diff options
| author | Justus Winter <4winter@informatik.uni-hamburg.de> | 2014-05-13 15:35:42 +0200 |
|---|---|---|
| committer | Justus Winter <4winter@informatik.uni-hamburg.de> | 2015-04-17 14:06:45 +0200 |
| commit | 8c050fb080c6e1981dc8e5a97a2313cd24e9b4b4 (patch) | |
| tree | 1fc940c6bf92a3de8a5ce0d60a687979d067d447 /tmpfs/tmpfs.c | |
| parent | f4823c00581eb91e5b42169405e641463256bbfa (diff) | |
tmpfs: use a seperate lock to protect all_nodes
Previously, tmpfs used diskfs_node_refcnt_lock to serialize access to
the all_nodes and some other related global state related to memory
consumption.
Use a separate lock to protect all_nodes, and atomic operations to
access the state related to memory consumption. Adjust the reference
counting accordingly. Every node in the all_nodes carries a light
reference. When we are asked to give up that light reference, we
reacquire our lock momentarily to check whether someone else
reacquired a reference through the all_nodes.
* tmpfs/tmpfs.h (num_files, tmpfs_space_used): Use atomic operations
for these variables.
(adjust_used): Use atomic operations.
(get_used): New convenience function to atomically retrieve
tmpfs_space_used.
* tmpfs/node.c (all_nodes_lock): New lock.
(diskfs_alloc_node): Use a separate lock to protect all_nodes.
Adjust the reference counting accordingly.
(diskfs_free_node): Likewise.
(diskfs_cached_lookup):Likewise.
(diskfs_node_iterate): Likewise.
(diskfs_node_norefs): Do not remove the node from all_nodes. This
actually looks like a mistake, I do not know why they did that here as
well as in diskfs_free_node.
(diskfs_try_dropping_softrefs): Check whether someone reacquired a
reference, and if so hold on to our light reference.
(diskfs_grow): Use atomic operations.
* tmpfs/tmpfs.c (diskfs_set_statfs): Likewise.
Diffstat (limited to 'tmpfs/tmpfs.c')
| -rw-r--r-- | tmpfs/tmpfs.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/tmpfs/tmpfs.c b/tmpfs/tmpfs.c index 1b5b3746..fd1c9aaf 100644 --- a/tmpfs/tmpfs.c +++ b/tmpfs/tmpfs.c @@ -67,10 +67,8 @@ diskfs_set_statfs (struct statfs *st) st->f_bsize = vm_page_size; st->f_blocks = tmpfs_page_limit; - pthread_spin_lock (&diskfs_node_refcnt_lock); - st->f_files = num_files; - pages = round_page (tmpfs_space_used) / vm_page_size; - pthread_spin_unlock (&diskfs_node_refcnt_lock); + st->f_files = __atomic_load_n (&num_files, __ATOMIC_RELAXED); + pages = round_page (get_used ()) / vm_page_size; st->f_bfree = pages < tmpfs_page_limit ? tmpfs_page_limit - pages : 0; st->f_bavail = st->f_bfree; |