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Use relaxed atomics to access the process madvise pid fd

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Relaxed atomics already provide sequentially consistent access to single
location data structures.
This commit is contained in:
lexprfuncall 2025-08-04 13:13:27 -07:00
parent 16c5abd1cd
commit c45b6223e5
1 changed files with 5 additions and 5 deletions
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10
src/pages.c
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@ -646,7 +646,7 @@ init_process_madvise(void) {
static bool
pages_purge_process_madvise_impl(
void *vec, size_t vec_len, size_t total_bytes) {
int pid_fd = atomic_load_i(&process_madvise_pidfd, ATOMIC_SEQ_CST);
int pid_fd = atomic_load_i(&process_madvise_pidfd, ATOMIC_RELAXED);
while (pid_fd == -1) {
int newfd = syscall(SYS_pidfd_open, getpid(), 0);
if (newfd == -1) {
@ -654,8 +654,8 @@ pages_purge_process_madvise_impl(
}
if (!atomic_compare_exchange_strong_i(&process_madvise_pidfd,
&pid_fd, newfd,
ATOMIC_SEQ_CST,
ATOMIC_SEQ_CST)) {
ATOMIC_RELAXED,
ATOMIC_RELAXED)) {
/* Someone else set the fd, so we close ours */
assert(pid_fd != -1);
close(newfd);
@ -671,9 +671,9 @@ pages_purge_process_madvise_impl(
void pages_postfork_child(void) {
/* Reset the file descriptor we inherited from parent process */
int pid_fd = atomic_load_i(&process_madvise_pidfd, ATOMIC_SEQ_CST);
int pid_fd = atomic_load_i(&process_madvise_pidfd, ATOMIC_RELAXED);
if (pid_fd != -1) {
atomic_store_i(&process_madvise_pidfd, -1, ATOMIC_SEQ_CST);
atomic_store_i(&process_madvise_pidfd, -1, ATOMIC_RELAXED);
close(pid_fd);
}
}