jemalloc/test/unit/percpu_arena_resume.c
Raúl Marín ebdd539dc2 Address review: exercise arena-level alloc/free in the percpu resume test
Allocate and free through each arena binding while bypassing the tcache
(MALLOCX_TCACHE_NONE), so the allocations and deallocations reach the
arena rather than the thread cache. Assert via arenas.lookup that a
region allocated while bound to the manual arena comes from it, and that
after resuming per-CPU selection allocations come from a per-CPU arena.
Finally free the manual-arena region while the thread is bound to a
per-CPU arena, covering deallocation routing across the rebinding.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-16 17:56:40 +02:00

81 lines
2.9 KiB
C

#include "test/jemalloc_test.h"
/*
* Under percpu_arena, binding a thread to a manual arena (an index at or above
* the per-CPU auto range) is one-way: percpu never reclaims it (see
* arena_choose_impl). Setting thread.arena back to an index in the auto range
* resumes per-CPU selection instead of failing with EPERM.
*/
TEST_BEGIN(test_thread_arena_resume_percpu) {
test_skip_if(!have_percpu_arena
|| !PERCPU_ARENA_ENABLED(opt_percpu_arena));
unsigned limit = percpu_arena_ind_limit(opt_percpu_arena);
/* Bypass the tcache so every allocation and free hits the arena. */
const int flags = MALLOCX_TCACHE_NONE;
void *warm = mallocx(1, 0);
expect_ptr_not_null(warm, "Unexpected mallocx() failure");
dallocx(warm, 0);
unsigned cur;
size_t sz = sizeof(cur);
expect_d_eq(mallctl("thread.arena", (void *)&cur, &sz, NULL, 0), 0,
"Unexpected mallctl() failure");
expect_u_lt(cur, limit, "Thread should start on a per-CPU arena");
unsigned manual;
sz = sizeof(manual);
expect_d_eq(mallctl("arenas.create", (void *)&manual, &sz, NULL, 0), 0,
"Unexpected arenas.create() failure");
expect_u_ge(manual, limit, "A manual arena is outside the per-CPU range");
unsigned old;
sz = sizeof(old);
expect_d_eq(mallctl("thread.arena", (void *)&old, &sz, (void *)&manual,
sizeof(manual)), 0, "Binding to a manual arena should be allowed");
sz = sizeof(cur);
expect_d_eq(mallctl("thread.arena", (void *)&cur, &sz, NULL, 0), 0,
"Unexpected mallctl() failure");
expect_u_eq(cur, manual, "Thread should be bound to the manual arena");
void *p_manual = mallocx(1024, flags);
expect_ptr_not_null(p_manual, "Unexpected mallocx() failure");
unsigned found;
sz = sizeof(found);
expect_d_eq(mallctl("arenas.lookup", (void *)&found, &sz,
(void *)&p_manual, sizeof(p_manual)), 0,
"Unexpected arenas.lookup() failure");
expect_u_eq(found, manual, "Allocation should come from the manual arena");
void *scratch = mallocx(1024, flags);
expect_ptr_not_null(scratch, "Unexpected mallocx() failure");
dallocx(scratch, flags);
unsigned resume = 0;
expect_d_eq(mallctl("thread.arena", NULL, NULL, (void *)&resume,
sizeof(resume)), 0, "Should resume per-CPU selection, not fail");
sz = sizeof(cur);
expect_d_eq(mallctl("thread.arena", (void *)&cur, &sz, NULL, 0), 0,
"Unexpected mallctl() failure");
expect_u_lt(cur, limit, "Thread should be back on a per-CPU arena");
void *p_percpu = mallocx(1024, flags);
expect_ptr_not_null(p_percpu, "Unexpected mallocx() failure");
sz = sizeof(found);
expect_d_eq(mallctl("arenas.lookup", (void *)&found, &sz,
(void *)&p_percpu, sizeof(p_percpu)), 0,
"Unexpected arenas.lookup() failure");
expect_u_lt(found, limit, "Allocation should come from a per-CPU arena");
dallocx(p_percpu, flags);
/* Free the manual-arena region while bound to a different arena. */
dallocx(p_manual, flags);
}
TEST_END
int
main(void) {
return test(
test_thread_arena_resume_percpu);
}