On Wed, Oct 02, 2019 at 01:58:21PM -0700, Steve MacLean wrote: > From: Steve MacLean <steve.macl...@microsoft.com> > > While a JIT is jitting code it will eventually need to commit more pages and > change these pages to executable permissions. > > Typically the JIT will want these colocated to minimize branch displacements. > > The kernel will coalesce these anonymous mapping with identical permissions > before sending an MMAP event for the new pages. This means the mmap event for > the new pages will include the older pages. > > These anonymous mmap events will obscure the jitdump injected pseudo events. > This means that the jitdump generated symbols, machine code, debugging info, > and unwind info will no longer be used. > > Observations: > > When a process emits a jit dump marker and a jitdump file, the perf-xxx.map > file represents inferior information which has been superseded by the > jitdump jit-xxx.dump file. > > Further the '//anon*' mmap events are only required for the legacy > perf-xxx.map mapping.
it's been some time I saw the code, Stephane? I added some comments below > > Summary: > > Add rbtree to track which pids have successfully injected a jitdump file. > > During "perf inject --jit", discard "//anon*" mmap events for any pid which > has successfully processed a jitdump file. > > Committer testing: > > // jitdump case > perf record <app with jitdump> > perf inject --jit --input perf.data --output perfjit.data > > // verify mmap "//anon" events present initially > perf script --input perf.data --show-mmap-events | grep '//anon' > // verify mmap "//anon" events removed > perf script --input perfjit.data --show-mmap-events | grep '//anon' > > // no jitdump case > perf record <app without jitdump> > perf inject --jit --input perf.data --output perfjit.data > > // verify mmap "//anon" events present initially > perf script --input perf.data --show-mmap-events | grep '//anon' > // verify mmap "//anon" events not removed > perf script --input perfjit.data --show-mmap-events | grep '//anon' > > Repro: > > This issue was discovered while testing the initial CoreCLR jitdump > implementation. https://github.com/dotnet/coreclr/pull/26897. > > Cc: Peter Zijlstra <pet...@infradead.org> > Cc: Ingo Molnar <mi...@redhat.com> > Cc: Arnaldo Carvalho de Melo <a...@kernel.org> > Cc: Mark Rutland <mark.rutl...@arm.com> > Cc: Alexander Shishkin <alexander.shish...@linux.intel.com> > Cc: Jiri Olsa <jo...@redhat.com> > Cc: Namhyung Kim <namhy...@kernel.org> > Cc: Stephane Eranian <eran...@google.com> > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Steve MacLean <steve.macl...@microsoft.com> > --- > tools/perf/builtin-inject.c | 4 +-- > tools/perf/util/jitdump.c | 63 > +++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 65 insertions(+), 2 deletions(-) > > diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c > index c14f40b8..4c921e0 100644 > --- a/tools/perf/builtin-inject.c > +++ b/tools/perf/builtin-inject.c > @@ -261,7 +261,7 @@ static int perf_event__jit_repipe_mmap(struct perf_tool > *tool, > * if jit marker, then inject jit mmaps and generate ELF images > */ > ret = jit_process(inject->session, &inject->output, machine, > - event->mmap.filename, sample->pid, &n); > + event->mmap.filename, event->mmap.pid, &n); > if (ret < 0) > return ret; > if (ret) { > @@ -299,7 +299,7 @@ static int perf_event__jit_repipe_mmap2(struct perf_tool > *tool, > * if jit marker, then inject jit mmaps and generate ELF images > */ > ret = jit_process(inject->session, &inject->output, machine, > - event->mmap2.filename, sample->pid, &n); > + event->mmap2.filename, event->mmap2.pid, &n); > if (ret < 0) > return ret; > if (ret) { > diff --git a/tools/perf/util/jitdump.c b/tools/perf/util/jitdump.c > index 22d09c4..6a1563f 100644 > --- a/tools/perf/util/jitdump.c > +++ b/tools/perf/util/jitdump.c > @@ -751,6 +751,59 @@ static int jit_repipe_debug_info(struct jit_buf_desc > *jd, union jr_entry *jr) > return 0; > } > > +struct pid_rbtree > +{ > + struct rb_node node; > + pid_t pid; > +}; > + > +static void jit_add_pid(struct rb_root *root, pid_t pid) > +{ > + struct rb_node **new = &(root->rb_node), *parent = NULL; we don't use the parenthesis like that > + struct pid_rbtree* data = NULL; > + > + /* Figure out where to put new node */ > + while (*new) { > + struct pid_rbtree *this = container_of(*new, struct pid_rbtree, > node); there's rb_entry macro for this > + pid_t nodePid = this->pid; > + > + parent = *new; > + if (pid < nodePid) > + new = &((*new)->rb_left); > + else if (pid > nodePid) > + new = &((*new)->rb_right); > + else > + return; > + } > + > + data = malloc(sizeof(struct pid_rbtree)); plz check every allocation anyway, I wonder if you could just use thread::priv flag for that, like: thread = machine__findnew_thread(machine, pid, pid); if (!thread) bad (int) thread->priv = 1; and check on thread->priv when ruling the pid out, should be faster then maintain rb tree thanks, jirka
