diff options
| author | Dipankar Sarma <dipankar@in.ibm.com> | 2005-09-09 13:04:13 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-09-09 13:57:55 -0700 |
| commit | ab2af1f5005069321c5d130f09cce577b03f43ef (patch) | |
| tree | 73a70ba486f522cd9eeeef376ede2b5a1c1b473b /include/linux/fs.h | |
| parent | 6e72ad2c581de121cc7e772469e2a8f6b1fd4379 (diff) | |
[PATCH] files: files struct with RCU
Patch to eliminate struct files_struct.file_lock spinlock on the reader side
and use rcu refcounting rcuref_xxx api for the f_count refcounter. The
updates to the fdtable are done by allocating a new fdtable structure and
setting files->fdt to point to the new structure. The fdtable structure is
protected by RCU thereby allowing lock-free lookup. For fd arrays/sets that
are vmalloced, we use keventd to free them since RCU callbacks can't sleep. A
global list of fdtable to be freed is not scalable, so we use a per-cpu list.
If keventd is already handling the current cpu's work, we use a timer to defer
queueing of that work.
Since the last publication, this patch has been re-written to avoid using
explicit memory barriers and use rcu_assign_pointer(), rcu_dereference()
premitives instead. This required that the fd information is kept in a
separate structure (fdtable) and updated atomically.
Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/linux/fs.h')
| -rw-r--r-- | include/linux/fs.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h index fd93ab7da90..7f61227827d 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -9,6 +9,7 @@ #include <linux/config.h> #include <linux/limits.h> #include <linux/ioctl.h> +#include <linux/rcuref.h> /* * It's silly to have NR_OPEN bigger than NR_FILE, but you can change @@ -597,12 +598,13 @@ struct file { spinlock_t f_ep_lock; #endif /* #ifdef CONFIG_EPOLL */ struct address_space *f_mapping; + struct rcu_head f_rcuhead; }; extern spinlock_t files_lock; #define file_list_lock() spin_lock(&files_lock); #define file_list_unlock() spin_unlock(&files_lock); -#define get_file(x) atomic_inc(&(x)->f_count) +#define get_file(x) rcuref_inc(&(x)->f_count) #define file_count(x) atomic_read(&(x)->f_count) #define MAX_NON_LFS ((1UL<<31) - 1) |