kiper220/mimalloc
1
0
Fork 0
mirror of https://github.com/microsoft/mimalloc.git synced 2025-07-01 17:24:38 +03:00
Code Issues Projects Releases Packages Wiki Activity Actions

add comments

Browse source
This commit is contained in:
daanx 2025-03-06 16:50:56 -08:00
parent dd3a74d89d
commit 7e721c881b
2 changed files with 9 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

11
src/bitmap.c
View file

@ -1557,7 +1557,7 @@ static inline bool mi_bbitmap_try_find_and_clear_generic(mi_bbitmap_t* bbitmap,
mi_assert_internal(MI_BFIELD_BITS >= MI_BCHUNK_FIELDS); mi_assert_internal(MI_BFIELD_BITS >= MI_BCHUNK_FIELDS);
const mi_bfield_t cmap_mask = mi_bfield_mask(cmap_max_count,0); const mi_bfield_t cmap_mask = mi_bfield_mask(cmap_max_count,0);
const size_t cmap_cycle = cmap_acc+1; const size_t cmap_cycle = cmap_acc+1;
const mi_bbin_t bbin = mi_bbin_of(n); const mi_bbin_t bbin = mi_bbin_of(n);
// visit each cmap entry // visit each cmap entry
size_t cmap_idx = 0; size_t cmap_idx = 0;
mi_bfield_cycle_iterate(cmap_mask, tseq, cmap_cycle, cmap_idx, X) mi_bfield_cycle_iterate(cmap_mask, tseq, cmap_cycle, cmap_idx, X)
@ -1576,11 +1576,15 @@ static inline bool mi_bbitmap_try_find_and_clear_generic(mi_bbitmap_t* bbitmap,
cmap_bins[MI_BBIN_NONE] &= ~cmap_bin; // clear bits that are in an assigned size bin cmap_bins[MI_BBIN_NONE] &= ~cmap_bin; // clear bits that are in an assigned size bin
} }
// consider only chunks for a particular size bin at a time // consider only chunks for a particular size bin at a time
// this picks the best bin only within a cmap entry (~ 1GiB address space), but avoids multiple
// iterations through all entries.
mi_assert_internal(bbin < MI_BBIN_NONE);
for (mi_bbin_t ibin = MI_BBIN_SMALL; ibin <= MI_BBIN_NONE; for (mi_bbin_t ibin = MI_BBIN_SMALL; ibin <= MI_BBIN_NONE;
// skip from bbin to NONE (so, say, a SMALL will never be placed in a OTHER, MEDIUM, or LARGE chunk to reduce fragmentation) // skip from bbin to NONE (so, say, a SMALL will never be placed in a OTHER, MEDIUM, or LARGE chunk to reduce fragmentation)
ibin = (ibin == bbin ? MI_BBIN_NONE : mi_bbin_inc(ibin))) ibin = (ibin == bbin ? MI_BBIN_NONE : mi_bbin_inc(ibin)))
{ {
mi_assert_internal(ibin < MI_BBIN_COUNT);
const mi_bfield_t cmap_bin = cmap_bins[ibin]; const mi_bfield_t cmap_bin = cmap_bins[ibin];
size_t eidx = 0; size_t eidx = 0;
mi_bfield_cycle_iterate(cmap_bin, tseq, cmap_entry_cycle, eidx, Y) mi_bfield_cycle_iterate(cmap_bin, tseq, cmap_entry_cycle, eidx, Y)
@ -1603,7 +1607,8 @@ static inline bool mi_bbitmap_try_find_and_clear_generic(mi_bbitmap_t* bbitmap,
return true; return true;
} }
else { else {
/* we may find that all are cleared only on a second iteration but that is ok as the chunkmap is a conservative approximation. */ // todo: should _on_find_ return a boolen if there is a chance all are clear to avoid calling `try_clear?`
// we may find that all are cleared only on a second iteration but that is ok as the chunkmap is a conservative approximation.
mi_bbitmap_chunkmap_try_clear(bbitmap, chunk_idx); mi_bbitmap_chunkmap_try_clear(bbitmap, chunk_idx);
} }
} }

2
src/bitmap.h
View file

@ -248,7 +248,7 @@ typedef mi_decl_align(MI_BCHUNK_SIZE) struct mi_bbitmap_s {
_Atomic(size_t) chunk_max_accessed; // max chunk index that was once cleared or set _Atomic(size_t) chunk_max_accessed; // max chunk index that was once cleared or set
size_t _padding[MI_BCHUNK_SIZE/MI_SIZE_SIZE - 2]; // suppress warning on msvc size_t _padding[MI_BCHUNK_SIZE/MI_SIZE_SIZE - 2]; // suppress warning on msvc
mi_bchunkmap_t chunkmap; mi_bchunkmap_t chunkmap;
mi_bchunkmap_t chunkmap_bins[MI_BBIN_COUNT - 1]; // chunkmaps with bit set if the chunk is in that size class (except MI_BBIN_NONE) mi_bchunkmap_t chunkmap_bins[MI_BBIN_COUNT - 1]; // chunkmaps with bit set if the chunk is in that size class (excluding MI_BBIN_NONE)
mi_bchunk_t chunks[MI_BITMAP_DEFAULT_CHUNK_COUNT]; // usually dynamic MI_BITMAP_MAX_CHUNK_COUNT mi_bchunk_t chunks[MI_BITMAP_DEFAULT_CHUNK_COUNT]; // usually dynamic MI_BITMAP_MAX_CHUNK_COUNT
} mi_bbitmap_t; } mi_bbitmap_t;