bcachefs: Always give out journal pre-res if we already have one

This is better than skipping the journal pre-reservation if we already
have one - we should still acount for the journal reservation we're
going to have to get.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2020-06-09 20:54:36 -04:00 committed by Kent Overstreet
parent 374153c2a9
commit 4efe71a646
3 changed files with 30 additions and 15 deletions

View File

@ -864,8 +864,11 @@ bch2_btree_update_start(struct btree_trans *trans, enum btree_id id,
{
struct bch_fs *c = trans->c;
struct btree_update *as;
int ret, disk_res_flags = (flags & BTREE_INSERT_NOFAIL)
int disk_res_flags = (flags & BTREE_INSERT_NOFAIL)
? BCH_DISK_RESERVATION_NOFAIL : 0;
int journal_flags = (flags & BTREE_INSERT_JOURNAL_RESERVED)
? JOURNAL_RES_GET_RECLAIM : 0;
int ret = 0;
/*
* This check isn't necessary for correctness - it's just to potentially
@ -888,10 +891,9 @@ bch2_btree_update_start(struct btree_trans *trans, enum btree_id id,
bch2_keylist_init(&as->new_keys, as->_new_keys);
bch2_keylist_init(&as->parent_keys, as->inline_keys);
if (!(flags & BTREE_INSERT_JOURNAL_RESERVED))
ret = bch2_journal_preres_get(&c->journal, &as->journal_preres,
BTREE_UPDATE_JOURNAL_RES,
JOURNAL_RES_GET_NONBLOCK);
ret = bch2_journal_preres_get(&c->journal, &as->journal_preres,
BTREE_UPDATE_JOURNAL_RES,
journal_flags|JOURNAL_RES_GET_NONBLOCK);
if (ret == -EAGAIN) {
if (flags & BTREE_INSERT_NOUNLOCK)
return ERR_PTR(-EINTR);
@ -899,7 +901,8 @@ bch2_btree_update_start(struct btree_trans *trans, enum btree_id id,
bch2_trans_unlock(trans);
ret = bch2_journal_preres_get(&c->journal, &as->journal_preres,
BTREE_UPDATE_JOURNAL_RES, 0);
BTREE_UPDATE_JOURNAL_RES,
journal_flags);
if (ret)
return ERR_PTR(ret);

View File

@ -427,9 +427,10 @@ int bch2_journal_res_get_slowpath(struct journal *j, struct journal_res *res,
static bool journal_preres_available(struct journal *j,
struct journal_preres *res,
unsigned new_u64s)
unsigned new_u64s,
unsigned flags)
{
bool ret = bch2_journal_preres_get_fast(j, res, new_u64s);
bool ret = bch2_journal_preres_get_fast(j, res, new_u64s, flags);
if (!ret)
bch2_journal_reclaim_work(&j->reclaim_work.work);
@ -439,13 +440,14 @@ static bool journal_preres_available(struct journal *j,
int __bch2_journal_preres_get(struct journal *j,
struct journal_preres *res,
unsigned new_u64s)
unsigned new_u64s,
unsigned flags)
{
int ret;
closure_wait_event(&j->preres_wait,
(ret = bch2_journal_error(j)) ||
journal_preres_available(j, res, new_u64s));
journal_preres_available(j, res, new_u64s, flags));
return ret;
}

View File

@ -301,6 +301,7 @@ int bch2_journal_res_get_slowpath(struct journal *, struct journal_res *,
#define JOURNAL_RES_GET_NONBLOCK (1 << 0)
#define JOURNAL_RES_GET_CHECK (1 << 1)
#define JOURNAL_RES_GET_RESERVED (1 << 2)
#define JOURNAL_RES_GET_RECLAIM (1 << 3)
static inline int journal_res_get_fast(struct journal *j,
struct journal_res *res,
@ -408,11 +409,12 @@ static inline void bch2_journal_preres_put(struct journal *j,
}
int __bch2_journal_preres_get(struct journal *,
struct journal_preres *, unsigned);
struct journal_preres *, unsigned, unsigned);
static inline int bch2_journal_preres_get_fast(struct journal *j,
struct journal_preres *res,
unsigned new_u64s)
unsigned new_u64s,
unsigned flags)
{
int d = new_u64s - res->u64s;
union journal_preres_state old, new;
@ -423,7 +425,15 @@ static inline int bch2_journal_preres_get_fast(struct journal *j,
new.reserved += d;
if (new.reserved > new.remaining)
/*
* If we're being called from the journal reclaim path, we have
* to unconditionally give out the pre-reservation, there's
* nothing else sensible we can do - otherwise we'd recurse back
* into the reclaim path and deadlock:
*/
if (!(flags & JOURNAL_RES_GET_RECLAIM) &&
new.reserved > new.remaining)
return 0;
} while ((v = atomic64_cmpxchg(&j->prereserved.counter,
old.v, new.v)) != old.v);
@ -440,13 +450,13 @@ static inline int bch2_journal_preres_get(struct journal *j,
if (new_u64s <= res->u64s)
return 0;
if (bch2_journal_preres_get_fast(j, res, new_u64s))
if (bch2_journal_preres_get_fast(j, res, new_u64s, flags))
return 0;
if (flags & JOURNAL_RES_GET_NONBLOCK)
return -EAGAIN;
return __bch2_journal_preres_get(j, res, new_u64s);
return __bch2_journal_preres_get(j, res, new_u64s, flags);
}
/* journal_entry_res: */