cosmopolitan/third_party/dlmalloc/locks.inc
Justine Tunney e557058ac8
Improve cosmo's conformance to libc-test
This change addresses various open source compatibility issues, so that
we pass 313/411 of the tests in https://github.com/jart/libc-test where
earlier today we were passing about 30/411 of them, due to header toil.
Please note that Glibc only passes 341/411 so 313 today is pretty good!

- Make the conformance of libc/isystem/ headers nearly perfect
- Import more of the remaining math library routines from Musl
- Fix inconsistencies with type signatures of calls like umask
- Write tests for getpriority/setpriority which work great now
- conform to `struct sockaddr *` on remaining socket functions
- Import a bunch of uninteresting stdlib functions e.g. rand48
- Introduce readdir_r, scandir, pthread_kill, sigsetjmp, etc..

Follow the instructions in our `tool/scripts/cosmocc` toolchain to run
these tests yourself. You use `make CC=cosmocc` on the test repository
2022-10-10 17:52:41 -07:00

98 lines
3.7 KiB
C++

// clang-format off
#include "third_party/nsync/mu.h"
#include "libc/atomic.h"
#include "libc/intrin/atomic.h"
#include "libc/calls/calls.h"
#include "libc/thread/tls.h"
/* --------------------------- Lock preliminaries ------------------------ */
/*
When locks are defined, there is one global lock, plus
one per-mspace lock.
The global lock_ensures that mparams.magic and other unique
mparams values are initialized only once. It also protects
sequences of calls to MORECORE. In many cases sys_alloc requires
two calls, that should not be interleaved with calls by other
threads. This does not protect against direct calls to MORECORE
by other threads not using this lock, so there is still code to
cope the best we can on interference.
Per-mspace locks surround calls to malloc, free, etc.
By default, locks are simple non-reentrant mutexes.
Because lock-protected regions generally have bounded times, it is
OK to use the supplied simple spinlocks. Spinlocks are likely to
improve performance for lightly contended applications, but worsen
performance under heavy contention.
If USE_LOCKS is > 1, the definitions of lock routines here are
bypassed, in which case you will need to define the type MLOCK_T,
and at least INITIAL_LOCK, DESTROY_LOCK, ACQUIRE_LOCK, RELEASE_LOCK
and TRY_LOCK. You must also declare a
static MLOCK_T malloc_global_mutex = { initialization values };.
*/
static int malloc_lock(atomic_int *lk) {
if (!__threaded) return 0;
while (atomic_exchange_explicit(lk, 1, memory_order_acquire)) {
donothing;
}
return 0;
}
static int malloc_trylock(atomic_int *lk) {
if (!__threaded) return 1;
return !atomic_exchange_explicit(lk, 1, memory_order_acquire);
}
static inline int malloc_unlock(atomic_int *lk) {
atomic_store_explicit(lk, 0, memory_order_release);
return 0;
}
#if !USE_LOCKS
#define USE_LOCK_BIT (0U)
#define INITIAL_LOCK(l) (0)
#define DESTROY_LOCK(l) (0)
#define ACQUIRE_MALLOC_GLOBAL_LOCK()
#define RELEASE_MALLOC_GLOBAL_LOCK()
#elif defined(TINY)
#define MLOCK_T atomic_int
#define ACQUIRE_LOCK(lk) malloc_lock(lk)
#define RELEASE_LOCK(lk) malloc_unlock(lk)
#define TRY_LOCK(lk) malloc_trylock(lk)
#define INITIAL_LOCK(lk) (*lk = 0, 0)
#define DESTROY_LOCK(lk)
#define ACQUIRE_MALLOC_GLOBAL_LOCK() ACQUIRE_LOCK(&malloc_global_mutex);
#define RELEASE_MALLOC_GLOBAL_LOCK() RELEASE_LOCK(&malloc_global_mutex);
static MLOCK_T malloc_global_mutex;
#else
#define MLOCK_T nsync_mu
#define ACQUIRE_LOCK(lk) (__threaded && (nsync_mu_lock(lk), 0))
#define RELEASE_LOCK(lk) (__threaded && (nsync_mu_unlock(lk), 0))
#define TRY_LOCK(lk) (__threaded ? nsync_mu_trylock(lk) : 1)
#define INITIAL_LOCK(lk) memset(lk, 0, sizeof(*lk))
#define DESTROY_LOCK(lk) memset(lk, -1, sizeof(*lk))
#define ACQUIRE_MALLOC_GLOBAL_LOCK() ACQUIRE_LOCK(&malloc_global_mutex);
#define RELEASE_MALLOC_GLOBAL_LOCK() RELEASE_LOCK(&malloc_global_mutex);
static MLOCK_T malloc_global_mutex;
#endif
#define USE_LOCK_BIT (2U)
struct malloc_chunk {
size_t prev_foot; /* Size of previous chunk (if free). */
size_t head; /* Size and inuse bits. */
struct malloc_chunk* fd; /* double links -- used only if free. */
struct malloc_chunk* bk;
};
typedef struct malloc_chunk mchunk;
typedef struct malloc_chunk* mchunkptr;
typedef struct malloc_chunk* sbinptr; /* The type of bins of chunks */
typedef unsigned int bindex_t; /* Described below */
typedef unsigned int binmap_t; /* Described below */
typedef unsigned int flag_t; /* The type of various bit flag sets */