Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf updates from Ingo Molnar:
 "As a first remark I'd like to note that the way to build perf tooling
  has been simplified and sped up, in the future it should be enough for
  you to build perf via:

        cd tools/perf/
        make install

  (ie without the -j option.) The build system will figure out the
  number of CPUs and will do a parallel build+install.

  The various build system inefficiencies and breakages Linus reported
  against the v3.12 pull request should now be resolved - please
  (re-)report any remaining annoyances or bugs.

  Main changes on the perf kernel side:

   * Performance optimizations:
      . perf ring-buffer code optimizations,          by Peter Zijlstra
      . perf ring-buffer code optimizations,          by Oleg Nesterov
      . x86 NMI call-stack processing optimizations,  by Peter Zijlstra
      . perf context-switch optimizations,            by Peter Zijlstra
      . perf sampling speedups,                       by Peter Zijlstra
      . x86 Intel PEBS processing speedups,           by Peter Zijlstra

   * Enhanced hardware support:
      . for Intel Ivy Bridge-EP uncore PMUs,          by Zheng Yan
      . for Haswell transactions,                     by Andi Kleen, Peter Zijlstra

   * Core perf events code enhancements and fixes by Oleg Nesterov:
      . for uprobes, if fork() is called with pending ret-probes
      . for uprobes platform support code

   * New ABI details by Andi Kleen:
      . Report x86 Haswell TSX transaction abort cost as weight

  Main changes on the perf tooling side (some of these tooling changes
  utilize the above kernel side changes):

   * 'perf report/top' enhancements:

      . Convert callchain children list to rbtree, greatly reducing the
        time taken for callchain processing, from Namhyung Kim.

      . Add new COMM infrastructure, further improving histogram
        processing, from Frédéric Weisbecker, one fix from Namhyung Kim.

      . Add /proc/kcore based live-annotation improvements, including
        build-id cache support, multi map 'call' instruction navigation
        fixes, kcore address validation, objdump workarounds.  From
        Adrian Hunter.

      . Show progress on histogram collapsing, that can take a long
        time, from Namhyung Kim.

      . Add --max-stack option to limit callchain stack scan in 'top'
        and 'report', improving callchain processing when reducing the
        stack depth is an option, from Waiman Long.

      . Add new option --ignore-vmlinux for perf top, from Willy
        Tarreau.

   * 'perf trace' enhancements:

      . 'perf trace' now can can use a 'perf probe' dynamic tracepoints
        to hook into the userspace -> kernel pathname copy so that it
        can map fds to pathnames without reading /proc/pid/fd/ symlinks.
        From Arnaldo Carvalho de Melo.

      . Show VFS path associated with fd in live sessions, using a
        'vfs_getname' 'perf probe' created dynamic tracepoint or by
        looking at /proc/pid/fd, from Arnaldo Carvalho de Melo.

      . Add 'trace' beautifiers for lots of syscall arguments, from
        Arnaldo Carvalho de Melo.

      . Implement more compact 'trace' output by suppressing zeroed
        args, from Arnaldo Carvalho de Melo.

      . Show thread COMM by default in 'trace', from Arnaldo Carvalho de
        Melo.

      . Add option to show full timestamp in 'trace', from David Ahern.

      . Add 'record' command in 'trace', to record raw_syscalls:*, from
        David Ahern.

      . Add summary option to dump syscall statistics in 'trace', from
        David Ahern.

      . Improve error messages in 'trace', providing hints about system
        configuration steps needed for using it, from Ramkumar
        Ramachandra.

      . 'perf trace' now emits hints as to why tracing is not possible,
        helping the user to setup the system to allow tracing in the
        desired permission granularity, telling if the problem is due to
        debugfs not being mounted or with not enough permission for
        !root, /proc/sys/kernel/perf_event_paranoit value, etc.  From
        Arnaldo Carvalho de Melo.

   * 'perf record' enhancements:

      . Check maximum frequency rate for record/top, emitting better
        error messages, from Jiri Olsa.

      . 'perf record' code cleanups, from David Ahern.

      . Improve write_output error message in 'perf record', from Adrian
        Hunter.

      . Allow specifying B/K/M/G unit to the --mmap-pages arguments,
        from Jiri Olsa.

      . Fix command line callchain attribute tests to handle the new
        -g/--call-chain semantics, from Arnaldo Carvalho de Melo.

   * 'perf kvm' enhancements:

      . Disable live kvm command if timerfd is not supported, from David
        Ahern.

      . Fix detection of non-core features, from David Ahern.

   * 'perf list' enhancements:

      . Add usage to 'perf list', from David Ahern.

      . Show error in 'perf list' if tracepoints not available, from
        Pekka Enberg.

   * 'perf probe' enhancements:

      . Support "$vars" meta argument syntax for local variables,
        allowing asking for all possible variables at a given probe
        point to be collected when it hits, from Masami Hiramatsu.

   * 'perf sched' enhancements:

      . Address the root cause of that 'perf sched' stack initialization
        build slowdown, by programmatically setting a big array after
        moving the global variable back to the stack.  Fix from Adrian
        Hunter.

   * 'perf script' enhancements:

      . Set up output options for in-stream attributes, from Adrian
        Hunter.

      . Print addr by default for BTS in 'perf script', from Adrian
        Juntmer

   * 'perf stat' enhancements:

      . Improved messages when doing profiling in all or a subset of
        CPUs using a workload as the session delimitator, as in:

         'perf stat --cpu 0,2 sleep 10s'

        from Arnaldo Carvalho de Melo.

      . Add units to nanosec-based counters in 'perf stat', from David
        Ahern.

      . Remove bogus info when using 'perf stat' -e cycles/instructions,
        from Ramkumar Ramachandra.

   * 'perf lock' enhancements:

      . 'perf lock' fixes and cleanups, from Davidlohr Bueso.

   * 'perf test' enhancements:

      . Fixup PERF_SAMPLE_TRANSACTION handling in sample synthesizing
        and 'perf test', from Adrian Hunter.

      . Clarify the "sample parsing" test entry, from Arnaldo Carvalho
        de Melo.

      . Consider PERF_SAMPLE_TRANSACTION in the "sample parsing" test,
        from Arnaldo Carvalho de Melo.

      . Memory leak fixes in 'perf test', from Felipe Pena.

   * 'perf bench' enhancements:

      . Change the procps visible command-name of invididual benchmark
        tests plus cleanups, from Ingo Molnar.

   * Generic perf tooling infrastructure/plumbing changes:

      . Separating data file properties from session, code
        reorganization from Jiri Olsa.

      . Fix version when building out of tree, as when using one of
        these:

        $ make help | grep perf
          perf-tar-src-pkg    - Build perf-3.12.0.tar source tarball
          perf-targz-src-pkg  - Build perf-3.12.0.tar.gz source tarball
          perf-tarbz2-src-pkg - Build perf-3.12.0.tar.bz2 source tarball
          perf-tarxz-src-pkg  - Build perf-3.12.0.tar.xz source tarball
        $

        from David Ahern.

      . Enhance option parse error message, showing just the help lines
        of the options affected, from Namhyung Kim.

      . libtraceevent updates from upstream trace-cmd repo, from Steven
        Rostedt.

      . Always use perf_evsel__set_sample_bit to set sample_type, from
        Adrian Hunter.

      . Memory and mmap leak fixes from Chenggang Qin.

      . Assorted build fixes for from David Ahern and Jiri Olsa.

      . Speed up and prettify the build system, from Ingo Molnar.

      . Implement addr2line directly using libbfd, from Roberto Vitillo.

      . Separate the GTK support in a separate libperf-gtk.so DSO, that
        is only loaded when --gtk is specified, from Namhyung Kim.

      . perf bash completion fixes and improvements from Ramkumar
        Ramachandra.

      . Support for Openembedded/Yocto -dbg packages, from Ricardo
        Ribalda Delgado.

  And lots and lots of other fixes and code reorganizations that did not
  make it into the list, see the shortlog, diffstat and the Git log for
  details!"

* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (300 commits)
  uprobes: Fix the memory out of bound overwrite in copy_insn()
  uprobes: Fix the wrong usage of current->utask in uprobe_copy_process()
  perf tools: Remove unneeded include
  perf record: Remove post_processing_offset variable
  perf record: Remove advance_output function
  perf record: Refactor feature handling into a separate function
  perf trace: Don't relookup fields by name in each sample
  perf tools: Fix version when building out of tree
  perf evsel: Ditch evsel->handler.data field
  uprobes: Export write_opcode() as uprobe_write_opcode()
  uprobes: Introduce arch_uprobe->ixol
  uprobes: Kill module_init() and module_exit()
  uprobes: Move function declarations out of arch
  perf/x86/intel: Add Ivy Bridge-EP uncore IRP box support
  perf/x86/intel/uncore: Add filter support for IvyBridge-EP QPI boxes
  perf: Factor out strncpy() in perf_event_mmap_event()
  tools/perf: Add required memory barriers
  perf: Fix arch_perf_out_copy_user default
  perf: Update a stale comment
  perf: Optimize perf_output_begin() -- address calculation
  ...

1 files changed, 97 insertions, 59 deletions

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 663f43a..8c875ef 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -175,8 +175,8 @@ int sysctl_perf_event_sample_rate __read_mostly	= DEFAULT_MAX_SAMPLE_RATE;
 static int max_samples_per_tick __read_mostly	= DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
 static int perf_sample_period_ns __read_mostly	= DEFAULT_SAMPLE_PERIOD_NS;
 
-static atomic_t perf_sample_allowed_ns __read_mostly =
-	ATOMIC_INIT( DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100);
+static int perf_sample_allowed_ns __read_mostly =
+	DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
 
 void update_perf_cpu_limits(void)
 {
@@ -184,7 +184,7 @@ void update_perf_cpu_limits(void)
 
 	tmp *= sysctl_perf_cpu_time_max_percent;
 	do_div(tmp, 100);
-	atomic_set(&perf_sample_allowed_ns, tmp);
+	ACCESS_ONCE(perf_sample_allowed_ns) = tmp;
 }
 
 static int perf_rotate_context(struct perf_cpu_context *cpuctx);
@@ -193,7 +193,7 @@ int perf_proc_update_handler(struct ctl_table *table, int write,
 		void __user *buffer, size_t *lenp,
 		loff_t *ppos)
 {
-	int ret = proc_dointvec(table, write, buffer, lenp, ppos);
+	int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
 
 	if (ret || !write)
 		return ret;
@@ -228,14 +228,15 @@ int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
  * we detect that events are taking too long.
  */
 #define NR_ACCUMULATED_SAMPLES 128
-DEFINE_PER_CPU(u64, running_sample_length);
+static DEFINE_PER_CPU(u64, running_sample_length);
 
 void perf_sample_event_took(u64 sample_len_ns)
 {
 	u64 avg_local_sample_len;
 	u64 local_samples_len;
+	u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
 
-	if (atomic_read(&perf_sample_allowed_ns) == 0)
+	if (allowed_ns == 0)
 		return;
 
 	/* decay the counter by 1 average sample */
@@ -251,7 +252,7 @@ void perf_sample_event_took(u64 sample_len_ns)
 	 */
 	avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;
 
-	if (avg_local_sample_len <= atomic_read(&perf_sample_allowed_ns))
+	if (avg_local_sample_len <= allowed_ns)
 		return;
 
 	if (max_samples_per_tick <= 1)
@@ -262,10 +263,9 @@ void perf_sample_event_took(u64 sample_len_ns)
 	perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
 
 	printk_ratelimited(KERN_WARNING
-			"perf samples too long (%lld > %d), lowering "
+			"perf samples too long (%lld > %lld), lowering "
 			"kernel.perf_event_max_sample_rate to %d\n",
-			avg_local_sample_len,
-			atomic_read(&perf_sample_allowed_ns),
+			avg_local_sample_len, allowed_ns,
 			sysctl_perf_event_sample_rate);
 
 	update_perf_cpu_limits();
@@ -899,6 +899,7 @@ static void unclone_ctx(struct perf_event_context *ctx)
 		put_ctx(ctx->parent_ctx);
 		ctx->parent_ctx = NULL;
 	}
+	ctx->generation++;
 }
 
 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
@@ -1136,6 +1137,8 @@ list_add_event(struct perf_event *event, struct perf_event_context *ctx)
 	ctx->nr_events++;
 	if (event->attr.inherit_stat)
 		ctx->nr_stat++;
+
+	ctx->generation++;
 }
 
 /*
@@ -1201,6 +1204,9 @@ static void perf_event__header_size(struct perf_event *event)
 	if (sample_type & PERF_SAMPLE_DATA_SRC)
 		size += sizeof(data->data_src.val);
 
+	if (sample_type & PERF_SAMPLE_TRANSACTION)
+		size += sizeof(data->txn);
+
 	event->header_size = size;
 }
 
@@ -1310,6 +1316,8 @@ list_del_event(struct perf_event *event, struct perf_event_context *ctx)
 	 */
 	if (event->state > PERF_EVENT_STATE_OFF)
 		event->state = PERF_EVENT_STATE_OFF;
+
+	ctx->generation++;
 }
 
 static void perf_group_detach(struct perf_event *event)
@@ -2146,22 +2154,38 @@ static void ctx_sched_out(struct perf_event_context *ctx,
 }
 
 /*
- * Test whether two contexts are equivalent, i.e. whether they
- * have both been cloned from the same version of the same context
- * and they both have the same number of enabled events.
- * If the number of enabled events is the same, then the set
- * of enabled events should be the same, because these are both
- * inherited contexts, therefore we can't access individual events
- * in them directly with an fd; we can only enable/disable all
- * events via prctl, or enable/disable all events in a family
- * via ioctl, which will have the same effect on both contexts.
+ * Test whether two contexts are equivalent, i.e. whether they have both been
+ * cloned from the same version of the same context.
+ *
+ * Equivalence is measured using a generation number in the context that is
+ * incremented on each modification to it; see unclone_ctx(), list_add_event()
+ * and list_del_event().
  */
 static int context_equiv(struct perf_event_context *ctx1,
 			 struct perf_event_context *ctx2)
 {
-	return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx
-		&& ctx1->parent_gen == ctx2->parent_gen
-		&& !ctx1->pin_count && !ctx2->pin_count;
+	/* Pinning disables the swap optimization */
+	if (ctx1->pin_count || ctx2->pin_count)
+		return 0;
+
+	/* If ctx1 is the parent of ctx2 */
+	if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
+		return 1;
+
+	/* If ctx2 is the parent of ctx1 */
+	if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
+		return 1;
+
+	/*
+	 * If ctx1 and ctx2 have the same parent; we flatten the parent
+	 * hierarchy, see perf_event_init_context().
+	 */
+	if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
+			ctx1->parent_gen == ctx2->parent_gen)
+		return 1;
+
+	/* Unmatched */
+	return 0;
 }
 
 static void __perf_event_sync_stat(struct perf_event *event,
@@ -2244,7 +2268,7 @@ static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
 {
 	struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
 	struct perf_event_context *next_ctx;
-	struct perf_event_context *parent;
+	struct perf_event_context *parent, *next_parent;
 	struct perf_cpu_context *cpuctx;
 	int do_switch = 1;
 
@@ -2256,10 +2280,18 @@ static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
 		return;
 
 	rcu_read_lock();
-	parent = rcu_dereference(ctx->parent_ctx);
 	next_ctx = next->perf_event_ctxp[ctxn];
-	if (parent && next_ctx &&
-	    rcu_dereference(next_ctx->parent_ctx) == parent) {
+	if (!next_ctx)
+		goto unlock;
+
+	parent = rcu_dereference(ctx->parent_ctx);
+	next_parent = rcu_dereference(next_ctx->parent_ctx);
+
+	/* If neither context have a parent context; they cannot be clones. */
+	if (!parent && !next_parent)
+		goto unlock;
+
+	if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
 		/*
 		 * Looks like the two contexts are clones, so we might be
 		 * able to optimize the context switch.  We lock both
@@ -2287,6 +2319,7 @@ static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
 		raw_spin_unlock(&next_ctx->lock);
 		raw_spin_unlock(&ctx->lock);
 	}
+unlock:
 	rcu_read_unlock();
 
 	if (do_switch) {
@@ -4572,6 +4605,9 @@ void perf_output_sample(struct perf_output_handle *handle,
 	if (sample_type & PERF_SAMPLE_DATA_SRC)
 		perf_output_put(handle, data->data_src.val);
 
+	if (sample_type & PERF_SAMPLE_TRANSACTION)
+		perf_output_put(handle, data->txn);
+
 	if (!event->attr.watermark) {
 		int wakeup_events = event->attr.wakeup_events;
 
@@ -5100,27 +5136,26 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
 	unsigned int size;
 	char tmp[16];
 	char *buf = NULL;
-	const char *name;
-
-	memset(tmp, 0, sizeof(tmp));
+	char *name;
 
 	if (file) {
 		struct inode *inode;
 		dev_t dev;
+
+		buf = kmalloc(PATH_MAX, GFP_KERNEL);
+		if (!buf) {
+			name = "//enomem";
+			goto cpy_name;
+		}
 		/*
-		 * d_path works from the end of the rb backwards, so we
+		 * d_path() works from the end of the rb backwards, so we
 		 * need to add enough zero bytes after the string to handle
 		 * the 64bit alignment we do later.
 		 */
-		buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL);
-		if (!buf) {
-			name = strncpy(tmp, "//enomem", sizeof(tmp));
-			goto got_name;
-		}
-		name = d_path(&file->f_path, buf, PATH_MAX);
+		name = d_path(&file->f_path, buf, PATH_MAX - sizeof(u64));
 		if (IS_ERR(name)) {
-			name = strncpy(tmp, "//toolong", sizeof(tmp));
-			goto got_name;
+			name = "//toolong";
+			goto cpy_name;
 		}
 		inode = file_inode(vma->vm_file);
 		dev = inode->i_sb->s_dev;
@@ -5128,34 +5163,39 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
 		gen = inode->i_generation;
 		maj = MAJOR(dev);
 		min = MINOR(dev);
-
+		goto got_name;
 	} else {
-		if (arch_vma_name(mmap_event->vma)) {
-			name = strncpy(tmp, arch_vma_name(mmap_event->vma),
-				       sizeof(tmp) - 1);
-			tmp[sizeof(tmp) - 1] = '\0';
-			goto got_name;
-		}
+		name = (char *)arch_vma_name(vma);
+		if (name)
+			goto cpy_name;
 
-		if (!vma->vm_mm) {
-			name = strncpy(tmp, "[vdso]", sizeof(tmp));
-			goto got_name;
-		} else if (vma->vm_start <= vma->vm_mm->start_brk &&
+		if (vma->vm_start <= vma->vm_mm->start_brk &&
 				vma->vm_end >= vma->vm_mm->brk) {
-			name = strncpy(tmp, "[heap]", sizeof(tmp));
-			goto got_name;
-		} else if (vma->vm_start <= vma->vm_mm->start_stack &&
+			name = "[heap]";
+			goto cpy_name;
+		}
+		if (vma->vm_start <= vma->vm_mm->start_stack &&
 				vma->vm_end >= vma->vm_mm->start_stack) {
-			name = strncpy(tmp, "[stack]", sizeof(tmp));
-			goto got_name;
+			name = "[stack]";
+			goto cpy_name;
 		}
 
-		name = strncpy(tmp, "//anon", sizeof(tmp));
-		goto got_name;
+		name = "//anon";
+		goto cpy_name;
 	}
 
+cpy_name:
+	strlcpy(tmp, name, sizeof(tmp));
+	name = tmp;
 got_name:
-	size = ALIGN(strlen(name)+1, sizeof(u64));
+	/*
+	 * Since our buffer works in 8 byte units we need to align our string
+	 * size to a multiple of 8. However, we must guarantee the tail end is
+	 * zero'd out to avoid leaking random bits to userspace.
+	 */
+	size = strlen(name)+1;
+	while (!IS_ALIGNED(size, sizeof(u64)))
+		name[size++] = '\0';
 
 	mmap_event->file_name = name;
 	mmap_event->file_size = size;
@@ -7129,7 +7169,6 @@ SYSCALL_DEFINE5(perf_event_open,
 	}
 
 	perf_install_in_context(ctx, event, event->cpu);
-	++ctx->generation;
 	perf_unpin_context(ctx);
 	mutex_unlock(&ctx->mutex);
 
@@ -7212,7 +7251,6 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
 	WARN_ON_ONCE(ctx->parent_ctx);
 	mutex_lock(&ctx->mutex);
 	perf_install_in_context(ctx, event, cpu);
-	++ctx->generation;
 	perf_unpin_context(ctx);
 	mutex_unlock(&ctx->mutex);