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a10787e6d5
To access per-task data, BPF programs usually creates a hash table with
pid as the key. This is not ideal because:
1. The user need to estimate the proper size of the hash table, which may
be inaccurate;
2. Big hash tables are slow;
3. To clean up the data properly during task terminations, the user need
to write extra logic.
Task local storage overcomes these issues and offers a better option for
these per-task data. Task local storage is only available to BPF_LSM. Now
enable it for tracing programs.
Unlike LSM programs, tracing programs can be called in IRQ contexts.
Helpers that access task local storage are updated to use
raw_spin_lock_irqsave() instead of raw_spin_lock_bh().
Tracing programs can attach to functions on the task free path, e.g.
exit_creds(). To avoid allocating task local storage after
bpf_task_storage_free(). bpf_task_storage_get() is updated to not allocate
new storage when the task is not refcounted (task->usage == 0).
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: KP Singh <kpsingh@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20210225234319.336131-2-songliubraving@fb.com
38 lines
1.5 KiB
Makefile
38 lines
1.5 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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obj-y := core.o
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ifneq ($(CONFIG_BPF_JIT_ALWAYS_ON),y)
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# ___bpf_prog_run() needs GCSE disabled on x86; see 3193c0836f203 for details
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cflags-nogcse-$(CONFIG_X86)$(CONFIG_CC_IS_GCC) := -fno-gcse
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endif
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CFLAGS_core.o += $(call cc-disable-warning, override-init) $(cflags-nogcse-yy)
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obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o tnum.o bpf_iter.o map_iter.o task_iter.o prog_iter.o
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obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o percpu_freelist.o bpf_lru_list.o lpm_trie.o map_in_map.o
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obj-$(CONFIG_BPF_SYSCALL) += local_storage.o queue_stack_maps.o ringbuf.o
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obj-$(CONFIG_BPF_SYSCALL) += bpf_local_storage.o bpf_task_storage.o
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obj-${CONFIG_BPF_LSM} += bpf_inode_storage.o
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obj-$(CONFIG_BPF_SYSCALL) += disasm.o
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obj-$(CONFIG_BPF_JIT) += trampoline.o
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obj-$(CONFIG_BPF_SYSCALL) += btf.o
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obj-$(CONFIG_BPF_JIT) += dispatcher.o
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ifeq ($(CONFIG_NET),y)
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obj-$(CONFIG_BPF_SYSCALL) += devmap.o
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obj-$(CONFIG_BPF_SYSCALL) += cpumap.o
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obj-$(CONFIG_BPF_SYSCALL) += offload.o
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obj-$(CONFIG_BPF_SYSCALL) += net_namespace.o
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endif
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ifeq ($(CONFIG_PERF_EVENTS),y)
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obj-$(CONFIG_BPF_SYSCALL) += stackmap.o
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endif
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obj-$(CONFIG_CGROUP_BPF) += cgroup.o
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ifeq ($(CONFIG_INET),y)
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obj-$(CONFIG_BPF_SYSCALL) += reuseport_array.o
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endif
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ifeq ($(CONFIG_SYSFS),y)
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obj-$(CONFIG_DEBUG_INFO_BTF) += sysfs_btf.o
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endif
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ifeq ($(CONFIG_BPF_JIT),y)
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obj-$(CONFIG_BPF_SYSCALL) += bpf_struct_ops.o
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obj-${CONFIG_BPF_LSM} += bpf_lsm.o
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endif
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obj-$(CONFIG_BPF_PRELOAD) += preload/
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