Commit e4222673 authored by Hari Bathini's avatar Hari Bathini Committed by Arnaldo Carvalho de Melo
Browse files

perf: Add PERF_RECORD_NAMESPACES to include namespaces related info 



With the advert of container technologies like docker, that depend on
namespaces for isolation, there is a need for tracing support for
namespaces. This patch introduces new PERF_RECORD_NAMESPACES event for
recording namespaces related info. By recording info for every
namespace, it is left to userspace to take a call on the definition of a
container and trace containers by updating perf tool accordingly.

Each namespace has a combination of device and inode numbers. Though
every namespace has the same device number currently, that may change in
future to avoid the need for a namespace of namespaces. Considering such
possibility, record both device and inode numbers separately for each
namespace.

Signed-off-by: default avatarHari Bathini <hbathini@linux.vnet.ibm.com>
Acked-by: default avatarJiri Olsa <jolsa@kernel.org>
Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Aravinda Prasad <aravinda@linux.vnet.ibm.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Sargun Dhillon <sargun@sargun.me>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/148891929686.25309.2827618988917007768.stgit@hbathini.in.ibm.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 3ef5b402

include/linux/perf_event.h

+2 −0
Original line number Diff line number Diff line
@@ -1112,6 +1112,7 @@ extern int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks 


extern void perf_event_exec(void);

extern void perf_event_comm(struct task_struct *tsk, bool exec);

extern void perf_event_namespaces(struct task_struct *tsk);

extern void perf_event_fork(struct task_struct *tsk);



/* Callchains */
@@ -1315,6 +1316,7 @@ static inline int perf_unregister_guest_info_callbacks 
static inline void perf_event_mmap(struct vm_area_struct *vma)		{ }

static inline void perf_event_exec(void)				{ }

static inline void perf_event_comm(struct task_struct *tsk, bool exec)	{ }

static inline void perf_event_namespaces(struct task_struct *tsk)	{ }

static inline void perf_event_fork(struct task_struct *tsk)		{ }

static inline void perf_event_init(void)				{ }

static inline int  perf_swevent_get_recursion_context(void)		{ return -1; }

include/uapi/linux/perf_event.h

+31 −1
Original line number Diff line number Diff line
@@ -344,7 +344,8 @@ struct perf_event_attr { 
				use_clockid    :  1, /* use @clockid for time fields */

				context_switch :  1, /* context switch data */

				write_backward :  1, /* Write ring buffer from end to beginning */

				__reserved_1   : 36;

				namespaces     :  1, /* include namespaces data */

				__reserved_1   : 35;



	union {

		__u32		wakeup_events;	  /* wakeup every n events */
@@ -610,6 +611,23 @@ struct perf_event_header { 
	__u16	size;

};



struct perf_ns_link_info {

	__u64	dev;

	__u64	ino;

};



enum {

	NET_NS_INDEX		= 0,

	UTS_NS_INDEX		= 1,

	IPC_NS_INDEX		= 2,

	PID_NS_INDEX		= 3,

	USER_NS_INDEX		= 4,

	MNT_NS_INDEX		= 5,

	CGROUP_NS_INDEX		= 6,



	NR_NAMESPACES,		/* number of available namespaces */

};



enum perf_event_type {



	/*
@@ -862,6 +880,18 @@ enum perf_event_type { 
	 */

	PERF_RECORD_SWITCH_CPU_WIDE		= 15,



	/*

	 * struct {

	 *	struct perf_event_header	header;

	 *	u32				pid;

	 *	u32				tid;

	 *	u64				nr_namespaces;

	 *	{ u64				dev, inode; } [nr_namespaces];

	 *	struct sample_id		sample_id;

	 * };

	 */

	PERF_RECORD_NAMESPACES			= 16,



	PERF_RECORD_MAX,			/* non-ABI */

};

kernel/events/core.c

+139 −0
Original line number Diff line number Diff line
@@ -48,6 +48,8 @@ 
#include <linux/parser.h>

#include <linux/sched/clock.h>

#include <linux/sched/mm.h>

#include <linux/proc_ns.h>

#include <linux/mount.h>



#include "internal.h"
@@ -379,6 +381,7 @@ static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events); 


static atomic_t nr_mmap_events __read_mostly;

static atomic_t nr_comm_events __read_mostly;

static atomic_t nr_namespaces_events __read_mostly;

static atomic_t nr_task_events __read_mostly;

static atomic_t nr_freq_events __read_mostly;

static atomic_t nr_switch_events __read_mostly;
@@ -3991,6 +3994,8 @@ static void unaccount_event(struct perf_event *event) 
		atomic_dec(&nr_mmap_events);

	if (event->attr.comm)

		atomic_dec(&nr_comm_events);

	if (event->attr.namespaces)

		atomic_dec(&nr_namespaces_events);

	if (event->attr.task)

		atomic_dec(&nr_task_events);

	if (event->attr.freq)
@@ -6491,6 +6496,7 @@ static void perf_event_task(struct task_struct *task, 
void perf_event_fork(struct task_struct *task)

{

	perf_event_task(task, NULL, 1);

	perf_event_namespaces(task);

}



/*
@@ -6592,6 +6598,132 @@ void perf_event_comm(struct task_struct *task, bool exec) 
	perf_event_comm_event(&comm_event);

}



/*

 * namespaces tracking

 */



struct perf_namespaces_event {

	struct task_struct		*task;



	struct {

		struct perf_event_header	header;



		u32				pid;

		u32				tid;

		u64				nr_namespaces;

		struct perf_ns_link_info	link_info[NR_NAMESPACES];

	} event_id;

};



static int perf_event_namespaces_match(struct perf_event *event)

{

	return event->attr.namespaces;

}



static void perf_event_namespaces_output(struct perf_event *event,

					 void *data)

{

	struct perf_namespaces_event *namespaces_event = data;

	struct perf_output_handle handle;

	struct perf_sample_data sample;

	int ret;



	if (!perf_event_namespaces_match(event))

		return;



	perf_event_header__init_id(&namespaces_event->event_id.header,

				   &sample, event);

	ret = perf_output_begin(&handle, event,

				namespaces_event->event_id.header.size);

	if (ret)

		return;



	namespaces_event->event_id.pid = perf_event_pid(event,

							namespaces_event->task);

	namespaces_event->event_id.tid = perf_event_tid(event,

							namespaces_event->task);



	perf_output_put(&handle, namespaces_event->event_id);



	perf_event__output_id_sample(event, &handle, &sample);



	perf_output_end(&handle);

}



static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,

				   struct task_struct *task,

				   const struct proc_ns_operations *ns_ops)

{

	struct path ns_path;

	struct inode *ns_inode;

	void *error;



	error = ns_get_path(&ns_path, task, ns_ops);

	if (!error) {

		ns_inode = ns_path.dentry->d_inode;

		ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);

		ns_link_info->ino = ns_inode->i_ino;

	}

}



void perf_event_namespaces(struct task_struct *task)

{

	struct perf_namespaces_event namespaces_event;

	struct perf_ns_link_info *ns_link_info;



	if (!atomic_read(&nr_namespaces_events))

		return;



	namespaces_event = (struct perf_namespaces_event){

		.task	= task,

		.event_id  = {

			.header = {

				.type = PERF_RECORD_NAMESPACES,

				.misc = 0,

				.size = sizeof(namespaces_event.event_id),

			},

			/* .pid */

			/* .tid */

			.nr_namespaces = NR_NAMESPACES,

			/* .link_info[NR_NAMESPACES] */

		},

	};



	ns_link_info = namespaces_event.event_id.link_info;



	perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],

			       task, &mntns_operations);



#ifdef CONFIG_USER_NS

	perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],

			       task, &userns_operations);

#endif

#ifdef CONFIG_NET_NS

	perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],

			       task, &netns_operations);

#endif

#ifdef CONFIG_UTS_NS

	perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],

			       task, &utsns_operations);

#endif

#ifdef CONFIG_IPC_NS

	perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],

			       task, &ipcns_operations);

#endif

#ifdef CONFIG_PID_NS

	perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],

			       task, &pidns_operations);

#endif

#ifdef CONFIG_CGROUPS

	perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],

			       task, &cgroupns_operations);

#endif



	perf_iterate_sb(perf_event_namespaces_output,

			&namespaces_event,

			NULL);

}



/*

 * mmap tracking

 */
@@ -9146,6 +9278,8 @@ static void account_event(struct perf_event *event) 
		atomic_inc(&nr_mmap_events);

	if (event->attr.comm)

		atomic_inc(&nr_comm_events);

	if (event->attr.namespaces)

		atomic_inc(&nr_namespaces_events);

	if (event->attr.task)

		atomic_inc(&nr_task_events);

	if (event->attr.freq)
@@ -9691,6 +9825,11 @@ SYSCALL_DEFINE5(perf_event_open, 
			return -EACCES;

	}



	if (attr.namespaces) {

		if (!capable(CAP_SYS_ADMIN))

			return -EACCES;

	}



	if (attr.freq) {

		if (attr.sample_freq > sysctl_perf_event_sample_rate)

			return -EINVAL;

kernel/fork.c

+2 −0
Original line number Diff line number Diff line
@@ -2352,6 +2352,8 @@ SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags) 
		}

	}



	perf_event_namespaces(current);



bad_unshare_cleanup_cred:

	if (new_cred)

		put_cred(new_cred);

kernel/nsproxy.c

+3 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ 
#include <linux/file.h>

#include <linux/syscalls.h>

#include <linux/cgroup.h>

#include <linux/perf_event.h>



static struct kmem_cache *nsproxy_cachep;
@@ -262,6 +263,8 @@ SYSCALL_DEFINE2(setns, int, fd, int, nstype) 
		goto out;

	}

	switch_task_namespaces(tsk, new_nsproxy);



	perf_event_namespaces(tsk);

out:

	fput(file);

	return err;

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