Hi,
this is a request for comments/help for a little patch I am working on.
It works to give me an inode for the executable file of an existing
task via taskstats, but I fail to get a device ID for that to be able
to then look for the correct filesystem in userspace. I am not sure if
that information is still supposed to be present at the time the stats
are produced. Basically, I want an efficient way to get the
path /proc/$pid/exe points to at process exit. I really would like to
not bother with individual tasks but only task groups (userspace
processes), but that seems to be tricky in taskstats, not being able to
tell a single-threaded process from a single thread of a multi-threaded
process … and also the tgid stats miss anything but the delay
accounting fields right now. My application in HPC just wants global
stats about wall-/cputime and memory use in a cluster, accounted for by
executable path, which encodes the used scientific software package and
version in our setup.
The one big hurdle I have at the moment is that I'm a n00b at kernel
development and just am taking gueses from the code I see. So far I
think I am accessing the correct struct member for the device ID, but
perhaps at the wrong time.
Also, I am open for suggestions for some better way of identifying the
executable. Instead of/in addition to the device ID, I would be
interested in the fsid (as given by `stat -c %i`) , for example. This
is stable for an NFS filesystem mounted on multiple nodes, where each
node has its own major:minor made up for the mount. But then, the
overlayfs for / on each netbooted node has a different fsid, while the
major:minor stays the same. So both would be good, I guess. Or a
filesystem UUID.
This is my commit/patch so far:
>From 9ed4c720448ff8a4308cfb14b70de0ee7d30c279 Mon Sep 17 00:00:00 2001
From: Thomas Orgis <thomas.or...@uni-hamburg.de>
Date: Sat, 3 Mar 2018 08:36:43 +0100
Subject: [PATCH] taskstats: introduce verison 9 with executable file info
This adds fields to the taskstats struct that give device and inode info
for the executable file associated with the process as a safer way
to get that than polling /proc/$pid/exe before a process ends.
The getdelay example program is accompanied by a variant that
just prints a stream of exiting tasks with the added info.
The idea is to be able to collect global statistics about use of certain
programs installed on a system by associating process/task stats with
an absolute executable path. The command field is unsuitable as it
does not distinguish between /foo/bar/v1.2.3/bin/bar_exe and
/foo/bar/v2.3.4/bin/bar_exe and is generally rather arbitrary.
I would like to just get the path communicated to userspace,
but I presume the growth of the struct by PATH_MAX bytes would
not be welcomed.
TODO: Device number is always zero. I am using it wrong.
Is it too late to get that info at task exit?
Signed-off-by: Thomas Orgis <thomas.or...@uni-hamburg.de>
---
include/uapi/linux/taskstats.h | 20 +-
kernel/taskstats.c | 17 ++
tools/accounting/.gitignore | 1 +
tools/accounting/procacct.c | 427 +++++++++++++++++++++++++++++++++++++++++
4 files changed, 464 insertions(+), 1 deletion(-)
create mode 100644 tools/accounting/procacct.c
diff --git a/include/uapi/linux/taskstats.h b/include/uapi/linux/taskstats.h
index b7aa7bb2349f..56b4a67f035c 100644
--- a/include/uapi/linux/taskstats.h
+++ b/include/uapi/linux/taskstats.h
@@ -34,7 +34,7 @@
*/
-#define TASKSTATS_VERSION 8
+#define TASKSTATS_VERSION 9
#define TS_COMM_LEN 32 /* should be >= TASK_COMM_LEN
* in linux/sched.h */
@@ -164,6 +164,24 @@ struct taskstats {
/* Delay waiting for memory reclaim */
__u64 freepages_count;
__u64 freepages_delay_total;
+
+ /*
+ * Version 9:
+ * Extra fields detailing executable file (/proc/$pid/exe).
+ * Values are both zero if there is no executable file
+ * Chose 64 bit for both to keep alignment. Only 32 bit expected
+ * for device, while userspace will usually only use 16 anyway.
+ * The client application is supposed to translate that to a
+ * file path itself, with knowledge about possible failure
+ * modes (changes in mounts, filesystem operations).
+ * Communicating the path from the kernel's view would mean
+ * adding PATH_MAX bytes to this struct and more work.
+ * I guess we do not want that. It would be convenient, though.
+ */
+ __u64 ac_exe_dev; /* device ID */
+ __u64 ac_exe_inode; /* inode number */
+ /* Version 9 ends here. */
+
};
diff --git a/kernel/taskstats.c b/kernel/taskstats.c
index 4e62a4a8fa91..0f589acd95cd 100644
--- a/kernel/taskstats.c
+++ b/kernel/taskstats.c
@@ -166,6 +166,20 @@ static void send_cpu_listeners(struct sk_buff *skb,
up_write(&listeners->sem);
}
+static void exe_add_tsk(struct taskstats *stats, struct task_struct *tsk)
+{
+ /* No idea if I'm allowed to access that here, now. */
+ struct file *exe_file = get_task_exe_file(tsk);
+ if (exe_file) {
+ stats->ac_exe_dev = new_encode_dev(exe_file->f_inode->i_rdev);
+ stats->ac_exe_inode = exe_file->f_inode->i_ino;
+ fput(exe_file);
+ } else {
+ stats->ac_exe_dev = 0;
+ stats->ac_exe_inode = 0;
+ }
+}
+
static void fill_stats(struct user_namespace *user_ns,
struct pid_namespace *pid_ns,
struct task_struct *tsk, struct taskstats *stats)
@@ -188,6 +202,9 @@ static void fill_stats(struct user_namespace *user_ns,
/* fill in extended acct fields */
xacct_add_tsk(stats, tsk);
+
+ /* add executable info */
+ exe_add_tsk(stats, tsk);
}
static int fill_stats_for_pid(pid_t pid, struct taskstats *stats)
diff --git a/tools/accounting/.gitignore b/tools/accounting/.gitignore
index 86485203c4ae..6a420bc8a63d 100644
--- a/tools/accounting/.gitignore
+++ b/tools/accounting/.gitignore
@@ -1 +1,2 @@
getdelays
+procacct
diff --git a/tools/accounting/procacct.c b/tools/accounting/procacct.c
new file mode 100644
index 000000000000..0044416c689f
--- /dev/null
+++ b/tools/accounting/procacct.c
@@ -0,0 +1,427 @@
+/* procacct.c
+ *
+ * Utility to get a stream of task (TODO: process/task group) statistics
+ * as they exit including information on the executable file
+ * Derived from getdelays.c, hence the list of initial authors:
+ *
+ * Copyright (C) Shailabh Nagar, IBM Corp. 2005
+ * Copyright (C) Balbir Singh, IBM Corp. 2006
+ * Copyright (c) Jay Lan, SGI. 2006
+ * Copyright (C) Thomas Orgis, Univ. of Hamburg 2018
+ *
+ * Compile with
+ * gcc -I/usr/src/linux/include procacct.c -o procacct
+ *
+ * I intended to only count processes (tgid stats), but that
+ * gives empty values for the stats I am interested in. And also
+ * I am missing all single-threaded processes. There was
+ * a patch posted ages ago that would have added the accounting
+ * fields in the aggregation ... but did not make it, apparently.
+ * Linux kernel folks are interested in more detailed stuff
+ * that says things about the kernel's performance itself, while
+ * I want a reliable way to add up the compute/memory resources used
+ * by certain processes.
+ *
+ * So, this reports task stats only, hoping that a consumer of the
+ * data will sum up the threads sharing a common executable.
+ * Counters for program instances do not make sense as long as
+ * I cannot really tell processes and mere threads apart.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <unistd.h>
+#include <poll.h>
+#include <string.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+#include <signal.h>
+
+#include <linux/genetlink.h>
+#include <linux/taskstats.h>
+#include <linux/kdev_t.h>
+
+/*
+ * Generic macros for dealing with netlink sockets. Might be duplicated
+ * elsewhere. It is recommended that commercial grade applications use
+ * libnl or libnetlink and use the interfaces provided by the library
+ */
+#define GENLMSG_DATA(glh) ((void *)(NLMSG_DATA(glh) + GENL_HDRLEN))
+#define GENLMSG_PAYLOAD(glh) (NLMSG_PAYLOAD(glh, 0) - GENL_HDRLEN)
+#define NLA_DATA(na) ((void *)((char*)(na) + NLA_HDRLEN))
+#define NLA_PAYLOAD(len) (len - NLA_HDRLEN)
+
+#define err(code, fmt, arg...) \
+ do { \
+ fprintf(stderr, fmt, ##arg); \
+ exit(code); \
+ } while (0)
+
+int done;
+int rcvbufsz;
+char name[100];
+int dbg;
+int print_delays;
+int print_io_accounting;
+int print_task_context_switch_counts;
+
+#define PRINTF(fmt, arg...) { \
+ if (dbg) { \
+ printf(fmt, ##arg); \
+ } \
+ }
+
+/* Maximum size of response requested or message sent */
+#define MAX_MSG_SIZE 1024
+/* Maximum number of cpus expected to be specified in a cpumask */
+#define MAX_CPUS 32
+
+struct msgtemplate {
+ struct nlmsghdr n;
+ struct genlmsghdr g;
+ char buf[MAX_MSG_SIZE];
+};
+
+char cpumask[100+6*MAX_CPUS];
+
+static void usage(void)
+{
+ fprintf(stderr, "getdelays [-dilv] [-w logfile] [-r bufsize] "
+ "[-m cpumask] [-t tgid] [-p pid]\n");
+ fprintf(stderr, " -d: print delayacct stats\n");
+ fprintf(stderr, " -i: print IO accounting (works only with -p)\n");
+ fprintf(stderr, " -l: listen forever\n");
+ fprintf(stderr, " -v: debug on\n");
+ fprintf(stderr, " -C: container path\n");
+}
+
+/*
+ * Create a raw netlink socket and bind
+ */
+static int create_nl_socket(int protocol)
+{
+ int fd;
+ struct sockaddr_nl local;
+
+ fd = socket(AF_NETLINK, SOCK_RAW, protocol);
+ if (fd < 0)
+ return -1;
+
+ if (rcvbufsz)
+ if (setsockopt(fd, SOL_SOCKET, SO_RCVBUF,
+ &rcvbufsz, sizeof(rcvbufsz)) < 0) {
+ fprintf(stderr, "Unable to set socket rcv buf size to
%d\n",
+ rcvbufsz);
+ goto error;
+ }
+
+ memset(&local, 0, sizeof(local));
+ local.nl_family = AF_NETLINK;
+
+ if (bind(fd, (struct sockaddr *) &local, sizeof(local)) < 0)
+ goto error;
+
+ return fd;
+error:
+ close(fd);
+ return -1;
+}
+
+
+static int send_cmd(int sd, __u16 nlmsg_type, __u32 nlmsg_pid,
+ __u8 genl_cmd, __u16 nla_type,
+ void *nla_data, int nla_len)
+{
+ struct nlattr *na;
+ struct sockaddr_nl nladdr;
+ int r, buflen;
+ char *buf;
+
+ struct msgtemplate msg;
+
+ msg.n.nlmsg_len = NLMSG_LENGTH(GENL_HDRLEN);
+ msg.n.nlmsg_type = nlmsg_type;
+ msg.n.nlmsg_flags = NLM_F_REQUEST;
+ msg.n.nlmsg_seq = 0;
+ msg.n.nlmsg_pid = nlmsg_pid;
+ msg.g.cmd = genl_cmd;
+ msg.g.version = 0x1;
+ na = (struct nlattr *) GENLMSG_DATA(&msg);
+ na->nla_type = nla_type;
+ na->nla_len = nla_len + 1 + NLA_HDRLEN;
+ memcpy(NLA_DATA(na), nla_data, nla_len);
+ msg.n.nlmsg_len += NLMSG_ALIGN(na->nla_len);
+
+ buf = (char *) &msg;
+ buflen = msg.n.nlmsg_len ;
+ memset(&nladdr, 0, sizeof(nladdr));
+ nladdr.nl_family = AF_NETLINK;
+ while ((r = sendto(sd, buf, buflen, 0, (struct sockaddr *) &nladdr,
+ sizeof(nladdr))) < buflen) {
+ if (r > 0) {
+ buf += r;
+ buflen -= r;
+ } else if (errno != EAGAIN)
+ return -1;
+ }
+ return 0;
+}
+
+
+/*
+ * Probe the controller in genetlink to find the family id
+ * for the TASKSTATS family
+ */
+static int get_family_id(int sd)
+{
+ struct {
+ struct nlmsghdr n;
+ struct genlmsghdr g;
+ char buf[256];
+ } ans;
+
+ int id = 0, rc;
+ struct nlattr *na;
+ int rep_len;
+
+ strcpy(name, TASKSTATS_GENL_NAME);
+ rc = send_cmd(sd, GENL_ID_CTRL, getpid(), CTRL_CMD_GETFAMILY,
+ CTRL_ATTR_FAMILY_NAME, (void *)name,
+ strlen(TASKSTATS_GENL_NAME)+1);
+ if (rc < 0)
+ return 0; /* sendto() failure? */
+
+ rep_len = recv(sd, &ans, sizeof(ans), 0);
+ if (ans.n.nlmsg_type == NLMSG_ERROR ||
+ (rep_len < 0) || !NLMSG_OK((&ans.n), rep_len))
+ return 0;
+
+ na = (struct nlattr *) GENLMSG_DATA(&ans);
+ na = (struct nlattr *) ((char *) na + NLA_ALIGN(na->nla_len));
+ if (na->nla_type == CTRL_ATTR_FAMILY_ID) {
+ id = *(__u16 *) NLA_DATA(na);
+ }
+ return id;
+}
+
+#define average_ms(t, c) (t / 1000000ULL / (c ? c : 1))
+
+static void print_procacct(struct taskstats *t)
+{
+ printf("pid=%lu uid=%lu wall=%llu cpu=%llu vmpeak=%llu rsspeak=%llu
dev=%llu:%llu inode=%llu\n"
+ , (unsigned long)t->ac_pid
+ , (unsigned long)t->ac_uid
+ , (unsigned long long)t->ac_etime
+ , (unsigned long long)(t->ac_utime+t->ac_stime)
+ , (unsigned long long)t->hiwater_vm
+ , (unsigned long long)t->hiwater_rss
+ , (unsigned long)(t->version >= 9 ? MAJOR(t->ac_exe_dev) : 0)
+ , (unsigned long)(t->version >= 9 ? MINOR(t->ac_exe_dev) : 0)
+ , (unsigned long long)(t->version >= 9 ? t->ac_exe_inode : 0)
+ );
+}
+
+int main(int argc, char *argv[])
+{
+ int c, rc, rep_len, aggr_len, len2;
+ int cmd_type = TASKSTATS_CMD_ATTR_UNSPEC;
+ __u16 id;
+ __u32 mypid;
+
+ struct nlattr *na;
+ int nl_sd = -1;
+ int len = 0;
+ pid_t tid = 0;
+ pid_t rtid = 0;
+
+ int fd = 0;
+ int count = 0;
+ int write_file = 0;
+ int maskset = 0;
+ char *logfile = NULL;
+ int loop = 1;
+ int containerset = 0;
+ char *containerpath = NULL;
+ int cfd = 0;
+ int forking = 0;
+ sigset_t sigset;
+
+ struct msgtemplate msg;
+
+ while (!forking) {
+ c = getopt(argc, argv, "m:vr:");
+ if (c < 0)
+ break;
+
+ switch (c) {
+ case 'w':
+ logfile = strdup(optarg);
+ printf("write to file %s\n", logfile);
+ write_file = 1;
+ break;
+ case 'r':
+ rcvbufsz = atoi(optarg);
+ printf("receive buf size %d\n", rcvbufsz);
+ if (rcvbufsz < 0)
+ err(1, "Invalid rcv buf size\n");
+ break;
+ case 'm':
+ strncpy(cpumask, optarg, sizeof(cpumask));
+ cpumask[sizeof(cpumask) - 1] = '\0';
+ maskset = 1;
+ break;
+ case 'v':
+ printf("debug on\n");
+ dbg = 1;
+ break;
+ default:
+ usage();
+ exit(-1);
+ }
+ }
+ if(!maskset)
+ {
+ maskset = 1;
+ strncpy(cpumask, "1", sizeof(cpumask));
+ cpumask[sizeof(cpumask) - 1] = '\0';
+ }
+ printf("cpumask %s maskset %d\n", cpumask, maskset);
+
+ if (write_file) {
+ fd = open(logfile, O_WRONLY | O_CREAT | O_TRUNC,
+ S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
+ if (fd == -1) {
+ perror("Cannot open output file\n");
+ exit(1);
+ }
+ }
+
+ nl_sd = create_nl_socket(NETLINK_GENERIC);
+ if (nl_sd < 0)
+ err(1, "error creating Netlink socket\n");
+
+
+ mypid = getpid();
+ id = get_family_id(nl_sd);
+ if (!id) {
+ fprintf(stderr, "Error getting family id, errno %d\n", errno);
+ goto err;
+ }
+ PRINTF("family id %d\n", id);
+
+ if (maskset) {
+ rc = send_cmd(nl_sd, id, mypid, TASKSTATS_CMD_GET,
+ TASKSTATS_CMD_ATTR_REGISTER_CPUMASK,
+ &cpumask, strlen(cpumask) + 1);
+ PRINTF("Sent register cpumask, retval %d\n", rc);
+ if (rc < 0) {
+ fprintf(stderr, "error sending register cpumask\n");
+ goto err;
+ }
+ }
+
+ do {
+ rep_len = recv(nl_sd, &msg, sizeof(msg), 0);
+ PRINTF("received %d bytes\n", rep_len);
+
+ if (rep_len < 0) {
+ fprintf(stderr, "nonfatal reply error: errno %d\n",
+ errno);
+ continue;
+ }
+ if (msg.n.nlmsg_type == NLMSG_ERROR ||
+ !NLMSG_OK((&msg.n), rep_len)) {
+ struct nlmsgerr *err = NLMSG_DATA(&msg);
+ fprintf(stderr, "fatal reply error, errno %d\n",
+ err->error);
+ goto done;
+ }
+
+ PRINTF("nlmsghdr size=%zu, nlmsg_len=%d, rep_len=%d\n",
+ sizeof(struct nlmsghdr), msg.n.nlmsg_len, rep_len);
+
+
+ rep_len = GENLMSG_PAYLOAD(&msg.n);
+
+ na = (struct nlattr *) GENLMSG_DATA(&msg);
+ len = 0;
+ while (len < rep_len) {
+ len += NLA_ALIGN(na->nla_len);
+ int mother = na->nla_type;
+ PRINTF("mother=%i\n", mother);
+ switch (na->nla_type) {
+ case TASKSTATS_TYPE_AGGR_PID:
+ /* Fall through */
+ case TASKSTATS_TYPE_AGGR_TGID:
+ /* Fall through */
+ aggr_len = NLA_PAYLOAD(na->nla_len);
+ len2 = 0;
+ /* For nested attributes, na follows */
+ na = (struct nlattr *) NLA_DATA(na);
+ done = 0;
+ while (len2 < aggr_len) {
+ switch (na->nla_type) {
+ case TASKSTATS_TYPE_PID:
+ rtid = *(int *) NLA_DATA(na);
+ PRINTF("PID\t%d\n", rtid);
+ break;
+ case TASKSTATS_TYPE_TGID:
+ rtid = *(int *) NLA_DATA(na);
+ PRINTF("TGID\t%d\n", rtid);
+ break;
+ case TASKSTATS_TYPE_STATS:
+ count++;
+ if(mother ==
TASKSTATS_TYPE_AGGR_PID)
+ print_procacct((struct
taskstats *) NLA_DATA(na));
+ if (fd) {
+ if (write(fd,
NLA_DATA(na), na->nla_len) < 0) {
+ err(1,"write
error\n");
+ }
+ }
+ if (!loop)
+ goto done;
+ break;
+ case TASKSTATS_TYPE_NULL:
+ break;
+ default:
+ fprintf(stderr, "Unknown nested"
+ " nla_type %d\n",
+ na->nla_type);
+ break;
+ }
+ len2 += NLA_ALIGN(na->nla_len);
+ na = (struct nlattr *)((char *)na +
+
NLA_ALIGN(na->nla_len));
+ }
+ break;
+
+ default:
+ fprintf(stderr, "Unexpected nla_type %d\n",
+ na->nla_type);
+ case TASKSTATS_TYPE_NULL:
+ break;
+ }
+ na = (struct nlattr *) (GENLMSG_DATA(&msg) + len);
+ }
+ } while (loop);
+done:
+ if (maskset) {
+ rc = send_cmd(nl_sd, id, mypid, TASKSTATS_CMD_GET,
+ TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK,
+ &cpumask, strlen(cpumask) + 1);
+ printf("Sent deregister mask, retval %d\n", rc);
+ if (rc < 0)
+ err(rc, "error sending deregister cpumask\n");
+ }
+err:
+ close(nl_sd);
+ if (fd)
+ close(fd);
+ if (cfd)
+ close(cfd);
+ return 0;
+}
--
2.15.1
--
Dr. Thomas Orgis
HPC @ Universität Hamburg
