From 68ef94a63caf214ee238434bf0d4c7a6a32c33a2 Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Tue, 19 Feb 2019 13:41:36 -0500 Subject: bcachefs: Add a pre-reserve mechanism for the journal Signed-off-by: Kent Overstreet --- fs/bcachefs/journal.h | 89 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 89 insertions(+) (limited to 'fs/bcachefs/journal.h') diff --git a/fs/bcachefs/journal.h b/fs/bcachefs/journal.h index 77d59fb0b151..809cf25f5a03 100644 --- a/fs/bcachefs/journal.h +++ b/fs/bcachefs/journal.h @@ -119,6 +119,7 @@ static inline void journal_wake(struct journal *j) { wake_up(&j->wait); closure_wake_up(&j->async_wait); + closure_wake_up(&j->preres_wait); } static inline struct journal_buf *journal_cur_buf(struct journal *j) @@ -274,6 +275,7 @@ 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) static inline int journal_res_get_fast(struct journal *j, struct journal_res *res, @@ -294,6 +296,10 @@ static inline int journal_res_get_fast(struct journal *j, EBUG_ON(!journal_state_count(new, new.idx)); + if (!(flags & JOURNAL_RES_GET_RESERVED) && + !test_bit(JOURNAL_MAY_GET_UNRESERVED, &j->flags)) + return 0; + if (flags & JOURNAL_RES_GET_CHECK) return 1; @@ -333,6 +339,89 @@ out: return 0; } +/* journal_preres: */ + +static inline bool journal_check_may_get_unreserved(struct journal *j) +{ + union journal_preres_state s = READ_ONCE(j->prereserved); + bool ret = s.reserved <= s.remaining && + fifo_free(&j->pin) > 8; + + lockdep_assert_held(&j->lock); + + if (ret != test_bit(JOURNAL_MAY_GET_UNRESERVED, &j->flags)) { + if (ret) { + set_bit(JOURNAL_MAY_GET_UNRESERVED, &j->flags); + journal_wake(j); + } else { + clear_bit(JOURNAL_MAY_GET_UNRESERVED, &j->flags); + } + } + return ret; +} + +static inline void bch2_journal_preres_put(struct journal *j, + struct journal_preres *res) +{ + union journal_preres_state s = { .reserved = res->u64s }; + + if (!res->u64s) + return; + + s.v = atomic64_sub_return(s.v, &j->prereserved.counter); + res->u64s = 0; + closure_wake_up(&j->preres_wait); + + if (s.reserved <= s.remaining && + !test_bit(JOURNAL_MAY_GET_UNRESERVED, &j->flags)) { + spin_lock(&j->lock); + journal_check_may_get_unreserved(j); + spin_unlock(&j->lock); + } +} + +int __bch2_journal_preres_get(struct journal *, + struct journal_preres *, unsigned); + +static inline int bch2_journal_preres_get_fast(struct journal *j, + struct journal_preres *res, + unsigned new_u64s) +{ + int d = new_u64s - res->u64s; + union journal_preres_state old, new; + u64 v = atomic64_read(&j->prereserved.counter); + + do { + old.v = new.v = v; + + new.reserved += d; + + if (new.reserved > new.remaining) + return 0; + } while ((v = atomic64_cmpxchg(&j->prereserved.counter, + old.v, new.v)) != old.v); + + res->u64s += d; + return 1; +} + +static inline int bch2_journal_preres_get(struct journal *j, + struct journal_preres *res, + unsigned new_u64s, + unsigned flags) +{ + if (new_u64s <= res->u64s) + return 0; + + if (bch2_journal_preres_get_fast(j, res, new_u64s)) + return 0; + + if (flags & JOURNAL_RES_GET_NONBLOCK) + return -EAGAIN; + + return __bch2_journal_preres_get(j, res, new_u64s); +} + /* journal_entry_res: */ void bch2_journal_entry_res_resize(struct journal *, -- cgit v1.2.3