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mdbx: use C11 atomics if available instead of legacy memory barriers.

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This done better support architectures with a weak/relaxed memory consistency model (ARM, AARCH64, PPC, MIPS, RISC-V, etc).

Change-Id: Iee831c8dc564f1d027ff84b0d6daa559325d5a9b
This commit is contained in:
Leonid Yuriev
2021-01-30 02:28:12 +03:00
parent bc33875a9e
commit 9f0ff865e8
7 changed files with 643 additions and 442 deletions
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14
src/lck-windows.c
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@@ -265,23 +265,25 @@ mdbx_suspend_threads_before_remap(MDBX_env *env, mdbx_handle_array_t **array) {
if (env->me_lck) {
/* Scan LCK for threads of the current process */
const MDBX_reader *const begin = env->me_lck->mti_readers;
const MDBX_reader *const end = begin + env->me_lck->mti_numreaders;
const MDBX_reader *const end =
begin + atomic_load32(&env->me_lck->mti_numreaders, mo_AcquireRelease);
const uintptr_t WriteTxnOwner = env->me_txn0 ? env->me_txn0->mt_owner : 0;
for (const MDBX_reader *reader = begin; reader < end; ++reader) {
if (reader->mr_pid != env->me_pid || !reader->mr_tid) {
if (reader->mr_pid.weak != env->me_pid || !reader->mr_tid.weak) {
skip_lck:
continue;
}
if (reader->mr_tid == CurrentTid || reader->mr_tid == WriteTxnOwner)
if (reader->mr_tid.weak == CurrentTid ||
reader->mr_tid.weak == WriteTxnOwner)
goto skip_lck;
if (env->me_flags & MDBX_NOTLS) {
/* Skip duplicates in no-tls mode */
for (const MDBX_reader *scan = reader; --scan >= begin;)
if (scan->mr_tid == reader->mr_tid)
if (scan->mr_tid.weak == reader->mr_tid.weak)
goto skip_lck;
}
rc = suspend_and_append(array, (mdbx_tid_t)reader->mr_tid);
rc = suspend_and_append(array, (mdbx_tid_t)reader->mr_tid.weak);
if (rc != MDBX_SUCCESS) {
bailout_lck:
(void)mdbx_resume_threads_after_remap(*array);
@@ -599,7 +601,7 @@ MDBX_INTERNAL_FUNC int mdbx_lck_destroy(MDBX_env *env,
if (env->me_map)
mdbx_munmap(&env->me_dxb_mmap);
if (env->me_lck) {
const bool synced = env->me_lck_mmap.lck->mti_unsynced_pages == 0;
const bool synced = env->me_lck_mmap.lck->mti_unsynced_pages.weak == 0;
mdbx_munmap(&env->me_lck_mmap);
if (synced && !inprocess_neighbor && env->me_lfd != INVALID_HANDLE_VALUE &&
mdbx_lck_upgrade(env) == MDBX_SUCCESS)