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davemarchevskyKernel Patches Daemon
davemarchevsky
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selftests/bpf: Add local_storage exclusive cache test
Validate local_storage exclusive caching functionality: * Adding >BPF_LOCAL_STORAGE_CACHE_SIZE task_storage maps w/ BPF_LOCAL_STORAGE_FORCE_CACHE results in failure to load program as there are free slots to claim. * Adding BPF_LOCAL_STORAGE_CACHE_SIZE task_storage maps w/ FORCE_CACHE succeeds and results in a filled idx_bitmap for the cache. After first bpf_task_storage_get call for each map, the map's local storage data is in the cache slot. Subsequent bpf_task_storage_get calls to non-exclusive-cached maps don't replace exclusive-cached maps. Signed-off-by: Dave Marchevsky <[email protected]>
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‎tools/testing/selftests/bpf/prog_tests/test_local_storage_excl_cache.c‎

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// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
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#include <linux/bitmap.h>
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#include <test_progs.h>
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#include "local_storage_excl_cache.skel.h"
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#include "local_storage_excl_cache_fail.skel.h"
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void test_test_local_storage_excl_cache(void)
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{
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u64 cache_idx_exclusive, cache_idx_exclusive_expected;
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struct local_storage_excl_cache_fail *skel_fail = NULL;
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struct local_storage_excl_cache *skel = NULL;
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u16 cache_size, i;
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int err;
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skel_fail = local_storage_excl_cache_fail__open_and_load();
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ASSERT_ERR_PTR(skel_fail, "excl_cache_fail load should fail");
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local_storage_excl_cache_fail__destroy(skel_fail);
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skel = local_storage_excl_cache__open_and_load();
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if (!ASSERT_OK_PTR(skel, "excl_cache load should succeed"))
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goto cleanup;
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cache_size = skel->data->__BPF_LOCAL_STORAGE_CACHE_SIZE;
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err = local_storage_excl_cache__attach(skel);
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if (!ASSERT_OK(err, "excl_cache__attach"))
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goto cleanup;
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/* trigger tracepoint */
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usleep(1);
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cache_idx_exclusive = skel->data->out__cache_bitmap;
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cache_idx_exclusive_expected = 0;
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for (i = 0; i < cache_size; i++)
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cache_idx_exclusive_expected |= (1U << i);
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if (!ASSERT_EQ(cache_idx_exclusive & cache_idx_exclusive_expected,
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cache_idx_exclusive_expected, "excl cache bitmap should be full"))
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goto cleanup;
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usleep(1);
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for (i = 0; i < cache_size; i++)
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if (!ASSERT_EQ(skel->data->out__cache_smaps[i],
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skel->data->out__declared_smaps[i],
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"cached map not equal"))
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goto cleanup;
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cleanup:
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local_storage_excl_cache__destroy(skel);
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}

‎tools/testing/selftests/bpf/progs/local_storage_excl_cache.c‎

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// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
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#include "vmlinux.h"
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#include <bpf/bpf_helpers.h>
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char _license[] SEC("license") = "GPL";
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#define make_task_local_excl_map(name, num) \
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struct { \
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__uint(type, BPF_MAP_TYPE_TASK_STORAGE); \
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__uint(map_flags, BPF_F_NO_PREALLOC); \
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__type(key, int); \
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__type(value, __u32); \
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__uint(map_extra, BPF_LOCAL_STORAGE_FORCE_CACHE); \
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} name ## num SEC(".maps");
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#define make_task_local_map(name, num) \
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struct { \
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__uint(type, BPF_MAP_TYPE_TASK_STORAGE); \
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__uint(map_flags, BPF_F_NO_PREALLOC); \
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__type(key, int); \
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__type(value, __u32); \
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} name ## num SEC(".maps");
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#define task_storage_get_excl(map, num) \
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({ \
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bpf_task_storage_get(&map ## num, task, 0, BPF_LOCAL_STORAGE_GET_F_CREATE); \
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bpf_probe_read_kernel(&out__cache_smaps[num], \
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sizeof(void *), \
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&task->bpf_storage->cache[num]->smap); \
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out__declared_smaps[num] = &map ## num; \
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})
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/* must match define in bpf_local_storage.h */
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#define BPF_LOCAL_STORAGE_CACHE_SIZE 16
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/* Try adding BPF_LOCAL_STORAGE_CACHE_SIZE task_storage maps w/ exclusive
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* cache slot
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*/
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make_task_local_excl_map(task_storage_map, 0);
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make_task_local_excl_map(task_storage_map, 1);
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make_task_local_excl_map(task_storage_map, 2);
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make_task_local_excl_map(task_storage_map, 3);
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make_task_local_excl_map(task_storage_map, 4);
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make_task_local_excl_map(task_storage_map, 5);
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make_task_local_excl_map(task_storage_map, 6);
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make_task_local_excl_map(task_storage_map, 7);
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make_task_local_excl_map(task_storage_map, 8);
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make_task_local_excl_map(task_storage_map, 9);
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make_task_local_excl_map(task_storage_map, 10);
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make_task_local_excl_map(task_storage_map, 11);
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make_task_local_excl_map(task_storage_map, 12);
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make_task_local_excl_map(task_storage_map, 13);
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make_task_local_excl_map(task_storage_map, 14);
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make_task_local_excl_map(task_storage_map, 15);
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make_task_local_map(task_storage_map, 16);
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extern const void task_cache __ksym;
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__u64 __BPF_LOCAL_STORAGE_CACHE_SIZE = BPF_LOCAL_STORAGE_CACHE_SIZE;
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__u64 out__cache_bitmap = -1;
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void *out__cache_smaps[BPF_LOCAL_STORAGE_CACHE_SIZE] = { (void *)-1 };
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void *out__declared_smaps[BPF_LOCAL_STORAGE_CACHE_SIZE] = { (void *)-1 };
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SEC("raw_tp/sys_enter")
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int handler(const void *ctx)
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{
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struct task_struct *task = bpf_get_current_task_btf();
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__u32 *ptr;
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bpf_probe_read_kernel(&out__cache_bitmap, sizeof(out__cache_bitmap),
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&task_cache +
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offsetof(struct bpf_local_storage_cache, idx_exclusive));
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/* Get all BPF_LOCAL_STORAGE_CACHE_SIZE exclusive-cache maps into cache,
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* and one that shouldn't be cached
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*/
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task_storage_get_excl(task_storage_map, 0);
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task_storage_get_excl(task_storage_map, 1);
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task_storage_get_excl(task_storage_map, 2);
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task_storage_get_excl(task_storage_map, 3);
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task_storage_get_excl(task_storage_map, 4);
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task_storage_get_excl(task_storage_map, 5);
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task_storage_get_excl(task_storage_map, 6);
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task_storage_get_excl(task_storage_map, 7);
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task_storage_get_excl(task_storage_map, 8);
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task_storage_get_excl(task_storage_map, 9);
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task_storage_get_excl(task_storage_map, 10);
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task_storage_get_excl(task_storage_map, 11);
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task_storage_get_excl(task_storage_map, 12);
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task_storage_get_excl(task_storage_map, 13);
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task_storage_get_excl(task_storage_map, 14);
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task_storage_get_excl(task_storage_map, 15);
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bpf_task_storage_get(&task_storage_map16, task, 0,
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BPF_LOCAL_STORAGE_GET_F_CREATE);
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return 0;
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}

‎tools/testing/selftests/bpf/progs/local_storage_excl_cache_fail.c‎

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// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
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#include "vmlinux.h"
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#include <bpf/bpf_helpers.h>
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char _license[] SEC("license") = "GPL";
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#define make_task_local_excl_map(name, num) \
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struct { \
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__uint(type, BPF_MAP_TYPE_TASK_STORAGE); \
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__uint(map_flags, BPF_F_NO_PREALLOC); \
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__type(key, int); \
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__type(value, __u32); \
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__uint(map_extra, BPF_LOCAL_STORAGE_FORCE_CACHE); \
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} name ## num SEC(".maps");
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/* Try adding BPF_LOCAL_STORAGE_CACHE_SIZE+1 task_storage maps w/ exclusive
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* cache slot */
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make_task_local_excl_map(task_storage_map, 0);
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make_task_local_excl_map(task_storage_map, 1);
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make_task_local_excl_map(task_storage_map, 2);
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make_task_local_excl_map(task_storage_map, 3);
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make_task_local_excl_map(task_storage_map, 4);
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make_task_local_excl_map(task_storage_map, 5);
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make_task_local_excl_map(task_storage_map, 6);
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make_task_local_excl_map(task_storage_map, 7);
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make_task_local_excl_map(task_storage_map, 8);
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make_task_local_excl_map(task_storage_map, 9);
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make_task_local_excl_map(task_storage_map, 10);
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make_task_local_excl_map(task_storage_map, 11);
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make_task_local_excl_map(task_storage_map, 12);
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make_task_local_excl_map(task_storage_map, 13);
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make_task_local_excl_map(task_storage_map, 14);
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make_task_local_excl_map(task_storage_map, 15);
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make_task_local_excl_map(task_storage_map, 16);

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