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| author | Kent Overstreet <kent.overstreet@gmail.com> | 2021-04-04 04:31:02 +0300 |
|---|---|---|
| committer | Kent Overstreet <kent.overstreet@linux.dev> | 2023-10-23 00:08:59 +0300 |
| commit | 671cc8a51b019b49a8538aceaaa5e770c1694c1b (patch) | |
| tree | 712f2a3ec1ecb449caa883416e04fb1dfd8cd03d /fs/bcachefs/journal.h | |
| parent | 08e337618f67abb9be1ff4b022a14e8721c5def2 (diff) | |
| download | linux-671cc8a51b019b49a8538aceaaa5e770c1694c1b.tar.xz | |
bcachefs: Eliminate memory barrier from fast path of journal_preres_put()
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Diffstat (limited to 'fs/bcachefs/journal.h')
| -rw-r--r-- | fs/bcachefs/journal.h | 39 |
1 files changed, 22 insertions, 17 deletions
diff --git a/fs/bcachefs/journal.h b/fs/bcachefs/journal.h index a0d19fad3bdd..cc497125889f 100644 --- a/fs/bcachefs/journal.h +++ b/fs/bcachefs/journal.h @@ -411,7 +411,12 @@ static inline void bch2_journal_preres_put(struct journal *j, s.v = atomic64_sub_return(s.v, &j->prereserved.counter); res->u64s = 0; - closure_wake_up(&j->preres_wait); + + if (unlikely(s.waiting)) { + clear_bit(ilog2((((union journal_preres_state) { .waiting = 1 }).v)), + (unsigned long *) &j->prereserved.v); + closure_wake_up(&j->preres_wait); + } if (s.reserved <= s.remaining && !test_bit(JOURNAL_MAY_GET_UNRESERVED, &j->flags)) { @@ -427,32 +432,32 @@ int __bch2_journal_preres_get(struct journal *, static inline int bch2_journal_preres_get_fast(struct journal *j, struct journal_preres *res, unsigned new_u64s, - unsigned flags) + unsigned flags, + bool set_waiting) { int d = new_u64s - res->u64s; union journal_preres_state old, new; u64 v = atomic64_read(&j->prereserved.counter); + int ret; do { old.v = new.v = v; - - new.reserved += d; - - /* - * 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_RESERVED) && - new.reserved > new.remaining) + ret = 0; + + if ((flags & JOURNAL_RES_GET_RESERVED) || + new.reserved + d < new.remaining) { + new.reserved += d; + ret = 1; + } else if (set_waiting && !new.waiting) + new.waiting = true; + else return 0; } while ((v = atomic64_cmpxchg(&j->prereserved.counter, old.v, new.v)) != old.v); - res->u64s += d; - return 1; + if (ret) + res->u64s += d; + return ret; } static inline int bch2_journal_preres_get(struct journal *j, @@ -463,7 +468,7 @@ 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, flags)) + if (bch2_journal_preres_get_fast(j, res, new_u64s, flags, false)) return 0; if (flags & JOURNAL_RES_GET_NONBLOCK) |