mirror of
https://github.com/rui314/mold.git
synced 2024-10-05 17:17:40 +03:00
Allow numbers other than 1 for MOLD_JOBS
This commit is contained in:
parent
b83b1950c0
commit
863893057e
@ -272,6 +272,12 @@ if(NOT APPLE AND NOT MSVC)
|
||||
target_link_options(mold PRIVATE -pthread)
|
||||
endif()
|
||||
|
||||
# shm_open needs -lrt
|
||||
find_library(LIBRT rt)
|
||||
if(LIBRT)
|
||||
target_link_libraries(mold PRIVATE rt)
|
||||
endif()
|
||||
|
||||
check_symbol_exists(madvise sys/mman.h HAVE_MADVISE)
|
||||
|
||||
# Create a .cc file containing the current git hash for `mold --version`.
|
||||
|
@ -8,43 +8,138 @@
|
||||
// This file implements a feature that limits the number of concurrent
|
||||
// mold processes to just 1 for each user. It is intended to be used as
|
||||
// `MOLD_JOBS=1 ninja` or `MOLD_JOBS=1 make -j$(nproc)`.
|
||||
//
|
||||
// We can't use POSIX semaphores because the counter will not be
|
||||
// decremented automatically when a process exits abnormally. That would
|
||||
// results in a deadlock. Therefore, we use lockf-based regional file
|
||||
// locking instead. Unlike POSIX semaphores, the lock will automatically
|
||||
// released on process termination.
|
||||
//
|
||||
// To wake processes that may be waiting on the lock file, we use a
|
||||
// pthread condition variable. On normal exit, mold sends notifications to
|
||||
// all waiting processes. In case of abnormal exit, we use
|
||||
// pthread_cond_timedwait so that waiters will not wait forever.
|
||||
|
||||
#include "common.h"
|
||||
|
||||
#include <atomic>
|
||||
#include <fcntl.h>
|
||||
#include <pthread.h>
|
||||
#include <pwd.h>
|
||||
#include <stdlib.h>
|
||||
#include <sys/mman.h>
|
||||
#include <sys/stat.h>
|
||||
#include <sys/types.h>
|
||||
#include <unistd.h>
|
||||
|
||||
namespace mold {
|
||||
|
||||
static constexpr i64 MAX_JOBS = 128;
|
||||
|
||||
struct SharedData {
|
||||
std::atomic_bool initialized;
|
||||
pthread_mutex_t mu;
|
||||
pthread_cond_t cond;
|
||||
};
|
||||
|
||||
static int num_jobs = -1;
|
||||
static int lock_fd = -1;
|
||||
static SharedData *shared_data = nullptr;
|
||||
|
||||
static i64 get_mold_jobs() {
|
||||
char *env = getenv("MOLD_JOBS");
|
||||
if (!env)
|
||||
return 0;
|
||||
|
||||
i64 jobs = std::stol(env);
|
||||
if (jobs < 0)
|
||||
return 0;
|
||||
return std::min(jobs, MAX_JOBS);
|
||||
}
|
||||
|
||||
static bool do_lock() {
|
||||
for (i64 i = 0; i < num_jobs; i++) {
|
||||
lseek(lock_fd, i, SEEK_SET);
|
||||
if (lockf(lock_fd, F_TLOCK, 1) == 0)
|
||||
return true;
|
||||
}
|
||||
return false;
|
||||
}
|
||||
|
||||
static SharedData *get_shared_data() {
|
||||
// Create a shared memory object and mmap it
|
||||
std::string name = "/mold-signal-" + std::to_string(getuid());
|
||||
|
||||
int shm_fd = shm_open(name.c_str(), O_CREAT | O_RDWR, 0600);
|
||||
if (shm_fd == -1) {
|
||||
perror("shm_open");
|
||||
exit(-1);
|
||||
}
|
||||
|
||||
i64 size = sizeof(SharedData);
|
||||
ftruncate(shm_fd, size);
|
||||
SharedData *data = (SharedData *)mmap(0, size, PROT_READ | PROT_WRITE,
|
||||
MAP_SHARED, shm_fd, 0);
|
||||
close(shm_fd);
|
||||
|
||||
if (data->initialized.exchange(true) == false) {
|
||||
pthread_mutexattr_t mu_attr;
|
||||
pthread_mutexattr_init(&mu_attr);
|
||||
pthread_mutexattr_setpshared(&mu_attr, PTHREAD_PROCESS_SHARED);
|
||||
pthread_mutexattr_setrobust(&mu_attr, PTHREAD_MUTEX_ROBUST);
|
||||
pthread_mutex_init(&data->mu, &mu_attr);
|
||||
|
||||
pthread_condattr_t cond_attr;
|
||||
pthread_condattr_init(&cond_attr);
|
||||
pthread_condattr_setpshared(&cond_attr, PTHREAD_PROCESS_SHARED);
|
||||
pthread_cond_init(&data->cond, &cond_attr);
|
||||
}
|
||||
return data;
|
||||
}
|
||||
|
||||
void acquire_global_lock() {
|
||||
char *jobs = getenv("MOLD_JOBS");
|
||||
if (!jobs || jobs != "1"s)
|
||||
num_jobs = get_mold_jobs();
|
||||
if (num_jobs == 0)
|
||||
return;
|
||||
|
||||
shared_data = get_shared_data();
|
||||
|
||||
std::string path;
|
||||
if (char *dir = getenv("XDG_RUNTIME_DIR"))
|
||||
path = dir + "/mold-lock"s;
|
||||
path = dir + "/mold.lock"s;
|
||||
else
|
||||
path = "/tmp/mold-lock-"s + getpwuid(getuid())->pw_name;
|
||||
path = "/tmp/mold-" + std::to_string(getuid()) + ".lock";
|
||||
|
||||
int fd = open(path.c_str(), O_WRONLY | O_CREAT | O_CLOEXEC, 0600);
|
||||
if (fd == -1)
|
||||
lock_fd = open(path.c_str(), O_WRONLY | O_CREAT | O_CLOEXEC, 0600);
|
||||
if (lock_fd == -1 || do_lock())
|
||||
return;
|
||||
|
||||
if (lockf(fd, F_LOCK, 0) == -1)
|
||||
return;
|
||||
lock_fd = fd;
|
||||
pthread_mutex_t *mu = &shared_data->mu;
|
||||
pthread_cond_t *cond = &shared_data->cond;
|
||||
|
||||
// If the previous process got killed while holding the mutex, the
|
||||
// mutex has became inconsistent. We need to fix it in that case.
|
||||
if (pthread_mutex_lock(mu) == EOWNERDEAD)
|
||||
pthread_mutex_consistent(mu);
|
||||
|
||||
for (;;) {
|
||||
struct timespec ts;
|
||||
clock_gettime(CLOCK_REALTIME, &ts);
|
||||
ts.tv_sec += 1;
|
||||
|
||||
int r = pthread_cond_timedwait(cond, mu, &ts);
|
||||
if (do_lock() || r != ETIMEDOUT)
|
||||
break;
|
||||
}
|
||||
|
||||
pthread_mutex_unlock(mu);
|
||||
}
|
||||
|
||||
void release_global_lock() {
|
||||
if (lock_fd != -1)
|
||||
if (lock_fd == -1)
|
||||
return;
|
||||
close(lock_fd);
|
||||
pthread_cond_broadcast(&shared_data->cond);
|
||||
}
|
||||
|
||||
} // namespace mold
|
||||
|
@ -832,8 +832,6 @@ but as `-o magic`.
|
||||
consider setting this environment variable to `1` to see if it addresses the
|
||||
OOM issue.
|
||||
|
||||
Currently, any value other than `1` is silently ignored.
|
||||
|
||||
* `MOLD_DEBUG`:
|
||||
If this variable is set to a non-empty string, `mold` embeds its
|
||||
command-line options in the output file's `.comment` section.
|
||||
|
20
test/elf/mold-jobs.sh
Executable file
20
test/elf/mold-jobs.sh
Executable file
@ -0,0 +1,20 @@
|
||||
#!/bin/bash
|
||||
. $(dirname $0)/common.inc
|
||||
|
||||
cat <<EOF | $CC -o $t/a.o -c -xc - -fno-PIE
|
||||
#include <stdio.h>
|
||||
int main() {
|
||||
printf("Hello world\n");
|
||||
}
|
||||
EOF
|
||||
|
||||
for i in `seq 1 20`; do
|
||||
rm -f $t/exe$i
|
||||
( MOLD_JOBS=2 $CC -B. -o $t/exe$i $t/a.o -no-pie; echo $i) &
|
||||
done
|
||||
|
||||
wait
|
||||
|
||||
for i in `seq 1 20`; do
|
||||
$QEMU $t/exe$i | grep -q 'Hello world'
|
||||
done
|
Loading…
Reference in New Issue
Block a user