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mdbx: переработка LRU-отметок для спиллинга.

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Два существенных изменения:

1. Инкремент и обновление LRU происходит при изменении страницы,
   но не при доступе к ней.

2. Устранен регресс, из-за которого страницы в стеке курсора хоть
   помечались, но могли быть ошибочно пролиты на диск,
   так как dpl_age() возвращал не 0.
This commit is contained in:
Леонид Юрьев (Leonid Yuriev) 2022-12-14 23:43:32 +03:00
parent bf2f3bfbbf
commit b247b081af
1 changed files with 41 additions and 21 deletions
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62
src/core.c
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@ -3062,11 +3062,12 @@ static __inline uint32_t dpl_age(const MDBX_txn *txn, size_t i) {
tASSERT(txn, (txn->mt_flags & MDBX_WRITEMAP) == 0 || MDBX_AVOID_MSYNC);
const MDBX_dpl *dl = txn->tw.dirtylist;
assert((intptr_t)i > 0 && i <= dl->length);
return (txn->tw.dirtylru + 1 - dl->items[i].mlru) >> 1;
return (txn->tw.dirtylru >> 1) - (dl->items[i].mlru >> 1);
}
static __inline uint32_t txn_lru_inc(MDBX_txn *txn) {
if (unlikely(++txn->tw.dirtylru > UINT32_MAX / 3))
static __inline uint32_t txn_lru_turn(MDBX_txn *txn) {
txn->tw.dirtylru += 2;
if (unlikely(txn->tw.dirtylru > UINT32_MAX / 3))
txn_lru_reduce(txn);
return txn->tw.dirtylru & MDBX_dp_lru_mask;
}
@ -3077,7 +3078,7 @@ static __always_inline int __must_check_result dpl_append(MDBX_txn *txn,
size_t npages) {
tASSERT(txn, (txn->mt_flags & MDBX_TXN_RDONLY) == 0);
tASSERT(txn, (txn->mt_flags & MDBX_WRITEMAP) == 0 || MDBX_AVOID_MSYNC);
const MDBX_dp dp = {page, pgno, txn_lru_inc(txn) + (npages > 1)};
const MDBX_dp dp = {page, pgno, txn_lru_turn(txn) + (npages > 1)};
MDBX_dpl *dl = txn->tw.dirtylist;
tASSERT(txn, dl->length <= MDBX_PGL_LIMIT + MDBX_PNL_GRANULATE);
tASSERT(txn, dl->items[0].pgno == 0 &&
@ -4692,7 +4693,7 @@ static int spill_page(MDBX_txn *txn, iov_ctx_t *ctx, MDBX_page *dp,
/* Set unspillable LRU-label for dirty pages watched by txn.
* Returns the number of pages marked as unspillable. */
static size_t cursor_keep(MDBX_txn *txn, MDBX_cursor *mc) {
static size_t cursor_keep(const MDBX_txn *const txn, const MDBX_cursor *mc) {
tASSERT(txn, (txn->mt_flags & MDBX_TXN_RDONLY) == 0);
tASSERT(txn, (txn->mt_flags & MDBX_WRITEMAP) == 0 || MDBX_AVOID_MSYNC);
size_t keep = 0;
@ -4706,10 +4707,11 @@ static size_t cursor_keep(MDBX_txn *txn, MDBX_cursor *mc) {
if (IS_MODIFIABLE(txn, mp)) {
size_t const n = dpl_search(txn, mp->mp_pgno);
if (txn->tw.dirtylist->items[n].pgno == mp->mp_pgno &&
dpl_age(txn, n)) {
/* не считаем дважды */ dpl_age(txn, n)) {
txn->tw.dirtylist->items[n].mlru =
(txn->tw.dirtylist->items[n].mlru & MDBX_dp_multi_mask) +
(txn->tw.dirtylru & MDBX_dp_lru_mask);
tASSERT(txn, dpl_age(txn, n) == 0);
++keep;
}
}
@ -4727,8 +4729,8 @@ static size_t cursor_keep(MDBX_txn *txn, MDBX_cursor *mc) {
}
static size_t txn_keep(MDBX_txn *txn, MDBX_cursor *m0) {
tASSERT(txn, (txn->mt_flags & MDBX_TXN_RDONLY) == 0);
tASSERT(txn, (txn->mt_flags & MDBX_WRITEMAP) == 0 || MDBX_AVOID_MSYNC);
txn_lru_turn(txn);
size_t keep = m0 ? cursor_keep(txn, m0) : 0;
for (size_t i = FREE_DBI; i < txn->mt_numdbs; ++i)
if (F_ISSET(txn->mt_dbistate[i], DBI_DIRTY | DBI_VALID) &&
@ -4831,6 +4833,7 @@ static __inline int txn_spill(MDBX_txn *const txn, MDBX_cursor *const m0,
const size_t need) {
tASSERT(txn, (txn->mt_flags & MDBX_TXN_RDONLY) == 0);
tASSERT(txn, (txn->mt_flags & MDBX_WRITEMAP) == 0 || MDBX_AVOID_MSYNC);
tASSERT(txn, !m0 || cursor_is_tracked(m0));
intptr_t wanna_spill_entries = need - txn->tw.dirtyroom - txn->tw.loose_count;
intptr_t wanna_spill_npages =
@ -4863,7 +4866,7 @@ static size_t spill_gate(const MDBX_env *env, intptr_t part,
: 0);
part = (part < spill_max) ? part : spill_max;
part = (part > spill_min) ? part : spill_min;
eASSERT(env, part > 0 && (size_t)part <= total);
eASSERT(env, part >= 0 && (size_t)part <= total);
return (size_t)part;
}
@ -4951,7 +4954,7 @@ __cold static int txn_spill_slowpath(MDBX_txn *const txn, MDBX_cursor *const m0,
if (likely(txn->tw.dirtyroom + txn->tw.loose_count >= need))
return MDBX_SUCCESS;
#endif /* xMDBX_DEBUG_SPILLING */
ERROR("all %zu dirty pages are unspillable since referenced "
ERROR("all %zu dirty pages are unspillable since referenced "
"by a cursor(s), use fewer cursors or increase "
"MDBX_opt_txn_dp_limit",
unspillable);
@ -7661,6 +7664,8 @@ done:
__hot static pgr_t page_alloc(const MDBX_cursor *const mc) {
MDBX_txn *const txn = mc->mc_txn;
tASSERT(txn, mc->mc_txn->mt_flags & MDBX_TXN_DIRTY);
tASSERT(txn, F_ISSET(txn->mt_dbistate[mc->mc_dbi], DBI_DIRTY | DBI_VALID));
/* If there are any loose pages, just use them */
while (likely(txn->tw.loose_pages)) {
@ -7799,6 +7804,9 @@ __hot static int page_touch(MDBX_cursor *mc) {
MDBX_txn *txn = mc->mc_txn;
int rc;
tASSERT(txn, mc->mc_txn->mt_flags & MDBX_TXN_DIRTY);
tASSERT(txn, F_ISSET(*mc->mc_dbistate, DBI_DIRTY | DBI_VALID));
tASSERT(txn, !IS_OVERFLOW(mp));
if (ASSERT_ENABLED()) {
if (mc->mc_flags & C_SUB) {
MDBX_xcursor *mx = container_of(mc->mc_db, MDBX_xcursor, mx_db);
@ -7806,16 +7814,30 @@ __hot static int page_touch(MDBX_cursor *mc) {
tASSERT(txn, mc->mc_db == &couple->outer.mc_xcursor->mx_db);
tASSERT(txn, mc->mc_dbx == &couple->outer.mc_xcursor->mx_dbx);
tASSERT(txn, *couple->outer.mc_dbistate & DBI_DIRTY);
} else {
tASSERT(txn, *mc->mc_dbistate & DBI_DIRTY);
}
tASSERT(txn, mc->mc_txn->mt_flags & MDBX_TXN_DIRTY);
tASSERT(txn, !IS_OVERFLOW(mp));
tASSERT(txn, dirtylist_check(txn));
}
if (IS_MODIFIABLE(txn, mp) || IS_SUBP(mp))
if (IS_MODIFIABLE(txn, mp)) {
if (!txn->tw.dirtylist) {
tASSERT(txn, (txn->mt_flags & MDBX_WRITEMAP) && !MDBX_AVOID_MSYNC);
return MDBX_SUCCESS;
}
if (IS_SUBP(mp))
return MDBX_SUCCESS;
tASSERT(txn, (txn->mt_flags & MDBX_WRITEMAP) == 0 || MDBX_AVOID_MSYNC);
const size_t n = dpl_search(txn, mp->mp_pgno);
txn->tw.dirtylist->items[n].mlru =
(txn->tw.dirtylist->items[n].mlru & MDBX_dp_multi_mask) +
txn_lru_turn(txn);
return MDBX_SUCCESS;
}
if (IS_SUBP(mp)) {
np = (MDBX_page *)mp;
np->mp_txnid = txn->mt_front;
return MDBX_SUCCESS;
}
tASSERT(txn, !IS_OVERFLOW(mp));
if (IS_FROZEN(txn, mp)) {
/* CoW the page */
@ -8847,7 +8869,7 @@ static int txn_renew(MDBX_txn *txn, const unsigned flags) {
if (unlikely(rc != MDBX_SUCCESS))
goto bailout;
txn->tw.dirtyroom = txn->mt_env->me_options.dp_limit;
txn->tw.dirtylru = MDBX_DEBUG ? ~42u : 0;
txn->tw.dirtylru = MDBX_DEBUG ? UINT32_MAX / 3 - 42 : 0;
} else {
tASSERT(txn, txn->tw.dirtylist == nullptr);
txn->tw.dirtylist = nullptr;
@ -12422,7 +12444,8 @@ static int sync_locked(MDBX_env *env, unsigned flags, MDBX_meta *const pending,
assert(rc == MDBX_RESULT_TRUE /* carry non-steady */);
skip_incore_sync:
eASSERT(env, env->me_lck->mti_unsynced_pages.weak > 0);
eASSERT(env, env->me_lck->mti_eoos_timestamp.weak != 0);
/* Может быть нулевым если unsynced_pages > 0 в результате спиллинга.
* eASSERT(env, env->me_lck->mti_eoos_timestamp.weak != 0); */
unaligned_poke_u64(4, pending->mm_sign, MDBX_DATASIGN_WEAK);
}
@ -15405,9 +15428,6 @@ __hot static __always_inline pgr_t page_get_inline(const uint16_t ILL,
const size_t i = dpl_search(spiller, pgno);
tASSERT(txn, (intptr_t)i > 0);
if (spiller->tw.dirtylist->items[i].pgno == pgno) {
const uint32_t is_multi =
spiller->tw.dirtylist->items[i].mlru & MDBX_dp_multi_mask;
spiller->tw.dirtylist->items[i].mlru = is_multi + txn_lru_inc(txn);
r.page = spiller->tw.dirtylist->items[i].ptr;
break;
}
@ -17729,13 +17749,13 @@ __hot int mdbx_cursor_del(MDBX_cursor *mc, MDBX_put_flags_t flags) {
mc->mc_xcursor->mx_db.md_mod_txnid = mc->mc_txn->mt_txnid;
memcpy(db, &mc->mc_xcursor->mx_db, sizeof(MDBX_db));
} else {
MDBX_cursor *m2;
/* shrink fake page */
node_shrink(mp, mc->mc_ki[mc->mc_top]);
node = page_node(mp, mc->mc_ki[mc->mc_top]);
mc->mc_xcursor->mx_cursor.mc_pg[0] = node_data(node);
/* fix other sub-DB cursors pointed at fake pages on this page */
for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2 = m2->mc_next) {
for (MDBX_cursor *m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2;
m2 = m2->mc_next) {
if (m2 == mc || m2->mc_snum < mc->mc_snum)
continue;
if (!(m2->mc_flags & C_INITIALIZED))