Avoid spurious preemption by using the
percpu_{down,up}_preempt_{dis,en}able() APIs. This reduces things down
to a single preemption point at the end of this sequence (in the
normal case).Signed-off-by: Peter Zijlstra (Intel) <[email protected]> --- fs/locks.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) --- a/fs/locks.c +++ b/fs/locks.c @@ -930,7 +930,7 @@ static int flock_lock_inode(struct inode return -ENOMEM; } - percpu_down_read(&file_rwsem); + percpu_down_read_preempt_disable(&file_rwsem); spin_lock(&ctx->flc_lock); if (request->fl_flags & FL_ACCESS) goto find_conflict; @@ -971,7 +971,7 @@ static int flock_lock_inode(struct inode out: spin_unlock(&ctx->flc_lock); - percpu_up_read(&file_rwsem); + percpu_up_read_preempt_enable(&file_rwsem); if (new_fl) locks_free_lock(new_fl); locks_dispose_list(&dispose); @@ -1008,7 +1008,7 @@ static int posix_lock_inode(struct inode new_fl2 = locks_alloc_lock(); } - percpu_down_read(&file_rwsem); + percpu_down_read_preempt_disable(&file_rwsem); spin_lock(&ctx->flc_lock); /* * New lock request. Walk all POSIX locks and look for conflicts. If @@ -1180,7 +1180,7 @@ static int posix_lock_inode(struct inode } out: spin_unlock(&ctx->flc_lock); - percpu_up_read(&file_rwsem); + percpu_up_read_preempt_enable(&file_rwsem); /* * Free any unused locks. */ @@ -1455,7 +1455,7 @@ int __break_lease(struct inode *inode, u return error; } - percpu_down_read(&file_rwsem); + percpu_down_read_preempt_disable(&file_rwsem); spin_lock(&ctx->flc_lock); time_out_leases(inode, &dispose); @@ -1507,13 +1507,13 @@ int __break_lease(struct inode *inode, u locks_insert_block(fl, new_fl); trace_break_lease_block(inode, new_fl); spin_unlock(&ctx->flc_lock); - percpu_up_read(&file_rwsem); + percpu_up_read_preempt_enable(&file_rwsem); locks_dispose_list(&dispose); error = wait_event_interruptible_timeout(new_fl->fl_wait, !new_fl->fl_next, break_time); - percpu_down_read(&file_rwsem); + percpu_down_read_preempt_disable(&file_rwsem); spin_lock(&ctx->flc_lock); trace_break_lease_unblock(inode, new_fl); locks_delete_block(new_fl); @@ -1530,7 +1530,7 @@ int __break_lease(struct inode *inode, u } out: spin_unlock(&ctx->flc_lock); - percpu_up_read(&file_rwsem); + percpu_up_read_preempt_enable(&file_rwsem); locks_dispose_list(&dispose); locks_free_lock(new_fl); return error; @@ -1685,7 +1685,7 @@ generic_add_lease(struct file *filp, lon return -EINVAL; } - percpu_down_read(&file_rwsem); + percpu_down_read_preempt_disable(&file_rwsem); spin_lock(&ctx->flc_lock); time_out_leases(inode, &dispose); error = check_conflicting_open(dentry, arg, lease->fl_flags); @@ -1756,7 +1756,7 @@ generic_add_lease(struct file *filp, lon lease->fl_lmops->lm_setup(lease, priv); out: spin_unlock(&ctx->flc_lock); - percpu_up_read(&file_rwsem); + percpu_up_read_preempt_enable(&file_rwsem); locks_dispose_list(&dispose); if (is_deleg) inode_unlock(inode); @@ -1779,7 +1779,7 @@ static int generic_delete_lease(struct f return error; } - percpu_down_read(&file_rwsem); + percpu_down_read_preempt_disable(&file_rwsem); spin_lock(&ctx->flc_lock); list_for_each_entry(fl, &ctx->flc_lease, fl_list) { if (fl->fl_file == filp && @@ -1792,7 +1792,7 @@ static int generic_delete_lease(struct f if (victim) error = fl->fl_lmops->lm_change(victim, F_UNLCK, &dispose); spin_unlock(&ctx->flc_lock); - percpu_up_read(&file_rwsem); + percpu_up_read_preempt_enable(&file_rwsem); locks_dispose_list(&dispose); return error; }
