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author | Frederic Weisbecker <fweisbec@gmail.com> | 2009-05-08 20:01:09 +0200 |
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committer | Frederic Weisbecker <fweisbec@gmail.com> | 2009-09-14 07:18:21 +0200 |
commit | c63e3c0b2498adec921b06c670d12c8c74b85538 (patch) | |
tree | 27ca06415b5fdd51e369361ea8aa8f8e8e1ac741 | |
parent | d6f5b0aa08078c3dabe377d5b1a6077e9c9352d3 (diff) | |
download | op-kernel-dev-c63e3c0b2498adec921b06c670d12c8c74b85538.zip op-kernel-dev-c63e3c0b2498adec921b06c670d12c8c74b85538.tar.gz |
kill-the-bkl/reiserfs: use mutex_lock in reiserfs_mutex_lock_safe
reiserfs_mutex_lock_safe() is a hack to avoid any dependency between
an internal reiserfs mutex and the write lock, it has been proposed
to follow the old bkl logic.
The code does the following:
while (!mutex_trylock(m)) {
reiserfs_write_unlock(s);
schedule();
reiserfs_write_lock(s);
}
It then imitate the implicit behaviour of the lock when it was
a Bkl and hadn't such dependency:
mutex_lock(m) {
if (fastpath)
let's go
else {
wait_for_mutex() {
schedule() {
unlock_kernel()
reacquire_lock_kernel()
}
}
}
}
The problem is that by using such explicit schedule(), we don't
benefit of the adaptive mutex spinning on owner.
The logic in use now is:
reiserfs_write_unlock(s);
mutex_lock(m); // -> possible adaptive spinning
reiserfs_write_lock(s);
[ Impact: restore the use of adaptive spinning mutexes in reiserfs ]
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
-rw-r--r-- | fs/reiserfs/journal.c | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c index ffb7f50..e9a972b 100644 --- a/fs/reiserfs/journal.c +++ b/fs/reiserfs/journal.c @@ -566,11 +566,9 @@ static inline void insert_journal_hash(struct reiserfs_journal_cnode **table, static inline void reiserfs_mutex_lock_safe(struct mutex *m, struct super_block *s) { - while (!mutex_trylock(m)) { - reiserfs_write_unlock(s); - schedule(); - reiserfs_write_lock(s); - } + reiserfs_write_unlock(s); + mutex_lock(m); + reiserfs_write_lock(s); } /* lock the current transaction */ |