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path: root/kernel/bpf/bpf_local_storage.c
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2021-02-26bpf: Enable task local storage for tracing programsSong Liu
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
2020-12-02bpf: Eliminate rlimit-based memory accounting for bpf local storage mapsRoman Gushchin
Do not use rlimit-based memory accounting for bpf local storage maps. It has been replaced with the memcg-based memory accounting. Signed-off-by: Roman Gushchin <guro@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20201201215900.3569844-32-guro@fb.com
2020-12-02bpf: Memcg-based memory accounting for bpf local storage mapsRoman Gushchin
Account memory used by bpf local storage maps: per-socket, per-inode and per-task storages. Signed-off-by: Roman Gushchin <guro@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20201201215900.3569844-16-guro@fb.com
2020-09-19bpf: Use hlist_add_head_rcu when linking to local_storageMartin KaFai Lau
The local_storage->list will be traversed by rcu reader in parallel. Thus, hlist_add_head_rcu() is needed in bpf_selem_link_storage_nolock(). This patch fixes it. This part of the code has recently been refactored in bpf-next and this patch makes changes to the new file "bpf_local_storage.c". Instead of using the original offending commit in the Fixes tag, the commit that created the file "bpf_local_storage.c" is used. A separate fix has been provided to the bpf tree. Fixes: 450af8d0f6be ("bpf: Split bpf_local_storage to bpf_sk_storage") Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20200916204453.2003915-1-kafai@fb.com
2020-08-25bpf: Split bpf_local_storage to bpf_sk_storageKP Singh
A purely mechanical change: bpf_sk_storage.c = bpf_sk_storage.c + bpf_local_storage.c bpf_sk_storage.h = bpf_sk_storage.h + bpf_local_storage.h Signed-off-by: KP Singh <kpsingh@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20200825182919.1118197-5-kpsingh@chromium.org