linux-stable/include/linux/bpf_mem_alloc.h
Martin KaFai Lau e65a5c6edb bpf: Add a few bpf mem allocator functions
This patch adds a few bpf mem allocator functions which will
be used in the bpf_local_storage in a later patch.

bpf_mem_cache_alloc_flags(..., gfp_t flags) is added. When the
flags == GFP_KERNEL, it will fallback to __alloc(..., GFP_KERNEL).
bpf_local_storage knows its running context is sleepable (GFP_KERNEL)
and provides a better guarantee on memory allocation.

bpf_local_storage has some uncommon cases that its selem
cannot be reused immediately. It handles its own
rcu_head and goes through a rcu_trace gp and then free it.
bpf_mem_cache_raw_free() is added for direct free purpose
without leaking the LLIST_NODE_SZ internal knowledge.
During free time, the 'struct bpf_mem_alloc *ma' is no longer
available. However, the caller should know if it is
percpu memory or not and it can call different raw_free functions.
bpf_local_storage does not support percpu value, so only
the non-percpu 'bpf_mem_cache_raw_free()' is added in
this patch.

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20230322215246.1675516-2-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-03-25 19:52:51 -07:00

37 lines
1.3 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
#ifndef _BPF_MEM_ALLOC_H
#define _BPF_MEM_ALLOC_H
#include <linux/compiler_types.h>
#include <linux/workqueue.h>
struct bpf_mem_cache;
struct bpf_mem_caches;
struct bpf_mem_alloc {
struct bpf_mem_caches __percpu *caches;
struct bpf_mem_cache __percpu *cache;
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);
/* kmalloc/kfree equivalent: */
void *bpf_mem_alloc(struct bpf_mem_alloc *ma, size_t size);
void bpf_mem_free(struct bpf_mem_alloc *ma, void *ptr);
/* kmem_cache_alloc/free equivalent: */
void *bpf_mem_cache_alloc(struct bpf_mem_alloc *ma);
void bpf_mem_cache_free(struct bpf_mem_alloc *ma, void *ptr);
void bpf_mem_cache_raw_free(void *ptr);
void *bpf_mem_cache_alloc_flags(struct bpf_mem_alloc *ma, gfp_t flags);
#endif /* _BPF_MEM_ALLOC_H */