reviewed-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Ricardo Robaina <rrobaina@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-08-27sched_ext: Add missing cfi stub for ops.tickTejun Heo
The cfi stub for ops.tick was missing which will fail scheduler loading after pending BPF changes. Add it. Signed-off-by: Tejun Heo <tj@kernel.org>
2024-08-27rcu/kvfree: Add kvfree_rcu_barrier() APIUladzislau Rezki (Sony)
Add a kvfree_rcu_barrier() function. It waits until all in-flight pointers are freed over RCU machinery. It does not wait any GP completion and it is within its right to return immediately if there are no outstanding pointers. This function is useful when there is a need to guarantee that a memory is fully freed before destroying memory caches. For example, during unloading a kernel module. Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
2024-08-27Merge v6.11-rc5 into drm-nextDaniel Vetter
amdgpu pr conconflicts due to patches cherry-picked to -fixes, I might as well catch up with a backmerge and handle them all. Plus both misc and intel maintainers asked for a backmerge anyway. Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2024-08-27genirq: Get rid of global lock in irq_do_set_affinity()Marc Zyngier
Kunkun Jiang reports that for a workload involving the simultaneous startup of a large number of VMs (for a total of about 200 vcpus), a lot of CPU time gets spent on spinning on the tmp_mask_lock that exists as a static raw spinlock in irq_do_set_affinity(). This lock protects a global cpumask (tmp_mask) that is used as a temporary variable to compute the resulting affinity. While this is triggered by KVM issuing a irq_set_affinity() call each time a vcpu is about to execute, it is obvious that having a single global resource is not very scalable. Since a cpumask can be a fairly large structure on systems with a high core count, a stack allocation is not really appropriate. Instead, turn the global cpumask into a per-CPU variable, removing the need for locking altogether as the code is executed with preemption and interrupts disabled. [ tglx: Moved the per CPU variable declaration outside of the function ] Reported-by: Kunkun Jiang <jiangkunkun@huawei.com> Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Kunkun Jiang <jiangkunkun@huawei.com> Link: https://lore.kernel.org/all/20240826080618.3886694-1-maz@kernel.org Link: https://lore.kernel.org/all/a7fc58e4-64c2-77fc-c1dc-f5eb78dbbb01@huawei.com
2024-08-27Merge tag 'vfs-6.11-rc6.fixes' of ↵Linus Torvalds
gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs Pull vfs fixes from Christian Brauner: "VFS: - Ensure that backing files uses file->f_ops->splice_write() for splice netfs: - Revert the removal of PG_private_2 from netfs_release_folio() as cephfs still relies on this - When AS_RELEASE_ALWAYS is set on a mapping the folio needs to always be invalidated during truncation - Fix losing untruncated data in a folio by making letting netfs_release_folio() return false if the folio is dirty - Fix trimming of streaming-write folios in netfs_inval_folio() - Reset iterator before retrying a short read - Fix interaction of streaming writes with zero-point tracker afs: - During truncation afs currently calls truncate_setsize() which sets i_size, expands the pagecache and truncates it. The first two operations aren't needed because they will have already been done. So call truncate_pagecache() instead and skip the redundant parts overlayfs: - Fix checking of the number of allowed lower layers so 500 layers can actually be used instead of just 499 - Add missing '\n' to pr_err() output - Pass string to ovl_parse_layer() and thus allow it to be used for Opt_lowerdir as well pidfd: - Revert blocking the creation of pidfds for kthread as apparently userspace relies on this. Specifically, it breaks systemd during shutdown romfs: - Fix romfs_read_folio() to use the correct offset with folio_zero_tail()" * tag 'vfs-6.11-rc6.fixes' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: netfs: Fix interaction of streaming writes with zero-point tracker netfs: Fix missing iterator reset on retry of short read netfs: Fix trimming of streaming-write folios in netfs_inval_folio() netfs: Fix netfs_release_folio() to say no if folio dirty afs: Fix post-setattr file edit to do truncation correctly mm: Fix missing folio invalidation calls during truncation ovl: ovl_parse_param_lowerdir: Add missed '\n' for pr_err ovl: fix wrong lowerdir number check for parameter Opt_lowerdir ovl: pass string to ovl_parse_layer() backing-file: convert to using fops->splice_write Revert "pidfd: prevent creation of pidfds for kthreads" romfs: fix romfs_read_folio() netfs, ceph: Partially revert "netfs: Replace PG_fscache by setting folio->private and marking dirty"
2024-08-26tracing: Add option to set an instance to be the trace_printk destinationSteven Rostedt
Add a option "trace_printk_dest" that will make the tracing instance the location that trace_printk() will go to. This is useful if the trace_printk or one of the top level tracers is too noisy and there's a need to separate the two. Then an instance can be created, the trace_printk can be set to go there instead, where it will not be lost in the noise of the top level tracer. Note, only one instance can be the destination of trace_printk at a time. If an instance sets this flag, the instance that had it set will have it cleared. There is always one instance that has this set. By default, that is the top instance. This flag cannot be cleared from the top instance. Doing so will result in an -EINVAL. The only way this flag can be cleared from the top instance is by another instance setting it. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Vincent Donnefort <vdonnefort@google.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vineeth Pillai <vineeth@bitbyteword.org> Cc: Beau Belgrave <beaub@linux.microsoft.com> Cc: Alexander Graf <graf@amazon.com> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: David Howells <dhowells@redhat.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Ross Zwisler <zwisler@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Alexander Aring <aahringo@redhat.com> Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com> Cc: Tomas Glozar <tglozar@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: "Jonathan Corbet" <corbet@lwn.net> Link: https://lore.kernel.org/20240823014019.545459018@goodmis.org Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>