diff options
Diffstat (limited to 'deps/jemalloc/src/eset.c')
-rw-r--r-- | deps/jemalloc/src/eset.c | 282 |
1 files changed, 282 insertions, 0 deletions
diff --git a/deps/jemalloc/src/eset.c b/deps/jemalloc/src/eset.c new file mode 100644 index 0000000..6f8f335 --- /dev/null +++ b/deps/jemalloc/src/eset.c @@ -0,0 +1,282 @@ +#include "jemalloc/internal/jemalloc_preamble.h" +#include "jemalloc/internal/jemalloc_internal_includes.h" + +#include "jemalloc/internal/eset.h" + +#define ESET_NPSIZES (SC_NPSIZES + 1) + +static void +eset_bin_init(eset_bin_t *bin) { + edata_heap_new(&bin->heap); + /* + * heap_min doesn't need initialization; it gets filled in when the bin + * goes from non-empty to empty. + */ +} + +static void +eset_bin_stats_init(eset_bin_stats_t *bin_stats) { + atomic_store_zu(&bin_stats->nextents, 0, ATOMIC_RELAXED); + atomic_store_zu(&bin_stats->nbytes, 0, ATOMIC_RELAXED); +} + +void +eset_init(eset_t *eset, extent_state_t state) { + for (unsigned i = 0; i < ESET_NPSIZES; i++) { + eset_bin_init(&eset->bins[i]); + eset_bin_stats_init(&eset->bin_stats[i]); + } + fb_init(eset->bitmap, ESET_NPSIZES); + edata_list_inactive_init(&eset->lru); + eset->state = state; +} + +size_t +eset_npages_get(eset_t *eset) { + return atomic_load_zu(&eset->npages, ATOMIC_RELAXED); +} + +size_t +eset_nextents_get(eset_t *eset, pszind_t pind) { + return atomic_load_zu(&eset->bin_stats[pind].nextents, ATOMIC_RELAXED); +} + +size_t +eset_nbytes_get(eset_t *eset, pszind_t pind) { + return atomic_load_zu(&eset->bin_stats[pind].nbytes, ATOMIC_RELAXED); +} + +static void +eset_stats_add(eset_t *eset, pszind_t pind, size_t sz) { + size_t cur = atomic_load_zu(&eset->bin_stats[pind].nextents, + ATOMIC_RELAXED); + atomic_store_zu(&eset->bin_stats[pind].nextents, cur + 1, + ATOMIC_RELAXED); + cur = atomic_load_zu(&eset->bin_stats[pind].nbytes, ATOMIC_RELAXED); + atomic_store_zu(&eset->bin_stats[pind].nbytes, cur + sz, + ATOMIC_RELAXED); +} + +static void +eset_stats_sub(eset_t *eset, pszind_t pind, size_t sz) { + size_t cur = atomic_load_zu(&eset->bin_stats[pind].nextents, + ATOMIC_RELAXED); + atomic_store_zu(&eset->bin_stats[pind].nextents, cur - 1, + ATOMIC_RELAXED); + cur = atomic_load_zu(&eset->bin_stats[pind].nbytes, ATOMIC_RELAXED); + atomic_store_zu(&eset->bin_stats[pind].nbytes, cur - sz, + ATOMIC_RELAXED); +} + +void +eset_insert(eset_t *eset, edata_t *edata) { + assert(edata_state_get(edata) == eset->state); + + size_t size = edata_size_get(edata); + size_t psz = sz_psz_quantize_floor(size); + pszind_t pind = sz_psz2ind(psz); + + edata_cmp_summary_t edata_cmp_summary = edata_cmp_summary_get(edata); + if (edata_heap_empty(&eset->bins[pind].heap)) { + fb_set(eset->bitmap, ESET_NPSIZES, (size_t)pind); + /* Only element is automatically the min element. */ + eset->bins[pind].heap_min = edata_cmp_summary; + } else { + /* + * There's already a min element; update the summary if we're + * about to insert a lower one. + */ + if (edata_cmp_summary_comp(edata_cmp_summary, + eset->bins[pind].heap_min) < 0) { + eset->bins[pind].heap_min = edata_cmp_summary; + } + } + edata_heap_insert(&eset->bins[pind].heap, edata); + + if (config_stats) { + eset_stats_add(eset, pind, size); + } + + edata_list_inactive_append(&eset->lru, edata); + size_t npages = size >> LG_PAGE; + /* + * All modifications to npages hold the mutex (as asserted above), so we + * don't need an atomic fetch-add; we can get by with a load followed by + * a store. + */ + size_t cur_eset_npages = + atomic_load_zu(&eset->npages, ATOMIC_RELAXED); + atomic_store_zu(&eset->npages, cur_eset_npages + npages, + ATOMIC_RELAXED); +} + +void +eset_remove(eset_t *eset, edata_t *edata) { + assert(edata_state_get(edata) == eset->state || + edata_state_in_transition(edata_state_get(edata))); + + size_t size = edata_size_get(edata); + size_t psz = sz_psz_quantize_floor(size); + pszind_t pind = sz_psz2ind(psz); + if (config_stats) { + eset_stats_sub(eset, pind, size); + } + + edata_cmp_summary_t edata_cmp_summary = edata_cmp_summary_get(edata); + edata_heap_remove(&eset->bins[pind].heap, edata); + if (edata_heap_empty(&eset->bins[pind].heap)) { + fb_unset(eset->bitmap, ESET_NPSIZES, (size_t)pind); + } else { + /* + * This is a little weird; we compare if the summaries are + * equal, rather than if the edata we removed was the heap + * minimum. The reason why is that getting the heap minimum + * can cause a pairing heap merge operation. We can avoid this + * if we only update the min if it's changed, in which case the + * summaries of the removed element and the min element should + * compare equal. + */ + if (edata_cmp_summary_comp(edata_cmp_summary, + eset->bins[pind].heap_min) == 0) { + eset->bins[pind].heap_min = edata_cmp_summary_get( + edata_heap_first(&eset->bins[pind].heap)); + } + } + edata_list_inactive_remove(&eset->lru, edata); + size_t npages = size >> LG_PAGE; + /* + * As in eset_insert, we hold eset->mtx and so don't need atomic + * operations for updating eset->npages. + */ + size_t cur_extents_npages = + atomic_load_zu(&eset->npages, ATOMIC_RELAXED); + assert(cur_extents_npages >= npages); + atomic_store_zu(&eset->npages, + cur_extents_npages - (size >> LG_PAGE), ATOMIC_RELAXED); +} + +/* + * Find an extent with size [min_size, max_size) to satisfy the alignment + * requirement. For each size, try only the first extent in the heap. + */ +static edata_t * +eset_fit_alignment(eset_t *eset, size_t min_size, size_t max_size, + size_t alignment) { + pszind_t pind = sz_psz2ind(sz_psz_quantize_ceil(min_size)); + pszind_t pind_max = sz_psz2ind(sz_psz_quantize_ceil(max_size)); + + for (pszind_t i = + (pszind_t)fb_ffs(eset->bitmap, ESET_NPSIZES, (size_t)pind); + i < pind_max; + i = (pszind_t)fb_ffs(eset->bitmap, ESET_NPSIZES, (size_t)i + 1)) { + assert(i < SC_NPSIZES); + assert(!edata_heap_empty(&eset->bins[i].heap)); + edata_t *edata = edata_heap_first(&eset->bins[i].heap); + uintptr_t base = (uintptr_t)edata_base_get(edata); + size_t candidate_size = edata_size_get(edata); + assert(candidate_size >= min_size); + + uintptr_t next_align = ALIGNMENT_CEILING((uintptr_t)base, + PAGE_CEILING(alignment)); + if (base > next_align || base + candidate_size <= next_align) { + /* Overflow or not crossing the next alignment. */ + continue; + } + + size_t leadsize = next_align - base; + if (candidate_size - leadsize >= min_size) { + return edata; + } + } + + return NULL; +} + +/* + * Do first-fit extent selection, i.e. select the oldest/lowest extent that is + * large enough. + * + * lg_max_fit is the (log of the) maximum ratio between the requested size and + * the returned size that we'll allow. This can reduce fragmentation by + * avoiding reusing and splitting large extents for smaller sizes. In practice, + * it's set to opt_lg_extent_max_active_fit for the dirty eset and SC_PTR_BITS + * for others. + */ +static edata_t * +eset_first_fit(eset_t *eset, size_t size, bool exact_only, + unsigned lg_max_fit) { + edata_t *ret = NULL; + edata_cmp_summary_t ret_summ JEMALLOC_CC_SILENCE_INIT({0}); + + pszind_t pind = sz_psz2ind(sz_psz_quantize_ceil(size)); + + if (exact_only) { + return edata_heap_empty(&eset->bins[pind].heap) ? NULL : + edata_heap_first(&eset->bins[pind].heap); + } + + for (pszind_t i = + (pszind_t)fb_ffs(eset->bitmap, ESET_NPSIZES, (size_t)pind); + i < ESET_NPSIZES; + i = (pszind_t)fb_ffs(eset->bitmap, ESET_NPSIZES, (size_t)i + 1)) { + assert(!edata_heap_empty(&eset->bins[i].heap)); + if (lg_max_fit == SC_PTR_BITS) { + /* + * We'll shift by this below, and shifting out all the + * bits is undefined. Decreasing is safe, since the + * page size is larger than 1 byte. + */ + lg_max_fit = SC_PTR_BITS - 1; + } + if ((sz_pind2sz(i) >> lg_max_fit) > size) { + break; + } + if (ret == NULL || edata_cmp_summary_comp( + eset->bins[i].heap_min, ret_summ) < 0) { + /* + * We grab the edata as early as possible, even though + * we might change it later. Practically, a large + * portion of eset_fit calls succeed at the first valid + * index, so this doesn't cost much, and we get the + * effect of prefetching the edata as early as possible. + */ + edata_t *edata = edata_heap_first(&eset->bins[i].heap); + assert(edata_size_get(edata) >= size); + assert(ret == NULL || edata_snad_comp(edata, ret) < 0); + assert(ret == NULL || edata_cmp_summary_comp( + eset->bins[i].heap_min, + edata_cmp_summary_get(edata)) == 0); + ret = edata; + ret_summ = eset->bins[i].heap_min; + } + if (i == SC_NPSIZES) { + break; + } + assert(i < SC_NPSIZES); + } + + return ret; +} + +edata_t * +eset_fit(eset_t *eset, size_t esize, size_t alignment, bool exact_only, + unsigned lg_max_fit) { + size_t max_size = esize + PAGE_CEILING(alignment) - PAGE; + /* Beware size_t wrap-around. */ + if (max_size < esize) { + return NULL; + } + + edata_t *edata = eset_first_fit(eset, max_size, exact_only, lg_max_fit); + + if (alignment > PAGE && edata == NULL) { + /* + * max_size guarantees the alignment requirement but is rather + * pessimistic. Next we try to satisfy the aligned allocation + * with sizes in [esize, max_size). + */ + edata = eset_fit_alignment(eset, esize, max_size, alignment); + } + + return edata; +} |