9fdbf671ba
This fixes a long-standing bug caused by the lack of separate COMM and EXEC record types, which makes "perf report" lose track of symbols when a process renames itself. With this fix (suggested by Stephane Eranian), a COMM (rename) no longer flushes the maps, which is the correct behavior. An EXEC also no longer flushes the maps, but this doesn't matter because as new mappings are created (for the executable and the libraries) the old mappings are automatically removed. This is not by accident: the functionality is necessary because DLLs can be explicitly loaded at any time with dlopen(), possibly on top of existing text, so "perf report" handles correctly the clobbering of new mappings on top of old ones. An alternative patch (which I proposed earlier) would be to introduce a separate PERF_RECORD_EXEC type, but it is a much larger change (about 300 lines) and is not necessary. Signed-off-by: Luigi Semenzato <semenzato@chromium.org> Tested-by: Stephane Eranian <eranian@google.com> Acked-by: Stephane Eranian <eranian@google.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andi Kleen <ak@linux.intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Lucas De Marchi <lucas.demarchi@profusion.mobi> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Olof Johansson <olofj@chromium.org> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Robert Richter <robert.richter@amd.com> Cc: Sonny Rao <sonnyrao@chromium.org> Cc: Stephane Eranian <eranian@google.com> Cc: Stephen Wilson <wilsons@start.ca> Cc: Tejun Heo <tj@kernel.org> Cc: Vasiliy Kulikov <segoon@openwall.com> Link: http://lkml.kernel.org/r/1345585940-6497-1-git-send-email-semenzato@chromium.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
139 lines
2.7 KiB
C
139 lines
2.7 KiB
C
#include "../perf.h"
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include "session.h"
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#include "thread.h"
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#include "util.h"
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#include "debug.h"
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static struct thread *thread__new(pid_t pid)
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{
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struct thread *self = zalloc(sizeof(*self));
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if (self != NULL) {
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map_groups__init(&self->mg);
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self->pid = pid;
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self->comm = malloc(32);
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if (self->comm)
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snprintf(self->comm, 32, ":%d", self->pid);
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}
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return self;
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}
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void thread__delete(struct thread *self)
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{
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map_groups__exit(&self->mg);
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free(self->comm);
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free(self);
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}
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int thread__set_comm(struct thread *self, const char *comm)
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{
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int err;
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if (self->comm)
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free(self->comm);
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self->comm = strdup(comm);
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err = self->comm == NULL ? -ENOMEM : 0;
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if (!err) {
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self->comm_set = true;
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}
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return err;
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}
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int thread__comm_len(struct thread *self)
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{
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if (!self->comm_len) {
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if (!self->comm)
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return 0;
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self->comm_len = strlen(self->comm);
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}
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return self->comm_len;
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}
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static size_t thread__fprintf(struct thread *self, FILE *fp)
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{
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return fprintf(fp, "Thread %d %s\n", self->pid, self->comm) +
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map_groups__fprintf(&self->mg, verbose, fp);
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}
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struct thread *machine__findnew_thread(struct machine *self, pid_t pid)
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{
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struct rb_node **p = &self->threads.rb_node;
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struct rb_node *parent = NULL;
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struct thread *th;
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/*
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* Font-end cache - PID lookups come in blocks,
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* so most of the time we dont have to look up
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* the full rbtree:
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*/
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if (self->last_match && self->last_match->pid == pid)
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return self->last_match;
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while (*p != NULL) {
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parent = *p;
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th = rb_entry(parent, struct thread, rb_node);
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if (th->pid == pid) {
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self->last_match = th;
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return th;
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}
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if (pid < th->pid)
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p = &(*p)->rb_left;
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else
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p = &(*p)->rb_right;
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}
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th = thread__new(pid);
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if (th != NULL) {
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rb_link_node(&th->rb_node, parent, p);
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rb_insert_color(&th->rb_node, &self->threads);
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self->last_match = th;
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}
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return th;
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}
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void thread__insert_map(struct thread *self, struct map *map)
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{
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map_groups__fixup_overlappings(&self->mg, map, verbose, stderr);
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map_groups__insert(&self->mg, map);
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}
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int thread__fork(struct thread *self, struct thread *parent)
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{
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int i;
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if (parent->comm_set) {
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if (self->comm)
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free(self->comm);
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self->comm = strdup(parent->comm);
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if (!self->comm)
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return -ENOMEM;
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self->comm_set = true;
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}
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for (i = 0; i < MAP__NR_TYPES; ++i)
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if (map_groups__clone(&self->mg, &parent->mg, i) < 0)
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return -ENOMEM;
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return 0;
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}
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size_t machine__fprintf(struct machine *machine, FILE *fp)
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{
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size_t ret = 0;
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struct rb_node *nd;
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for (nd = rb_first(&machine->threads); nd; nd = rb_next(nd)) {
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struct thread *pos = rb_entry(nd, struct thread, rb_node);
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ret += thread__fprintf(pos, fp);
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}
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return ret;
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}
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