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>
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@ -566,12 +566,10 @@ static inline void insert_journal_hash(struct reiserfs_journal_cnode **table,
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static inline void reiserfs_mutex_lock_safe(struct mutex *m,
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struct super_block *s)
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{
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while (!mutex_trylock(m)) {
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reiserfs_write_unlock(s);
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schedule();
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mutex_lock(m);
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reiserfs_write_lock(s);
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}
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}
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/* lock the current transaction */
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static inline void lock_journal(struct super_block *sb)
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