Commit c5815ac7 authored by Daniel T. Lee's avatar Daniel T. Lee Committed by Andrii Nakryiko
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samples: bpf: Refactor hbm program with libbpf 



This commit refactors the existing cgroup programs with libbpf
bpf loader. Since bpf_program__attach doesn't support cgroup program
attachment, this explicitly attaches cgroup bpf program with
bpf_program__attach_cgroup(bpf_prog, cg1).

Also, to change attach_type of bpf program, this uses libbpf's
bpf_program__set_expected_attach_type helper to switch EGRESS to
INGRESS. To keep bpf program attached to the cgroup hierarchy even
after the exit, this commit uses the BPF_LINK_PINNING to pin the link
attachment even after it is closed.

Besides, this program was broken due to the typo of BPF MAP definition.
But this commit solves the problem by fixing this from 'queue_stats' map
struct hvm_queue_stats -> hbm_queue_stats.

Fixes: 36b5d471 ("selftests/bpf: samples/bpf: Split off legacy stuff from bpf_helpers.h")
Signed-off-by: default avatarDaniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201124090310.24374-2-danieltimlee@gmail.com
parent fb355812

samples/bpf/.gitignore

+3 −0
Original line number Diff line number Diff line
@@ -52,3 +52,6 @@ xdp_tx_iptunnel 
xdpsock

xsk_fwd

testfile.img

hbm_out.log

iperf.*

*.out

samples/bpf/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -110,7 +110,7 @@ xdp_fwd-objs := xdp_fwd_user.o 
task_fd_query-objs := bpf_load.o task_fd_query_user.o $(TRACE_HELPERS)

xdp_sample_pkts-objs := xdp_sample_pkts_user.o $(TRACE_HELPERS)

ibumad-objs := bpf_load.o ibumad_user.o $(TRACE_HELPERS)

hbm-objs := bpf_load.o hbm.o $(CGROUP_HELPERS)

hbm-objs := hbm.o $(CGROUP_HELPERS)



# Tell kbuild to always build the programs

always-y := $(tprogs-y)

samples/bpf/do_hbm_test.sh

+14 −18
Original line number Diff line number Diff line
@@ -91,6 +91,16 @@ qdisc="" 
flags=""

do_stats=0



BPFFS=/sys/fs/bpf

function config_bpffs () {

	if mount | grep $BPFFS > /dev/null; then

		echo "bpffs already mounted"

	else

		echo "bpffs not mounted. Mounting..."

		mount -t bpf none $BPFFS

	fi

}



function start_hbm () {

  rm -f hbm.out

  echo "./hbm $dir -n $id -r $rate -t $dur $flags $dbg $prog" > hbm.out
@@ -192,6 +202,7 @@ processArgs () { 
}



processArgs

config_bpffs



if [ $debug_flag -eq 1 ] ; then

  rm -f hbm_out.log
@@ -201,7 +212,7 @@ hbm_pid=$(start_hbm) 
usleep 100000



host=`hostname`

cg_base_dir=/sys/fs/cgroup

cg_base_dir=/sys/fs/cgroup/unified

cg_dir="$cg_base_dir/cgroup-test-work-dir/hbm$id"



echo $$ >> $cg_dir/cgroup.procs
@@ -411,23 +422,8 @@ fi 


sleep 1



# Detach any BPF programs that may have lingered

ttx=`bpftool cgroup tree | grep hbm`

v=2

for x in $ttx ; do

    if [ "${x:0:36}" == "/sys/fs/cgroup/cgroup-test-work-dir/" ] ; then

	cg=$x ; v=0

    else

	if [ $v -eq 0 ] ; then

	    id=$x ; v=1

	else

	    if [ $v -eq 1 ] ; then

		type=$x ; bpftool cgroup detach $cg $type id $id

		v=0

	    fi

	fi

    fi

done

# Detach any pinned BPF programs that may have lingered

rm -rf $BPFFS/hbm*



if [ $use_netperf -ne 0 ] ; then

  if [ "$server" == "" ] ; then

samples/bpf/hbm.c

+59 −52
Original line number Diff line number Diff line
@@ -46,7 +46,6 @@ 
#include <bpf/bpf.h>

#include <getopt.h>



#include "bpf_load.h"

#include "bpf_rlimit.h"

#include "cgroup_helpers.h"

#include "hbm.h"
@@ -70,9 +69,9 @@ static void do_error(char *msg, bool errno_flag); 


#define DEBUGFS "/sys/kernel/debug/tracing/"



struct bpf_object *obj;

int bpfprog_fd;

int cgroup_storage_fd;

static struct bpf_program *bpf_prog;

static struct bpf_object *obj;

static int queue_stats_fd;



static void read_trace_pipe2(void)

{
@@ -121,56 +120,50 @@ static void do_error(char *msg, bool errno_flag) 


static int prog_load(char *prog)

{

	struct bpf_prog_load_attr prog_load_attr = {

		.prog_type = BPF_PROG_TYPE_CGROUP_SKB,

		.file = prog,

		.expected_attach_type = BPF_CGROUP_INET_EGRESS,

	};

	int map_fd;

	struct bpf_map *map;



	int ret = 0;



	if (access(prog, O_RDONLY) < 0) {

		printf("Error accessing file %s: %s\n", prog, strerror(errno));

	obj = bpf_object__open_file(prog, NULL);

	if (libbpf_get_error(obj)) {

		printf("ERROR: opening BPF object file failed\n");

		return 1;

	}

	if (bpf_prog_load_xattr(&prog_load_attr, &obj, &bpfprog_fd))

		ret = 1;

	if (!ret) {

		map = bpf_object__find_map_by_name(obj, "queue_stats");

		map_fd = bpf_map__fd(map);

		if (map_fd < 0) {

			printf("Map not found: %s\n", strerror(map_fd));

			ret = 1;



	/* load BPF program */

	if (bpf_object__load(obj)) {

		printf("ERROR: loading BPF object file failed\n");

		goto err;

	}



	bpf_prog = bpf_object__find_program_by_title(obj, "cgroup_skb/egress");

	if (!bpf_prog) {

		printf("ERROR: finding a prog in obj file failed\n");

		goto err;

	}



	if (ret) {

		printf("ERROR: bpf_prog_load_xattr failed for: %s\n", prog);

		printf("  Output from verifier:\n%s\n------\n", bpf_log_buf);

		ret = -1;

	} else {

		ret = map_fd;

	queue_stats_fd = bpf_object__find_map_fd_by_name(obj, "queue_stats");

	if (queue_stats_fd < 0) {

		printf("ERROR: finding a map in obj file failed\n");

		goto err;

	}



	return ret;

	return 0;



err:

	bpf_object__close(obj);

	return 1;

}



static int run_bpf_prog(char *prog, int cg_id)

{

	int map_fd;

	int rc = 0;

	struct hbm_queue_stats qstats = {0};

	char cg_dir[100], cg_pin_path[100];

	struct bpf_link *link = NULL;

	int key = 0;

	int cg1 = 0;

	int type = BPF_CGROUP_INET_EGRESS;

	char cg_dir[100];

	struct hbm_queue_stats qstats = {0};

	int rc = 0;



	sprintf(cg_dir, "/hbm%d", cg_id);

	map_fd = prog_load(prog);

	if (map_fd  == -1)

		return 1;

	rc = prog_load(prog);

	if (rc != 0)

		return rc;



	if (setup_cgroup_environment()) {

		printf("ERROR: setting cgroup environment\n");
@@ -190,16 +183,24 @@ static int run_bpf_prog(char *prog, int cg_id) 
	qstats.stats = stats_flag ? 1 : 0;

	qstats.loopback = loopback_flag ? 1 : 0;

	qstats.no_cn = no_cn_flag ? 1 : 0;

	if (bpf_map_update_elem(map_fd, &key, &qstats, BPF_ANY)) {

	if (bpf_map_update_elem(queue_stats_fd, &key, &qstats, BPF_ANY)) {

		printf("ERROR: Could not update map element\n");

		goto err;

	}



	if (!outFlag)

		type = BPF_CGROUP_INET_INGRESS;

	if (bpf_prog_attach(bpfprog_fd, cg1, type, 0)) {

		printf("ERROR: bpf_prog_attach fails!\n");

		log_err("Attaching prog");

		bpf_program__set_expected_attach_type(bpf_prog, BPF_CGROUP_INET_INGRESS);



	link = bpf_program__attach_cgroup(bpf_prog, cg1);

	if (libbpf_get_error(link)) {

		fprintf(stderr, "ERROR: bpf_program__attach_cgroup failed\n");

		goto err;

	}



	sprintf(cg_pin_path, "/sys/fs/bpf/hbm%d", cg_id);

	rc = bpf_link__pin(link, cg_pin_path);

	if (rc < 0) {

		printf("ERROR: bpf_link__pin failed: %d\n", rc);

		goto err;

	}
@@ -213,7 +214,7 @@ static int run_bpf_prog(char *prog, int cg_id) 
#define DELTA_RATE_CHECK 10000		/* in us */

#define RATE_THRESHOLD 9500000000	/* 9.5 Gbps */



		bpf_map_lookup_elem(map_fd, &key, &qstats);

		bpf_map_lookup_elem(queue_stats_fd, &key, &qstats);

		if (gettimeofday(&t0, NULL) < 0)

			do_error("gettimeofday failed", true);

		t_last = t0;
@@ -242,7 +243,7 @@ static int run_bpf_prog(char *prog, int cg_id) 
			fclose(fin);

			printf("  new_eth_tx_bytes:%llu\n",

			       new_eth_tx_bytes);

			bpf_map_lookup_elem(map_fd, &key, &qstats);

			bpf_map_lookup_elem(queue_stats_fd, &key, &qstats);

			new_cg_tx_bytes = qstats.bytes_total;

			delta_bytes = new_eth_tx_bytes - last_eth_tx_bytes;

			last_eth_tx_bytes = new_eth_tx_bytes;
@@ -289,14 +290,14 @@ static int run_bpf_prog(char *prog, int cg_id) 
					rate = minRate;

				qstats.rate = rate;

			}

			if (bpf_map_update_elem(map_fd, &key, &qstats, BPF_ANY))

			if (bpf_map_update_elem(queue_stats_fd, &key, &qstats, BPF_ANY))

				do_error("update map element fails", false);

		}

	} else {

		sleep(dur);

	}

	// Get stats!

	if (stats_flag && bpf_map_lookup_elem(map_fd, &key, &qstats)) {

	if (stats_flag && bpf_map_lookup_elem(queue_stats_fd, &key, &qstats)) {

		char fname[100];

		FILE *fout;
@@ -394,14 +395,20 @@ static int run_bpf_prog(char *prog, int cg_id) 


	if (debugFlag)

		read_trace_pipe2();

	return rc;

	goto cleanup;



err:

	rc = 1;



	if (cg1)

cleanup:

	bpf_link__destroy(link);

	bpf_object__close(obj);



	if (cg1 != -1)

		close(cg1);

	cleanup_cgroup_environment();



	if (rc != 0)

		cleanup_cgroup_environment();

	return rc;

}

samples/bpf/hbm_kern.h

+1 −1
Original line number Diff line number Diff line
@@ -69,7 +69,7 @@ struct { 
	__uint(type, BPF_MAP_TYPE_ARRAY);

	__uint(max_entries, 1);

	__type(key, u32);

	__type(value, struct hvm_queue_stats);

	__type(value, struct hbm_queue_stats);

} queue_stats SEC(".maps");



struct hbm_pkt_info {

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