diff options
Diffstat (limited to 'deps/jemalloc/include/jemalloc/internal/sz.h')
| -rw-r--r-- | deps/jemalloc/include/jemalloc/internal/sz.h | 97 |
1 files changed, 75 insertions, 22 deletions
diff --git a/deps/jemalloc/include/jemalloc/internal/sz.h b/deps/jemalloc/include/jemalloc/internal/sz.h index 68e558abf..3c0fc1da3 100644 --- a/deps/jemalloc/include/jemalloc/internal/sz.h +++ b/deps/jemalloc/include/jemalloc/internal/sz.h @@ -22,6 +22,12 @@ * size that would result from such an allocation. */ +/* Page size index type. */ +typedef unsigned pszind_t; + +/* Size class index type. */ +typedef unsigned szind_t; + /* * sz_pind2sz_tab encodes the same information as could be computed by * sz_pind2sz_compute(). @@ -39,34 +45,62 @@ extern size_t sz_index2size_tab[SC_NSIZES]; */ extern uint8_t sz_size2index_tab[]; -static const size_t sz_large_pad = -#ifdef JEMALLOC_CACHE_OBLIVIOUS - PAGE -#else - 0 -#endif - ; +/* + * Padding for large allocations: PAGE when opt_cache_oblivious == true (to + * enable cache index randomization); 0 otherwise. + */ +extern size_t sz_large_pad; -extern void sz_boot(const sc_data_t *sc_data); +extern void sz_boot(const sc_data_t *sc_data, bool cache_oblivious); JEMALLOC_ALWAYS_INLINE pszind_t sz_psz2ind(size_t psz) { + assert(psz > 0); if (unlikely(psz > SC_LARGE_MAXCLASS)) { return SC_NPSIZES; } - pszind_t x = lg_floor((psz<<1)-1); - pszind_t shift = (x < SC_LG_NGROUP + LG_PAGE) ? + /* x is the lg of the first base >= psz. */ + pszind_t x = lg_ceil(psz); + /* + * sc.h introduces a lot of size classes. These size classes are divided + * into different size class groups. There is a very special size class + * group, each size class in or after it is an integer multiple of PAGE. + * We call it first_ps_rg. It means first page size regular group. The + * range of first_ps_rg is (base, base * 2], and base == PAGE * + * SC_NGROUP. off_to_first_ps_rg begins from 1, instead of 0. e.g. + * off_to_first_ps_rg is 1 when psz is (PAGE * SC_NGROUP + 1). + */ + pszind_t off_to_first_ps_rg = (x < SC_LG_NGROUP + LG_PAGE) ? 0 : x - (SC_LG_NGROUP + LG_PAGE); - pszind_t grp = shift << SC_LG_NGROUP; - pszind_t lg_delta = (x < SC_LG_NGROUP + LG_PAGE + 1) ? - LG_PAGE : x - SC_LG_NGROUP - 1; + /* + * Same as sc_s::lg_delta. + * Delta for off_to_first_ps_rg == 1 is PAGE, + * for each increase in offset, it's multiplied by two. + * Therefore, lg_delta = LG_PAGE + (off_to_first_ps_rg - 1). + */ + pszind_t lg_delta = (off_to_first_ps_rg == 0) ? + LG_PAGE : LG_PAGE + (off_to_first_ps_rg - 1); - size_t delta_inverse_mask = ZU(-1) << lg_delta; - pszind_t mod = ((((psz-1) & delta_inverse_mask) >> lg_delta)) & - ((ZU(1) << SC_LG_NGROUP) - 1); + /* + * Let's write psz in binary, e.g. 0011 for 0x3, 0111 for 0x7. + * The leftmost bits whose len is lg_base decide the base of psz. + * The rightmost bits whose len is lg_delta decide (pgz % PAGE). + * The middle bits whose len is SC_LG_NGROUP decide ndelta. + * ndelta is offset to the first size class in the size class group, + * starts from 1. + * If you don't know lg_base, ndelta or lg_delta, see sc.h. + * |xxxxxxxxxxxxxxxxxxxx|------------------------|yyyyyyyyyyyyyyyyyyyyy| + * |<-- len: lg_base -->|<-- len: SC_LG_NGROUP-->|<-- len: lg_delta -->| + * |<-- ndelta -->| + * rg_inner_off = ndelta - 1 + * Why use (psz - 1)? + * To handle case: psz % (1 << lg_delta) == 0. + */ + pszind_t rg_inner_off = (((psz - 1)) >> lg_delta) & (SC_NGROUP - 1); - pszind_t ind = grp + mod; + pszind_t base_ind = off_to_first_ps_rg << SC_LG_NGROUP; + pszind_t ind = base_ind + rg_inner_off; return ind; } @@ -152,10 +186,15 @@ sz_size2index_compute(size_t size) { } JEMALLOC_ALWAYS_INLINE szind_t -sz_size2index_lookup(size_t size) { +sz_size2index_lookup_impl(size_t size) { assert(size <= SC_LOOKUP_MAXCLASS); - szind_t ret = (sz_size2index_tab[(size + (ZU(1) << SC_LG_TINY_MIN) - 1) - >> SC_LG_TINY_MIN]); + return sz_size2index_tab[(size + (ZU(1) << SC_LG_TINY_MIN) - 1) + >> SC_LG_TINY_MIN]; +} + +JEMALLOC_ALWAYS_INLINE szind_t +sz_size2index_lookup(size_t size) { + szind_t ret = sz_size2index_lookup_impl(size); assert(ret == sz_size2index_compute(size)); return ret; } @@ -195,8 +234,13 @@ sz_index2size_compute(szind_t index) { } JEMALLOC_ALWAYS_INLINE size_t +sz_index2size_lookup_impl(szind_t index) { + return sz_index2size_tab[index]; +} + +JEMALLOC_ALWAYS_INLINE size_t sz_index2size_lookup(szind_t index) { - size_t ret = (size_t)sz_index2size_tab[index]; + size_t ret = sz_index2size_lookup_impl(index); assert(ret == sz_index2size_compute(index)); return ret; } @@ -207,6 +251,12 @@ sz_index2size(szind_t index) { return sz_index2size_lookup(index); } +JEMALLOC_ALWAYS_INLINE void +sz_size2index_usize_fastpath(size_t size, szind_t *ind, size_t *usize) { + *ind = sz_size2index_lookup_impl(size); + *usize = sz_index2size_lookup_impl(*ind); +} + JEMALLOC_ALWAYS_INLINE size_t sz_s2u_compute(size_t size) { if (unlikely(size > SC_LARGE_MAXCLASS)) { @@ -266,7 +316,7 @@ sz_sa2u(size_t size, size_t alignment) { assert(alignment != 0 && ((alignment - 1) & alignment) == 0); /* Try for a small size class. */ - if (size <= SC_SMALL_MAXCLASS && alignment < PAGE) { + if (size <= SC_SMALL_MAXCLASS && alignment <= PAGE) { /* * Round size up to the nearest multiple of alignment. * @@ -315,4 +365,7 @@ sz_sa2u(size_t size, size_t alignment) { return usize; } +size_t sz_psz_quantize_floor(size_t size); +size_t sz_psz_quantize_ceil(size_t size); + #endif /* JEMALLOC_INTERNAL_SIZE_H */ |