Commit 5d5de3a4 authored by Hou Tao's avatar Hou Tao Committed by Alexei Starovoitov
Browse files

bpf: Only allocate one bpf_mem_cache for bpf_cpumask_ma 



The size of bpf_cpumask is fixed, so there is no need to allocate many
bpf_mem_caches for bpf_cpumask_ma, just one bpf_mem_cache is enough.
Also add comments for bpf_mem_alloc_init() in bpf_mem_alloc.h to prevent
future miuse.

Signed-off-by: default avatarHou Tao <houtao1@huawei.com>
Acked-by: default avatarJiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230216024821.2202916-1-houtao@huaweicloud.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent dbd8d228

include/linux/bpf_mem_alloc.h

+7 −0
Original line number Diff line number Diff line
@@ -14,6 +14,13 @@ struct bpf_mem_alloc { 
	struct work_struct work;

};



/* 'size != 0' is for bpf_mem_alloc which manages fixed-size objects.

 * Alloc and free are done with bpf_mem_cache_{alloc,free}().

 *

 * 'size = 0' is for bpf_mem_alloc which manages many fixed-size objects.

 * Alloc and free are done with bpf_mem_{alloc,free}() and the size of

 * the returned object is given by the size argument of bpf_mem_alloc().

 */

int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, bool percpu);

void bpf_mem_alloc_destroy(struct bpf_mem_alloc *ma);

kernel/bpf/cpumask.c

+3 −3
Original line number Diff line number Diff line
@@ -55,7 +55,7 @@ __bpf_kfunc struct bpf_cpumask *bpf_cpumask_create(void) 
	/* cpumask must be the first element so struct bpf_cpumask be cast to struct cpumask. */

	BUILD_BUG_ON(offsetof(struct bpf_cpumask, cpumask) != 0);



	cpumask = bpf_mem_alloc(&bpf_cpumask_ma, sizeof(*cpumask));

	cpumask = bpf_mem_cache_alloc(&bpf_cpumask_ma);

	if (!cpumask)

		return NULL;
@@ -123,7 +123,7 @@ __bpf_kfunc void bpf_cpumask_release(struct bpf_cpumask *cpumask) 


	if (refcount_dec_and_test(&cpumask->usage)) {

		migrate_disable();

		bpf_mem_free(&bpf_cpumask_ma, cpumask);

		bpf_mem_cache_free(&bpf_cpumask_ma, cpumask);

		migrate_enable();

	}

}
@@ -468,7 +468,7 @@ static int __init cpumask_kfunc_init(void) 
		},

	};



	ret = bpf_mem_alloc_init(&bpf_cpumask_ma, 0, false);

	ret = bpf_mem_alloc_init(&bpf_cpumask_ma, sizeof(struct bpf_cpumask), false);

	ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &cpumask_kfunc_set);

	ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS, &cpumask_kfunc_set);

	return  ret ?: register_btf_id_dtor_kfuncs(cpumask_dtors,