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improve performance of clearNX

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daanx 2025-02-08 09:36:09 -08:00
parent bc7fe059a6
commit 2017181a69
2 changed files with 2 additions and 20 deletions
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18
src/bitmap.c
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@ -167,14 +167,13 @@ static inline bool mi_bfield_atomic_setX(_Atomic(mi_bfield_t)*b, size_t* already
// `all_clear` is set to `true` if the new bfield became zero. // `all_clear` is set to `true` if the new bfield became zero.
static inline bool mi_bfield_atomic_try_clear_mask_of(_Atomic(mi_bfield_t)*b, mi_bfield_t mask, mi_bfield_t expect, bool* all_clear) { static inline bool mi_bfield_atomic_try_clear_mask_of(_Atomic(mi_bfield_t)*b, mi_bfield_t mask, mi_bfield_t expect, bool* all_clear) {
mi_assert_internal(mask != 0); mi_assert_internal(mask != 0);
mi_assert_internal((expect & mask) == mask);
// try to atomically clear the mask bits // try to atomically clear the mask bits
while mi_unlikely(!mi_atomic_cas_strong_acq_rel(b, &expect, expect & ~mask)) { do {
if ((expect & mask) != mask) { if ((expect & mask) != mask) {
if (all_clear != NULL) { *all_clear = (expect == 0); } if (all_clear != NULL) { *all_clear = (expect == 0); }
return false; return false;
} }
} } while (!mi_atomic_cas_weak_acq_rel(b, &expect, expect & ~mask));
if (all_clear != NULL) { *all_clear = ((expect & ~mask) == 0); } if (all_clear != NULL) { *all_clear = ((expect & ~mask) == 0); }
return true; return true;
} }
@ -696,10 +695,6 @@ static mi_decl_noinline bool mi_bchunk_try_find_and_clear8(mi_bchunk_t* chunk, s
// note: there must be an atomic release/acquire in between or otherwise the registers may not be reloaded } // note: there must be an atomic release/acquire in between or otherwise the registers may not be reloaded }
} }
#else #else
// first skip allset fields to reduce fragmentation (not needed for binned bitmaps)
// for(int i = 0; i < MI_BCHUNK_FIELDS; i++) {
// if (mi_bchunk_try_find_and_clear8_at(chunk, i, pidx, false /* don't allow allset fields */)) return true;
// }
for (int i = 0; i < MI_BCHUNK_FIELDS; i++) { for (int i = 0; i < MI_BCHUNK_FIELDS; i++) {
if (mi_bchunk_try_find_and_clear8_at(chunk, i, pidx)) return true; if (mi_bchunk_try_find_and_clear8_at(chunk, i, pidx)) return true;
} }
@ -892,15 +887,6 @@ static mi_decl_noinline bool mi_bchunk_try_find_and_clearN_(mi_bchunk_t* chunk,
} }
//static inline bool mi_bchunk_try_find_and_clearN(mi_bchunk_t* chunk, size_t n, size_t* pidx) {
// if (n==1) return mi_bchunk_try_find_and_clear(chunk, pidx); // small pages
// if (n==8) return mi_bchunk_try_find_and_clear8(chunk, pidx); // medium pages
// // if (n==MI_BFIELD_BITS) return mi_bchunk_try_find_and_clearX(chunk, pidx); // large pages
// if (n==0 || n > MI_BCHUNK_BITS) return false; // cannot be more than a chunk
// if (n<=MI_BFIELD_BITS) return mi_bchunk_try_find_and_clearNX(chunk, n, pidx);
// return mi_bchunk_try_find_and_clearN_(chunk, n, pidx);
//}
// ------- mi_bchunk_clear_once_set --------------------------------------- // ------- mi_bchunk_clear_once_set ---------------------------------------

4
src/bitmap.h
View file

@ -271,10 +271,6 @@ void mi_bbitmap_unsafe_setN(mi_bbitmap_t* bbitmap, size_t idx, size_t n);
// `n` cannot cross chunk boundaries (and `n <= MI_BCHUNK_BITS`)! // `n` cannot cross chunk boundaries (and `n <= MI_BCHUNK_BITS`)!
bool mi_bbitmap_setN(mi_bbitmap_t* bbitmap, size_t idx, size_t n); bool mi_bbitmap_setN(mi_bbitmap_t* bbitmap, size_t idx, size_t n);
// Clear a sequence of `n` bits in the bitmap; returns `true` if atomically transitioned from all 1's to 0's
// `n` cannot cross chunk boundaries (and `n <= MI_BCHUNK_BITS`)!
bool mi_bbitmap_clearN(mi_bbitmap_t* bbitmap, size_t idx, size_t n);
// Is a sequence of n bits already all set/cleared? // Is a sequence of n bits already all set/cleared?
bool mi_bbitmap_is_xsetN(mi_xset_t set, mi_bbitmap_t* bbitmap, size_t idx, size_t n); bool mi_bbitmap_is_xsetN(mi_xset_t set, mi_bbitmap_t* bbitmap, size_t idx, size_t n);