korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-12-28 21:45:01 +08:00
Code Issues Packages Projects Releases Wiki Activity
ce4326d275
linux/tools/perf/util/jitdump.c
Steve MacLean c8f6ae1fb2 perf inject jit: Remove //anon mmap events 
**perf-<pid>.map and jit-<pid>.dump designs:

When a JIT generates code to be executed, it must allocate memory and
mark it executable using an mmap call.

*** perf-<pid>.map design

The perf-<pid>.map assumes that any sample recorded in an anonymous
memory page is JIT code. It then tries to resolve the symbol name by
looking at the process' perf-<pid>.map.

*** jit-<pid>.dump design

The jit-<pid>.dump mechanism takes a different approach. It requires a
JIT to write a `<path>/jit-<pid>.dump` file. This file must also be
mmapped so that perf inject -jit can find the file. The JIT must also
add JIT_CODE_LOAD records for any functions it generates. The records
are timestamped using a clock which can be correlated to the perf record
clock.

After perf record,  the `perf inject -jit` pass parses the recording
looking for a `<path>/jit-<pid>.dump` file. When it finds the file, it
parses it and for each JIT_CODE_LOAD record:
* creates an elf file `<path>/jitted-<pid>-<code_index>.so
* injects a new mmap record mapping the new elf file into the process.

*** Coexistence design

The kernel and perf support both of these mechanisms. We need to make
sure perf works on an app supporting either or both of these mechanisms.
Both designs rely on mmap records to determine how to resolve an ip
address.

The mmap records of both techniques by definition overlap. When the JIT
compiles a method, it must:

* allocate memory (mmap)
* add execution privilege (mprotect or mmap. either will
generate an mmap event form the kernel to perf)
* compile code into memory
* add a function record to perf-<pid>.map and/or jit-<pid>.dump

Because the jit-<pid>.dump mechanism supports greater capabilities, perf
prefers the symbols from jit-<pid>.dump. It implements this based on
timestamp ordering of events. There is an implicit ASSUMPTION that the
JIT_CODE_LOAD record timestamp will be after the // anon mmap event that
was generated during memory allocation or adding the execution privilege setting.

*** Problems with the ASSUMPTION

The ASSUMPTION made in the Coexistence design section above is violated
in the following scenario.

*** Scenario

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 collocated to minimize branch displacements.

The kernel will coalesce these anonymous mapping with identical
permissions before sending an MMAP event for the new pages. The address
range of the new mmap will not be just the most recently mmap pages.
It will include the entire coalesced mmap region.

See mm/mmap.c

unsigned long mmap_region(struct file *file, unsigned long addr,
                unsigned long len, vm_flags_t vm_flags, unsigned long pgoff,
                struct list_head *uf)
{
...
        /*
         * Can we just expand an old mapping?
         */
...
        perf_event_mmap(vma);
...
}

*** Symptoms

The coalesced // anon mmap event will be timestamped after the
JIT_CODE_LOAD records. This means it will be used as the most recent
mapping for that entire address range. For remaining events it will look
at the inferior perf-<pid>.map for symbols.

If both mechanisms are supported, the symbol will appear twice with
different module names. This causes weird behavior in reporting.

If only jit-<pid>.dump is supported, the symbol will no longer be resolved.

** Implemented solution

This patch solves the issue by removing // anon mmap events for any
process which has a valid jit-<pid>.dump file.

It tracks on a per process basis to handle the case where some running
apps support jit-<pid>.dump, but some only support perf-<pid>.map.

It adds new assumptions:
* // anon mmap events are only required for perf-<pid>.map support.
* An app that uses jit-<pid>.dump, no longer needs
perf-<pid>.map support. It assumes that any perf-<pid>.map info is
inferior.

*** Details

Use thread->priv to store whether a jitdump file has been processed

During "perf inject --jit", discard "//anon*" mmap events for any pid which
has sucessfully processed a jitdump file.

** 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.

** Alternate solutions considered

These were also briefly considered:

* Change kernel to not coalesce mmap regions.

* Change kernel reporting of coalesced mmap regions to perf. Only
include newly mapped memory.

* Only strip parts of // anon mmap events overlapping existing
jitted-<pid>-<code_index>.so mmap events.

Signed-off-by: Steve MacLean <Steve.MacLean@Microsoft.com>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/1590544271-125795-1-git-send-email-steve.maclean@linux.microsoft.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-07-08 13:51:12 -03:00

822 lines
18 KiB
C
Raw Blame History

// SPDX-License-Identifier: GPL-2.0
#include <sys/sysmacros.h>
#include <sys/types.h>
#include <errno.h>
#include <libgen.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <inttypes.h>
#include <byteswap.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <linux/stringify.h>
#include "build-id.h"
#include "event.h"
#include "debug.h"
#include "evlist.h"
#include "symbol.h"
#include <elf.h>
#include "tsc.h"
#include "session.h"
#include "jit.h"
#include "jitdump.h"
#include "genelf.h"
#include "thread.h"
#include <linux/ctype.h>
#include <linux/zalloc.h>
struct jit_buf_desc {
struct perf_data *output;
struct perf_session *session;
struct machine *machine;
union jr_entry *entry;
void *buf;
uint64_t sample_type;
size_t bufsize;
FILE *in;
bool needs_bswap; /* handles cross-endianness */
bool use_arch_timestamp;
void *debug_data;
void *unwinding_data;
uint64_t unwinding_size;
uint64_t unwinding_mapped_size;
uint64_t eh_frame_hdr_size;
size_t nr_debug_entries;
uint32_t code_load_count;
u64 bytes_written;
struct rb_root code_root;
char dir[PATH_MAX];
};
struct debug_line_info {
unsigned long vma;
unsigned int lineno;
/* The filename format is unspecified, absolute path, relative etc. */
char const filename[];
};
struct jit_tool {
struct perf_tool tool;
struct perf_data output;
struct perf_data input;
u64 bytes_written;
};
#define hmax(a, b) ((a) > (b) ? (a) : (b))
#define get_jit_tool(t) (container_of(tool, struct jit_tool, tool))
static int
jit_emit_elf(char *filename,
const char *sym,
uint64_t code_addr,
const void *code,
int csize,
void *debug,
int nr_debug_entries,
void *unwinding,
uint32_t unwinding_header_size,
uint32_t unwinding_size)
{
int ret, fd;
if (verbose > 0)
fprintf(stderr, "write ELF image %s\n", filename);
fd = open(filename, O_CREAT|O_TRUNC|O_WRONLY, 0644);
if (fd == -1) {
pr_warning("cannot create jit ELF %s: %s\n", filename, strerror(errno));
return -1;
}
ret = jit_write_elf(fd, code_addr, sym, (const void *)code, csize, debug, nr_debug_entries,
unwinding, unwinding_header_size, unwinding_size);
close(fd);
if (ret)
unlink(filename);
return ret;
}
static void
jit_close(struct jit_buf_desc *jd)
{
if (!(jd && jd->in))
return;
funlockfile(jd->in);
fclose(jd->in);
jd->in = NULL;
}
static int
jit_validate_events(struct perf_session *session)
{
struct evsel *evsel;
/*
* check that all events use CLOCK_MONOTONIC
*/
evlist__for_each_entry(session->evlist, evsel) {
if (evsel->core.attr.use_clockid == 0 || evsel->core.attr.clockid != CLOCK_MONOTONIC)
return -1;
}
return 0;
}
static int
jit_open(struct jit_buf_desc *jd, const char *name)
{
struct jitheader header;
struct jr_prefix *prefix;
ssize_t bs, bsz = 0;
void *n, *buf = NULL;
int ret, retval = -1;
jd->in = fopen(name, "r");
if (!jd->in)
return -1;
bsz = hmax(sizeof(header), sizeof(*prefix));
buf = malloc(bsz);
if (!buf)
goto error;
/*
* protect from writer modifying the file while we are reading it
*/
flockfile(jd->in);
ret = fread(buf, sizeof(header), 1, jd->in);
if (ret != 1)
goto error;
memcpy(&header, buf, sizeof(header));
if (header.magic != JITHEADER_MAGIC) {
if (header.magic != JITHEADER_MAGIC_SW)
goto error;
jd->needs_bswap = true;
}
if (jd->needs_bswap) {
header.version = bswap_32(header.version);
header.total_size = bswap_32(header.total_size);
header.pid = bswap_32(header.pid);
header.elf_mach = bswap_32(header.elf_mach);
header.timestamp = bswap_64(header.timestamp);
header.flags = bswap_64(header.flags);
}
jd->use_arch_timestamp = header.flags & JITDUMP_FLAGS_ARCH_TIMESTAMP;
if (verbose > 2)
pr_debug("version=%u\nhdr.size=%u\nts=0x%llx\npid=%d\nelf_mach=%d\nuse_arch_timestamp=%d\n",
header.version,
header.total_size,
(unsigned long long)header.timestamp,
header.pid,
header.elf_mach,
jd->use_arch_timestamp);
if (header.version > JITHEADER_VERSION) {
pr_err("wrong jitdump version %u, expected " __stringify(JITHEADER_VERSION),
header.version);
goto error;
}
if (header.flags & JITDUMP_FLAGS_RESERVED) {
pr_err("jitdump file contains invalid or unsupported flags 0x%llx\n",
(unsigned long long)header.flags & JITDUMP_FLAGS_RESERVED);
goto error;
}
if (jd->use_arch_timestamp && !jd->session->time_conv.time_mult) {
pr_err("jitdump file uses arch timestamps but there is no timestamp conversion\n");
goto error;
}
/*
* validate event is using the correct clockid
*/
if (!jd->use_arch_timestamp && jit_validate_events(jd->session)) {
pr_err("error, jitted code must be sampled with perf record -k 1\n");
goto error;
}
bs = header.total_size - sizeof(header);
if (bs > bsz) {
n = realloc(buf, bs);
if (!n)
goto error;
bsz = bs;
buf = n;
/* read extra we do not know about */
ret = fread(buf, bs - bsz, 1, jd->in);
if (ret != 1)
goto error;
}
/*
* keep dirname for generating files and mmap records
*/
strcpy(jd->dir, name);
dirname(jd->dir);
return 0;
error:
funlockfile(jd->in);
fclose(jd->in);
return retval;
}
static union jr_entry *
jit_get_next_entry(struct jit_buf_desc *jd)
{
struct jr_prefix *prefix;
union jr_entry *jr;
void *addr;
size_t bs, size;
int id, ret;
if (!(jd && jd->in))
return NULL;
if (jd->buf == NULL) {
size_t sz = getpagesize();
if (sz < sizeof(*prefix))
sz = sizeof(*prefix);
jd->buf = malloc(sz);
if (jd->buf == NULL)
return NULL;
jd->bufsize = sz;
}
prefix = jd->buf;
/*
* file is still locked at this point
*/
ret = fread(prefix, sizeof(*prefix), 1, jd->in);
if (ret != 1)
return NULL;
if (jd->needs_bswap) {
prefix->id = bswap_32(prefix->id);
prefix->total_size = bswap_32(prefix->total_size);
prefix->timestamp = bswap_64(prefix->timestamp);
}
id = prefix->id;
size = prefix->total_size;
bs = (size_t)size;
if (bs < sizeof(*prefix))
return NULL;
if (id >= JIT_CODE_MAX) {
pr_warning("next_entry: unknown record type %d, skipping\n", id);
}
if (bs > jd->bufsize) {
void *n;
n = realloc(jd->buf, bs);
if (!n)
return NULL;
jd->buf = n;
jd->bufsize = bs;
}
addr = ((void *)jd->buf) + sizeof(*prefix);
ret = fread(addr, bs - sizeof(*prefix), 1, jd->in);
if (ret != 1)
return NULL;
jr = (union jr_entry *)jd->buf;
switch(id) {
case JIT_CODE_DEBUG_INFO:
if (jd->needs_bswap) {
uint64_t n;
jr->info.code_addr = bswap_64(jr->info.code_addr);
jr->info.nr_entry = bswap_64(jr->info.nr_entry);
for (n = 0 ; n < jr->info.nr_entry; n++) {
jr->info.entries[n].addr = bswap_64(jr->info.entries[n].addr);
jr->info.entries[n].lineno = bswap_32(jr->info.entries[n].lineno);
jr->info.entries[n].discrim = bswap_32(jr->info.entries[n].discrim);
}
}
break;
case JIT_CODE_UNWINDING_INFO:
if (jd->needs_bswap) {
jr->unwinding.unwinding_size = bswap_64(jr->unwinding.unwinding_size);
jr->unwinding.eh_frame_hdr_size = bswap_64(jr->unwinding.eh_frame_hdr_size);
jr->unwinding.mapped_size = bswap_64(jr->unwinding.mapped_size);
}
break;
case JIT_CODE_CLOSE:
break;
case JIT_CODE_LOAD:
if (jd->needs_bswap) {
jr->load.pid = bswap_32(jr->load.pid);
jr->load.tid = bswap_32(jr->load.tid);
jr->load.vma = bswap_64(jr->load.vma);
jr->load.code_addr = bswap_64(jr->load.code_addr);
jr->load.code_size = bswap_64(jr->load.code_size);
jr->load.code_index= bswap_64(jr->load.code_index);
}
jd->code_load_count++;
break;
case JIT_CODE_MOVE:
if (jd->needs_bswap) {
jr->move.pid = bswap_32(jr->move.pid);
jr->move.tid = bswap_32(jr->move.tid);
jr->move.vma = bswap_64(jr->move.vma);
jr->move.old_code_addr = bswap_64(jr->move.old_code_addr);
jr->move.new_code_addr = bswap_64(jr->move.new_code_addr);
jr->move.code_size = bswap_64(jr->move.code_size);
jr->move.code_index = bswap_64(jr->move.code_index);
}
break;
case JIT_CODE_MAX:
default:
/* skip unknown record (we have read them) */
break;
}
return jr;
}
static int
jit_inject_event(struct jit_buf_desc *jd, union perf_event *event)
{
ssize_t size;
size = perf_data__write(jd->output, event, event->header.size);
if (size < 0)
return -1;
jd->bytes_written += size;
return 0;
}
static uint64_t convert_timestamp(struct jit_buf_desc *jd, uint64_t timestamp)
{
struct perf_tsc_conversion tc;
if (!jd->use_arch_timestamp)
return timestamp;
tc.time_shift = jd->session->time_conv.time_shift;
tc.time_mult = jd->session->time_conv.time_mult;
tc.time_zero = jd->session->time_conv.time_zero;
if (!tc.time_mult)
return 0;
return tsc_to_perf_time(timestamp, &tc);
}
static int jit_repipe_code_load(struct jit_buf_desc *jd, union jr_entry *jr)
{
struct perf_sample sample;
union perf_event *event;
struct perf_tool *tool = jd->session->tool;
uint64_t code, addr;
uintptr_t uaddr;
char *filename;
struct stat st;
size_t size;
u16 idr_size;
const char *sym;
uint64_t count;
int ret, csize, usize;
pid_t pid, tid;
struct {
u32 pid, tid;
u64 time;
} *id;
pid = jr->load.pid;
tid = jr->load.tid;
csize = jr->load.code_size;
usize = jd->unwinding_mapped_size;
addr = jr->load.code_addr;
sym = (void *)((unsigned long)jr + sizeof(jr->load));
code = (unsigned long)jr + jr->load.p.total_size - csize;
count = jr->load.code_index;
idr_size = jd->machine->id_hdr_size;
event = calloc(1, sizeof(*event) + idr_size);
if (!event)
return -1;
filename = event->mmap2.filename;
size = snprintf(filename, PATH_MAX, "%s/jitted-%d-%" PRIu64 ".so",
jd->dir,
pid,
count);
size++; /* for \0 */
size = PERF_ALIGN(size, sizeof(u64));
uaddr = (uintptr_t)code;
ret = jit_emit_elf(filename, sym, addr, (const void *)uaddr, csize, jd->debug_data, jd->nr_debug_entries,
jd->unwinding_data, jd->eh_frame_hdr_size, jd->unwinding_size);
if (jd->debug_data && jd->nr_debug_entries) {
zfree(&jd->debug_data);
jd->nr_debug_entries = 0;
}
if (jd->unwinding_data && jd->eh_frame_hdr_size) {
zfree(&jd->unwinding_data);
jd->eh_frame_hdr_size = 0;
jd->unwinding_mapped_size = 0;
jd->unwinding_size = 0;
}
if (ret) {
free(event);
return -1;
}
if (stat(filename, &st))
memset(&st, 0, sizeof(st));
event->mmap2.header.type = PERF_RECORD_MMAP2;
event->mmap2.header.misc = PERF_RECORD_MISC_USER;
event->mmap2.header.size = (sizeof(event->mmap2) -
(sizeof(event->mmap2.filename) - size) + idr_size);
event->mmap2.pgoff = GEN_ELF_TEXT_OFFSET;
event->mmap2.start = addr;
event->mmap2.len = usize ? ALIGN_8(csize) + usize : csize;
event->mmap2.pid = pid;
event->mmap2.tid = tid;
event->mmap2.ino = st.st_ino;
event->mmap2.maj = major(st.st_dev);
event->mmap2.min = minor(st.st_dev);
event->mmap2.prot = st.st_mode;
event->mmap2.flags = MAP_SHARED;
event->mmap2.ino_generation = 1;
id = (void *)((unsigned long)event + event->mmap.header.size - idr_size);
if (jd->sample_type & PERF_SAMPLE_TID) {
id->pid = pid;
id->tid = tid;
}
if (jd->sample_type & PERF_SAMPLE_TIME)
id->time = convert_timestamp(jd, jr->load.p.timestamp);
/*
* create pseudo sample to induce dso hit increment
* use first address as sample address
*/
memset(&sample, 0, sizeof(sample));
sample.cpumode = PERF_RECORD_MISC_USER;
sample.pid = pid;
sample.tid = tid;
sample.time = id->time;
sample.ip = addr;
ret = perf_event__process_mmap2(tool, event, &sample, jd->machine);
if (ret)
return ret;
ret = jit_inject_event(jd, event);
/*
* mark dso as use to generate buildid in the header
*/
if (!ret)
build_id__mark_dso_hit(tool, event, &sample, NULL, jd->machine);
return ret;
}
static int jit_repipe_code_move(struct jit_buf_desc *jd, union jr_entry *jr)
{
struct perf_sample sample;
union perf_event *event;
struct perf_tool *tool = jd->session->tool;
char *filename;
size_t size;
struct stat st;
int usize;
u16 idr_size;
int ret;
pid_t pid, tid;
struct {
u32 pid, tid;
u64 time;
} *id;
pid = jr->move.pid;
tid = jr->move.tid;
usize = jd->unwinding_mapped_size;
idr_size = jd->machine->id_hdr_size;
/*
* +16 to account for sample_id_all (hack)
*/
event = calloc(1, sizeof(*event) + 16);
if (!event)
return -1;
filename = event->mmap2.filename;
size = snprintf(filename, PATH_MAX, "%s/jitted-%d-%" PRIu64 ".so",
jd->dir,
pid,
jr->move.code_index);
size++; /* for \0 */
if (stat(filename, &st))
memset(&st, 0, sizeof(st));
size = PERF_ALIGN(size, sizeof(u64));
event->mmap2.header.type = PERF_RECORD_MMAP2;
event->mmap2.header.misc = PERF_RECORD_MISC_USER;
event->mmap2.header.size = (sizeof(event->mmap2) -
(sizeof(event->mmap2.filename) - size) + idr_size);
event->mmap2.pgoff = GEN_ELF_TEXT_OFFSET;
event->mmap2.start = jr->move.new_code_addr;
event->mmap2.len = usize ? ALIGN_8(jr->move.code_size) + usize
: jr->move.code_size;
event->mmap2.pid = pid;
event->mmap2.tid = tid;
event->mmap2.ino = st.st_ino;
event->mmap2.maj = major(st.st_dev);
event->mmap2.min = minor(st.st_dev);
event->mmap2.prot = st.st_mode;
event->mmap2.flags = MAP_SHARED;
event->mmap2.ino_generation = 1;
id = (void *)((unsigned long)event + event->mmap.header.size - idr_size);
if (jd->sample_type & PERF_SAMPLE_TID) {
id->pid = pid;
id->tid = tid;
}
if (jd->sample_type & PERF_SAMPLE_TIME)
id->time = convert_timestamp(jd, jr->load.p.timestamp);
/*
* create pseudo sample to induce dso hit increment
* use first address as sample address
*/
memset(&sample, 0, sizeof(sample));
sample.cpumode = PERF_RECORD_MISC_USER;
sample.pid = pid;
sample.tid = tid;
sample.time = id->time;
sample.ip = jr->move.new_code_addr;
ret = perf_event__process_mmap2(tool, event, &sample, jd->machine);
if (ret)
return ret;
ret = jit_inject_event(jd, event);
if (!ret)
build_id__mark_dso_hit(tool, event, &sample, NULL, jd->machine);
return ret;
}
static int jit_repipe_debug_info(struct jit_buf_desc *jd, union jr_entry *jr)
{
void *data;
size_t sz;
if (!(jd && jr))
return -1;
sz = jr->prefix.total_size - sizeof(jr->info);
data = malloc(sz);
if (!data)
return -1;
memcpy(data, &jr->info.entries, sz);
jd->debug_data = data;
/*
* we must use nr_entry instead of size here because
* we cannot distinguish actual entry from padding otherwise
*/
jd->nr_debug_entries = jr->info.nr_entry;
return 0;
}
static int
jit_repipe_unwinding_info(struct jit_buf_desc *jd, union jr_entry *jr)
{
void *unwinding_data;
uint32_t unwinding_data_size;
if (!(jd && jr))
return -1;
unwinding_data_size = jr->prefix.total_size - sizeof(jr->unwinding);
unwinding_data = malloc(unwinding_data_size);
if (!unwinding_data)
return -1;
memcpy(unwinding_data, &jr->unwinding.unwinding_data,
unwinding_data_size);
jd->eh_frame_hdr_size = jr->unwinding.eh_frame_hdr_size;
jd->unwinding_size = jr->unwinding.unwinding_size;
jd->unwinding_mapped_size = jr->unwinding.mapped_size;
jd->unwinding_data = unwinding_data;
return 0;
}
static int
jit_process_dump(struct jit_buf_desc *jd)
{
union jr_entry *jr;
int ret = 0;
while ((jr = jit_get_next_entry(jd))) {
switch(jr->prefix.id) {
case JIT_CODE_LOAD:
ret = jit_repipe_code_load(jd, jr);
break;
case JIT_CODE_MOVE:
ret = jit_repipe_code_move(jd, jr);
break;
case JIT_CODE_DEBUG_INFO:
ret = jit_repipe_debug_info(jd, jr);
break;
case JIT_CODE_UNWINDING_INFO:
ret = jit_repipe_unwinding_info(jd, jr);
break;
default:
ret = 0;
continue;
}
}
return ret;
}
static int
jit_inject(struct jit_buf_desc *jd, char *path)
{
int ret;
if (verbose > 0)
fprintf(stderr, "injecting: %s\n", path);
ret = jit_open(jd, path);
if (ret)
return -1;
ret = jit_process_dump(jd);
jit_close(jd);
if (verbose > 0)
fprintf(stderr, "injected: %s (%d)\n", path, ret);
return 0;
}
/*
* File must be with pattern .../jit-XXXX.dump
* where XXXX is the PID of the process which did the mmap()
* as captured in the RECORD_MMAP record
*/
static int
jit_detect(char *mmap_name, pid_t pid)
{
char *p;
char *end = NULL;
pid_t pid2;
if (verbose > 2)
fprintf(stderr, "jit marker trying : %s\n", mmap_name);
/*
* get file name
*/
p = strrchr(mmap_name, '/');
if (!p)
return -1;
/*
* match prefix
*/
if (strncmp(p, "/jit-", 5))
return -1;
/*
* skip prefix
*/
p += 5;
/*
* must be followed by a pid
*/
if (!isdigit(*p))
return -1;
pid2 = (int)strtol(p, &end, 10);
if (!end)
return -1;
/*
* pid does not match mmap pid
* pid==0 in system-wide mode (synthesized)
*/
if (pid && pid2 != pid)
return -1;
/*
* validate suffix
*/
if (strcmp(end, ".dump"))
return -1;
if (verbose > 0)
fprintf(stderr, "jit marker found: %s\n", mmap_name);
return 0;
}
static void jit_add_pid(struct machine *machine, pid_t pid)
{
struct thread *thread = machine__findnew_thread(machine, pid, pid);
if (!thread) {
pr_err("%s: thread %d not found or created\n", __func__, pid);
return;
}
thread->priv = (void *)1;
}
static bool jit_has_pid(struct machine *machine, pid_t pid)
{
struct thread *thread = machine__find_thread(machine, pid, pid);
if (!thread)
return 0;
return (bool)thread->priv;
}
int
jit_process(struct perf_session *session,
struct perf_data *output,
struct machine *machine,
char *filename,
pid_t pid,
u64 *nbytes)
{
struct evsel *first;
struct jit_buf_desc jd;
int ret;
/*
* first, detect marker mmap (i.e., the jitdump mmap)
*/
if (jit_detect(filename, pid)) {
// Strip //anon* mmaps if we processed a jitdump for this pid
if (jit_has_pid(machine, pid) && (strncmp(filename, "//anon", 6) == 0))
return 1;
return 0;
}
memset(&jd, 0, sizeof(jd));
jd.session = session;
jd.output = output;
jd.machine = machine;
/*
* track sample_type to compute id_all layout
* perf sets the same sample type to all events as of now
*/
first = evlist__first(session->evlist);
jd.sample_type = first->core.attr.sample_type;
*nbytes = 0;
ret = jit_inject(&jd, filename);
if (!ret) {
jit_add_pid(machine, pid);
*nbytes = jd.bytes_written;
ret = 1;
}
return ret;
}
Reference in New Issue View Git Blame Copy Permalink