[PATCH v4 1/3] malloc: Avoid func call for tcache quick path in free()

[Wangyang Guo]

Tcache is an important optimzation to accelerate memory free(), things
within this code path should be kept as simple as possible. This commit
try to remove the function call when free() invokes tcache code path by
inlining _int_free().

Result of bench-malloc-thread benchmark

Test Platform: Xeon-8380
Ratio: New / Original time_per_iteration (Lower is Better)

Threads#   | Ratio
-----------|------
1 thread   | 0.879
4 threads  | 0.874

The performance data shows it can improve bench-malloc-thread benchmark
by ~12% in both single thread and multi-thread scenario.

---
Changes in v4:
- inline _int_free instead of manual inlining.
- Link to v3: https://sourceware.org/pipermail/libc-alpha/2024-August/159505.html
No Changes in v3
Changes in v2:
- _int_free_check() should be put outside of USE_TCACHE.
- Link to v1: https://sourceware.org/pipermail/libc-alpha/2024-August/159359.html
---
 malloc/malloc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/malloc/malloc.c b/malloc/malloc.c
index 32dbc272a8..81ddd2c3a8 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -4677,7 +4677,7 @@ _int_free_chunk (mstate av, mchunkptr p, INTERNAL_SIZE_T size, int have_lock)
    P has already been locked.  It will perform sanity check, then try the
    fast path to free into tcache.  If the attempt not success, free the
    chunk to arena.  */
-static void
+static inline void
 _int_free (mstate av, mchunkptr p, int have_lock)
 {
   INTERNAL_SIZE_T size;        /* its size */
-- 
2.43.5