server-skynet-source-3rd-je.../include/jemalloc/jemalloc_protos.h.in
gnzlbg 08260a6b94 Add experimental API: smallocx_return_t smallocx(size, flags)
---

Motivation:

This new experimental memory-allocaction API returns a pointer to
the allocation as well as the usable size of the allocated memory
region.

The `s` in `smallocx` stands for `sized`-`mallocx`, attempting to
convey that this API returns the size of the allocated memory region.

It should allow C++ P0901r0 [0] and Rust Alloc::alloc_excess to make
use of it.

The main purpose of these APIs is to improve telemetry. It is more accurate
to register `smallocx(size, flags)` than `smallocx(nallocx(size), flags)`,
for example. The latter will always line up perfectly with the existing
size classes, causing a loss of telemetry information about the internal
fragmentation induced by potentially poor size-classes choices.

Instrumenting `nallocx` does not help much since user code can cache its
result and use it repeatedly.

---

Implementation:

The implementation adds a new `usize` option to `static_opts_s` and an `usize`
variable to `dynamic_opts_s`. These are then used to cache the result of
`sz_index2size` and similar functions in the code paths in which they are
unconditionally invoked. In the code-paths in which these functions are not
unconditionally invoked, `smallocx` calls, as opposed to `mallocx`, these
functions explicitly.

---

[0]: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p0901r0.html
2018-10-17 07:12:28 -07:00

71 lines
3.4 KiB
C

/*
* The @je_@ prefix on the following public symbol declarations is an artifact
* of namespace management, and should be omitted in application code unless
* JEMALLOC_NO_DEMANGLE is defined (see jemalloc_mangle@install_suffix@.h).
*/
extern JEMALLOC_EXPORT const char *@je_@malloc_conf;
extern JEMALLOC_EXPORT void (*@je_@malloc_message)(void *cbopaque,
const char *s);
JEMALLOC_EXPORT JEMALLOC_ALLOCATOR JEMALLOC_RESTRICT_RETURN
void JEMALLOC_NOTHROW *@je_@malloc(size_t size)
JEMALLOC_CXX_THROW JEMALLOC_ATTR(malloc) JEMALLOC_ALLOC_SIZE(1);
JEMALLOC_EXPORT JEMALLOC_ALLOCATOR JEMALLOC_RESTRICT_RETURN
void JEMALLOC_NOTHROW *@je_@calloc(size_t num, size_t size)
JEMALLOC_CXX_THROW JEMALLOC_ATTR(malloc) JEMALLOC_ALLOC_SIZE2(1, 2);
JEMALLOC_EXPORT int JEMALLOC_NOTHROW @je_@posix_memalign(void **memptr,
size_t alignment, size_t size) JEMALLOC_CXX_THROW JEMALLOC_ATTR(nonnull(1));
JEMALLOC_EXPORT JEMALLOC_ALLOCATOR JEMALLOC_RESTRICT_RETURN
void JEMALLOC_NOTHROW *@je_@aligned_alloc(size_t alignment,
size_t size) JEMALLOC_CXX_THROW JEMALLOC_ATTR(malloc)
JEMALLOC_ALLOC_SIZE(2);
JEMALLOC_EXPORT JEMALLOC_ALLOCATOR JEMALLOC_RESTRICT_RETURN
void JEMALLOC_NOTHROW *@je_@realloc(void *ptr, size_t size)
JEMALLOC_CXX_THROW JEMALLOC_ALLOC_SIZE(2);
JEMALLOC_EXPORT void JEMALLOC_NOTHROW @je_@free(void *ptr)
JEMALLOC_CXX_THROW;
JEMALLOC_EXPORT JEMALLOC_ALLOCATOR JEMALLOC_RESTRICT_RETURN
void JEMALLOC_NOTHROW *@je_@mallocx(size_t size, int flags)
JEMALLOC_ATTR(malloc) JEMALLOC_ALLOC_SIZE(1);
#ifdef JEMALLOC_EXPERIMENTAL_SMALLOCX_API
JEMALLOC_EXPORT JEMALLOC_ALLOCATOR JEMALLOC_RESTRICT_RETURN
smallocx_return_t JEMALLOC_NOTHROW @je_@smallocx(size_t size, int flags);
#endif
JEMALLOC_EXPORT JEMALLOC_ALLOCATOR JEMALLOC_RESTRICT_RETURN
void JEMALLOC_NOTHROW *@je_@rallocx(void *ptr, size_t size,
int flags) JEMALLOC_ALLOC_SIZE(2);
JEMALLOC_EXPORT size_t JEMALLOC_NOTHROW @je_@xallocx(void *ptr, size_t size,
size_t extra, int flags);
JEMALLOC_EXPORT size_t JEMALLOC_NOTHROW @je_@sallocx(const void *ptr,
int flags) JEMALLOC_ATTR(pure);
JEMALLOC_EXPORT void JEMALLOC_NOTHROW @je_@dallocx(void *ptr, int flags);
JEMALLOC_EXPORT void JEMALLOC_NOTHROW @je_@sdallocx(void *ptr, size_t size,
int flags);
JEMALLOC_EXPORT size_t JEMALLOC_NOTHROW @je_@nallocx(size_t size, int flags)
JEMALLOC_ATTR(pure);
JEMALLOC_EXPORT int JEMALLOC_NOTHROW @je_@mallctl(const char *name,
void *oldp, size_t *oldlenp, void *newp, size_t newlen);
JEMALLOC_EXPORT int JEMALLOC_NOTHROW @je_@mallctlnametomib(const char *name,
size_t *mibp, size_t *miblenp);
JEMALLOC_EXPORT int JEMALLOC_NOTHROW @je_@mallctlbymib(const size_t *mib,
size_t miblen, void *oldp, size_t *oldlenp, void *newp, size_t newlen);
JEMALLOC_EXPORT void JEMALLOC_NOTHROW @je_@malloc_stats_print(
void (*write_cb)(void *, const char *), void *@je_@cbopaque,
const char *opts);
JEMALLOC_EXPORT size_t JEMALLOC_NOTHROW @je_@malloc_usable_size(
JEMALLOC_USABLE_SIZE_CONST void *ptr) JEMALLOC_CXX_THROW;
#ifdef JEMALLOC_OVERRIDE_MEMALIGN
JEMALLOC_EXPORT JEMALLOC_ALLOCATOR JEMALLOC_RESTRICT_RETURN
void JEMALLOC_NOTHROW *@je_@memalign(size_t alignment, size_t size)
JEMALLOC_CXX_THROW JEMALLOC_ATTR(malloc);
#endif
#ifdef JEMALLOC_OVERRIDE_VALLOC
JEMALLOC_EXPORT JEMALLOC_ALLOCATOR JEMALLOC_RESTRICT_RETURN
void JEMALLOC_NOTHROW *@je_@valloc(size_t size) JEMALLOC_CXX_THROW
JEMALLOC_ATTR(malloc);
#endif