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mdbx: start find_oldest() from steady-point.

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Change-Id: Icc102f98f86e557e1ccba9cd74255c3da9225d41
This commit is contained in:
Leo Yuriev 2017-06-02 11:45:31 +03:00
parent 22b9409a8d
commit ddc5b9f34f
1 changed files with 49 additions and 23 deletions
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72
src/mdbx.c
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@ -1,4 +1,4 @@
/*
/*
* Copyright 2015-2017 Leonid Yuriev <leo@yuriev.ru>
* and other libmdbx authors: please see AUTHORS file.
* All rights reserved.
@ -1396,21 +1396,34 @@ static __inline uint64_t mdbx_meta_sign(const MDBX_meta *meta) {
return (sign > MDBX_DATASIGN_WEAK) ? sign : ~sign;
}
enum meta_choise_mode { prefer_last, prefer_noweak, prefer_steady };
static __inline bool mdbx_meta_ot(const MDBX_env *env, const MDBX_meta *a,
const MDBX_meta *b,
const bool roolback2steady) {
const enum meta_choise_mode mode) {
mdbx_jitter4testing(true);
txnid_t txnid_a = mdbx_meta_txnid_fluid(env, a);
txnid_t txnid_b = mdbx_meta_txnid_fluid(env, b);
if (txnid_a == txnid_b)
return META_IS_STEADY(b);
return META_IS_STEADY(b) || (META_IS_WEAK(a) && !META_IS_WEAK(a));
mdbx_jitter4testing(true);
if (roolback2steady && META_IS_STEADY(a) != META_IS_STEADY(b))
return META_IS_STEADY(b);
mdbx_jitter4testing(true);
return txnid_a < txnid_b;
switch (mode) {
default:
assert(false);
/* fall through */
case prefer_steady:
if (META_IS_STEADY(a) != META_IS_STEADY(b))
return META_IS_STEADY(b);
/* fall through */
case prefer_noweak:
if (META_IS_WEAK(a) != META_IS_WEAK(b))
return !META_IS_WEAK(b);
/* fall through */
case prefer_last:
mdbx_jitter4testing(true);
return txnid_a < txnid_b;
}
}
static __inline bool mdbx_meta_eq(const MDBX_env *env, const MDBX_meta *a,
@ -1443,37 +1456,42 @@ static int mdbx_meta_eq_mask(const MDBX_env *env) {
static __inline MDBX_meta *mdbx_meta_recent(const MDBX_env *env, MDBX_meta *a,
MDBX_meta *b,
const bool roolback2steady) {
const bool a_older_that_b = mdbx_meta_ot(env, a, b, roolback2steady);
const enum meta_choise_mode mode) {
const bool a_older_that_b = mdbx_meta_ot(env, a, b, mode);
mdbx_assert(env, !mdbx_meta_eq(env, a, b));
return a_older_that_b ? b : a;
}
static __inline MDBX_meta *mdbx_meta_ancient(const MDBX_env *env, MDBX_meta *a,
MDBX_meta *b,
const bool roolback2steady) {
const bool a_older_that_b = mdbx_meta_ot(env, a, b, roolback2steady);
const enum meta_choise_mode mode) {
const bool a_older_that_b = mdbx_meta_ot(env, a, b, mode);
mdbx_assert(env, !mdbx_meta_eq(env, a, b));
return a_older_that_b ? a : b;
}
static __inline MDBX_meta *mdbx_meta_mostrecent(const MDBX_env *env,
const bool roolback2steady) {
static __inline MDBX_meta *
mdbx_meta_mostrecent(const MDBX_env *env, const enum meta_choise_mode mode) {
MDBX_meta *m0 = METAPAGE(env, 0);
MDBX_meta *m1 = METAPAGE(env, 1);
MDBX_meta *m2 = METAPAGE(env, 2);
MDBX_meta *head = mdbx_meta_recent(env, m0, m1, roolback2steady);
head = mdbx_meta_recent(env, head, m2, roolback2steady);
MDBX_meta *head = mdbx_meta_recent(env, m0, m1, mode);
head = mdbx_meta_recent(env, head, m2, mode);
return head;
}
static __hot MDBX_meta *mdbx_meta_steady(const MDBX_env *env) {
return mdbx_meta_mostrecent(env, true);
return mdbx_meta_mostrecent(env, prefer_steady);
}
static __hot MDBX_meta *mdbx_meta_head(const MDBX_env *env) {
return mdbx_meta_mostrecent(env, false);
return mdbx_meta_mostrecent(env, prefer_last);
}
static __hot txnid_t mdbx_reclaiming_detent(const MDBX_env *env) {
MDBX_meta *meta = mdbx_meta_mostrecent(env, prefer_noweak);
return mdbx_meta_txnid_stable(env, meta);
}
static const char *mdbx_durable_str(const MDBX_meta *const meta) {
@ -1490,10 +1508,12 @@ static const char *mdbx_durable_str(const MDBX_meta *const meta) {
/* Find oldest txnid still referenced. */
static txnid_t mdbx_find_oldest(MDBX_txn *txn) {
mdbx_tassert(txn, (txn->mt_flags & MDBX_RDONLY) == 0);
MDBX_lockinfo *const lck = txn->mt_env->me_lck;
const MDBX_env *env = txn->mt_env;
MDBX_lockinfo *const lck = env->me_lck;
txnid_t oldest = mdbx_reclaiming_detent(env);
mdbx_tassert(txn, oldest <= txn->mt_txnid - 1);
const txnid_t last_oldest = lck->mti_oldest;
txnid_t oldest = txn->mt_txnid - 1;
mdbx_tassert(txn, oldest >= last_oldest);
if (last_oldest == oldest ||
lck->mti_reader_finished_flag == MDBX_STRING_TETRAD("None"))
@ -1849,8 +1869,8 @@ static int mdbx_page_alloc(MDBX_cursor *mc, unsigned num, MDBX_page **mp,
((flags & MDBX_ALLOC_KICK) || rc == MDBX_MAP_FULL)) {
MDBX_meta *steady = mdbx_meta_steady(env);
if (oldest == mdbx_meta_txnid_stable(env, steady) && META_IS_WEAK(head) &&
!META_IS_WEAK(steady)) {
if (oldest == mdbx_meta_txnid_stable(env, steady) &&
!META_IS_STEADY(head) && META_IS_STEADY(steady)) {
/* LY: Here an oom was happened:
* - all pages had allocated;
* - reclaiming was stopped at the last steady-sync;
@ -10398,10 +10418,16 @@ static txnid_t __cold mdbx_oomkick(MDBX_env *env, const txnid_t laggard) {
int retry;
for (retry = 0; retry < INT_MAX; ++retry) {
txnid_t oldest = mdbx_reclaiming_detent(env);
mdbx_assert(env, oldest < env->me_txn0->mt_txnid);
mdbx_assert(env, oldest >= laggard);
mdbx_assert(env, oldest >= env->me_oldest[0]);
if (oldest == laggard)
return oldest;
if (MDBX_IS_ERROR(mdbx_reader_check0(env, false, NULL)))
break;
txnid_t oldest = env->me_txn0->mt_txnid - 1;
MDBX_reader *const rtbl = env->me_lck->mti_readers;
MDBX_reader *asleep = nullptr;
for (int i = env->me_lck->mti_numreaders; --i >= 0;) {