refactor(mt): move final job-table teardown order to Rust

Normal MT context teardown still let the C wrapper directly sequence
per-job synchronization destruction before Rust released the opaque job-table
storage, while failed create and expansion transactions already used a Rust
helper for that same order. Route the normal teardown through a repr(C)
projection so Rust owns the destroy-before-storage-free policy consistently.
The synchronization callback, descriptor storage, and custom allocator remain
opaque C-owned operations. Add matching C/Rust layout assertions and a focused
callback-order test.

Test Plan:
- `git diff --cached --check` -- passed
- Cargo, make, native tests, and heavy verification were not run per request
This commit is contained in:
2026-07-21 09:15:05 +02:00
parent 19c3414095
commit 10b8b25865
2 changed files with 164 additions and 5 deletions
+34 -2
View File
@@ -1024,6 +1024,30 @@ typedef int (*ZSTDMT_jobTableInitFn)(void* jobTable, unsigned nbJobs,
size_t jobSize);
typedef void (*ZSTDMT_jobTableDestroyFn)(void* jobTable, unsigned nbJobs,
size_t jobSize);
typedef struct {
void* jobTable;
unsigned nbJobs;
size_t jobSize;
ZSTD_customMem cMem;
ZSTDMT_jobTableDestroyFn destroySync;
} ZSTDMT_RustFreeJobsTableProjection;
typedef char ZSTDMT_rust_free_jobs_table_projection_layout[
(sizeof(ZSTDMT_jobTableDestroyFn) == sizeof(void*)
&& offsetof(ZSTDMT_RustFreeJobsTableProjection, jobTable) == 0
&& offsetof(ZSTDMT_RustFreeJobsTableProjection, nbJobs)
== sizeof(void*)
&& offsetof(ZSTDMT_RustFreeJobsTableProjection, jobSize)
== (sizeof(void*) == 8 ? 16 : 8)
&& offsetof(ZSTDMT_RustFreeJobsTableProjection, cMem)
== offsetof(ZSTDMT_RustFreeJobsTableProjection, jobSize)
+ sizeof(size_t)
&& offsetof(ZSTDMT_RustFreeJobsTableProjection, destroySync)
== offsetof(ZSTDMT_RustFreeJobsTableProjection, cMem)
+ sizeof(ZSTD_customMem)
&& sizeof(ZSTDMT_RustFreeJobsTableProjection)
== offsetof(ZSTDMT_RustFreeJobsTableProjection, destroySync)
+ sizeof(ZSTDMT_jobTableDestroyFn))
? 1 : -1];
void* ZSTDMT_rust_createJobsTable(
unsigned* nbJobsPtr, size_t jobSize, ZSTD_customMem cMem,
ZSTDMT_jobTableInitFn initSync, ZSTDMT_jobTableDestroyFn destroySync);
@@ -1032,6 +1056,8 @@ size_t ZSTDMT_rust_expandJobsTable(
size_t jobSize, ZSTD_customMem cMem,
ZSTDMT_jobTableInitFn initSync,
ZSTDMT_jobTableDestroyFn destroySync);
void ZSTDMT_rust_freeJobsTable(
const ZSTDMT_RustFreeJobsTableProjection* projection);
typedef struct ZSTDMT_bufferPool_s {
ZSTDMT_RustBufferPool* rustPool;
@@ -2214,8 +2240,14 @@ static void ZSTDMT_projectJob(void* opaque, unsigned jobID,
static void ZSTDMT_freeJobsTable(ZSTDMT_jobDescription* jobTable, U32 nbJobs, ZSTD_customMem cMem)
{
if (jobTable == NULL) return;
ZSTDMT_job_table_destroy_sync(jobTable, nbJobs, sizeof(*jobTable));
ZSTDMT_rust_job_table_free(jobTable, nbJobs, sizeof(*jobTable), cMem);
ZSTDMT_RustFreeJobsTableProjection const projection = {
jobTable,
nbJobs,
sizeof(*jobTable),
cMem,
ZSTDMT_job_table_destroy_sync
};
ZSTDMT_rust_freeJobsTable(&projection);
}
int ZSTDMT_job_table_init_sync(void* jobTable, unsigned nbJobs, size_t jobSize)
+130 -3
View File
@@ -4654,6 +4654,45 @@ unsafe fn free_job_table_storage(job_table: *mut c_void, custom_mem: ZstdCustomM
type JobTableInitSync = unsafe extern "C" fn(*mut c_void, c_uint, usize) -> c_int;
type JobTableDestroySync = unsafe extern "C" fn(*mut c_void, c_uint, usize);
/// Projection for the final MT job-table release. Rust owns the
/// destroy-before-storage-free order; C retains the descriptor synchronization
/// callback and custom allocator behind this opaque projection.
#[repr(C)]
#[derive(Clone, Copy)]
pub struct ZSTDMT_RustFreeJobsTableProjection {
jobTable: *mut c_void,
nbJobs: c_uint,
jobSize: usize,
customMem: ZstdCustomMem,
destroySync: Option<JobTableDestroySync>,
}
const _: () = {
assert!(size_of::<JobTableDestroySync>() == size_of::<usize>());
assert!(offset_of!(ZSTDMT_RustFreeJobsTableProjection, jobTable) == 0);
assert!(
offset_of!(ZSTDMT_RustFreeJobsTableProjection, nbJobs) == size_of::<usize>()
);
assert!(
offset_of!(ZSTDMT_RustFreeJobsTableProjection, jobSize)
== if size_of::<usize>() == 8 { 16 } else { 8 }
);
assert!(
offset_of!(ZSTDMT_RustFreeJobsTableProjection, customMem)
== offset_of!(ZSTDMT_RustFreeJobsTableProjection, jobSize) + size_of::<usize>()
);
assert!(
offset_of!(ZSTDMT_RustFreeJobsTableProjection, destroySync)
== offset_of!(ZSTDMT_RustFreeJobsTableProjection, customMem)
+ size_of::<ZstdCustomMem>()
);
assert!(
size_of::<ZSTDMT_RustFreeJobsTableProjection>()
== offset_of!(ZSTDMT_RustFreeJobsTableProjection, destroySync)
+ size_of::<JobTableDestroySync>()
);
};
unsafe fn free_job_table_with_sync(
job_table: *mut c_void,
nb_jobs: c_uint,
@@ -4661,11 +4700,29 @@ unsafe fn free_job_table_with_sync(
custom_mem: ZstdCustomMem,
destroy_sync: JobTableDestroySync,
) {
if job_table.is_null() {
let projection = ZSTDMT_RustFreeJobsTableProjection {
jobTable: job_table,
nbJobs: nb_jobs,
jobSize: job_size,
customMem: custom_mem,
destroySync: Some(destroy_sync),
};
unsafe { free_job_table_with_sync_projection(projection) };
}
unsafe fn free_job_table_with_sync_projection(
projection: ZSTDMT_RustFreeJobsTableProjection,
) {
if projection.jobTable.is_null() {
return;
}
unsafe { destroy_sync(job_table, nb_jobs, job_size) };
unsafe { ZSTDMT_rust_job_table_free(job_table, nb_jobs, job_size, custom_mem) };
let Some(destroy_sync) = projection.destroySync else {
return;
};
unsafe {
destroy_sync(projection.jobTable, projection.nbJobs, projection.jobSize);
free_job_table_storage(projection.jobTable, projection.customMem);
}
}
unsafe fn create_job_table_with_sync(
@@ -4777,6 +4834,19 @@ pub unsafe extern "C" fn ZSTDMT_rust_job_table_free(
unsafe { free_job_table_storage(job_table, custom_mem) }
}
/// Release the C-owned synchronization objects before Rust releases the
/// opaque job-table storage. This is the normal teardown counterpart to the
/// same order used by failed create/expand transactions.
#[no_mangle]
pub unsafe extern "C" fn ZSTDMT_rust_freeJobsTable(
projection: *const ZSTDMT_RustFreeJobsTableProjection,
) {
let Some(projection) = (unsafe { projection.as_ref() }).copied() else {
return;
};
unsafe { free_job_table_with_sync_projection(projection) };
}
/// Expand the C-owned MT job table when the requested worker count outgrows
/// its masked capacity. The table storage and custom allocator calls stay in
/// Rust; C supplies callbacks for the private descriptor synchronization
@@ -8862,6 +8932,63 @@ mod tests {
JOB_TABLE_DESTROY_CALLS.fetch_add(1, Ordering::Relaxed);
}
#[derive(Default)]
struct FreeJobsTableTestContext {
events: Vec<&'static str>,
}
unsafe extern "C" fn free_jobs_table_test_alloc(
_opaque: *mut c_void,
_size: usize,
) -> *mut c_void {
ptr::null_mut()
}
unsafe extern "C" fn free_jobs_table_test_destroy(
job_table: *mut c_void,
_nb_jobs: c_uint,
_job_size: usize,
) {
unsafe {
(*job_table.cast::<FreeJobsTableTestContext>())
.events
.push("destroy-sync");
}
}
unsafe extern "C" fn free_jobs_table_test_free(
opaque: *mut c_void,
allocation: *mut c_void,
) {
assert_eq!(allocation, opaque);
unsafe {
(*opaque.cast::<FreeJobsTableTestContext>())
.events
.push("free-storage");
}
}
#[test]
fn free_jobs_table_orders_sync_destruction_before_storage_release() {
let mut context = FreeJobsTableTestContext::default();
let context_ptr = (&mut context as *mut FreeJobsTableTestContext).cast::<c_void>();
let projection = ZSTDMT_RustFreeJobsTableProjection {
jobTable: context_ptr,
nbJobs: 8,
jobSize: 128,
customMem: ZstdCustomMem {
customAlloc: Some(free_jobs_table_test_alloc),
customFree: Some(free_jobs_table_test_free),
opaque: context_ptr,
},
destroySync: Some(free_jobs_table_test_destroy),
};
unsafe { ZSTDMT_rust_freeJobsTable(&projection) };
assert_eq!(context.events, ["destroy-sync", "free-storage"]);
}
fn rsync_prime_power() -> u64 {
(0..RSYNC_LENGTH - 1).fold(1, |power, _| power.wrapping_mul(PRIME8_BYTES))
}