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mdbx: minor refine get_reasonable_db_maxsize().

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Change-Id: I5d654940a325c0c3966a59a37615820587c52c78
This commit is contained in:
Leonid Yuriev 2021-04-08 02:21:27 +03:00
parent 7f5cbf7dd8
commit 20299f87cb
1 changed files with 7 additions and 12 deletions
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19
src/core.c
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@ -10532,20 +10532,15 @@ __cold static intptr_t get_reasonable_db_maxsize(intptr_t *cached_result) {
*cached_result = (intptr_t)((size_t)total_ram_pages * 207 >> 7) * pagesize;
/* Round to the nearest human-readable granulation. */
for (int i = 10; i < MDBX_WORDBITS - 1; i += 10) {
const size_t unit = (size_t)1 << i;
for (size_t unit = MEGABYTE; unit; unit <<= 5) {
const size_t floor = floor_powerof2(*cached_result, unit);
const size_t ceil = ceil_powerof2(*cached_result, unit);
if (*cached_result - floor < ceil - *cached_result ||
ceil > MAX_MAPSIZE) {
if (*cached_result - floor > (size_t)*cached_result / 16)
break;
*cached_result = floor;
} else {
if (ceil - *cached_result > (size_t)*cached_result / 16)
break;
*cached_result = ceil;
}
const size_t threshold = (size_t)*cached_result >> 4;
const bool down =
*cached_result - floor < ceil - *cached_result || ceil > MAX_MAPSIZE;
if (threshold < (down ? *cached_result - floor : ceil - *cached_result))
break;
*cached_result = down ? floor : ceil;
}
}
return *cached_result;