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Commit 9d8b612d authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by David S. Miller
Browse files

samples/bpf: add bpf map stress test 



this test calls bpf programs from different contexts:
from inside of slub, from rcu, from pretty much everywhere,
since it kprobes all spin_lock functions.
It stresses the bpf hash and percpu map pre-allocation,
deallocation logic and call_rcu mechanisms.
User space part adding more stress by walking and deleting map elements.

Note that due to nature bpf_load.c the earlier kprobe+bpf programs are
already active while loader loads new programs, creates new kprobes and
attaches them.

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e28e87ed

samples/bpf/Makefile

+4 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ hostprogs-y += tracex6 
hostprogs-y += trace_output

hostprogs-y += lathist

hostprogs-y += offwaketime

hostprogs-y += spintest



test_verifier-objs := test_verifier.o libbpf.o

test_maps-objs := test_maps.o libbpf.o
@@ -34,6 +35,7 @@ tracex6-objs := bpf_load.o libbpf.o tracex6_user.o 
trace_output-objs := bpf_load.o libbpf.o trace_output_user.o

lathist-objs := bpf_load.o libbpf.o lathist_user.o

offwaketime-objs := bpf_load.o libbpf.o offwaketime_user.o

spintest-objs := bpf_load.o libbpf.o spintest_user.o



# Tell kbuild to always build the programs

always := $(hostprogs-y)
@@ -50,6 +52,7 @@ always += trace_output_kern.o 
always += tcbpf1_kern.o

always += lathist_kern.o

always += offwaketime_kern.o

always += spintest_kern.o



HOSTCFLAGS += -I$(objtree)/usr/include
@@ -67,6 +70,7 @@ HOSTLOADLIBES_tracex6 += -lelf 
HOSTLOADLIBES_trace_output += -lelf -lrt

HOSTLOADLIBES_lathist += -lelf

HOSTLOADLIBES_offwaketime += -lelf

HOSTLOADLIBES_spintest += -lelf



# point this to your LLVM backend with bpf support

LLC=$(srctree)/tools/bpf/llvm/bld/Debug+Asserts/bin/llc

samples/bpf/spintest_kern.c

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+59 −0
Original line number Diff line number Diff line 
/* Copyright (c) 2016, Facebook

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of version 2 of the GNU General Public

 * License as published by the Free Software Foundation.

 */

#include <linux/skbuff.h>

#include <linux/netdevice.h>

#include <linux/version.h>

#include <uapi/linux/bpf.h>

#include "bpf_helpers.h"



struct bpf_map_def SEC("maps") my_map = {

	.type = BPF_MAP_TYPE_HASH,

	.key_size = sizeof(long),

	.value_size = sizeof(long),

	.max_entries = 1024,

};

struct bpf_map_def SEC("maps") my_map2 = {

	.type = BPF_MAP_TYPE_PERCPU_HASH,

	.key_size = sizeof(long),

	.value_size = sizeof(long),

	.max_entries = 1024,

};



#define PROG(foo) \

int foo(struct pt_regs *ctx) \

{ \

	long v = ctx->ip, *val; \

\

	val = bpf_map_lookup_elem(&my_map, &v); \

	bpf_map_update_elem(&my_map, &v, &v, BPF_ANY); \

	bpf_map_update_elem(&my_map2, &v, &v, BPF_ANY); \

	bpf_map_delete_elem(&my_map2, &v); \

	return 0; \

}



/* add kprobes to all possible *spin* functions */

SEC("kprobe/spin_unlock")PROG(p1)

SEC("kprobe/spin_lock")PROG(p2)

SEC("kprobe/mutex_spin_on_owner")PROG(p3)

SEC("kprobe/rwsem_spin_on_owner")PROG(p4)

SEC("kprobe/spin_unlock_irqrestore")PROG(p5)

SEC("kprobe/_raw_spin_unlock_irqrestore")PROG(p6)

SEC("kprobe/_raw_spin_unlock_bh")PROG(p7)

SEC("kprobe/_raw_spin_unlock")PROG(p8)

SEC("kprobe/_raw_spin_lock_irqsave")PROG(p9)

SEC("kprobe/_raw_spin_trylock_bh")PROG(p10)

SEC("kprobe/_raw_spin_lock_irq")PROG(p11)

SEC("kprobe/_raw_spin_trylock")PROG(p12)

SEC("kprobe/_raw_spin_lock")PROG(p13)

SEC("kprobe/_raw_spin_lock_bh")PROG(p14)

/* and to inner bpf helpers */

SEC("kprobe/htab_map_update_elem")PROG(p15)

SEC("kprobe/__htab_percpu_map_update_elem")PROG(p16)

SEC("kprobe/htab_map_alloc")PROG(p17)



char _license[] SEC("license") = "GPL";

u32 _version SEC("version") = LINUX_VERSION_CODE;

samples/bpf/spintest_user.c

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+50 −0
Original line number Diff line number Diff line 
#include <stdio.h>

#include <unistd.h>

#include <linux/bpf.h>

#include <string.h>

#include <assert.h>

#include <sys/resource.h>

#include "libbpf.h"

#include "bpf_load.h"



int main(int ac, char **argv)

{

	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};

	long key, next_key, value;

	char filename[256];

	struct ksym *sym;

	int i;



	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);

	setrlimit(RLIMIT_MEMLOCK, &r);



	if (load_kallsyms()) {

		printf("failed to process /proc/kallsyms\n");

		return 2;

	}



	if (load_bpf_file(filename)) {

		printf("%s", bpf_log_buf);

		return 1;

	}



	for (i = 0; i < 5; i++) {

		key = 0;

		printf("kprobing funcs:");

		while (bpf_get_next_key(map_fd[0], &key, &next_key) == 0) {

			bpf_lookup_elem(map_fd[0], &next_key, &value);

			assert(next_key == value);

			sym = ksym_search(value);

			printf(" %s", sym->name);

			key = next_key;

		}

		if (key)

			printf("\n");

		key = 0;

		while (bpf_get_next_key(map_fd[0], &key, &next_key) == 0)

			bpf_delete_elem(map_fd[0], &next_key);

		sleep(1);

	}



	return 0;

}