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Changwoo MinandTejun Heo
ee8391ba11
Extend struct user_exit_info with an exit_cpu field so BPF schedulers and the userspace report path can see the CPU that triggered the exit, matching the kernel-side dump. UEI_RECORD() defaults the field to -1 before the CO-RE-gated copy so that running against an older kernel without exit_cpu stays distinguishable from "exit happened on CPU 0". UEI_REPORT() appends "on CPU N" to the EXIT line when the value is valid, surfacing the most diagnostically useful piece of exit info to any sched_ext userspace tool without needing to crack open the debug dump. Signed-off-by: Changwoo Min <changwoo@igalia.com> Signed-off-by: Tejun Heo <tj@kernel.org>
44 lines
1.4 KiB
C
44 lines
1.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Define struct user_exit_info which is shared between BPF and userspace parts
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* to communicate exit status and other information.
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*
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* Copyright (c) 2022 Meta Platforms, Inc. and affiliates.
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* Copyright (c) 2022 Tejun Heo <tj@kernel.org>
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* Copyright (c) 2022 David Vernet <dvernet@meta.com>
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*/
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#ifndef __USER_EXIT_INFO_BPF_H
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#define __USER_EXIT_INFO_BPF_H
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#ifndef LSP
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#include "vmlinux.h"
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#endif
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#include <bpf/bpf_core_read.h>
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#include "user_exit_info_common.h"
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#define UEI_DEFINE(__name) \
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char RESIZABLE_ARRAY(data, __name##_dump); \
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const volatile u32 __name##_dump_len; \
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struct user_exit_info __name SEC(".data")
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#define UEI_RECORD(__uei_name, __ei) ({ \
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bpf_probe_read_kernel_str(__uei_name.reason, \
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sizeof(__uei_name.reason), (__ei)->reason); \
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bpf_probe_read_kernel_str(__uei_name.msg, \
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sizeof(__uei_name.msg), (__ei)->msg); \
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bpf_probe_read_kernel_str(__uei_name##_dump, \
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__uei_name##_dump_len, (__ei)->dump); \
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if (bpf_core_field_exists((__ei)->exit_code)) \
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__uei_name.exit_code = (__ei)->exit_code; \
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__uei_name.exit_cpu = -1; \
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if (bpf_core_field_exists((__ei)->exit_cpu)) \
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__uei_name.exit_cpu = (__ei)->exit_cpu; \
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/* use __sync to force memory barrier */ \
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__sync_val_compare_and_swap(&__uei_name.kind, __uei_name.kind, \
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(__ei)->kind); \
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})
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#endif /* __USER_EXIT_INFO_BPF_H */
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